From: Chris Hanson Date: Sun, 23 Apr 2017 01:45:49 +0000 (-0700) Subject: Redefine substring as different from string-copy. X-Git-Tag: mit-scheme-pucked-9.2.12~158^2~11 X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=9a54477f0223a6cfa3fb056d74dbc893eea70cb4;p=mit-scheme.git Redefine substring as different from string-copy. They are different in only one respect: string-copy always returns a mutable string, while substring always returns an immutable string. --- diff --git a/src/runtime/runtime.pkg b/src/runtime/runtime.pkg index 767ba31a5..362698c5c 100644 --- a/src/runtime/runtime.pkg +++ b/src/runtime/runtime.pkg @@ -962,7 +962,6 @@ USA. substringstring @@ -1052,6 +1051,7 @@ USA. string>=? string>? string? + substring substring? vector->string) (export (runtime predicate-metadata) diff --git a/src/runtime/ustring.scm b/src/runtime/ustring.scm index e9f26c0db..c72d76d50 100644 --- a/src/runtime/ustring.scm +++ b/src/runtime/ustring.scm @@ -375,11 +375,33 @@ USA. (%general-copy! to 0 string start end) to))))) +(define (substring string #!optional start end) + (let* ((len (string-length string)) + (end (fix:end-index end (string-length string) 'substring)) + (start (fix:start-index start end 'substring))) + ;; It shouldn't be necessary to copy immutable substrings, but some of these + ;; find their way to Edwin so we can't return a slice here. We will + ;; probably need to implement a procedure to map an arbitrary string to a + ;; legacy string for Edwin's use. + (if (and (fix:= start 0) + (fix:= end len) + (not (slice? string)) + (not (ustring-mutable? string))) + string + (translate-slice string start end + (lambda (string start end) + (let ((to + (immutable-ustring-allocate + (fix:- end start) + (%general-max-cp string start end)))) + (%general-copy! to 0 string start end) + to)))))) + (define (string-head string end) - (string-copy string 0 end)) + (substring string 0 end)) (define (string-tail string start) - (string-copy string start)) + (substring string start)) (define (%general-copy! to at from start end) @@ -1731,7 +1753,7 @@ USA. (receive (delimiter allow-runs? copy?) (string-splitter-options options 'string-splitter) (let ((predicate (splitter-delimiter->predicate delimiter)) - (get-part (if copy? string-copy string-slice))) + (get-part (if copy? substring string-slice))) (lambda (string #!optional start end) (let* ((end (fix:end-index end (string-length string) 'string-splitter)) @@ -1780,7 +1802,7 @@ USA. (define (string-trimmer . options) (receive (where copy? trim-char?) (string-trimmer-options options 'string-trimmer) - (let ((get-trimmed (if copy? string-copy string-slice))) + (let ((get-trimmed (if copy? substring string-slice))) (lambda (string) (let ((end (string-length string))) (get-trimmed