[racket-dev] The `var` pattern in `match`

From: David Van Horn (dvanhorn at ccs.neu.edu)
Date: Thu Nov 29 13:40:05 EST 2012

On 11/29/12 7:31 AM, Carl Eastlund wrote:
> Having something like the "var" pattern can be useful for macros that
> expand into uses of match, if the macro doesn't want to expose that a
> bound variable will be a match pattern and therefore must not be "_" or
> "...".  Granted, there are ways around this, but personally I think it
> would be nice if match supported this pattern.  I would, however,
> entirely support renaming this pattern to something more obscure, like
> "match:pattern-variable" or something, so that unintentional uses stop
> being a problem.

I think the real solution is to have (whatever name you give) `var' be 
something that is matched as an identifier and not a literal so that 
programmers can rename the pattern.  But I know from talking with Sam 
this would be a big change for match.

In the meantime, something more obscure than `var' would go a long way 
toward me not cursing Sam's good name every time I write an AST.


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