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Diffstat (limited to 'dump/strings.scm')
-rw-r--r-- | dump/strings.scm | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/dump/strings.scm b/dump/strings.scm new file mode 100644 index 0000000..c67d7fc --- /dev/null +++ b/dump/strings.scm @@ -0,0 +1,88 @@ +(define-module (dump strings) + #:use-module (srfi srfi-1) + #:use-module (srfi srfi-19) + #:use-module (ice-9 match) + #:use-module (ice-9 string-fun) + #:export (string-blank? + time-unix->string + string-blank? + string-split-substring + delete-substrings + replace-substrings + sanitize-rdf-string + snake->lower-camel)) + +(define (time-unix->string seconds . maybe-format) + "Given an integer saying the number of seconds since the Unix +epoch (1970-01-01 00:00:00), SECONDS, format it as a human readable +date and time-string, possible using the MAYBE-FORMAT." + (letrec ([time-unix->time-utc + (lambda (seconds) + (add-duration + (date->time-utc (make-date 0 0 0 0 1 1 1970 0)) + (make-time time-duration 0 seconds)))]) + (apply date->string + (time-utc->date (time-unix->time-utc seconds)) + maybe-format))) + +(define (string-blank? str) + "Return non-#f if STR consists only of whitespace characters." + (string-every char-set:whitespace str)) + +(define (string-split-substring str substr) + "Split the string @var{str} into a list of substrings delimited by the +substring @var{substr}." + + (define substrlen (string-length substr)) + (define strlen (string-length str)) + + (define (loop index start) + (cond + ((>= start strlen) (list "")) + ((not index) (list (substring str start))) + (else + (cons (substring str start index) + (let ((new-start (+ index substrlen))) + (loop (string-contains str substr new-start) + new-start)))))) + + (cond + ((string-contains str substr) => (lambda (idx) (loop idx 0))) + (else (list str)))) + +(define (delete-substrings str . substrings) + "Delete SUBSTRINGS, a list of strings, from STR." + (fold (lambda (substring result) + (string-replace-substring result substring "")) + str + substrings)) + +(define (replace-substrings str replacement-alist) + "Replace substrings in STR according to REPLACEMENT-ALIST, an +association list mapping substrings to their replacements." + (fold (match-lambda* + (((substring . replacement) str) + (string-replace-substring str substring replacement))) + str + replacement-alist)) + +(define (sanitize-rdf-string str) + (replace-substrings + (string-trim-both str) + '(("\r" . "\\r") + ("\n" . "\\n") + ("\"" . "'") + ("\v" . "")))) + +(define (snake->lower-camel str) + (let ((char-list (string->list str))) + (call-with-output-string + (lambda (port) + (put-char port (char-downcase (string-ref str 0))) + (map (lambda (char previous-char) + (unless (char=? char #\_) + (put-char port (if (char=? previous-char #\_) + (char-upcase char) + char)))) + (drop char-list 1) + char-list))))) |