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utils: Support defaults in substitute-keyword-arguments.
* guix/utils.scm (collect-default-args, expand-default-args): New syntax. (substitute-keyword-arguments): Allow default value declarations. * tests/utils.scm (substitute-keyword-arguments): New test.
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2 changed files with 35 additions and 4 deletions
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@ -375,13 +375,24 @@ (define (default-keyword-arguments args defaults)
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(()
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args))))
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(define-syntax collect-default-args
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(syntax-rules ()
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((_)
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'())
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((_ (_ _) rest ...)
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(collect-default-args rest ...))
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((_ (kw _ dflt) rest ...)
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(cons* kw dflt (collect-default-args rest ...)))))
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(define-syntax substitute-keyword-arguments
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(syntax-rules ()
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"Return a new list of arguments where the value for keyword arg KW is
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replaced by EXP. EXP is evaluated in a context where VAR is boud to the
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previous value of the keyword argument."
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((_ original-args ((kw var) exp) ...)
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(let loop ((args original-args)
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replaced by EXP. EXP is evaluated in a context where VAR is bound to the
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previous value of the keyword argument, or DFLT if given."
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((_ original-args ((kw var dflt ...) exp) ...)
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(let loop ((args (default-keyword-arguments
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original-args
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(collect-default-args (kw var dflt ...) ...)))
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(before '()))
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(match args
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((kw var rest (... ...))
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@ -123,6 +123,26 @@ (define temp-file
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(default-keyword-arguments '(#:bar 3) '(#:foo 2))
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(default-keyword-arguments '(#:foo 2 #:bar 3) '(#:bar 6))))
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(test-equal "substitute-keyword-arguments"
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'((#:foo 3)
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(#:foo 3)
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(#:foo 3 #:bar (1 2))
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(#:bar (1 2) #:foo 3)
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(#:foo 3))
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(list (substitute-keyword-arguments '(#:foo 2)
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((#:foo f) (1+ f)))
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(substitute-keyword-arguments '()
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((#:foo f 2) (1+ f)))
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(substitute-keyword-arguments '(#:foo 2 #:bar (2))
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((#:foo f) (1+ f))
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((#:bar b) (cons 1 b)))
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(substitute-keyword-arguments '(#:foo 2)
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((#:foo _) 3)
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((#:bar b '(2)) (cons 1 b)))
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(substitute-keyword-arguments '(#:foo 2)
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((#:foo f 1) (1+ f))
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((#:bar b) (cons 42 b)))))
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(test-assert "filtered-port, file"
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(let* ((file (search-path %load-path "guix.scm"))
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(input (open-file file "r0b")))
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