chickadee » chicken » string

Module (chicken string)

This module contains procedures which can perform various useful string operations.


conc X ...procedure

Returns a string with the string-represenation of all arguments concatenated together. conc could be implemented as

(define (conc . args)
  (apply string-append (map ->string args)) )


->string Xprocedure

Returns a string-representation of X.


string-chop STRING LENGTHprocedure

Returns a list of substrings taken by chopping STRING every LENGTH characters:

(string-chop "one two three" 4)  ==>  ("one " "two " "thre" "e")


string-chomp STRING #!optional SUFFIXprocedure

If STRING ends with SUFFIX, then this procedure returns a copy of its first argument with the suffix removed, otherwise returns STRING unchanged. SUFFIX defaults to "\n".


string-compare3 STRING1 STRING2procedure
string-compare3-ci STRING1 STRING2procedure

Perform a three-way comparison between the STRING1 and STRING2, returning either -1 if STRING1 is lexicographically less than STRING2, 0 if it is equal, or 1 if it s greater. string-compare3-ci performs a case-insensitive comparison.


string-intersperse LIST #!optional STRINGprocedure

Returns a string that contains all strings in LIST concatenated together. STRING is placed between each concatenated string and defaults to " ".

(string-intersperse '("one" "two") "three")

is equivalent to

(apply string-append (intersperse '("one" "two") "three"))


string-split STRING #!optional DELIMITER-STRING KEEPEMPTYprocedure

Split string into substrings delimited by any of the characters given in the delimiter string. If no delimiters are specified, a string comprising the tab, newline and space characters is assumed. If the parameter KEEPEMPTY is given and not #f, then empty substrings are retained:

(string-split "one  two  three") ==> ("one" "two" "three")
(string-split "foo:bar::baz:" ":" #t) ==> ("foo" "bar" "" "baz" "")
(string-split "foo:bar:baz,quux,zot" ":," ) ==> ("foo" "bar" "baz" "quux" "zot")


string-translate STRING FROM #!optional TOprocedure

Returns a fresh copy of STRING with characters matching FROM translated to TO. If TO is omitted, then matching characters are removed. FROM and TO may be a character, a string or a list. If both FROM and TO are strings, then the character at the same position in TO as the matching character in FROM is substituted.


string-translate* STRING SMAPprocedure

Substitutes elements of STRING according to SMAP. SMAP should be an association-list where each element of the list is a pair of the form (MATCH . REPLACEMENT). Every occurrence of the string MATCH in STRING will be replaced by the string REPLACEMENT:

  "<h1>this is a \"string\"</h1>"
  '(("<" . "&lt;") (">" . "&gt;") ("\"" . "&quot;")) )
=>  "&lt;h1&gt;this is a &quot;string&quot;&lt;/h1&gt;"


substring=? STRING1 STRING2 #!optional START1 START2 LENGTHprocedure
substring-ci=? STRING1 STRING2 #!optional START1 START2 LENGTHprocedure

Returns #t if the strings STRING1 and STRING2 are equal, or #f otherwise. The comparison starts at the positions START1 and START2 (which default to 0), comparing LENGTH characters (which defaults to the minimum of the remaining length of both strings).


substring-index MAYBE-SUBSTRING STRING #!optional STARTprocedure
substring-index-ci MAYBE-SUBSTRING STRING #!optional STARTprocedure

Searches for first index in string STRING where string MAYBE-SUBSTRING occurs. If the optional argument START is given, then the search starts at that index. substring-index-ci is a case-insensitive version of substring-index.


reverse-list->string LISTprocedure

Returns a string with the characters in LIST in reverse order. This is equivalent to (list->string (reverse LIST)), but much more efficient.


reverse-string-append LISTprocedure

(apply string-append (reverse LIST))

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