syntax error - versions 2.0.4 and 2.0.5

The trailing colon in the when expression is seems to be allowed in Ruby 1.8.7 but not required. However, Ruby 1.9.1p0 will not allow the trailing colon.

I don't have the source for earlier versions of ruby but parse.y for 1.9.1p0 doesn't have a provision for a trailing colon so it's being glommed on to the preceeding symbol.

So here's another possible fix:

when String, Symbol:

when String, Symbol :

This change passes muster with 1.9.1p0. The rule seems to be "then | :" is optional when associated code begins on a new line. What I'm still unclear about is why the older ruby parsed the colon as a separate token rather than part of the preceding symbol. I'm guessing there was a precedence change in there somewhere.

That previous possible fix does not work. I must be losing the connection between my eyes and my brain.

A colon is no longer allowed in association with the when expression. The relevant rules from parse.y are:

@@@case_body : keyword_when args then

      compstmt
      cases
        {
        /*%%%*/
        $$ = NEW_WHEN($2, $4, $5);
        /*%
        $$ = dispatch3(when, $2, $4, escape_Qundef($5));
        %*/
        }
    ;

then : term

        /*%c%*/
        /*%c
        { $$ = Qnil; }
        %*/
    | keyword_then
    | term keyword_then
        /*%c%*/
        /*%c
        { $$ = $2; }
        %*/
    ;

The definition of then is what changed.  Here's the relevant snip from 1.8.7 parse.y:

@@@then		: term
		| ':'
		| kTHEN
		| term kTHEN
		;