Arto,
How about this patch, which extends your syntax to allow arbitrary delimiters?
#;6> ,x #r/\/path\/to\/file:i
(regexp "/path/to/file" #t #f #f)
#;6> ,x #r:/path/to/file:i
(regexp "/path/to/file" #t #f #f)
#;6> ,x #r{/path/to/file}i
(regexp "/path/to/file" #t #f #f)
#;7> (string-split-fields #r:[^/]+: "/path/to/file")
("path" "to" "file")
#;10> (string-match #r/\/path\/to\/file/ "/path/to/file")
("/path/to/file")
#;8> (string-match #r:/path/(to)/file: "/path/to/file")
("/path/to/file" "to")
The drawback over Perl is that nestable delimiters don't nest, so
#r(hi(bye)) is not valid; you have to escape the parentheses with
backslash, or use a different delimiter if you want grouping.
On 6/27/07, Arto Bendiken <[EMAIL PROTECTED]> wrote:
First, the `regex-literals' egg [2] provides precompiled regular
expression literals of the
form `#/[a-z0-9]+/i', the Perl-like #/.../[ixu] syntax sure to be
instantly familiar to most everyone:
Index: regex-literals.scm
===================================================================
--- regex-literals.scm (revision 4721)
+++ regex-literals.scm (working copy)
@@ -26,9 +26,17 @@
(declare
(export read-regex-literal) ) )
-;;;; Exported procedures
+;;;; Internal procedures
-(define (read-regex-literal #!optional (port (current-output-port)))
+(define (delimiter c)
+ (let ((delimiters '((#\{ . #\})
+ (#\( . #\))
+ (#\[ . #\])
+ (#\< . #\>)) ))
+ (cond ((assq c delimiters) => cdr)
+ (else c))))
+
+(define (read-regex-literal/delim delim #!optional (port
(current-output-port)))
(define (read-option)
(let ((char (peek-char port)))
(cond ((eq? char #\i) (read-char port) 'caseless)
@@ -37,7 +45,7 @@
(else #f) ) ) )
(let loop ((buffer '()))
(let ((char (read-char port)))
- (cond ((char=? char #\/)
+ (cond ((char=? char delim)
(let ((options (list (read-option) (read-option) (read-option))))
`(regexp ,(list->string (reverse buffer))
,(not (not (memq 'caseless options)))
@@ -48,9 +56,18 @@
(else
(loop (cons char buffer)) ) ) ) ) )
+;;;; Exported procedures
+
+(define (read-regex-literal #!optional (port (current-output-port)))
+ (read-regex-literal/delim #\/ port))
+
;;;; Initialization
(define-inline (init-regex-literals!)
- (set-sharp-read-syntax! #\/ read-regex-literal) )
+ (set-sharp-read-syntax! #\/ read-regex-literal)
+ (set-sharp-read-syntax! #\r
+ (lambda (port)
+ (let ((c (read-char port)))
+ (read-regex-literal/delim (delimiter c) port)))))
(init-regex-literals!)
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