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@@ -1027,24 +1027,24 @@ and the <a href="../sophia_stdlib/#call">Call</a> namespaces in the documentatio
<p>To call a function in another contract you need the address to an instance of
the contract. The type of the address must be a contract type, which consists
of a number of type definitions and entrypoint declarations. For instance,</p>
<div class="highlight"><pre><span></span><code><span class="c1">// A contract type</span>
<span class="k">contract</span><span class="w"> </span><span class="k">interface</span><span class="w"> </span><span class="nf">VotingType</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">vote</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="kt">unit</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
// A contract type
contract interface VotingType =
entrypoint vote : string =&gt; unit</code></p>
<p>Now given contract address of type <code>VotingType</code> you can call the <code>vote</code>
entrypoint of that contract:</p>
<div class="highlight"><pre><span></span><code><span class="k">contract</span><span class="w"> </span><span class="nf">VoteTwice</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">voteTwice</span><span class="p">(</span><span class="n">v</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nf">VotingType</span><span class="p">,</span><span class="w"> </span><span class="n">alt</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="n">v</span><span class="p">.</span><span class="n">vote</span><span class="p">(</span><span class="n">alt</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="n">v</span><span class="p">.</span><span class="n">vote</span><span class="p">(</span><span class="n">alt</span><span class="p">)</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
contract VoteTwice =
entrypoint voteTwice(v : VotingType, alt : string) =
v.vote(alt)
v.vote(alt)</code></p>
<p>Contract calls take two optional named arguments <code>gas : int</code> and <code>value : int</code>
that lets you set a gas limit and provide tokens to a contract call. If omitted
the defaults are no gas limit and no tokens. Suppose there is a fee for voting:</p>
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">voteTwice</span><span class="p">(</span><span class="n">v</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nf">VotingType</span><span class="p">,</span><span class="w"> </span><span class="n">fee</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">int</span><span class="p">,</span><span class="w"> </span><span class="n">alt</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="n">v</span><span class="p">.</span><span class="n">vote</span><span class="p">(</span><span class="n">value</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">fee</span><span class="p">,</span><span class="w"> </span><span class="n">alt</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="n">v</span><span class="p">.</span><span class="n">vote</span><span class="p">(</span><span class="n">value</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">fee</span><span class="p">,</span><span class="w"> </span><span class="n">alt</span><span class="p">)</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
entrypoint voteTwice(v : VotingType, fee : int, alt : string) =
v.vote(value = fee, alt)
v.vote(value = fee, alt)</code></p>
<p>Named arguments can be given in any order.</p>
<p>Note that reentrant calls are not permitted. In other words, when calling
another contract it cannot call you back (directly or indirectly).</p>
@@ -1057,9 +1057,9 @@ fails.</p>
<p>To recover the underlying <code>address</code> of a contract instance there is a field
<code>address : address</code>. For instance, to send tokens to the voting contract (given that it is payable)
without calling it you can write</p>
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">pay</span><span class="p">(</span><span class="n">v</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nf">VotingType</span><span class="p">,</span><span class="w"> </span><span class="n">amount</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">int</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nc">Chain</span><span class="p">.</span><span class="n">spend</span><span class="p">(</span><span class="n">v</span><span class="p">.</span><span class="kt">address</span><span class="p">,</span><span class="w"> </span><span class="n">amount</span><span class="p">)</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
entrypoint pay(v : VotingType, amount : int) =
Chain.spend(v.address, amount)</code></p>
<h3 id="protected-contract-calls">Protected contract calls</h3>
<p>If a contract call fails for any reason (for instance, the remote contract
crashes or runs out of gas, or the entrypoint doesn't exist or has the wrong
@@ -1069,15 +1069,15 @@ contract calls takes a named argument <code>protected : bool</code> (default <co
changes the type of the contract call, wrapping the result in an <code>option</code> type.
If the call fails the result is <code>None</code>, otherwise it's <code>Some(r)</code> where <code>r</code> is
the return value of the call.</p>
<div class="highlight"><pre><span></span><code><span class="k">contract</span><span class="w"> </span><span class="k">interface</span><span class="w"> </span><span class="nf">VotingType</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="n">vote</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="kt">unit</span><span class="w"></span>
<span class="k">contract</span><span class="w"> </span><span class="nf">Voter</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">tryVote</span><span class="p">(</span><span class="n">v</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nf">VotingType</span><span class="p">,</span><span class="w"> </span><span class="n">alt</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">switch</span><span class="p">(</span><span class="n">v</span><span class="p">.</span><span class="n">vote</span><span class="p">(</span><span class="n">alt</span><span class="p">,</span><span class="w"> </span><span class="n">protected</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="kc">true</span><span class="p">)</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">option</span><span class="p">(</span><span class="kt">unit</span><span class="p">))</span><span class="w"></span>
<span class="w"> </span><span class="nf">None</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="s2">&quot;Voting failed&quot;</span><span class="w"></span>
<span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">_</span><span class="p">)</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="s2">&quot;Voting successful&quot;</span><span class="w"></span>
</code></pre></div>
<p>```sophia
contract interface VotingType =
entrypoint : vote : string =&gt; unit</p>
<p>contract Voter =
entrypoint tryVote(v : VotingType, alt : string) =
switch(v.vote(alt, protected = true) : option(unit))
None =&gt; "Voting failed"
Some(_) =&gt; "Voting successful"
```</p>
<p>Any gas that was consumed by the contract call before the failure stays
consumed, which means that in order to protect against the remote contract
running out of gas it is necessary to set a gas limit using the <code>gas</code> argument.
@@ -1098,16 +1098,16 @@ arguments – please refer to their documentation for the details.</p>
<p>While <code>Chain.clone</code> requires only a <code>contract interface</code> and a living instance
of a given contract on the chain, <code>Chain.create</code> needs a full definition of a
to-create contract defined by the standard <code>contract</code> syntax, for example</p>
<div class="highlight"><pre><span></span><code><span class="k">contract</span><span class="w"> </span><span class="nf">IntHolder</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">type</span><span class="w"> </span><span class="nb">state</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="kt">int</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">init</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">x</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">get</span><span class="p">()</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nb">state</span><span class="w"></span>
<span class="k">main</span><span class="w"> </span><span class="k">contract</span><span class="w"> </span><span class="nf">IntHolderFactory</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">new</span><span class="p">(</span><span class="n">x</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">int</span><span class="p">)</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nf">IntHolder</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">let</span><span class="w"> </span><span class="n">ih</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nc">Chain</span><span class="p">.</span><span class="n">create</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nf">IntHolder</span><span class="w"></span>
<span class="w"> </span><span class="n">ih</span><span class="w"></span>
</code></pre></div>
<p>```sophia
contract IntHolder =
type state = int
entrypoint init(x) = x
entrypoint get() = state</p>
<p>main contract IntHolderFactory =
stateful entrypoint new(x : int) : IntHolder =
let ih = Chain.create(x) : IntHolder
ih
```</p>
<p>In case of a presence of child contracts (<code>IntHolder</code> in this case), the main
contract must be pointed out with the <code>main</code> keyword as shown in the example.</p>
<h2 id="mutable-state">Mutable state</h2>
@@ -1135,9 +1135,9 @@ provides special syntax for map/record updates.</p>
<p>Top-level functions and entrypoints must be annotated with the
<code>stateful</code> keyword to be allowed to affect the state of the running contract.
For instance,</p>
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">set_state</span><span class="p">(</span><span class="n">s</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nb">state</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nb">put</span><span class="p">(</span><span class="n">s</span><span class="p">)</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
stateful entrypoint set_state(s : state) =
put(s)</code></p>
<p>Without the <code>stateful</code> annotation the compiler does not allow the call to
<code>put</code>. A <code>stateful</code> annotation is required to</p>
<ul>
@@ -1167,10 +1167,10 @@ For instance,</p>
<p>A concrete contract is by default <em>not</em> payable. Any attempt at spending to such
a contract (either a <code>Chain.spend</code> or a normal spend transaction) will fail. If a
contract shall be able to receive funds in this way it has to be declared <code>payable</code>:</p>
<div class="highlight"><pre><span></span><code><span class="c1">// A payable contract</span>
<span class="k">payable</span><span class="w"> </span><span class="k">contract</span><span class="w"> </span><span class="nf">ExampleContract</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">do_stuff</span><span class="p">()</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="p">...</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
// A payable contract
payable contract ExampleContract =
stateful entrypoint do_stuff() = ...</code></p>
<p>If in doubt, it is possible to check if an address is payable using
<code>Address.is_payable(addr)</code>.</p>
<h3 id="payable-entrypoints">Payable entrypoints</h3>
@@ -1178,12 +1178,12 @@ contract shall be able to receive funds in this way it has to be declared <code>
(either a <a href="#calling-other-contracts">Remote call</a> or a contract call transaction)
that has a non-zero <code>value</code> will fail. Contract entrypoints that should be called
with a non-zero value should be declared <code>payable</code>.</p>
<div class="highlight"><pre><span></span><code><span class="k">payable</span><span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">buy</span><span class="p">(</span><span class="n">to</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">address</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">if</span><span class="p">(</span><span class="nc">Call</span><span class="p">.</span><span class="n">value</span><span class="w"> </span><span class="ow">&gt;</span><span class="w"> </span><span class="mi">42</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="n">transfer_item</span><span class="p">(</span><span class="n">to</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="k">else</span><span class="w"></span>
<span class="w"> </span><span class="nb">abort</span><span class="p">(</span><span class="s2">&quot;Value too low&quot;</span><span class="p">)</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
payable stateful entrypoint buy(to : address) =
if(Call.value &gt; 42)
transfer_item(to)
else
abort("Value too low")</code></p>
<p>Note: In the æternity VM (AEVM) contracts and entrypoints were by default
payable until the Lima release.</p>
<h2 id="namespaces">Namespaces</h2>
@@ -1192,65 +1192,61 @@ can appear at the top-level and can contain type and function definitions, but
not entrypoints. Outside the namespace you can refer to the (non-private) names
by qualifying them with the namespace (<code>Namespace.name</code>).
For example,</p>
<div class="highlight"><pre><span></span><code><span class="k">namespace</span><span class="w"> </span><span class="nf">Library</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">type</span><span class="w"> </span><span class="n">number</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="kt">int</span><span class="w"></span>
<span class="w"> </span><span class="k">function</span><span class="w"> </span><span class="n">inc</span><span class="p">(</span><span class="n">x</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="n">number</span><span class="p">)</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="n">number</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="ow">+</span><span class="w"> </span><span class="mi">1</span><span class="w"></span>
<span class="k">contract</span><span class="w"> </span><span class="nf">MyContract</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">plus2</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nc">Library</span><span class="p">.</span><span class="n">number</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nc">Library</span><span class="p">.</span><span class="n">inc</span><span class="p">(</span><span class="nc">Library</span><span class="p">.</span><span class="n">inc</span><span class="p">(</span><span class="n">x</span><span class="p">))</span><span class="w"></span>
</code></pre></div>
<p>```sophia
namespace Library =
type number = int
function inc(x : number) : number = x + 1</p>
<p>contract MyContract =
entrypoint plus2(x) : Library.number =
Library.inc(Library.inc(x))
```</p>
<p>Functions in namespaces have access to the same environment (including the
<code>Chain</code>, <code>Call</code>, and <code>Contract</code>, builtin namespaces) as function in a contract,
with the exception of <code>state</code>, <code>put</code> and <code>Chain.event</code> since these are
dependent on the specific state and event types of the contract.</p>
<p>To avoid mentioning the namespace every time it is used, Sophia allows
including the namespace in the current scope with the <code>using</code> keyword:
<div class="highlight"><pre><span></span><code>include &quot;Pair.aes&quot;
<code>include "Pair.aes"
using Pair
contract C =
type state = int
entrypoint init() =
let p = (1, 2)
fst(p) // this is the same as Pair.fst(p)
</code></pre></div></p>
fst(p) // this is the same as Pair.fst(p)</code></p>
<p>It is also possible to make an alias for the namespace with the <code>as</code> keyword:
<div class="highlight"><pre><span></span><code>include &quot;Pair.aes&quot;
<code>include "Pair.aes"
contract C =
using Pair as P
type state = int
entrypoint init() =
let p = (1, 2)
P.fst(p) // this is the same as Pair.fst(p)
</code></pre></div></p>
P.fst(p) // this is the same as Pair.fst(p)</code></p>
<p>Having the same alias for multiple namespaces is possible and it allows
referening functions that are defined in different namespaces and have
different names with the same alias:
<div class="highlight"><pre><span></span><code>namespace Xa = function f() = 1
<code>namespace Xa = function f() = 1
namespace Xb = function g() = 2
contract Cntr =
using Xa as A
using Xb as A
type state = int
entrypoint init() = A.f() + A.g()
</code></pre></div></p>
entrypoint init() = A.f() + A.g()</code></p>
<p>Note that using functions with the same name would result in an ambiguous name
error:
<div class="highlight"><pre><span></span><code>namespace Xa = function f() = 1
```
namespace Xa = function f() = 1
namespace Xb = function f() = 2
contract Cntr =
using Xa as A
using Xb as A
type state = int
// the next line has an error because f is defined in both Xa and Xb
type state = int</p>
<p>// the next line has an error because f is defined in both Xa and Xb
entrypoint init() = A.f()
</code></pre></div></p>
```</p>
<p>Importing specific parts of a namespace or hiding these parts can also be
done like this:
<div class="highlight"><pre><span></span><code>using Pair for [fst, snd] // this will only import fst and snd
using Triple hiding [fst, snd] // this will import everything except for fst and snd
</code></pre></div></p>
<code>using Pair for [fst, snd] // this will only import fst and snd
using Triple hiding [fst, snd] // this will import everything except for fst and snd</code></p>
<p>Note that it is possible to use a namespace in the top level of the file, in the
contract level, namespace level, or in the function level.</p>
<h2 id="splitting-code-over-multiple-files">Splitting code over multiple files</h2>
@@ -1258,14 +1254,14 @@ contract level, namespace level, or in the function level.</p>
statement. These must appear at the top-level (outside the main contract). The
included file can contain one or more namespaces and abstract contracts. For
example, if the file <code>library.aes</code> contains</p>
<div class="highlight"><pre><span></span><code><span class="k">namespace</span><span class="w"> </span><span class="nf">Library</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">function</span><span class="w"> </span><span class="n">inc</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="ow">+</span><span class="w"> </span><span class="mi">1</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
namespace Library =
function inc(x) = x + 1</code></p>
<p>you can use it from another file using an <code>include</code>:</p>
<div class="highlight"><pre><span></span><code><span class="k">include</span><span class="w"> </span><span class="s2">&quot;library.aes&quot;</span><span class="w"></span>
<span class="k">contract</span><span class="w"> </span><span class="nf">MyContract</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">plus2</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nc">Library</span><span class="p">.</span><span class="n">inc</span><span class="p">(</span><span class="nc">Library</span><span class="p">.</span><span class="n">inc</span><span class="p">(</span><span class="n">x</span><span class="p">))</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
include "library.aes"
contract MyContract =
entrypoint plus2(x) = Library.inc(Library.inc(x))</code></p>
<p>This behaves as if the contents of <code>library.aes</code> was textually inserted into
the file, except that error messages will refer to the original source
locations. The language will try to include each file at most one time automatically,
@@ -1277,14 +1273,14 @@ namespaces like <code>Chain</code>, <code>Contract</code>, <code>Map</code>
are included by default and are supported internally by the compiler.
Others like <code>List</code>, <code>Frac</code>, <code>Option</code> need to be manually included using the
<code>include</code> directive. For example
<div class="highlight"><pre><span></span><code><span class="k">include</span><span class="w"> </span><span class="s2">&quot;List.aes&quot;</span><span class="w"></span>
<span class="k">include</span><span class="w"> </span><span class="s2">&quot;Pair.aes&quot;</span><span class="w"></span>
<span class="ow">--</span><span class="w"> </span><span class="nf">Map</span><span class="w"> </span><span class="n">is</span><span class="w"> </span><span class="n">already</span><span class="w"> </span><span class="n">there</span><span class="ow">!</span><span class="w"></span>
<span class="k">namespace</span><span class="w"> </span><span class="nf">C</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">keys</span><span class="p">(</span><span class="n">m</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">map</span><span class="p">(</span><span class="nv">&#39;a</span><span class="p">,</span><span class="w"> </span><span class="nv">&#39;b</span><span class="p">))</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">list</span><span class="p">(</span><span class="nv">&#39;a</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nc">List</span><span class="p">.</span><span class="n">map</span><span class="p">(</span><span class="nc">Pair</span><span class="p">.</span><span class="n">fst</span><span class="p">,</span><span class="w"> </span><span class="p">(</span><span class="nc">Map</span><span class="p">.</span><span class="n">to_list</span><span class="p">(</span><span class="n">m</span><span class="p">)))</span><span class="w"></span>
</code></pre></div></p>
```sophia
include "List.aes"
include "Pair.aes"
-- Map is already there!</p>
<p>namespace C =
entrypoint keys(m : map('a, 'b)) : list('a) =
List.map(Pair.fst, (Map.to_list(m)))
```</p>
<h2 id="types">Types</h2>
<p>Sophia has the following types:</p>
<table>
@@ -1510,57 +1506,57 @@ corresponding integer, so setting very high bits can be expensive).</p>
<h2 id="type-aliases">Type aliases</h2>
<p>Type aliases can be introduced with the <code>type</code> keyword and can be
parameterized. For instance</p>
<div class="highlight"><pre><span></span><code><span class="k">type</span><span class="w"> </span><span class="n">number</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="kt">int</span><span class="w"></span>
<span class="k">type</span><span class="w"> </span><span class="n">string_map</span><span class="p">(</span><span class="nv">&#39;a</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="kt">map</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="nv">&#39;a</span><span class="p">)</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
type number = int
type string_map('a) = map(string, 'a)</code></p>
<p>A type alias and its definition can be used interchangeably. Sophia does not support
higher-kinded types, meaning that following type alias is invalid: <code>type wrap('f, 'a) = 'f('a)</code></p>
<h2 id="algebraic-data-types">Algebraic data types</h2>
<p>Sophia supports algebraic data types (variant types) and pattern matching. Data
types are declared by giving a list of constructors with
their respective arguments. For instance,</p>
<div class="highlight"><pre><span></span><code><span class="k">datatype</span><span class="w"> </span><span class="n">one_or_both</span><span class="p">(</span><span class="nv">&#39;a</span><span class="p">,</span><span class="w"> </span><span class="nv">&#39;b</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nf">Left</span><span class="p">(</span><span class="nv">&#39;a</span><span class="p">)</span><span class="w"> </span><span class="ow">|</span><span class="w"> </span><span class="nf">Right</span><span class="p">(</span><span class="nv">&#39;b</span><span class="p">)</span><span class="w"> </span><span class="ow">|</span><span class="w"> </span><span class="nf">Both</span><span class="p">(</span><span class="nv">&#39;a</span><span class="p">,</span><span class="w"> </span><span class="nv">&#39;b</span><span class="p">)</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
datatype one_or_both('a, 'b) = Left('a) | Right('b) | Both('a, 'b)</code></p>
<p>Elements of data types can be pattern matched against, using the <code>switch</code> construct:</p>
<div class="highlight"><pre><span></span><code><span class="k">function</span><span class="w"> </span><span class="n">get_left</span><span class="p">(</span><span class="n">x</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="n">one_or_both</span><span class="p">(</span><span class="nv">&#39;a</span><span class="p">,</span><span class="w"> </span><span class="nv">&#39;b</span><span class="p">))</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">option</span><span class="p">(</span><span class="nv">&#39;a</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">switch</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="nf">Left</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="nf">Right</span><span class="p">(</span><span class="n">_</span><span class="p">)</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="nf">None</span><span class="w"></span>
<span class="w"> </span><span class="nf">Both</span><span class="p">(</span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="n">_</span><span class="p">)</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
function get_left(x : one_or_both('a, 'b)) : option('a) =
switch(x)
Left(x) =&gt; Some(x)
Right(_) =&gt; None
Both(x, _) =&gt; Some(x)</code></p>
<p>or directly in the left-hand side:
<div class="highlight"><pre><span></span><code><span class="k">function</span><span class="w"></span>
<span class="w"> </span><span class="n">get_left</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="n">one_or_both</span><span class="p">(</span><span class="nv">&#39;a</span><span class="p">,</span><span class="w"> </span><span class="nv">&#39;b</span><span class="p">)</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="kt">option</span><span class="p">(</span><span class="nv">&#39;a</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="n">get_left</span><span class="p">(</span><span class="nf">Left</span><span class="p">(</span><span class="n">x</span><span class="p">))</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="n">get_left</span><span class="p">(</span><span class="nf">Right</span><span class="p">(</span><span class="n">_</span><span class="p">))</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nf">None</span><span class="w"></span>
<span class="w"> </span><span class="n">get_left</span><span class="p">(</span><span class="nf">Both</span><span class="p">(</span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="n">_</span><span class="p">))</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"></span>
</code></pre></div></p>
<code>sophia
function
get_left : one_or_both('a, 'b) =&gt; option('a)
get_left(Left(x)) = Some(x)
get_left(Right(_)) = None
get_left(Both(x, _)) = Some(x)</code></p>
<p><em>NOTE: Data types cannot currently be recursive.</em></p>
<p>Sophia also supports the assignment of patterns to variables:
<div class="highlight"><pre><span></span><code><span class="k">function</span><span class="w"> </span><span class="n">f</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="k">switch</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="n">h1</span><span class="ow">::</span><span class="p">(</span><span class="n">t</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">h2</span><span class="ow">::</span><span class="n">_</span><span class="p">)</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="p">(</span><span class="n">h1</span><span class="w"> </span><span class="ow">+</span><span class="w"> </span><span class="n">h2</span><span class="p">)</span><span class="ow">::</span><span class="n">t</span><span class="w"> </span><span class="c1">// same as `h1::h2::k =&gt; (h1 + h2)::h2::k`</span>
<span class="w"> </span><span class="n">_</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="n">x</span><span class="w"></span>
<span class="k">function</span><span class="w"> </span><span class="n">g</span><span class="p">(</span><span class="n">p</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="ow">*</span><span class="w"> </span><span class="kt">option</span><span class="p">(</span><span class="kt">int</span><span class="p">))</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">let</span><span class="w"> </span><span class="p">(</span><span class="n">a</span><span class="p">,</span><span class="w"> </span><span class="p">(</span><span class="n">o</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">b</span><span class="p">)))</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">p</span><span class="w"> </span><span class="c1">// o is equal to Pair.snd(p)</span>
<span class="w"> </span><span class="n">b</span><span class="w"></span>
</code></pre></div></p>
<code>``sophia
function f(x) = switch(x)
h1::(t = h2::_) =&gt; (h1 + h2)::t // same as</code>h1::h2::k =&gt; (h1 + h2)::h2::k`
_ =&gt; x</p>
<p>function g(p : int * option(int)) : int =
let (a, (o = Some(b))) = p // o is equal to Pair.snd(p)
b
```</p>
<p>Guards are boolean expressions that can be used on patterns in both switch
statements and functions definitions. If a guard expression evaluates to
<code>true</code>, then the corresponding body will be used. Otherwise, the next pattern
will be checked:</p>
<div class="highlight"><pre><span></span><code><span class="k">function</span><span class="w"> </span><span class="n">get_left_if_positive</span><span class="p">(</span><span class="n">x</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="n">one_or_both</span><span class="p">(</span><span class="kt">int</span><span class="p">,</span><span class="w"> </span><span class="nv">&#39;b</span><span class="p">))</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">option</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">switch</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="nf">Left</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="ow">|</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="ow">&gt;</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="nf">Both</span><span class="p">(</span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="n">_</span><span class="p">)</span><span class="w"> </span><span class="ow">|</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="ow">&gt;</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="n">_</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="nf">None</span><span class="w"></span>
</code></pre></div>
<div class="highlight"><pre><span></span><code><span class="k">function</span><span class="w"></span>
<span class="w"> </span><span class="n">get_left_if_positive</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="n">one_or_both</span><span class="p">(</span><span class="kt">int</span><span class="p">,</span><span class="w"> </span><span class="nv">&#39;b</span><span class="p">)</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="kt">option</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="n">get_left_if_positive</span><span class="p">(</span><span class="nf">Left</span><span class="p">(</span><span class="n">x</span><span class="p">))</span><span class="w"> </span><span class="ow">|</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="ow">&gt;</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="n">get_left_if_positive</span><span class="p">(</span><span class="nf">Both</span><span class="p">(</span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="n">_</span><span class="p">))</span><span class="w"> </span><span class="ow">|</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="ow">&gt;</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="n">get_left_if_positive</span><span class="p">(</span><span class="n">_</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nf">None</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
function get_left_if_positive(x : one_or_both(int, 'b)) : option(int) =
switch(x)
Left(x) | x &gt; 0 =&gt; Some(x)
Both(x, _) | x &gt; 0 =&gt; Some(x)
_ =&gt; None</code></p>
<p><code>sophia
function
get_left_if_positive : one_or_both(int, 'b) =&gt; option(int)
get_left_if_positive(Left(x)) | x &gt; 0 = Some(x)
get_left_if_positive(Both(x, _)) | x &gt; 0 = Some(x)
get_left_if_positive(_) = None</code></p>
<p>Guards cannot be stateful even when used inside a stateful function.</p>
<h2 id="lists">Lists</h2>
<p>A Sophia list is a dynamically sized, homogenous, immutable, singly
@@ -1568,10 +1564,10 @@ linked list. A list is constructed with the syntax <code>[1, 2, 3]</code>. The
elements of a list can be any of datatype but they must have the same
type. The type of lists with elements of type <code>'e</code> is written
<code>list('e)</code>. For example we can have the following lists:</p>
<div class="highlight"><pre><span></span><code><span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">33</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">666</span><span class="p">]</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">list</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="w"></span>
<span class="p">[(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="s2">&quot;aaa&quot;</span><span class="p">),</span><span class="w"> </span><span class="p">(</span><span class="mi">10</span><span class="p">,</span><span class="w"> </span><span class="s2">&quot;jjj&quot;</span><span class="p">),</span><span class="w"> </span><span class="p">(</span><span class="mi">666</span><span class="p">,</span><span class="w"> </span><span class="s2">&quot;the beast&quot;</span><span class="p">)]</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">list</span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="ow">*</span><span class="w"> </span><span class="kt">string</span><span class="p">)</span><span class="w"></span>
<span class="p">[{[</span><span class="mi">1</span><span class="p">]</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="s2">&quot;aaa&quot;</span><span class="p">,</span><span class="w"> </span><span class="p">[</span><span class="mi">10</span><span class="p">]</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="s2">&quot;jjj&quot;</span><span class="p">},</span><span class="w"> </span><span class="p">{[</span><span class="mi">5</span><span class="p">]</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="s2">&quot;eee&quot;</span><span class="p">,</span><span class="w"> </span><span class="p">[</span><span class="mi">666</span><span class="p">]</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="s2">&quot;the beast&quot;</span><span class="p">}]</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">list</span><span class="p">(</span><span class="kt">map</span><span class="p">(</span><span class="kt">int</span><span class="p">,</span><span class="w"> </span><span class="kt">string</span><span class="p">))</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
[1, 33, 2, 666] : list(int)
[(1, "aaa"), (10, "jjj"), (666, "the beast")] : list(int * string)
[{[1] = "aaa", [10] = "jjj"}, {[5] = "eee", [666] = "the beast"}] : list(map(int, string))</code></p>
<p>New elements can be prepended to the front of a list with the <code>::</code>
operator. So <code>42 :: [1, 2, 3]</code> returns the list <code>[42, 1, 2, 3]</code>. The
concatenation operator <code>++</code> appends its second argument to its first
@@ -1579,21 +1575,21 @@ and returns the resulting list. So concatenating two lists
<code>[1, 22, 33] ++ [10, 18, 55]</code> returns the list <code>[1, 22, 33, 10, 18, 55]</code>.</p>
<p>Sophia supports list comprehensions known from languages like Python, Haskell or Erlang.
Example syntax:
<div class="highlight"><pre><span></span><code><span class="p">[</span><span class="n">x</span><span class="w"> </span><span class="ow">+</span><span class="w"> </span><span class="n">y</span><span class="w"> </span><span class="ow">|</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="ow">&lt;-</span><span class="w"> </span><span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">,</span><span class="mi">4</span><span class="p">,</span><span class="mi">5</span><span class="p">],</span><span class="w"> </span><span class="k">let</span><span class="w"> </span><span class="n">k</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">x</span><span class="ow">*</span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">k</span><span class="w"> </span><span class="ow">&gt;</span><span class="w"> </span><span class="mi">5</span><span class="p">),</span><span class="w"> </span><span class="n">y</span><span class="w"> </span><span class="ow">&lt;-</span><span class="w"> </span><span class="p">[</span><span class="n">k</span><span class="p">,</span><span class="w"> </span><span class="n">k</span><span class="ow">+</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="n">k</span><span class="ow">+</span><span class="mi">2</span><span class="p">]]</span><span class="w"></span>
<span class="c1">// yields [12,13,14,20,21,22,30,31,32]</span>
</code></pre></div></p>
<code>sophia
[x + y | x &lt;- [1,2,3,4,5], let k = x*x, if (k &gt; 5), y &lt;- [k, k+1, k+2]]
// yields [12,13,14,20,21,22,30,31,32]</code></p>
<p>Lists can be constructed using the range syntax using special <code>..</code> operator:
<div class="highlight"><pre><span></span><code><span class="p">[</span><span class="mi">1</span><span class="p">..</span><span class="mi">4</span><span class="p">]</span><span class="w"> </span><span class="ow">==</span><span class="w"> </span><span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">,</span><span class="mi">4</span><span class="p">]</span><span class="w"></span>
</code></pre></div>
<code>sophia
[1..4] == [1,2,3,4]</code>
The ranges are always ascending and have step equal to 1.</p>
<p>Please refer to the <a href="../sophia_stdlib/#list">standard library</a> for the predefined functionalities.</p>
<h2 id="maps-and-records">Maps and records</h2>
<p>A Sophia record type is given by a fixed set of fields with associated,
possibly different, types. For instance
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="k">record</span><span class="w"> </span><span class="n">account</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="n">name</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">,</span><span class="w"></span>
<span class="w"> </span><span class="n">balance</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">int</span><span class="p">,</span><span class="w"></span>
<span class="w"> </span><span class="n">history</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">list</span><span class="p">(</span><span class="n">transaction</span><span class="p">)</span><span class="w"> </span><span class="p">}</span><span class="w"></span>
</code></pre></div></p>
<code>sophia
record account = { name : string,
balance : int,
history : list(transaction) }</code></p>
<p>Maps, on the other hand, can contain an arbitrary number of key-value bindings,
but of a fixed type. The type of maps with keys of type <code>'k</code> and values of type
<code>'v</code> is written <code>map('k, 'v)</code>. The key type can be any type that does not
@@ -1602,19 +1598,19 @@ contain a map or a function type.</p>
<h3 id="constructing-maps-and-records">Constructing maps and records</h3>
<p>A value of record type is constructed by giving a value for each of the fields.
For the example above,
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="k">function</span><span class="w"> </span><span class="n">new_account</span><span class="p">(</span><span class="n">name</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="p">{</span><span class="n">name</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">name</span><span class="p">,</span><span class="w"> </span><span class="n">balance</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="n">history</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="p">[]}</span><span class="w"></span>
</code></pre></div>
<code>sophia
function new_account(name) =
{name = name, balance = 0, history = []}</code>
Maps are constructed similarly, with keys enclosed in square brackets
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="k">function</span><span class="w"> </span><span class="n">example_map</span><span class="p">()</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">map</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="p">{[</span><span class="s2">&quot;key1&quot;</span><span class="p">]</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="p">[</span><span class="s2">&quot;key2&quot;</span><span class="p">]</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="mi">2</span><span class="p">}</span><span class="w"></span>
</code></pre></div>
<code>sophia
function example_map() : map(string, int) =
{["key1"] = 1, ["key2"] = 2}</code>
The empty map is written <code>{}</code>.</p>
<h3 id="accessing-values">Accessing values</h3>
<p>Record fields access is written <code>r.f</code> and map lookup <code>m[k]</code>. For instance,
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="k">function</span><span class="w"> </span><span class="n">get_balance</span><span class="p">(</span><span class="n">a</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">address</span><span class="p">,</span><span class="w"> </span><span class="n">accounts</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">map</span><span class="p">(</span><span class="kt">address</span><span class="p">,</span><span class="w"> </span><span class="n">account</span><span class="p">))</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="n">accounts</span><span class="p">[</span><span class="n">a</span><span class="p">].</span><span class="n">balance</span><span class="w"></span>
</code></pre></div>
<code>sophia
function get_balance(a : address, accounts : map(address, account)) =
accounts[a].balance</code>
Looking up a non-existing key in a map results in contract execution failing. A
default value to return for non-existing keys can be provided using the syntax
<code>m[k = default]</code>. See also <code>Map.member</code> and <code>Map.lookup</code> below.</p>
@@ -1632,14 +1628,14 @@ in the map or execution fails, but a default value can be provided:
<code>m{ [k = default] @ x = v }</code>. In this case <code>x</code> is bound to <code>default</code> if
<code>k</code> is not in the map.</p>
<p>Updates can be nested:
<div class="highlight"><pre><span></span><code><span class="k">function</span><span class="w"> </span><span class="n">clear_history</span><span class="p">(</span><span class="n">a</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">address</span><span class="p">,</span><span class="w"> </span><span class="n">accounts</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">map</span><span class="p">(</span><span class="kt">address</span><span class="p">,</span><span class="w"> </span><span class="n">account</span><span class="p">))</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">map</span><span class="p">(</span><span class="kt">address</span><span class="p">,</span><span class="w"> </span><span class="n">account</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="n">accounts</span><span class="p">{</span><span class="w"> </span><span class="p">[</span><span class="n">a</span><span class="p">].</span><span class="n">history</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="p">[]</span><span class="w"> </span><span class="p">}</span><span class="w"></span>
</code></pre></div>
<code>sophia
function clear_history(a : address, accounts : map(address, account)) : map(address, account) =
accounts{ [a].history = [] }</code>
This is equivalent to <code>accounts{ [a] @ acc = acc{ history = [] } }</code> and thus
requires <code>a</code> to be present in the accounts map. To have <code>clear_history</code> create
an account if <code>a</code> is not in the map you can write (given a function <code>empty_account</code>):
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="n">accounts</span><span class="p">{</span><span class="w"> </span><span class="p">[</span><span class="n">a</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">empty_account</span><span class="p">()].</span><span class="n">history</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="p">[]</span><span class="w"> </span><span class="p">}</span><span class="w"></span>
</code></pre></div></p>
<code>sophia
accounts{ [a = empty_account()].history = [] }</code></p>
<h3 id="map-implementation">Map implementation</h3>
<p>Internally in the VM maps are implemented as hash maps and support fast lookup
and update. Large maps can be stored in the contract state and the size of the
@@ -1678,54 +1674,46 @@ through the Oracle interface.</p>
For a functionality documentation refer to the <a href="../sophia_stdlib/#oracle">standard library</a>.</p>
<h3 id="example">Example</h3>
<p>Example for an oracle answering questions of type <code>string</code> with answers of type <code>int</code>:
<div class="highlight"><pre><span></span><code><span class="k">contract</span><span class="w"> </span><span class="nf">Oracles</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">registerOracle</span><span class="p">(</span><span class="n">acct</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">address</span><span class="p">,</span><span class="w"></span>
<span class="w"> </span><span class="n">sign</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">signature</span><span class="p">,</span><span class="w"> </span><span class="c1">// Signed network id + oracle address + contract address</span>
<span class="w"> </span><span class="n">qfee</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">int</span><span class="p">,</span><span class="w"></span>
<span class="w"> </span><span class="n">ttl</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nc">Chain</span><span class="p">.</span><span class="n">ttl</span><span class="p">)</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nc">Oracle</span><span class="p">.</span><span class="n">register</span><span class="p">(</span><span class="n">acct</span><span class="p">,</span><span class="w"> </span><span class="kt">signature</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">sign</span><span class="p">,</span><span class="w"> </span><span class="n">qfee</span><span class="p">,</span><span class="w"> </span><span class="n">ttl</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">queryFee</span><span class="p">(</span><span class="n">o</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">))</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nc">Oracle</span><span class="p">.</span><span class="n">query_fee</span><span class="p">(</span><span class="n">o</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="k">payable</span><span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">createQuery</span><span class="p">(</span><span class="n">o</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle_query</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">),</span><span class="w"></span>
<span class="w"> </span><span class="n">q</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">,</span><span class="w"></span>
<span class="w"> </span><span class="n">qfee</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">int</span><span class="p">,</span><span class="w"></span>
<span class="w"> </span><span class="n">qttl</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nc">Chain</span><span class="p">.</span><span class="n">ttl</span><span class="p">,</span><span class="w"></span>
<span class="w"> </span><span class="n">rttl</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">int</span><span class="p">)</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle_query</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nb">require</span><span class="p">(</span><span class="n">qfee</span><span class="w"> </span><span class="ow">=&lt;</span><span class="w"> </span><span class="nc">Call</span><span class="p">.</span><span class="n">value</span><span class="p">,</span><span class="w"> </span><span class="s2">&quot;insufficient value for qfee&quot;</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="nc">Oracle</span><span class="p">.</span><span class="n">query</span><span class="p">(</span><span class="n">o</span><span class="p">,</span><span class="w"> </span><span class="n">q</span><span class="p">,</span><span class="w"> </span><span class="n">qfee</span><span class="p">,</span><span class="w"> </span><span class="n">qttl</span><span class="p">,</span><span class="w"> </span><span class="nf">RelativeTTL</span><span class="p">(</span><span class="n">rttl</span><span class="p">))</span><span class="w"></span>
<span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">extendOracle</span><span class="p">(</span><span class="n">o</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">),</span><span class="w"></span>
<span class="w"> </span><span class="n">ttl</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nc">Chain</span><span class="p">.</span><span class="n">ttl</span><span class="p">)</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">unit</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nc">Oracle</span><span class="p">.</span><span class="n">extend</span><span class="p">(</span><span class="n">o</span><span class="p">,</span><span class="w"> </span><span class="n">ttl</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">signExtendOracle</span><span class="p">(</span><span class="n">o</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">),</span><span class="w"></span>
<span class="w"> </span><span class="n">sign</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">signature</span><span class="p">,</span><span class="w"> </span><span class="c1">// Signed network id + oracle address + contract address</span>
<span class="w"> </span><span class="n">ttl</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nc">Chain</span><span class="p">.</span><span class="n">ttl</span><span class="p">)</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">unit</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nc">Oracle</span><span class="p">.</span><span class="n">extend</span><span class="p">(</span><span class="n">o</span><span class="p">,</span><span class="w"> </span><span class="kt">signature</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">sign</span><span class="p">,</span><span class="w"> </span><span class="n">ttl</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">respond</span><span class="p">(</span><span class="n">o</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">),</span><span class="w"></span>
<span class="w"> </span><span class="n">q</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle_query</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">),</span><span class="w"></span>
<span class="w"> </span><span class="n">sign</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">signature</span><span class="p">,</span><span class="w"> </span><span class="c1">// Signed network id + oracle query id + contract address</span>
<span class="w"> </span><span class="n">r</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">int</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nc">Oracle</span><span class="p">.</span><span class="n">respond</span><span class="p">(</span><span class="n">o</span><span class="p">,</span><span class="w"> </span><span class="n">q</span><span class="p">,</span><span class="w"> </span><span class="kt">signature</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">sign</span><span class="p">,</span><span class="w"> </span><span class="n">r</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">getQuestion</span><span class="p">(</span><span class="n">o</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">),</span><span class="w"></span>
<span class="w"> </span><span class="n">q</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle_query</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">))</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nc">Oracle</span><span class="p">.</span><span class="n">get_question</span><span class="p">(</span><span class="n">o</span><span class="p">,</span><span class="w"> </span><span class="n">q</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">hasAnswer</span><span class="p">(</span><span class="n">o</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">),</span><span class="w"></span>
<span class="w"> </span><span class="n">q</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle_query</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">))</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">switch</span><span class="p">(</span><span class="nc">Oracle</span><span class="p">.</span><span class="n">get_answer</span><span class="p">(</span><span class="n">o</span><span class="p">,</span><span class="w"> </span><span class="n">q</span><span class="p">))</span><span class="w"></span>
<span class="w"> </span><span class="nf">None</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="kc">false</span><span class="w"></span>
<span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">_</span><span class="p">)</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="kc">true</span><span class="w"></span>
<span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">getAnswer</span><span class="p">(</span><span class="n">o</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">),</span><span class="w"></span>
<span class="w"> </span><span class="n">q</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">oracle_query</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">))</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">option</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nc">Oracle</span><span class="p">.</span><span class="n">get_answer</span><span class="p">(</span><span class="n">o</span><span class="p">,</span><span class="w"> </span><span class="n">q</span><span class="p">)</span><span class="w"></span>
</code></pre></div></p>
```sophia
contract Oracles =</p>
<p>stateful entrypoint registerOracle(acct : address,
sign : signature, // Signed network id + oracle address + contract address
qfee : int,
ttl : Chain.ttl) : oracle(string, int) =
Oracle.register(acct, signature = sign, qfee, ttl)</p>
<p>entrypoint queryFee(o : oracle(string, int)) : int =
Oracle.query_fee(o)</p>
<p>payable stateful entrypoint createQuery(o : oracle_query(string, int),
q : string,
qfee : int,
qttl : Chain.ttl,
rttl : int) : oracle_query(string, int) =
require(qfee =&lt; Call.value, "insufficient value for qfee")
Oracle.query(o, q, qfee, qttl, RelativeTTL(rttl))</p>
<p>stateful entrypoint extendOracle(o : oracle(string, int),
ttl : Chain.ttl) : unit =
Oracle.extend(o, ttl)</p>
<p>stateful entrypoint signExtendOracle(o : oracle(string, int),
sign : signature, // Signed network id + oracle address + contract address
ttl : Chain.ttl) : unit =
Oracle.extend(o, signature = sign, ttl)</p>
<p>stateful entrypoint respond(o : oracle(string, int),
q : oracle_query(string, int),
sign : signature, // Signed network id + oracle query id + contract address
r : int) =
Oracle.respond(o, q, signature = sign, r)</p>
<p>entrypoint getQuestion(o : oracle(string, int),
q : oracle_query(string, int)) : string =
Oracle.get_question(o, q)</p>
<p>entrypoint hasAnswer(o : oracle(string, int),
q : oracle_query(string, int)) =
switch(Oracle.get_answer(o, q))
None =&gt; false
Some(_) =&gt; true</p>
<p>entrypoint getAnswer(o : oracle(string, int),
q : oracle_query(string, int)) : option(int) =
Oracle.get_answer(o, q)
```</p>
<h3 id="sanity-checks">Sanity checks</h3>
<p>When an Oracle literal is passed to a contract, no deep checks are performed.
For extra safety <a href="../sophia_stdlib/#check">Oracle.check</a> and <a href="../sophia_stdlib/#check_query">Oracle.check_query</a>
@@ -1741,30 +1729,30 @@ an account with address <code>addr</code>. In order to allow a contract <code>ct
<a href="#delegation-signature">signature</a> <code>sig</code> of <code>addr | name.hash | ct.address</code>.</p>
<p>Armed with this information we can for example write a function that extends
the name if it expires within 1000 blocks:
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">extend_if_necessary</span><span class="p">(</span><span class="n">addr</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">address</span><span class="p">,</span><span class="w"> </span><span class="n">name</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="n">sig</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">signature</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">switch</span><span class="p">(</span><span class="nc">AENS</span><span class="p">.</span><span class="n">lookup</span><span class="p">(</span><span class="n">name</span><span class="p">))</span><span class="w"></span>
<span class="w"> </span><span class="nf">None</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="p">()</span><span class="w"></span>
<span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="nc">AENS</span><span class="p">.</span><span class="nf">Name</span><span class="p">(</span><span class="n">_</span><span class="p">,</span><span class="w"> </span><span class="nf">FixedTTL</span><span class="p">(</span><span class="n">expiry</span><span class="p">),</span><span class="w"> </span><span class="n">_</span><span class="p">))</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"></span>
<span class="w"> </span><span class="k">if</span><span class="p">(</span><span class="nc">Chain</span><span class="p">.</span><span class="n">block_height</span><span class="w"> </span><span class="ow">+</span><span class="w"> </span><span class="mi">1000</span><span class="w"> </span><span class="ow">&gt;</span><span class="w"> </span><span class="n">expiry</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="nc">AENS</span><span class="p">.</span><span class="n">update</span><span class="p">(</span><span class="n">addr</span><span class="p">,</span><span class="w"> </span><span class="n">name</span><span class="p">,</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="nf">RelativeTTL</span><span class="p">(</span><span class="mi">50000</span><span class="p">)),</span><span class="w"> </span><span class="nf">None</span><span class="p">,</span><span class="w"> </span><span class="nf">None</span><span class="p">,</span><span class="w"> </span><span class="kt">signature</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">sig</span><span class="p">)</span><span class="w"></span>
</code></pre></div></p>
<code>sophia
stateful entrypoint extend_if_necessary(addr : address, name : string, sig : signature) =
switch(AENS.lookup(name))
None =&gt; ()
Some(AENS.Name(_, FixedTTL(expiry), _)) =&gt;
if(Chain.block_height + 1000 &gt; expiry)
AENS.update(addr, name, Some(RelativeTTL(50000)), None, None, signature = sig)</code></p>
<p>And we can write functions that adds and removes keys from the pointers of the
name:
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">add_key</span><span class="p">(</span><span class="n">addr</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">address</span><span class="p">,</span><span class="w"> </span><span class="n">name</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="n">key</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">,</span><span class="w"></span>
<span class="w"> </span><span class="n">pt</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nc">AENS</span><span class="p">.</span><span class="n">pointee</span><span class="p">,</span><span class="w"> </span><span class="n">sig</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">signature</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">switch</span><span class="p">(</span><span class="nc">AENS</span><span class="p">.</span><span class="n">lookup</span><span class="p">(</span><span class="n">name</span><span class="p">))</span><span class="w"></span>
<span class="w"> </span><span class="nf">None</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="p">()</span><span class="w"></span>
<span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="nc">AENS</span><span class="p">.</span><span class="nf">Name</span><span class="p">(</span><span class="n">_</span><span class="p">,</span><span class="w"> </span><span class="n">_</span><span class="p">,</span><span class="w"> </span><span class="n">ptrs</span><span class="p">))</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"></span>
<span class="w"> </span><span class="nc">AENS</span><span class="p">.</span><span class="n">update</span><span class="p">(</span><span class="n">addr</span><span class="p">,</span><span class="w"> </span><span class="n">name</span><span class="p">,</span><span class="w"> </span><span class="nf">None</span><span class="p">,</span><span class="w"> </span><span class="nf">None</span><span class="p">,</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">ptrs</span><span class="p">{[</span><span class="n">key</span><span class="p">]</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">pt</span><span class="p">}),</span><span class="w"> </span><span class="kt">signature</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">sig</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="k">stateful</span><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">delete_key</span><span class="p">(</span><span class="n">addr</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">address</span><span class="p">,</span><span class="w"> </span><span class="n">name</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">,</span><span class="w"></span>
<span class="w"> </span><span class="n">key</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="n">sig</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">signature</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">switch</span><span class="p">(</span><span class="nc">AENS</span><span class="p">.</span><span class="n">lookup</span><span class="p">(</span><span class="n">name</span><span class="p">))</span><span class="w"></span>
<span class="w"> </span><span class="nf">None</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"> </span><span class="p">()</span><span class="w"></span>
<span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="nc">AENS</span><span class="p">.</span><span class="nf">Name</span><span class="p">(</span><span class="n">_</span><span class="p">,</span><span class="w"> </span><span class="n">_</span><span class="p">,</span><span class="w"> </span><span class="n">ptrs</span><span class="p">))</span><span class="w"> </span><span class="ow">=&gt;</span><span class="w"></span>
<span class="w"> </span><span class="k">let</span><span class="w"> </span><span class="n">ptrs</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nc">Map</span><span class="p">.</span><span class="n">delete</span><span class="p">(</span><span class="n">key</span><span class="p">,</span><span class="w"> </span><span class="n">ptrs</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="nc">AENS</span><span class="p">.</span><span class="n">update</span><span class="p">(</span><span class="n">addr</span><span class="p">,</span><span class="w"> </span><span class="n">name</span><span class="p">,</span><span class="w"> </span><span class="nf">None</span><span class="p">,</span><span class="w"> </span><span class="nf">None</span><span class="p">,</span><span class="w"> </span><span class="nf">Some</span><span class="p">(</span><span class="n">ptrs</span><span class="p">),</span><span class="w"> </span><span class="kt">signature</span><span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="n">sig</span><span class="p">)</span><span class="w"></span>
</code></pre></div></p>
```sophia
stateful entrypoint add_key(addr : address, name : string, key : string,
pt : AENS.pointee, sig : signature) =
switch(AENS.lookup(name))
None =&gt; ()
Some(AENS.Name(<em>, </em>, ptrs)) =&gt;
AENS.update(addr, name, None, None, Some(ptrs{[key] = pt}), signature = sig)</p>
<p>stateful entrypoint delete_key(addr : address, name : string,
key : string, sig : signature) =
switch(AENS.lookup(name))
None =&gt; ()
Some(AENS.Name(<em>, </em>, ptrs)) =&gt;
let ptrs = Map.delete(key, ptrs)
AENS.update(addr, name, None, None, Some(ptrs), signature = sig)
```</p>
<p><em>Note:</em> From the Iris hardfork more strict rules apply for AENS pointers, when
a Sophia contract lookup or update (bad) legacy pointers, the bad keys are
automatically removed so they will not appear in the pointers map.</p>
@@ -1775,12 +1763,12 @@ Solidity</a>.
Events are further discussed in the <a href="https://github.com/aeternity/protocol/blob/master/contracts/events.md">protocol</a>.</p>
<p>To use events a contract must declare a datatype <code>event</code>, and events are then
logged using the <code>Chain.event</code> function:</p>
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="k">datatype</span><span class="w"> </span><span class="kt">event</span><span class="w"></span>
<span class="w"> </span><span class="ow">=</span><span class="w"> </span><span class="nf">Event1</span><span class="p">(</span><span class="kt">int</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">,</span><span class="w"> </span><span class="kt">string</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="ow">|</span><span class="w"> </span><span class="nf">Event2</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">address</span><span class="p">)</span><span class="w"></span>
<span class="w"> </span><span class="nc">Chain</span><span class="p">.</span><span class="n">event</span><span class="p">(</span><span class="n">e</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">event</span><span class="p">)</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">unit</span><span class="w"></span>
</code></pre></div>
<p>```sophia
datatype event
= Event1(int, int, string)
| Event2(string, address)</p>
<p>Chain.event(e : event) : unit
```</p>
<p>The event can have 0-3 <em>indexed</em> fields, and an optional <em>payload</em> field. A
field is indexed if it fits in a 32-byte word, i.e.
- <code>bool</code>
@@ -1796,44 +1784,43 @@ The fields can appear in any order.</p>
<p><em>NOTE:</em> Indexing is not part of the core æternity node.</p>
<p>Events are emitted by using the <code>Chain.event</code> function. The following function
will emit one Event of each kind in the example.</p>
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="k">entrypoint</span><span class="w"> </span><span class="n">emit_events</span><span class="p">()</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="p">()</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="nc">Chain</span><span class="p">.</span><span class="n">event</span><span class="p">(</span><span class="nf">Event1</span><span class="p">(</span><span class="mi">42</span><span class="p">,</span><span class="w"> </span><span class="mi">34</span><span class="p">,</span><span class="w"> </span><span class="s2">&quot;foo&quot;</span><span class="p">))</span><span class="w"></span>
<span class="w"> </span><span class="nc">Chain</span><span class="p">.</span><span class="n">event</span><span class="p">(</span><span class="nf">Event2</span><span class="p">(</span><span class="s2">&quot;This is not indexed&quot;</span><span class="p">,</span><span class="w"> </span><span class="nc">Contract</span><span class="p">.</span><span class="n">address</span><span class="p">))</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
entrypoint emit_events() : () =
Chain.event(Event1(42, 34, "foo"))
Chain.event(Event2("This is not indexed", Contract.address))</code></p>
<h3 id="argument-order">Argument order</h3>
<p>It is only possible to have one (1) <code>string</code> parameter in the event, but it can
be placed in any position (and its value will end up in the <code>data</code> field), i.e.
<div class="highlight"><pre><span></span><code><span class="nf">AnotherEvent</span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="k">indexed</span><span class="w"> </span><span class="kt">address</span><span class="p">)</span><span class="w"></span>
<span class="p">...</span><span class="w"></span>
<span class="nc">Chain</span><span class="p">.</span><span class="n">event</span><span class="p">(</span><span class="nf">AnotherEvent</span><span class="p">(</span><span class="s2">&quot;This is not indexed&quot;</span><span class="p">,</span><span class="w"> </span><span class="nc">Contract</span><span class="p">.</span><span class="n">address</span><span class="p">))</span><span class="w"></span>
</code></pre></div>
```sophia
AnotherEvent(string, indexed address)</p>
<p>...</p>
<p>Chain.event(AnotherEvent("This is not indexed", Contract.address))
```
would yield exactly the same result in the example above!</p>
<h2 id="compiler-pragmas">Compiler pragmas</h2>
<p>To enforce that a contract is only compiled with specific versions of the
Sophia compiler, you can give one or more <code>@compiler</code> pragmas at the
top-level (typically at the beginning) of a file. For instance, to enforce that
a contract is compiled with version 4.3 of the compiler you write</p>
<div class="highlight"><pre><span></span><code><span class="ow">@</span><span class="n">compiler</span><span class="w"> </span><span class="ow">&gt;=</span><span class="w"> </span><span class="mi">4</span><span class="p">.</span><span class="mi">3</span><span class="w"></span>
<span class="ow">@</span><span class="n">compiler</span><span class="w"> </span><span class="ow">&lt;</span><span class="w"> </span><span class="mi">4</span><span class="p">.</span><span class="mi">4</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
@compiler &gt;= 4.3
@compiler &lt; 4.4</code></p>
<p>Valid operators in compiler pragmas are <code>&lt;</code>, <code>=&lt;</code>, <code>==</code>, <code>&gt;=</code>, and <code>&gt;</code>. Version
numbers are given as a sequence of non-negative integers separated by dots.
Trailing zeros are ignored, so <code>4.0.0 == 4</code>. If a constraint is violated an
error is reported and compilation fails.</p>
<h2 id="exceptions">Exceptions</h2>
<p>Contracts can fail with an (uncatchable) exception using the built-in function</p>
<div class="highlight"><pre><span></span><code><span class="nb">abort</span><span class="p">(</span><span class="n">reason</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">)</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="nv">&#39;a</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
abort(reason : string) : 'a</code></p>
<p>Calling abort causes the top-level call transaction to return an error result
containing the <code>reason</code> string. Only the gas used up to and including the abort
call is charged. This is different from termination due to a crash which
consumes all available gas.</p>
<p>For convenience the following function is also built-in:</p>
<div class="highlight"><pre><span></span><code><span class="k">function</span><span class="w"> </span><span class="nb">require</span><span class="p">(</span><span class="n">b</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">bool</span><span class="p">,</span><span class="w"> </span><span class="n">err</span><span class="w"> </span><span class="ow">:</span><span class="w"> </span><span class="kt">string</span><span class="p">)</span><span class="w"> </span><span class="ow">=</span><span class="w"></span>
<span class="w"> </span><span class="k">if</span><span class="p">(</span><span class="ow">!</span><span class="n">b</span><span class="p">)</span><span class="w"> </span><span class="nb">abort</span><span class="p">(</span><span class="n">err</span><span class="p">)</span><span class="w"></span>
</code></pre></div>
<p><code>sophia
function require(b : bool, err : string) =
if(!b) abort(err)</code></p>
<h2 id="delegation-signature">Delegation signature</h2>
<p>Some chain operations (<code>Oracle.&lt;operation&gt;</code> and <code>AENS.&lt;operation&gt;</code>) have an
optional delegation signature. This is typically used when a user/accounts