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| author | Ludovic Courtès <ludo@gnu.org> | 2017-07-20 15:48:09 +0200 |
|---|---|---|
| committer | Ludovic Courtès <ludo@gnu.org> | 2017-07-20 18:08:00 +0200 |
| commit | 302d46e63f406f0f8acb024557498deaef2d4255 (patch) | |
| tree | df2a11a0f30678327c2463c5d9195a54d92bff3f /guix/gexp.scm | |
| parent | fb5dfa86b1b2a6601a773869f021a959757076fd (diff) | |
| download | gnu-guix-302d46e63f406f0f8acb024557498deaef2d4255.tar gnu-guix-302d46e63f406f0f8acb024557498deaef2d4255.tar.gz | |
gexp: Slightly improve error reporting for 'local-file'.
Reported by Ricardo Wurmus.
* guix/gexp.scm (local-file): Define using 'syntax-case' instead of
'syntax-rules'. Explicitly handle the zero-argument case and the
use-as-an-identifier case.
Diffstat (limited to 'guix/gexp.scm')
| -rw-r--r-- | guix/gexp.scm | 26 |
1 files changed, 20 insertions, 6 deletions
diff --git a/guix/gexp.scm b/guix/gexp.scm index 2094c495d6..2622c5cb62 100644 --- a/guix/gexp.scm +++ b/guix/gexp.scm @@ -269,8 +269,9 @@ vicinity of DIRECTORY." (string-append directory "/" file)) (else file)))) -(define-syntax-rule (local-file file rest ...) - "Return an object representing local file FILE to add to the store; this +(define-syntax local-file + (lambda (s) + "Return an object representing local file FILE to add to the store; this object can be used in a gexp. If FILE is a relative file name, it is looked up relative to the source file where this form appears. FILE will be added to the store under NAME--by default the base name of FILE. @@ -283,10 +284,23 @@ When RECURSIVE? is true, call (SELECT? FILE STAT) for each directory entry, where FILE is the entry's absolute file name and STAT is the result of 'lstat'; exclude entries for which SELECT? does not return true. -This is the declarative counterpart of the 'interned-file' monadic procedure." - (%local-file file - (delay (absolute-file-name file (current-source-directory))) - rest ...)) +This is the declarative counterpart of the 'interned-file' monadic procedure. +It is implemented as a macro to capture the current source directory where it +appears." + (syntax-case s () + ((_ file rest ...) + #'(%local-file file + (delay (absolute-file-name file (current-source-directory))) + rest ...)) + ((_) + #'(syntax-error "missing file name")) + (id + (identifier? #'id) + ;; XXX: We could return #'(lambda (file . rest) ...). However, + ;; (syntax-source #'id) is #f so (current-source-directory) would not + ;; work. Thus, simply forbid this form. + #'(syntax-error + "'local-file' is a macro and cannot be used like this"))))) (define (local-file-absolute-file-name file) "Return the absolute file name for FILE, a <local-file> instance. A |