From b8b129ebd8d017c957094f3d977a1c452d7d450f Mon Sep 17 00:00:00 2001
From: Eric Bavier <bavier@member.fsf.org>
Date: Tue, 20 Sep 2016 15:41:31 -0500
Subject: [PATCH] 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.
---
guix/utils.scm | 19 +++++++++++++++----
tests/utils.scm | 20 ++++++++++++++++++++
2 files changed, 35 insertions(+), 4 deletions(-)
diff --git a/guix/utils.scm b/guix/utils.scm
index ded31142aab..decadf64a60 100644
--- a/guix/utils.scm
+++ b/guix/utils.scm
@@ -375,13 +375,24 @@ (define (default-keyword-arguments args defaults)
(()
args))))
+(define-syntax collect-default-args
+ (syntax-rules ()
+ ((_)
+ '())
+ ((_ (_ _) rest ...)
+ (collect-default-args rest ...))
+ ((_ (kw _ dflt) rest ...)
+ (cons* kw dflt (collect-default-args rest ...)))))
+
(define-syntax substitute-keyword-arguments
(syntax-rules ()
"Return a new list of arguments where the value for keyword arg KW is
-replaced by EXP. EXP is evaluated in a context where VAR is boud to the
-previous value of the keyword argument."
- ((_ original-args ((kw var) exp) ...)
- (let loop ((args original-args)
+replaced by EXP. EXP is evaluated in a context where VAR is bound to the
+previous value of the keyword argument, or DFLT if given."
+ ((_ original-args ((kw var dflt ...) exp) ...)
+ (let loop ((args (default-keyword-arguments
+ original-args
+ (collect-default-args (kw var dflt ...) ...)))
(before '()))
(match args
((kw var rest (... ...))
diff --git a/tests/utils.scm b/tests/utils.scm
index 960928c842f..bcfaa14faac 100644
--- a/tests/utils.scm
+++ b/tests/utils.scm
@@ -123,6 +123,26 @@ (define temp-file
(default-keyword-arguments '(#:bar 3) '(#:foo 2))
(default-keyword-arguments '(#:foo 2 #:bar 3) '(#:bar 6))))
+(test-equal "substitute-keyword-arguments"
+ '((#:foo 3)
+ (#:foo 3)
+ (#:foo 3 #:bar (1 2))
+ (#:bar (1 2) #:foo 3)
+ (#:foo 3))
+ (list (substitute-keyword-arguments '(#:foo 2)
+ ((#:foo f) (1+ f)))
+ (substitute-keyword-arguments '()
+ ((#:foo f 2) (1+ f)))
+ (substitute-keyword-arguments '(#:foo 2 #:bar (2))
+ ((#:foo f) (1+ f))
+ ((#:bar b) (cons 1 b)))
+ (substitute-keyword-arguments '(#:foo 2)
+ ((#:foo _) 3)
+ ((#:bar b '(2)) (cons 1 b)))
+ (substitute-keyword-arguments '(#:foo 2)
+ ((#:foo f 1) (1+ f))
+ ((#:bar b) (cons 42 b)))))
+
(test-assert "filtered-port, file"
(let* ((file (search-path %load-path "guix.scm"))
(input (open-file file "r0b")))
--
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