diff --git a/src/Parser.lama b/src/Parser.lama
index 5482215c6..53c6a4259 100644
--- a/src/Parser.lama
+++ b/src/Parser.lama
@@ -35,7 +35,7 @@ var stmt = memo $ eta syntax (
       kRead x=inbr[s("("), lident, s(")")]        {Read(x)}         |
       kWrite e=inbr[s("("), exp, s(")")]          {Write(e)}        |
       kSkip                                       {Skip}            |
-      x=lident s(":=") e=exp                      {Assn(x, e)}      |
+      x=lident s[":="] e=exp                      {Assn(x, e)}      |
       head = (kRead x=inbr[s("("), lident, s(")")]        {Read(x)} |
              kWrite e=inbr[s("("), exp, s(")")]          {Write(e)} |
              kSkip                                       {Skip}      |