[elpa] externals/peg cb46f6f 3/7: Introduce an operator to match string literals.

[Stefan Monnier]

branch: externals/peg
commit cb46f6f76b080c314826a4ea510336efff5b2810
Author: Helmut Eller <address@hidden>
Commit: Helmut Eller <address@hidden>

    Introduce an operator to match string literals.
    
    * peg.el (translate =): Add = operator.
    (peg-ex-split): Example use.
---
 ChangeLog | 140 +++++++++++++++++++++++++++-----------------------------------
 peg.el    |  47 ++++++++++++++++++++-
 2 files changed, 106 insertions(+), 81 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 577288c..7abe671 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,122 +1,104 @@
-Author: Helmut Eller <address@hidden>
-Date:   Mon Dec 22 09:13:05 2008 +0100
+2009-03-06  Helmut Eller  <address@hidden>
 
-    Fix typo.
+       Introduce an operator to match string literals.
 
-Author: Helmut Eller <address@hidden>
-Date:   Sun Dec 21 09:38:06 2008 +0100
+       * peg.el (translate =): Add = operator.
+       (peg-ex-split): Example use.
 
-    Version 0.5 for savannah.
+2008-12-22  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Thu Dec 18 10:19:18 2008 +0100
+       Fix typo.
 
-    Remove *list op.
+2008-12-21  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Wed Dec 17 18:59:23 2008 +0100
+       Version 0.5 for savannah.
 
-    Bump version number to 0.4.
+2008-12-18  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Wed Dec 17 18:52:55 2008 +0100
+       Remove *list op.
 
-    Add some more operators for actions.
-    list: Factored out of *list.  Collects all items on the stack.
-    region: New. Pushes start and end.
-    replaces: Replaces match.
+2008-12-17  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Wed Dec 17 18:08:28 2008 +0100
+       Bump version number to 0.4.
 
-    Fix normalizer for \`: Push values in left-to-right order.
-    peg-postprocess: turn positions in to markers to
-    support replacement ops in the actions.
+2008-12-17  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Mon Dec 1 19:10:21 2008 +0100
+       Add some more operators for actions.
+       list: Factored out of *list.  Collects all items on the stack.
+       region: New. Pushes start and end.
+       replaces: Replaces match.
 
-    (peg-ex-lisp): Minor change to allow comments in more places.
+2008-12-17  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Mon Dec 1 15:19:31 2008 +0100
+       Fix normalizer for \`: Push values in left-to-right order.
+       peg-postprocess: turn positions in to markers to
+       support replacement ops in the actions.
 
-    (peg-ex-uri): Fix some stack actions so that the file: example works.
+2008-12-01  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Fri Nov 28 15:21:35 2008 +0100
+       (peg-ex-lisp): Minor change to allow comments in more places.
 
-    Remove dups from char sets to avoid clashes with [:CLASS:] syntax.
-    There's still no way to include syntax classes in charsets. There
-    really should be.
+2008-12-01  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Fri Nov 28 12:09:31 2008 +0100
+       (peg-ex-uri): Fix some stack actions so that the file: example works.
 
-    Handle ^ in charsets.
+2008-11-28  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Fri Nov 28 10:12:24 2008 +0100
+       Remove dups from char sets to avoid clashes with [:CLASS:] syntax.
+       There's still no way to include syntax classes in charsets. There
+       really should be.
 
-    Use (declare (indent )) again.  Emacs 21 compatibility is to hard
-    due to broken ,@ or something.
+2008-11-28  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Fri Nov 28 08:50:10 2008 +0100
+       Handle ^ in charsets.
 
-    Don't use (declare (indent 3)) because that doesn' work in Emacs 21.
+2008-11-28  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Fri Nov 28 08:44:03 2008 +0100
+       Use (declare (indent )) again.  Emacs 21 compatibility is to hard
+       due to broken ,@ or something.
 
-    Fix minor spelling error.
+2008-11-28  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Fri Nov 28 08:35:16 2008 +0100
+       Don't use (declare (indent 3)) because that doesn' work in Emacs 21.
 
-    Fix range translator: we need to check for eob.
-    Thanks to Hugo Schmitt.
+2008-11-28  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Thu Nov 27 23:54:18 2008 +0100
+       Fix minor spelling error.
 
-    *** empty log message ***
+2008-11-28  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Thu Nov 27 23:52:25 2008 +0100
+       Fix range translator: we need to check for eob.
+       Thanks to Hugo Schmitt.
 
-    Make file byte-compileable in Emacs 22.
+2008-11-28  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Thu Nov 27 10:07:40 2008 +0100
+       Make file byte-compileable in Emacs 22.
 
-    Add mini test suite
-    Restore subtring operator.
-    Add translate method for <fail>.
+2008-11-27  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Thu Nov 27 09:26:33 2008 +0100
+       Add mini test suite
+       Restore subtring operator.
+       Add translate method for <fail>.
 
-    Add *list operator.
+2008-11-27  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Sat Nov 8 14:37:40 2008 +0100
+       Add *list operator.
 
-    More friendly syntax for character sets.
-    For example (set A-Z 0-9 "_!-" ?%).
-    [A-Z] is now the same as (set A-Z) which should look familiar.
+2008-11-08  Helmut Eller  <address@hidden>
 
-    Fix bug in *-loops.  We must backtrack.
+       More friendly syntax for character sets.
+       For example (set A-Z 0-9 "_!-" ?%).
+       [A-Z] is now the same as (set A-Z) which should look familiar.
 
-    Add somewhat bigger examples to parse URIs and Lisp-style Sexps.
+       Fix bug in *-loops.  We must backtrack.
 
-Author: Helmut Eller <address@hidden>
-Date:   Thu Nov 6 12:18:26 2008 +0100
+       Add somewhat bigger examples to parse URIs and Lisp-style Sexps.
 
-    Detect infinite loops.
-    Use a single peg-add-method macro for all gfs.
+2008-11-06  Helmut Eller  <address@hidden>
 
-Author: Helmut Eller <address@hidden>
-Date:   Wed Nov 5 23:12:05 2008 +0100
+       Detect infinite loops.
+       Use a single peg-add-method macro for all gfs.
 
-    Add peg.el.
+2008-11-06  Helmut Eller  <address@hidden>
+
+       Add peg.el.
diff --git a/peg.el b/peg.el
index 8494d2f..d51fa2d 100644
--- a/peg.el
+++ b/peg.el
@@ -81,7 +81,7 @@
 ;; (substring E)  ; match E and push the substring for the matched region
 ;; (region E)     ; match E and push the corresponding start and end positions
 ;; (replace E RPL); match E and replace the matched region with RPL.
-;; (list E)       ; match E and push a list of all items that E produces.
+;; (list E)       ; match E and push a list out of the items that E produces.
 ;;
 ;; Regexp equivalents:
 ;;
@@ -225,7 +225,7 @@ Note: a PE can't \"call\" rules by name."
         (error "Invalid parsing expression: %S" exp))))
 
 (defvar peg-leaf-types '(null fail any call action char range str set
-                             bob eob bol eol bow eow bos eos syntax-class))
+                             bob eob bol eol bow eow bos eos syntax-class =))
 
 (dolist (type peg-leaf-types)
   (puthash type `(lambda (&rest args) (cons ',type args)) 
@@ -421,6 +421,12 @@ Note: a PE can't \"call\" rules by name."
          (t (error "Invalid syntax class: %S\nMust be one of: %s" class
                    (mapcar #'car peg-syntax-classes))))))
 
+(peg-add-method translate = (string)
+  `(let ((str ,string))
+     (when (zerop (length str)) 
+       (error "Empty strings not allowed for ="))
+     (search-forward str (+ (point) (length str)) t)))
+
 (peg-add-method translate * (e)
   (let ((cp (peg-make-choicepoint)))
     `(progn (while (,@(peg-save-choicepoint cp)
@@ -584,6 +590,7 @@ input.  PATH is the list of rules that we have visited so 
far."
 (peg-add-method detect-cycles eow   (path)       t)
 (peg-add-method detect-cycles bos   (path)       t)
 (peg-add-method detect-cycles eos   (path)       t)
+(peg-add-method detect-cycles =     (path s)     nil)
 (peg-add-method detect-cycles syntax-class (p n) nil)
 (peg-add-method detect-cycles action (path form) t)
 
@@ -653,6 +660,9 @@ input.  PATH is the list of rules that we have visited so 
far."
   (assert (not (peg-parse-string ((s (bos))) " x")))
   (assert (peg-parse-string ((s "x" (eos))) "x"))
   (assert (peg-parse-string ((s (syntax-class whitespace))) " "))
+  (assert (peg-parse-string ((s (= "foo"))) "foo"))
+  (assert (let ((f "foo")) (peg-parse-string ((s (= f))) "foo")))
+  (assert (not (peg-parse-string ((s (= "foo"))) "xfoo")))
   (assert (equal (peg-parse-string ((s `(-- 1 2))) "") '(t (2 1))))
   (assert (equal (peg-parse-string ((s `(-- 1 2) `(a b -- a b))) "")
                 '(t (2 1))))
@@ -821,6 +831,39 @@ input.  PATH is the list of rules that we have visited so 
far."
 ;; (peg-ex-uri)file:/bar/baz.html?foo=df#x
 ;; (peg-ex-uri)http://address@hidden:8080/bar/baz.html?x=1#foo
 
+;; Split STRING where SEPARATOR occurs.
+(defun peg-ex-split (string separator)
+  (peg-parse-string ((s (list (* (* sep) elt)))
+                    (elt (substring (+ (not sep) (any))))
+                    (sep (= separator)))
+                   string))
+
+;; (peg-ex-split "-abc-cd-" "-")
+
+;; Find the last digit in a string.
+(defun peg-ex-last-digit (string)
+  (peg-parse-string ((s (or (and (any) s)
+                           (substring [0-9]))))
+                   string))
+
+;; (peg-ex-last-digit "ab0cd1ef2gh")
+;; (peg-ex-last-digit (make-string 50 ?-))
+;; (peg-ex-last-digit (make-string 1000 ?-))
+
+;; Find the last digit without recursion.
+(defun peg-ex-last-digit2 (string)
+  (peg-parse-string ((s `(-- nil) 
+                       (+ (* (not digit) (any))
+                          (substring digit)
+                          `(d1 d2 -- d2)))
+                    (digit [0-9]))
+                   string))
+
+;; (peg-ex-last-digit2 "ab0cd1ef2gh")
+;; (peg-ex-last-digit2 (concat (make-string 500000 ?-) "8a9b"))
+;; (peg-ex-last-digit2 (make-string 500000 ?-))
+;; (peg-ex-last-digit2 (make-string 500000 ?5))
+
 ;; Parse a lisp style Sexp.
 ;; [To keep the example short, ' and . are handled as ordinary symbol.]
 (defun peg-ex-lisp ()