Rest and patterns
David Van Horn
(18 May 2005 20:47 UTC)
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Re: Rest and patterns
Neil W. Van Dyke
(18 May 2005 22:00 UTC)
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How about dropping semi-variable-arity?
Petrofsky, The Reverend Al
(19 May 2005 02:01 UTC)
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Re: Rest and patterns
David Van Horn
(19 May 2005 16:40 UTC)
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Re: Rest and patterns Neil W. Van Dyke (19 May 2005 18:22 UTC)
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Re: Rest and patterns Neil W. Van Dyke 19 May 2005 18:22 UTC
Thanks for clarifying for me. David Van Horn <xxxxxx@cs.uvm.edu> wrote at 2005-05-19T12:24:35-0400: > I agree with your concerns about making this a general pattern > matching SRFI; I actually just meant that I wouldn't want to add a pattern language to "let" until I'm confident the language is consistent with whatever (generalized or specialized) pattern language I've heard rumors the shadowy R6RS is considering. OK, so this is a summarization of three extensions to "let" and "let*" that I understand are currently proposed in this working SRFI: 1. Multiple-value binding in a binding expression by giving multiple variables rather than just one. 2. LHS of the binding expression as a pattern language (simple now, with the "values" keyword, but possibly to be extended in the future) that is applied to the multiple values of the RHS. ( { <variable>+ | <let-pattern-language> } <expr>) 3. Zero-values binding expressions in "let*" for interspersing sequenced side-effect expressions with bindings. I might find occasion to use all 3 of these in my own portable code. But I estimate that 99% of the benefit to my code would come from #1 alone. So my perspective on #2 and #3 is colored by a desire that they not risk compromising my goal of getting #1. I can't assess the level of risk, but please keep this consideration in mind as you decide what to package into a single SRFI. -- http://www.neilvandyke.org/