[[ StdMlc ]] Added 'repeat for each char' custom iterator syntax to char module.

runrevmark · runrevmark · commit 46d92ea5f3a3 · 2014-12-08T13:38:43.000Z
diff --git a/libscript/src/char.mlc b/libscript/src/char.mlc
@@ -18,6 +18,8 @@ public foreign handler MCCharEvalOffsetOfCharsAfter(in IsFirst as bool, in Needl
 
 public foreign handler MCCharEvalNewlineCharacter(out Value as string) as undefined binds to "<builtin>"
 
+public foreign handler MCCharRepeatForEachChar(inout Iterator as optional pointer, out Iterand as string, in Container as string) as bool binds to "<builtin>"
+
 --
 
 /*
@@ -220,4 +222,10 @@ begin
     MCCharEvalNewlineCharacter(output)
 end syntax
 
+syntax RepeatForEachChar is iterator
+    "char" <Iterand: Expression>
+begin
+    MCCharRepeatForEachChar(iterator, Iterand, container)
+end syntax
+
 end module
diff --git a/libscript/src/module-char.cpp b/libscript/src/module-char.cpp
@@ -156,6 +156,33 @@ extern "C" void MCCharEvalNewlineCharacter(MCStringRef& r_output)
     MCStringFormat(r_output, "\n");
 }
 
+// Iterate syntax methods have special calling convention at the moment:
+//
+// Post assignment of out / inout variables only occurs if the method returns true.
+// If the method returns false, then it means iteration has finished *not* that an
+// error has been thrown.
+//
+// This means that the iterand out binding will not be updated on the final test
+// of the loop which means that:
+//   repeat for each char tChar in tVar
+//   end repeat
+// Will result in tChar containing the value it had at the point of end repeat.
+extern "C" bool MCCharRepeatForEachChar(void*& x_iterator, MCStringRef& r_iterand, MCStringRef p_string)
+{
+    uindex_t t_offset;
+    t_offset = (uindex_t)x_iterator;
+    
+    if (t_offset == MCStringGetLength(p_string))
+        return false;
+    
+    if (!MCStringCopySubstring(p_string, MCRangeMake(t_offset, 1), r_iterand))
+        return false;
+    
+    x_iterator = (void *)(t_offset + 1);
+    
+    return true;
+}
+
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 #ifdef _TEST
