John Cowan:
> http://trac.sacrideo.us/wg/wiki/BracketsBraces 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.

On guile's development list, svanleent asked if we could (also?) define a recommended filename extension for curly-infix.  Obviously we could.  But this *rarity* of conflict in existing implementations (thanks for the analysis!) suggests something else.

Maybe we should just drop the marker completely (e.g., #!srfi-105).  Not needing a marker or any other indicator would simplify things.  In particular, it would mean that we don't need an ugly marker in every file, and implementations would no longer need to look for it (and maybe handle it specially).  Chibi's {} can already be enabled or disabled by a compile-time flag; perhaps the implementer would be willing to add another flag for an alternative semantic using {}.  Besides, if an implementation doesn't support curly-infix, having a marker won't help :-).

Thoughts?

--- David A. Wheeler