From dcef89b48691ee746201757f7ad0e1001631d0a7 Mon Sep 17 00:00:00 2001
From: radrow <radrowicki@gmail.com>
Date: Thu, 15 Jul 2021 20:41:38 +0200
Subject: [PATCH] Add Option.force_msg

---
 docs/sophia_stdlib.md  | 12 +++++++++++-
 priv/stdlib/Option.aes |  6 ++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/docs/sophia_stdlib.md b/docs/sophia_stdlib.md
index 694629b..64df2d9 100644
--- a/docs/sophia_stdlib.md
+++ b/docs/sophia_stdlib.md
@@ -1293,7 +1293,17 @@ Escapes `option` wrapping by providing default value for `None`.
 Option.force(o : option('a)) : 'a
 ```
 
-Forcefully escapes `option` wrapping assuming it is `Some`. Throws error on `None`.
+Forcefully escapes the `option` wrapping assuming it is `Some`. 
+Aborts on `None`.
+
+
+#### force_msg
+```
+Option.force_msg(o : option('a), err : string) : 'a
+```
+
+Forcefully escapes the `option` wrapping assuming it is `Some`.
+Aborts with `err` error message on `None`.
 
 
 #### contains
diff --git a/priv/stdlib/Option.aes b/priv/stdlib/Option.aes
index 0e00cd4..45e6594 100644
--- a/priv/stdlib/Option.aes
+++ b/priv/stdlib/Option.aes
@@ -26,6 +26,12 @@ namespace Option =
     None    => abort("Forced None value")
     Some(x) => x
 
+/** Assume it is `Some` with custom error message
+ */
+  function force_msg(o : option('a), err : string) : 'a = switch(o)
+    None    => abort(err)
+    Some(x) => x
+
   function contains(e : 'a, o : option('a)) = o == Some(e)
 
   function on_elem(o : option('a), f : 'a => unit) : unit = match((), f, o)