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| author | Ludovic Courtès <ludo@gnu.org> | 2018-03-11 22:04:12 +0100 |
|---|---|---|
| committer | Ludovic Courtès <ludo@gnu.org> | 2018-03-11 22:04:39 +0100 |
| commit | 5c6391b33acaaae75746f6ae30089d4aec14c349 (patch) | |
| tree | 34d09d3b0fe68b08c1539212e817bb0756f48785 /guix/build/utils.scm | |
| parent | 5e268faf85c60b5e12cbc742c5e3bf3d20771cb9 (diff) | |
utils: Add 'false-if-file-not-found'.
* guix/build/utils.scm (false-if-file-not-found): New macro.
Diffstat (limited to 'guix/build/utils.scm')
| -rw-r--r-- | guix/build/utils.scm | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/guix/build/utils.scm b/guix/build/utils.scm index d7ed3d5177..ab309aa0df 100644 --- a/guix/build/utils.scm +++ b/guix/build/utils.scm @@ -1,5 +1,5 @@ ;;; GNU Guix --- Functional package management for GNU -;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org> +;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org> ;;; Copyright © 2013 Andreas Enge <andreas@enge.fr> ;;; Copyright © 2013 Nikita Karetnikov <nikita@karetnikov.org> ;;; Copyright © 2015 Mark H Weaver <mhw@netris.org> @@ -61,6 +61,7 @@ delete-file-recursively file-name-predicate find-files + false-if-file-not-found search-path-as-list set-path-environment-variable @@ -396,6 +397,15 @@ also be included. If FAIL-ON-ERROR? is true, raise an exception upon error." stat) string<?))) +(define-syntax-rule (false-if-file-not-found exp) + "Evaluate EXP but return #f if it raises to 'system-error with ENOENT." + (catch 'system-error + (lambda () exp) + (lambda args + (if (= ENOENT (system-error-errno args)) + #f + (apply throw args))))) + ;;; ;;; Search paths. |