Re: Do we NEED a marker at all? Jens Axel S√łgaard 05 Sep 2012 20:34 UTC

2012/9/5 David A. Wheeler <>:
> John Cowan:
>> shows the meaning
>> of square brackets and curly braces in my Scheme test suite, which
>> currently includes 45 implementations.  Only Chibi and RScheme currently
>> do something special with braces; the other implementations treat them
>> as either synonyms for parentheses, lexical syntax errors, or identifier
>> characters.

In Racket read-syntax will store the type of parenthesis used in the
syntax object.
This implies that macros can use this information during expansion.


Combining this with #%app one can make (foo bar) mean one thing and {foo bar}
mean another thing without messing with the reader.

A random example of this:

But search the Racket mailing list archive for other examples.

/Jens Axel