Improve the interface to the compiler

It is now more consistent though we can still discuss how we want the
interface to look.

src/aeso_compiler.erl

@@ -21,8 +21,8 @@
 -include("aeso_icode.hrl").
 
 
--type option() :: pp_sophia_code | pp_ast | pp_icode | pp_assembler |
-                  pp_bytecode.
+-type option() :: pp_sophia_code | pp_ast | pp_types | pp_typed_ast |
+		  pp_icode| pp_assembler | pp_bytecode.
 -type options() :: [option()].
 
 -export_type([ option/0
@@ -43,12 +43,17 @@ file(Filename) ->
     file(Filename, []).
 
 -spec file(string(), options()) -> map().
-file(Filename, Options) ->
-    C = read_contract(Filename),
-    from_string(C, Options).
+file(File, Options) ->
+    case read_contract(File) of
+        {ok, Bin} -> from_string(Bin, Options);
+        {error, Error} -> {error, {File, Error}}
+    end.
 
--spec from_string(string(), options()) -> map().
+-spec from_string(binary() | string(), options()) -> map().
+from_string(ContractBin, Options) when is_binary(ContractBin) ->
+    from_string(binary_to_list(ContractBin), Options);
 from_string(ContractString, Options) ->
+    try
 	Ast = parse(ContractString, Options),
 	ok = pp_sophia_code(Ast, Options),
 	ok = pp_ast(Ast, Options),
@@ -63,9 +68,26 @@ from_string(ContractString, Options) ->
 	ByteCodeList = to_bytecode(Assembler, Options),
 	ByteCode = << << B:8 >> || B <- ByteCodeList >>,
 	ok = pp_bytecode(ByteCode, Options),
-    #{byte_code => ByteCode, type_info => TypeInfo,
+	{ok,#{byte_code => ByteCode,
+	      compiler_version => version(),
 	      contract_source => ContractString,
-      compiler_version => version()}.
+	      type_info => TypeInfo
+	     }}
+    catch
+        %% The compiler errors.
+        error:{parse_errors,Errors} ->
+	    {error,join_errors("Parse errors", Errors, fun(E) -> E end)};
+        error:{type_errors,Errors} ->
+	    {error,join_errors("Type errors", Errors, fun(E) -> E end)};
+        error:{code_errors,Errors} ->
+            {error,join_errors("Code errors", Errors,
+			       fun (E) -> io_lib:format("~p", [E]) end)}
+        %% General programming errors in the compiler just signal error.
+    end.
+
+join_errors(Prefix, Errors, Pfun) ->
+    Ess = [ Pfun(E) || E <- Errors ],
+    list_to_binary(string:join([Prefix|Ess], "\n")).
 
 -define(CALL_NAME, "__call").
 
@@ -76,6 +98,7 @@ from_string(ContractString, Options) ->
 -spec check_call(string(), options()) -> {ok, string(), {[Type], Type | any}, [term()]} | {error, term()}
     when Type :: term().
 check_call(ContractString, Options) ->
+    try
 	Ast = parse(ContractString, Options),
 	ok = pp_sophia_code(Ast, Options),
 	ok = pp_ast(Ast, Options),
@@ -91,11 +114,20 @@ check_call(ContractString, Options) ->
 	ok = pp_icode(Icode, Options),
 	#{ functions := Funs } = Icode,
 	ArgIcode = get_arg_icode(Funs),
-    try [ icode_to_term(T, Arg) || {T, Arg} <- lists:zip(ArgVMTypes, ArgIcode) ] of
-        ArgTerms ->
+	ArgTerms = [ icode_to_term(T, Arg) ||
+		       {T, Arg} <- lists:zip(ArgVMTypes, ArgIcode) ],
 	{ok, FunName, {ArgVMTypes, RetVMType}, ArgTerms}
-    catch throw:Err ->
-        {error, Err}
+    catch
+	error:{parse_errors, Errors} ->
+	    {error,join_errors("Parse errors", Errors, fun (E) -> E end)};
+	error:{type_errors, Errors} ->
+	    {error,join_errors("Type errors", Errors, fun (E) -> E end)};
+	error:{badmatch,{error,missing_call_function}} ->
+	    {error,join_errors("Type errors", ["missing __call function"],
+			       fun (E) -> E end)};
+	throw:Error ->				%Don't ask
+            {error,join_errors("Code errors", [Error],
+			       fun (E) -> io_lib:format("~p", [E]) end)}
     end.
 
 -spec create_calldata(map(), string(), string()) ->
@@ -252,6 +284,5 @@ parse_error({Line,Pos}, ErrorString) ->
     error({parse_errors,[Error]}).
 
 read_contract(Name) ->
-    {ok, Bin} = file:read_file(Name),
-    binary_to_list(Bin).
+    file:read_file(Name).