lace.error: Split out subword collection logic

2 files changed, 11 insertions, 6 deletions

diff --git a/lib/lace/builtin.lua b/lib/lace/builtin.lua
index 19ad796..7577610 100644
--- a/lib/lace/builtin.lua
+++ b/lib/lace/builtin.lua
@@ -35,12 +35,7 @@ local function run_conditions(exec_context, cond, anyof)
       end
       local res, msg = engine.test(exec_context, name)
       if res == nil then
-	 local subwords = msg.words
-	 if subwords and #subwords > 0 then
-	    msg.words = {{nr = i, sub = subwords}}
-	 else
-	    msg.words = {i}
-	 end
+	 msg.words = {err.subwords(msg, i)}
 	 return nil, msg
       end
       if invert then
diff --git a/lib/lace/error.lua b/lib/lace/error.lua
index 6277233..0ad0df6 100644
--- a/lib/lace/error.lua
+++ b/lib/lace/error.lua
@@ -76,6 +76,15 @@ local function _augment(err, source, linenr)
    return err
 end
 
+local function _subwords(err, word)
+   local subwords = err.words
+   if subwords and #subwords > 0 then
+      return {nr = word, sub = subwords}
+   else
+      return word
+   end
+end
+
 --- Render an error down to a string.
 --
 -- Error tables carry a message, an optional set of words which caused the
@@ -159,5 +168,6 @@ return {
    error = _error,
    offset = _offset,
    augment = _augment,
+   subwords = _subwords,
    render = _render,
 }