string-fill! - fill a string with a character

(import (rnrs mutable-strings))     ;R6RS
(import (scheme r5rs))              ;R7RS
(import (scheme base))              ;R7RS

(string-fill! string char)
(string-fill! string char start)      ;R7RS
(string-fill! string char start end)  ;R7RS

Stores char in every element of string.

R7RS

Only modifies string between start (inclusive) and end (exclusive). If omitted, start defaults to 0 and end defaults to the length of string.

;; R7RS example
(let ((s (make-string 4 #\x)))
  (string-fill! s #\y 2)
  s)  =>  "xxyy"

This procedure is used to fill strings that have already been created. It has marginal utility. The second argument to make-string(3scm) fills the entire string at creation time.

The start and end arguments are unique to R7RS.

This procedure can raise exceptions with the following condition types:

&assertion (R6RS)

The wrong number of arguments was passed or an argument was outside its domain.

R7RS

The assertions described above are errors. Implementations may signal an error, extend the procedure's domain of definition to include such arguments, or fail catastrophically.

Unsupported characters (R7RS)

It is an error to fill with a character which the implementation does not support. 7-bit ASCII (except #\null) must be supported. Any other character is optional and potentially an error (as described above). You can use the full-unicode feature identifier in cond-expand(3scm) to check if all of Unicode 6.0 is supported.

make-string(3scm), string-set!(3scm)

R4RS, R5RS, R6RS, R7RS

The first Scheme report to carry this procedure was R2RS, which also had substring-fill! that filled a substring, but used a different argument order: (substring-fill! string start end char). It is missing from IEEE Scheme.

This page is part of the scheme-manpages project. It includes materials from the RnRS documents. More information can be found at https://weinholt.se/scheme/manpages/.