Is there a Macro to use "λ" character as "lambda" in R5RS Scheme? From here In Gambit "scheme-r5rs" I tried:
(define-syntax λ
(syntax-rules ()
((_ . more) (lambda . more))))
But I keep getting Ill-formed expression error.
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1 Answers
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You seem to be looking for a reader macro, but I don't think they are standardised in Scheme.
This works:
# pu@pumbair: ~ cat test2.scm
(define-syntax λ
(syntax-rules ()
((_ param body ...) (lambda param body ...))))
(display ((λ (x y) (+ x y)) 1 2)) (newline)
(display ((λ () 1))) (newline)
(display ((λ (a . b) b) 'a 'b 'c)) (newline)
# pu@pumbair: ~ gsi -:s test2.scm
3
1
(b c)
uselpa
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1Neither version worked with Gambit R5RS. I will try the mailing list. – GlassGhost Oct 26 '14 at 11:24
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1@GlassGhost It does, in "standard" Scheme mode. See my update please. – uselpa Oct 26 '14 at 17:49
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Wow it works but only from the command line, not if the file is invoked as #!/usr/bin/env scheme-r5rs how do set the -:s option from within the file? – GlassGhost Oct 26 '14 at 17:56
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1@GlassGhost Use `#!/usr/bin/env scheme-r5rs -:s`. – uselpa Oct 26 '14 at 18:02
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I tried that, the linux #!/usr/bin/env doesn't pass command line options – GlassGhost Oct 26 '14 at 18:05
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@GlassGhost Works fine on OS X. Try without `env` then? – uselpa Oct 26 '14 at 18:10
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1You've already done so much, I'm gonna mark it as accepted and sort this out in the mailing list. – GlassGhost Oct 26 '14 at 18:16