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Diffstat (limited to 'gnu/home/services/utils.scm')
| -rw-r--r-- | gnu/home/services/utils.scm | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/gnu/home/services/utils.scm b/gnu/home/services/utils.scm new file mode 100644 index 0000000000..cea75ee896 --- /dev/null +++ b/gnu/home/services/utils.scm @@ -0,0 +1,105 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2021 Xinglu Chen <public@yoctocell.xyz> +;;; Copyright © 2021 Andrew Tropin <andrew@trop.in> +;;; +;;; This file is part of GNU Guix. +;;; +;;; GNU Guix is free software; you can redistribute it and/or modify it +;;; under the terms of the GNU General Public License as published by +;;; the Free Software Foundation; either version 3 of the License, or (at +;;; your option) any later version. +;;; +;;; GNU Guix is distributed in the hope that it will be useful, but +;;; WITHOUT ANY WARRANTY; without even the implied warranty of +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;;; GNU General Public License for more details. +;;; +;;; You should have received a copy of the GNU General Public License +;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>. + +(define-module (gnu home services utils) + #:use-module (ice-9 string-fun) + #:use-module (srfi srfi-1) + #:use-module (srfi srfi-26) + + #:export (maybe-object->string + object->snake-case-string + object->camel-case-string + list->human-readable-list)) + +(define (maybe-object->string object) + "Like @code{object->string} but don't do anyting if OBJECT already is +a string." + (if (string? object) + object + (object->string object))) + +;; Snake case: <https://en.wikipedia.org/wiki/Snake_case> +(define* (object->snake-case-string object #:optional (style 'lower)) + "Convert the object OBJECT to the equivalent string in ``snake +case''. STYLE can be three `@code{lower}', `@code{upper}', or +`@code{capitalize}', defaults to `@code{lower}'. + +@example +(object->snake-case-string 'variable-name 'upper) +@result{} \"VARIABLE_NAME\" @end example" + (if (not (member style '(lower upper capitalize))) + (error 'invalid-style (format #f "~a is not a valid style" style)) + (let ((stringified (maybe-object->string object))) + (string-replace-substring + (cond + ((equal? style 'lower) stringified) + ((equal? style 'upper) (string-upcase stringified)) + (else (string-capitalize stringified))) + "-" "_")))) + +(define* (object->camel-case-string object #:optional (style 'lower)) + "Convert the object OBJECT to the equivalent string in ``camel case''. +STYLE can be three `@code{lower}', `@code{upper}', defaults to +`@code{lower}'. + +@example +(object->camel-case-string 'variable-name 'upper) +@result{} \"VariableName\" +@end example" + (if (not (member style '(lower upper))) + (error 'invalid-style (format #f "~a is not a valid style" style)) + (let ((stringified (maybe-object->string object))) + (cond + ((eq? style 'upper) + (string-concatenate + (map string-capitalize + (string-split stringified (cut eqv? <> #\-))))) + ((eq? style 'lower) + (let ((splitted-string (string-split stringified (cut eqv? <> #\-)))) + (string-concatenate + (cons (first splitted-string) + (map string-capitalize + (cdr splitted-string)))))))))) + +(define* (list->human-readable-list lst + #:key + (cumulative? #f) + (proc identity)) + "Turn a list LST into a sequence of terms readable by humans. +If CUMULATIVE? is @code{#t}, use ``and'', otherwise use ``or'' before +the last term. + +PROC is a procedure to apply to each of the elements of a list before +turning them into a single human readable string. + +@example +(list->human-readable-list '(1 4 9) #:cumulative? #t #:proc sqrt) +@result{} \"1, 2, and 3\" +@end example + +yields:" + (let* ((word (if cumulative? "and " "or ")) + (init (append (drop-right lst 1)))) + (format #f "~a" (string-append + (string-join + (map (compose maybe-object->string proc) init) + ", " 'suffix) + word + (maybe-object->string (proc (last lst))))))) + |