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Update String PEGs

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* module/ice-9/peg/string-peg.scm: use new interface for extending PEG
   syntax
* module/ice-9/peg.scm: remove peg-extended-compile
This commit is contained in:
Noah Lavine 2011-03-31 17:42:36 -04:00 • committed by Andy Wingo
parent 94e8517c16
commit 172ac609c4
2 changed files with 22 additions and 23 deletions
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20
module/ice-9/peg.scm
View file

@ -22,7 +22,6 @@
define-nonterm
; define-nonterm-f
peg-match)
; #:export-syntax (define-nonterm)
#:use-module (ice-9 peg codegen)
#:use-module (ice-9 peg string-peg)
#:use-module (ice-9 peg simplify-tree)
@ -30,7 +29,6 @@
#:re-export (peg-sexp-compile
define-grammar
define-grammar-f
; define-nonterm
keyword-flatten
context-flatten
peg:start
@ -67,13 +65,6 @@ execute the STMTs and try again."
#f
(make-prec 0 (car res) string (string-collapse (cadr res))))))
(define (peg-extended-compile pattern accum)
(syntax-case pattern (peg)
((peg str)
(string? (syntax->datum #'str))
(peg-string-compile #'str (if (eq? accum 'all) 'body accum)))
(else (peg-sexp-compile pattern accum))))
;; The results of parsing using a nonterminal are cached. Think of it like a
;; hash with no conflict resolution. Process for deciding on the cache size
;; wasn't very scientific; just ran the benchmarks and stopped a little after
@ -85,7 +76,7 @@ execute the STMTs and try again."
(lambda (x)
(syntax-case x ()
((_ sym accum pat)
(let ((matchf (peg-extended-compile #'pat (syntax->datum #'accum)))
(let ((matchf (peg-sexp-compile #'pat (syntax->datum #'accum)))
(accumsym (syntax->datum #'accum))
(c (datum->syntax x (gensym))));; the cache
;; CODE is the code to parse the string if the result isn't cached.
@ -103,6 +94,11 @@ execute the STMTs and try again."
(list str at fres))
fres)))))))))))
(define (peg-like->peg pat)
(syntax-case pat ()
(str (string? (syntax->datum #'str)) #'(peg str))
(else pat)))
;; Searches through STRING for something that parses to PEG-MATCHER. Think
;; regexp search.
(define-syntax peg-match
@ -110,9 +106,7 @@ execute the STMTs and try again."
(syntax-case x ()
((_ pattern string-uncopied)
(let ((pmsym (syntax->datum #'pattern)))
(let ((matcher (if (string? (syntax->datum #'pattern))
(peg-string-compile #'pattern 'body)
(peg-sexp-compile #'pattern 'body))))
(let ((matcher (peg-sexp-compile (peg-like->peg #'pattern) 'body)))
;; We copy the string before using it because it might have been
;; modified in-place since the last time it was parsed, which would
;; invalidate the cache. Guile uses copy-on-write for strings, so

25
module/ice-9/peg/string-peg.scm
View file

@ -18,8 +18,7 @@
;;;;
(define-module (ice-9 peg string-peg)
#:export (peg-string-compile
peg-as-peg
#:export (peg-as-peg
define-grammar
define-grammar-f
peg-grammar)
@ -248,11 +247,17 @@ RB < ']'
(compressor-core (syntax->datum syn))))
;; Builds a lambda-expressions for the pattern STR using accum.
(define (peg-string-compile str-stx accum)
(let ((string (syntax->datum str-stx)))
(peg-sexp-compile
(compressor
(peg-pattern->defn
(peg:tree (peg-parse peg-pattern string)) str-stx)
str-stx)
accum)))
(define (peg-string-compile args accum)
(syntax-case args ()
((str-stx) (string? (syntax->datum #'str-stx))
(let ((string (syntax->datum #'str-stx)))
(peg-sexp-compile
(compressor
(peg-pattern->defn
(peg:tree (peg-parse peg-pattern string)) #'str-stx)
#'str-stx)
(if (eq? accum 'all) 'body accum))))
(else (error "Bad embedded PEG string" args))))
(add-peg-compiler! 'peg peg-string-compile)