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[elpa] master 25be509: * externals-list: Convert `tNFA` from subtree to
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From: |
Stefan Monnier |
|
Subject: |
[elpa] master 25be509: * externals-list: Convert `tNFA` from subtree to external |
|
Date: |
Mon, 14 Dec 2020 12:09:55 -0500 (EST) |
branch: master
commit 25be5093eb7cf078af0b099f2d438f6b9262c572
Author: Stefan Monnier <monnier@iro.umontreal.ca>
Commit: Stefan Monnier <monnier@iro.umontreal.ca>
* externals-list: Convert `tNFA` from subtree to external
---
externals-list | 1 +
packages/tNFA/tNFA.el | 1111 -------------------------------------------------
2 files changed, 1 insertion(+), 1111 deletions(-)
diff --git a/externals-list b/externals-list
index 93fe9a3..b9a64ca 100644
--- a/externals-list
+++ b/externals-list
@@ -286,6 +286,7 @@
("test-simple" :external "https://github.com/rocky/emacs-test-simple";)
("timerfunctions" :external nil)
("tiny" :external "https://github.com/abo-abo/tiny";)
+ ("tNFA" :external "http://www.dr-qubit.org/git/predictive.git";)
("tramp" :external
"https://git.savannah.gnu.org/cgit/tramp.git/?h=elpa";)
("tramp-theme" :external nil)
("transcribe" :external nil)
diff --git a/packages/tNFA/tNFA.el b/packages/tNFA/tNFA.el
deleted file mode 100644
index 5a13e41..0000000
--- a/packages/tNFA/tNFA.el
+++ /dev/null
@@ -1,1111 +0,0 @@
-;;; tNFA.el --- Tagged non-deterministic finite-state automata
-
-;; Copyright (C) 2008-2010, 2012, 2014 Free Software Foundation, Inc
-
-;; Author: Toby Cubitt <toby-predictive@dr-qubit.org>
-;; Version: 0.1.1
-;; Keywords: extensions, matching, data structures
-;; tNFA, NFA, DFA, finite state automata, automata, regexp
-;; Package-Requires: ((queue "0.1"))
-;; URL: http://www.dr-qubit.org/emacs.php
-;; Repository: http://www.dr-qubit.org/git/predictive.git
-
-;; This file is part of Emacs.
-;;
-;; GNU Emacs is free software: you can redistribute it and/or modify it under
-;; the terms of the GNU General Public License as published by the Free
-;; Software Foundation, either version 3 of the License, or (at your option)
-;; any later version.
-;;
-;; GNU Emacs is distributed in the hope that it will be useful, but WITHOUT
-;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-;; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
-;; more details.
-;;
-;; You should have received a copy of the GNU General Public License along
-;; with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
-
-
-;;; Commentary:
-;;
-;; A tagged, non-deterministic finite state automata (NFA) is an abstract
-;; computing machine that recognises regular languages. In layman's terms,
-;; they are used to decide whether a string matches a regular expression. The
-;; "tagged" part allows the NFA to do group-capture: it returns information
-;; about which parts of a string matched which subgroup of the regular
-;; expression.
-;;
-;; Why re-implement regular expression matching when Emacs comes with
-;; extensive built-in support for regexps? Primarily, because some algorithms
-;; require access to the NFA states produced part way through the regular
-;; expression matching process (see the trie.el package for an
-;; example). Secondarily, because Emacs regexps only work on strings, whereas
-;; regular expressions can usefully be used in Elisp code to match other
-;; sequence types, not just strings.
-;;
-;; A tagged NFA can be created from a regular expression using
-;; `tNFA-from-regexp', and its state can be updated using
-;; `tNFA-next-state'. You can discover whether a state is a matching state
-;; using `tNFA-match-p', extract subgroup capture data from it using
-;; `tNFA-group-data', check whether a state has any wildcard transitions using
-;; `tNFA-wildcard-p', and get a list of non-wildcard transitions using
-;; `tNFA-transitions'. Finally, `tNFA-regexp-match' uses tagged NFAs to decide
-;; whether a regexp matches a given string.
-;;
-;; Note that Emacs' regexps are not regular expressions in the original
-;; meaning of that phrase. Emacs regexps implement additional features (in
-;; particular, back-references) that allow them to match far more than just
-;; regular languages. This comes at a cost: regexp matching can potentially be
-;; very slow (NP-hard in fact, though the hard cases rarely crop up in
-;; practise), whereas there are efficient (polynomial-time) algorithms for
-;; matching regular expressions (in the original sense). Therefore, this
-;; package only supports a subset of the full Emacs regular expression
-;; syntax. See the function docstrings for more information.
-;;
-;; This package essentially implements Laurikari's algorithm, as described in
-;; his master's thesis, but it builds the corresponding tagged deterministic
-;; finite state automaton (DFA) on-the-fly as needed.
-;;
-;; This package uses the queue package queue.el.
-
-
-;;; Change Log:
-;;
-;; Version 0.1.1
-;; * work-around mysterious byte-compiler bug by defining
-;; `tNFA--NFA-state-create' and `tNFA--NFA-state-create-tag' via `defun'
-;; instead of directly in `defstruct'
-;;
-;; Version 0.1
-;; * initial version
-
-
-
-;;; Code:
-
-(eval-when-compile (require 'cl))
-(require 'queue)
-
-
-
-;;; ================================================================
-;;; Replcements for CL functions
-
-(defun* tNFA--assoc (item alist &key (test 'eq))
- ;; Return first cons cell in ALIST whose CAR matches ITEM according to
- ;; :test function (defaulting to `eq')
- (while (and alist
- (or (not (consp (car alist)))
- (not (funcall test item (caar alist)))))
- (setq alist (cdr alist)))
- (car alist))
-
-
-
-;;; ================================================================
-;;; Data structures
-
-;;; ----------------------------------------------------------------
-;;; tagged NFA states
-
-(defstruct
- (tNFA--state
- (:constructor nil)
- (:constructor tNFA--state-create-initial
- (NFA-state num-tags min-tags max-tags
- &aux
- (tags (tNFA--tags-create num-tags min-tags max-tags))))
- (:constructor tNFA--state-create (NFA-state tags))
- (:copier nil))
- NFA-state tags)
-
-(defmacro tNFA--state-id (state)
- `(tNFA--NFA-state-id (tNFA--state-NFA-state ,state)))
-
-(defmacro tNFA--state-type (state)
- `(tNFA--NFA-state-type (tNFA--state-NFA-state ,state)))
-
-(defmacro tNFA--state-label (state)
- `(tNFA--NFA-state-label (tNFA--state-NFA-state ,state)))
-
-(defmacro tNFA--state-in-degree (state)
- `(tNFA--NFA-state-in-degree (tNFA--state-NFA-state ,state)))
-
-(defmacro tNFA--state-next (state)
- `(tNFA--NFA-state-next (tNFA--state-NFA-state ,state)))
-
-(defmacro tNFA--state-count (state)
- `(tNFA--NFA-state-count (tNFA--state-NFA-state ,state)))
-
-
-
-;;; ----------------------------------------------------------------
-;;; NFA states
-
-(declare (special NFA--state-id))
-
-(defstruct
- (tNFA--NFA-state
- (:type vector)
- (:constructor nil)
- (:constructor tNFA---NFA-state-create
- (&optional type label next
- &aux
- (in-degree 0)
- (count 0)
- (id (incf NFA--state-id))
- ;; (dummy
- ;; (when next
- ;; (setf (tNFA--NFA-state-count next)
- ;; (incf (tNFA--NFA-state-in-degree next)))))
- ))
- (:constructor tNFA--NFA-state-create-branch
- (&rest next
- &aux
- (type 'branch)
- (in-degree 0)
- (count 0)
- (id (incf NFA--state-id))))
- (:constructor tNFA---NFA-state-create-tag
- (tag &optional next
- &aux
- (type 'tag)
- (label tag)
- (in-degree 0)
- (count 0)
- (id (incf NFA--state-id))
- ;; (dummy
- ;; (when next
- ;; (setf (tNFA--NFA-state-count next)
- ;; (incf (tNFA--NFA-state-in-degree next)))))
- ))
- (:copier nil))
- id type label in-degree
- count tNFA-state ; used internally in NFA evolution algorithms
- next)
-
-
-;; Define these via defun instead of using the dummy argument in the
-;; above defstruct to work around a mysterious byte-compiler bug.
-
-(defun tNFA--NFA-state-create (&optional type label next)
- (when next
- (setf (tNFA--NFA-state-count next)
- (incf (tNFA--NFA-state-in-degree next))))
- (tNFA---NFA-state-create type label next))
-
-(defun tNFA--NFA-state-create-tag (tag &optional next)
- (when next
- (setf (tNFA--NFA-state-count next)
- (incf (tNFA--NFA-state-in-degree next))))
- (tNFA---NFA-state-create-tag tag next))
-
-
-;; tag number for a tagged epsilon transition is stored in label slot
-(defalias 'tNFA--NFA-state-tag 'tNFA--NFA-state-label)
-
-(defmacro tNFA--NFA-state-tags (state)
- `(tNFA--state-tags (tNFA--NFA-state-tNFA-state ,state)))
-
-
-(defun tNFA--NFA-state-patch (attach state)
- ;; patch STATE onto ATTACH. Return value is meaningless
- (setf
- (tNFA--NFA-state-type attach)
- (tNFA--NFA-state-type state)
- (tNFA--NFA-state-label attach)
- (tNFA--NFA-state-label state)
- (tNFA--NFA-state-next attach)
- (tNFA--NFA-state-next state)
- (tNFA--NFA-state-count state)
- (incf (tNFA--NFA-state-in-degree state))))
-
-
-(defun tNFA--NFA-state-make-epsilon (state next)
- ;; create an epsilon transition from STATE to NEXT
- (setf
- (tNFA--NFA-state-type state) 'epsilon
- (tNFA--NFA-state-label state) nil
- (tNFA--NFA-state-next state) next
- (tNFA--NFA-state-count next)
- (incf (tNFA--NFA-state-in-degree next))))
-
-
-(defun tNFA--NFA-state-make-branch (state next)
- ;; create a branch from STATE to all states in NEXT list
- (setf (tNFA--NFA-state-type state) 'branch
- (tNFA--NFA-state-label state) nil
- (tNFA--NFA-state-next state) next)
- (dolist (n next)
- (setf (tNFA--NFA-state-count n)
- (incf (tNFA--NFA-state-in-degree n)))))
-
-
-(defun tNFA--NFA-state-copy (state)
- ;; Return a copy of STATE. The next link is *not* copied, it is `eq'
- ;; to the original next link. Use `tNFA--fragment-copy' if you want to
- ;; recursively copy a chain of states. Note: NFA--state-id must be
- ;; bound to something appropriate when this function is called.
- (let ((copy (copy-sequence state)))
- (setf (tNFA--NFA-state-id copy) (incf NFA--state-id))
- copy))
-
-
-
-;;; ----------------------------------------------------------------
-;;; NFA fragments
-
-(defstruct
- (tNFA--fragment
- (:type vector)
- (:constructor nil)
- (:constructor tNFA--fragment-create (initial final))
- (:copier nil))
- initial final)
-
-
-(defun tNFA--fragment-patch (frag1 frag2)
- ;; patch FRAG2 onto end of FRAG1; return value is meaningless
- (tNFA--NFA-state-patch (tNFA--fragment-final frag1)
- (tNFA--fragment-initial frag2))
- (setf (tNFA--fragment-final frag1) (tNFA--fragment-final frag2)))
-
-
-(defun tNFA--fragment-copy (fragment)
- ;; return a copy of FRAGMENT.
- (declare (special copied-states))
- (let (copied-states)
- (tNFA--fragment-create
- (tNFA--do-fragment-copy (tNFA--fragment-initial fragment))
- (cdr (assq (tNFA--fragment-final fragment) copied-states)))))
-
-
-(defun tNFA--do-fragment-copy (state)
- ;; return a copy of STATE, recursively following and copying links
- ;; (note: NFA--state-id must be bound to something appropriate when
- ;; this is called)
- (declare (special copied-states))
- (let ((copy (tNFA--NFA-state-copy state)))
- (push (cons state copy) copied-states)
-
- ;; if STATE is a branch, copy all links
- (cond
- ((eq (tNFA--NFA-state-type copy) 'branch)
- (setf (tNFA--NFA-state-next copy)
- (mapcar (lambda (next)
- (or (cdr (assq next copied-states))
- (tNFA--do-fragment-copy next)))
- (tNFA--NFA-state-next copy))))
-
- ;; if state doesn't have a next link, return
- ((or (eq (tNFA--NFA-state-type copy) 'match)
- (null (tNFA--NFA-state-type copy))))
-
- ;; otherwise, copy next link
- ((tNFA--NFA-state-type copy)
- ;; for a non-branch STATE, copy next link
- (setf (tNFA--NFA-state-next copy)
- ;; if we've already copied next state, set next link to that
- (or (cdr (assq (tNFA--NFA-state-next copy) copied-states))
- ;; otherwise, recursively copy next state
- (tNFA--do-fragment-copy (tNFA--NFA-state-next copy))))))
- copy))
-
-
-
-;;; ----------------------------------------------------------------
-;;; DFA states
-
-(defstruct
- (tNFA--DFA-state
- :named
- (:constructor nil)
- (:constructor tNFA--DFA-state--create
- (list pool
- &key
- (test 'eq)
- &aux
- (transitions ())))
- (:copier nil))
- list transitions test wildcard match pool)
-
-
-(defun* tNFA--DFA-state-create (state-list state-pool &key (test 'eq))
- ;; create DFA state and add it to the state pool
- (let ((DFA-state (tNFA--DFA-state--create
- state-list state-pool :test test)))
- (puthash state-list DFA-state (tNFA--DFA-state-pool DFA-state))
-
- (dolist (state state-list)
- ;; if state in state list is...
- (cond
- ;; literal state: add literal transition
- ((eq (tNFA--state-type state) 'literal)
- (pushnew (cons (tNFA--state-label state) t)
- (tNFA--DFA-state-transitions DFA-state)
- :test #'equal))
-
- ;; character alternative: add transitions for all alternatives
- ((eq (tNFA--state-type state) 'char-alt)
- (dolist (c (tNFA--state-label state))
- (pushnew (cons c t) (tNFA--DFA-state-transitions DFA-state)
- :test #'equal)))
-
- ;; wildcard or negated character alternative: add wildcard
- ;; transistion
- ((or (eq (tNFA--state-type state) 'wildcard)
- (eq (tNFA--state-type state) 'neg-char-alt))
- (setf (tNFA--DFA-state-wildcard DFA-state) t))
-
- ;; match state: set match tags
- ((eq (tNFA--state-type state) 'match)
- (setf (tNFA--DFA-state-match DFA-state)
- (tNFA--state-tags state)))))
-
- ;; return constructed state
- DFA-state))
-
-
-(defun* tNFA--DFA-state-create-initial (state-list &key (test 'eq))
- ;; create initial DFA state from initial tNFA state INITIAL-STATE
- (tNFA--DFA-state-create state-list
- (make-hash-table :test 'equal)
- :test test))
-
-
-(defalias 'tNFA-match-p 'tNFA--DFA-state-match
- "Return non-nil if STATE is a matching state, otherwise return nil.")
-
-
-(defalias 'tNFA-wildcard-p 'tNFA--DFA-state-wildcard
- "Return non-nil if STATE has a wildcard transition,
- otherwise return nil.")
-
-
-(defun tNFA-transitions (state)
- "Return list of literal transitions from tNFA state STATE."
- (mapcar 'car (tNFA--DFA-state-transitions state)))
-
-
-
-;;; ----------------------------------------------------------------
-;;; tag tables
-
-(defun tNFA--tags-create (num-tags min-tags max-tags)
- ;; construct a new tags table
- (let ((vec (make-vector num-tags nil)))
- (dolist (tag min-tags)
- (aset vec tag (cons -1 'min)))
- (dolist (tag max-tags)
- (aset vec tag (cons -1 'max)))
- vec))
-
-
-(defun tNFA--tags-copy (tags)
- ;; return a copy of TAGS table
- (let* ((len (length tags))
- (vec (make-vector len nil)))
- (dotimes (i len)
- (aset vec i (cons (car (aref tags i))
- (cdr (aref tags i)))))
- vec))
-
-
-(defmacro tNFA--tags-set (tags tag val)
- ;; set value of TAG in TAGS table to VAL
- `(setcar (aref ,tags ,tag) ,val))
-
-
-(defmacro tNFA--tags-get (tags tag)
- ;; get value of TAG in TAGS table
- `(car (aref ,tags ,tag)))
-
-
-(defmacro tNFA--tags-type (tags tag)
- ;; return tag type ('min or 'max)
- `(cdr (aref ,tags ,tag)))
-
-
-(defun tNFA--tags< (val tag tags)
- ;; return non-nil if VAL takes precedence over the value of TAG in
- ;; TAGS table, nil otherwise
- (setq tag (aref tags tag))
- (or (and (eq (cdr tag) 'min)
- (< val (car tag)))
- ;;(and (eq (cdr tag) 'max)
- (> val (car tag));)
- ))
-
-
-(defun tNFA--tags-to-groups (tags)
- ;; Convert TAGS table to a list of indices of group matches. The n'th
- ;; element of the list is a cons cell, whose car is the starting index
- ;; of the nth group and whose cdr is its end index. If a group didn't
- ;; match, the corresponding list element will be null."
- (let ((groups (make-list (/ (length tags) 2) nil))
- group-stack
- (grp 0))
- (dotimes (i (length tags))
- (if (eq (tNFA--tags-type tags i) 'max)
- (unless (= (tNFA--tags-get tags i) -1)
- (setf (nth (caar group-stack) groups)
- (cons (cdr (pop group-stack))
- (tNFA--tags-get tags i))))
- (unless (= (tNFA--tags-get tags i) -1)
- (push (cons grp (tNFA--tags-get tags i)) group-stack))
- (incf grp)))
- groups))
-
-
-
-
-;;; ================================================================
-;;; Regexp -> tNFA
-
-;;;###autoload
-(defun* tNFA-from-regexp (regexp &key (test 'eq))
- "Create a tagged NFA that recognizes the regular expression REGEXP.
-The return value is the initial state of the tagged NFA.
-
-REGEXP can be any sequence type (vector, list, or string); it
-need not be an actual string. Special characters in REGEXP are
-still just that: elements of the sequence that are characters
-which have a special meaning in regexps.
-
-The :test keyword argument specifies how to test whether two
-individual elements of STRING are identical. The default is `eq'.
-
-Only a subset of the full Emacs regular expression syntax is
-supported. There is no support for regexp constructs that are
-only meaningful for strings (character ranges and character
-classes inside character alternatives, and syntax-related
-backslash constructs). Back-references and non-greedy postfix
-operators are not supported, so `?' after a postfix operator
-loses its special meaning. Also, matches are always anchored, so
-`$' and `^' lose their special meanings (use `.*' at the
-beginning and end of the regexp to get an unanchored match)."
-
- ;; convert regexp to list, build NFA, and return initial state
- (declare (special NFA--state-id))
- (destructuring-bind (fragment num-tags min-tags max-tags regexp)
- (let ((NFA--state-id -1))
- (tNFA--from-regexp (append regexp nil) 0 '() '() 'top-level))
- (if regexp
- (error "Syntax error in regexp: missing \"(\"")
- (setf (tNFA--NFA-state-type (tNFA--fragment-final fragment))
- 'match)
- (tNFA--DFA-state-create-initial
- (tNFA--epsilon-boundary
- (list
- (tNFA--state-create-initial
- (tNFA--fragment-initial fragment) num-tags min-tags max-tags))
- 0)
- :test test)
- )))
-
-
-(defmacro tNFA--regexp-postfix-p (regexp)
- ;; return t if next token in REGEXP is a postfix operator, nil
- ;; otherwise
- `(or (eq (car ,regexp) ?*)
- (eq (car ,regexp) ?+)
- (eq (car ,regexp) ??)
- (and (eq (car ,regexp) ?\\)
- (cdr ,regexp)
- (eq (cadr ,regexp) ?{))))
-
-
-(defun tNFA--from-regexp (regexp num-tags min-tags max-tags
- &optional top-level shy-group)
- ;; Construct a tagged NFA fragment from REGEXP, up to first end-group
- ;; character or end of REGEXP. The TAGS arguments are used to pass the
- ;; tags created so far. A non-nil TOP-LEVEL indicates that REGEXP is
- ;; the complete regexp, so we're constructing the entire tNFA. A
- ;; non-nil SHY-GROUP indicates that we're constructing a shy subgroup
- ;; fragment. (Both optional arguments are only used for spotting
- ;; syntax errors in REGEXP.)
- ;;
- ;; Returns a list: (FRAGMENT NUM-TAGS MIN-TAGS MAX-TAGS
- ;; REGEXP). FRAGMENT is the constructed tNFA fragment, REGEXP is the
- ;; remaining, unused portion of the regexp, and the TAGS return values
- ;; give the tags created so far.
-
- (let* ((new (tNFA--NFA-state-create))
- (fragment-stack (list (tNFA--fragment-create new new)))
- fragment copy attach token type group-end-tag)
-
- (catch 'constructed
- (while t
- (setq regexp (tNFA--regexp-next-token regexp)
- type (nth 0 regexp)
- token (nth 1 regexp)
- regexp (nth 2 regexp))
- (setq fragment nil
- group-end-tag nil)
-
- ;; ----- construct new fragment -----
- (cond
- ;; syntax error: missing )
- ((and (null type) (not top-level))
- (error "Syntax error in regexp:\
- extra \"(\" or missing \")\""))
-
- ;; syntax error: extra )
- ((and (eq type 'shy-group-end) top-level)
- (error "Syntax error in regexp:\
- extra \")\" or missing \"(\""))
-
- ;; syntax error: ) ending a shy group
- ((and (eq type 'shy-group-end) (not shy-group))
- (error "Syntax error in regexp: \"(\" matched with \")?\""))
-
- ;; syntax error: )? ending a group
- ((and (eq type 'group-end) shy-group)
- (error "Syntax error in regexp: \"(?\" matched with \")\""))
-
- ;; syntax error: postfix operator not after atom
- ((eq type 'postfix)
- (error "Syntax error in regexp: unexpected \"%s\""
- (char-to-string token)))
-
-
- ;; regexp atom: construct new literal fragment
- ((or (eq type 'literal) (eq type 'wildcard)
- (eq type 'char-alt) (eq type 'neg-char-alt))
- (setq new (tNFA--NFA-state-create
- type token (tNFA--NFA-state-create))
- fragment (tNFA--fragment-create
- new (tNFA--NFA-state-next new))))
-
- ;; shy subgroup start: recursively construct subgroup fragment
- ((eq type 'shy-group-start)
- (setq new (tNFA--from-regexp
- regexp num-tags min-tags max-tags nil t)
- num-tags (nth 1 new)
- min-tags (nth 2 new)
- max-tags (nth 3 new)
- regexp (nth 4 new)
- fragment (nth 0 new)))
-
- ;; subgroup start: add minimize tag to current fragment, and
- ;; recursively construct subgroup fragment
- ((eq type 'group-start)
- (setq new (tNFA--NFA-state-create))
- (setq fragment
- (tNFA--fragment-create
- (tNFA--NFA-state-create-tag
- (car (push (1- (incf num-tags)) min-tags))
- new)
- new))
- (tNFA--fragment-patch (car fragment-stack) fragment)
- ;; reserve next tag number for subgroup end tag
- (setq group-end-tag num-tags)
- (incf num-tags)
- ;; recursively construct subgroup fragment
- (setq new (tNFA--from-regexp
- regexp num-tags min-tags max-tags)
- num-tags (nth 1 new)
- min-tags (nth 2 new)
- max-tags (nth 3 new)
- regexp (nth 4 new)
- fragment (nth 0 new)))
-
-
- ;; end of regexp or subgroup: ...
- ((or (null type) (eq type 'shy-group-end) (eq type 'group-end))
-
- ;; if fragment-stack contains only one fragment, throw
- ;; fragment up to recursion level above
- (cond
- ((null (nth 1 fragment-stack))
- (throw 'constructed
- (list (car fragment-stack)
- num-tags min-tags max-tags regexp)))
-
- ;; if fragment-stack contains multiple alternation fragments,
- ;; attach them all together
- ;;
- ;; .--fragment--.
- ;; / \
- ;; /----fragment----\
- ;; / \
- ;; ---o------fragment------o--->
- ;; \ . /
- ;; \ . /
- ;; .
- (t
- ;; create a new fragment containing start and end of
- ;; alternation
- (setq fragment
- (tNFA--fragment-create
- (tNFA--NFA-state-create-branch)
- (tNFA--NFA-state-create)))
- ;; patch alternation fragments into new fragment
- (dolist (frag fragment-stack)
- (push (tNFA--fragment-initial frag)
- (tNFA--NFA-state-next
- (tNFA--fragment-initial fragment)))
- (setf (tNFA--NFA-state-count
- (tNFA--fragment-initial frag))
- (incf (tNFA--NFA-state-in-degree
- (tNFA--fragment-initial frag))))
- (tNFA--NFA-state-make-epsilon (tNFA--fragment-final frag)
- (tNFA--fragment-final fragment)))
- ;; throw constructed fragment up to recursion level above
- (throw 'constructed
- (list fragment num-tags min-tags max-tags regexp)))
- ))
-
- ;; | alternation: start new fragment
- ((eq type 'alternation)
- (setq new (tNFA--NFA-state-create))
- (push (tNFA--fragment-create new new) fragment-stack)))
-
-
- ;; ----- attach new fragment -----
- (when fragment
- ;; if next token is not a postfix operator, attach new
- ;; fragment onto end of current NFA fragment
- (if (not (tNFA--regexp-postfix-p regexp))
- (tNFA--fragment-patch (car fragment-stack) fragment)
-
- ;; if next token is a postfix operator, splice new fragment
- ;; into NFA as appropriate
- (when (eq type 'alternation)
- (error "Syntax error in regexp: unexpected \"%s\""
- (char-to-string token)))
- (setq regexp (tNFA--regexp-next-token regexp)
- type (nth 0 regexp)
- token (nth 1 regexp)
- regexp (nth 2 regexp))
-
- (while fragment
- (setq attach (tNFA--fragment-final (car fragment-stack)))
- (setq new (tNFA--NFA-state-create))
- (cond
-
- ;; * postfix = \{0,\}:
- ;;
- ;; .--fragment--.
- ;; / \
- ;; \ ______/
- ;; \ /
- ;; ---attach-----new---
- ;;
- ((and (eq (car token) 0) (null (cdr token)))
- (tNFA--NFA-state-make-branch
- attach (list (tNFA--fragment-initial fragment) new))
- (tNFA--NFA-state-make-epsilon
- (tNFA--fragment-final fragment) attach)
- (setf (tNFA--fragment-final (car fragment-stack)) new)
- (setq fragment nil))
-
- ;; + postfix = \{1,\}:
- ;;
- ;; .----.
- ;; / \
- ;; / \
- ;; \ /
- ;; ---fragment-----new---
- ;;
- ((and (eq (car token) 1) (null (cdr token)))
- (tNFA--NFA-state-patch
- attach (tNFA--fragment-initial fragment))
- (tNFA--NFA-state-make-branch
- (tNFA--fragment-final fragment) (list attach new))
- (setf (tNFA--fragment-final (car fragment-stack)) new)
- (setq fragment nil))
-
- ;; \{0,n\} (note: ? postfix = \{0,1\}):
- ;;
- ;; .--fragment--.
- ;; / \
- ;; ---attach new---
- ;; \______________/
- ;;
- ((eq (car token) 0)
- ;; ? postfix = \{0,1\}: after this we're done
- (if (eq (cdr token) 1)
- (setq copy nil)
- (setq copy (tNFA--fragment-copy fragment)))
- ;; attach fragment
- (tNFA--NFA-state-make-branch
- attach (list (tNFA--fragment-initial fragment) new))
- (tNFA--NFA-state-make-epsilon
- (tNFA--fragment-final fragment) new)
- (setf (tNFA--fragment-final (car fragment-stack)) new)
- ;; prepare for next iteration
- (decf (cdr token))
- (setq fragment copy))
-
- ;; \{n,\} or \{n,m\}:
- ;;
- ;; ---attach----fragment----new---
- ;;
- (t
- (setq copy (tNFA--fragment-copy fragment))
- (tNFA--fragment-patch (car fragment-stack) fragment)
- ;; prepare for next iteration
- (decf (car token))
- (when (cdr token) (decf (cdr token)))
- (if (eq (cdr token) 0)
- (setq fragment nil)
- (setq fragment copy)))
- )))
-
-
- ;; if ending a group, add a maximize tag to end
- (when group-end-tag
- (setq new (tNFA--NFA-state-create)
- fragment (tNFA--fragment-create
- (tNFA--NFA-state-create-tag
- group-end-tag new)
- new))
- (push group-end-tag max-tags)
- (tNFA--fragment-patch (car fragment-stack) fragment)))
- )) ; end of infinite loop and catch
- ))
-
-
-
-;; Note: hard-coding the parsing like this is ugly, though sufficient
-;; for our purposes. Perhaps it would be more elegant to implement
-;; this in terms of a proper parser...
-
-(defun tNFA--regexp-next-token (regexp)
- ;; if regexp is empty, return null values for next token type, token
- ;; and remaining regexp
- (if (null regexp)
- (list nil nil nil)
-
- (let ((token (pop regexp))
- (type 'literal)) ; assume token is literal initially
- (cond
-
- ;; [: gobble up to closing ]
- ((eq token ?\[)
- ;; character alternatives are stored in lists
- (setq token '())
- (cond
- ;; gobble ] appearing straight after [
- ((eq (car regexp) ?\]) (push (pop regexp) token))
- ;; gobble ] appearing straight after [^
- ((and (eq (car regexp) ?^) (eq (nth 1 regexp) ?\]))
- (push (pop regexp) token)
- (push (pop regexp) token)))
- ;; gobble everything up to closing ]
- (while (not (eq (car regexp) ?\]))
- (push (pop regexp) token)
- (unless regexp
- (error "Syntax error in regexp: missing \"]\"")))
- (pop regexp) ; dump closing ]
- (if (not (eq (car (last token)) ?^))
- (setq type 'char-alt)
- (setq type 'neg-char-alt)
- (setq token (butlast token))))
-
- ;; ]: syntax error (always gobbled when parsing [)
- ((eq token ?\])
- (error "Syntax error in regexp: missing \"[\""))
-
- ;; . * + ?: set appropriate type
- ((eq token ?*) (setq type 'postfix token (cons 0 nil)))
- ((eq token ?+) (setq type 'postfix token (cons 1 nil)))
- ((eq token ??) (setq type 'postfix token (cons 0 1)))
- ((eq token ?.) (setq type 'wildcard))
-
- ;; \: look at next character
- ((eq token ?\\)
- (unless (setq token (pop regexp))
- (error "Syntax error in regexp:\
- missing character after \"\\\""))
- (cond
- ;; |: alternation
- ((eq token ?|) (setq type 'alternation))
- ;; \(?: shy group start
- ((and (eq token ?\() (eq (car regexp) ??))
- (setq type 'shy-group-start)
- (pop regexp))
- ;; \)?: shy group end
- ((and (eq token ?\)) (eq (car regexp) ??))
- (setq type 'shy-group-end)
- (pop regexp))
- ;; \(: group start
- ((eq token ?\() (setq type 'group-start))
- ;; \): group end
- ((eq token ?\)) (setq type 'group-end))
-
- ;; \{: postfix repetition operator
- ((eq token ?{)
- (setq type 'postfix token (cons nil nil))
- ;; extract first number from repetition operator
- (while (if (null regexp)
- (error "Syntax error in regexp:\
- malformed \\{...\\}")
- (not (or (eq (car regexp) ?,)
- (eq (car regexp) ?\\))))
- (setcar token
- (concat (car token) (char-to-string (pop regexp)))))
- (if (null (car token))
- (setcar token 0)
- (unless (string-match "[0-9]+" (car token))
- (error "Syntax error in regexp: malformed \\{...\\}"))
- (setcar token (string-to-number (car token))))
- (cond
- ;; if next character is "\", we expect "}" to follow
- ((eq (car regexp) ?\\)
- (pop regexp)
- (unless (eq (car regexp) ?})
- (error "Syntax error in regexp: expected \"}\""))
- (pop regexp)
- (unless (car token)
- (error "Syntax error in regexp: malformed \\{...\\}"))
- (setcdr token (car token)))
- ;; if next character is ",", we expect a second number to
- ;; follow
- ((eq (car regexp) ?,)
- (pop regexp)
- (while (if (null regexp)
- (error "Syntax error in regexp:\
- malformed \\{...\\}")
- (not (eq (car regexp) ?\\)))
- (setcdr token
- (concat (cdr token)
- (char-to-string (pop regexp)))))
- (unless (null (cdr token))
- (unless (string-match "[0-9]+" (cdr token))
- (error "Syntax error in regexp: malformed \\{...\\}"))
- (setcdr token (string-to-number (cdr token))))
- (pop regexp)
- (unless (eq (car regexp) ?})
- (error "Syntax error in regexp: expected \"}\""))
- (pop regexp))))
- ))
- )
-
- ;; return first token type, token, and remaining regexp
- (list type token regexp))))
-
-
-
-;;; ================================================================
-;;; tNFA evolution
-
-(defun tNFA-next-state (tNFA chr pos)
- "Evolve tNFA according to CHR, which corresponds to position
-POS in a string."
- (let (elem state)
- ;; if there is a transition for character CHR...
- (cond
- ((setq elem (tNFA--assoc chr (tNFA--DFA-state-transitions tNFA)
- :test (tNFA--DFA-state-test tNFA)))
- ;; if next state has not already been computed, do so
- (unless (tNFA--DFA-state-p (setq state (cdr elem)))
- (setq state (tNFA--DFA-next-state tNFA chr pos nil))
- (setcdr elem state)))
-
- ;; if there's a wildcard transition...
- ((setq state (tNFA--DFA-state-wildcard tNFA))
- ;; if next state has not already been computed, do so
- (unless (tNFA--DFA-state-p state)
- (setq state (tNFA--DFA-next-state tNFA chr pos t))
- (setf (tNFA--DFA-state-wildcard tNFA) state))))
- state))
-
-
-
-(defun tNFA--DFA-next-state (DFA-state chr pos wildcard)
- (let (state-list state)
- ;; add all states reached by a CHR transition from DFA-STATE to
- ;; state list
- (if wildcard
- (dolist (state (tNFA--DFA-state-list DFA-state))
- (when (or (eq (tNFA--state-type state) 'wildcard)
- (and (eq (tNFA--state-type state) 'neg-char-alt)
- (not (memq chr (tNFA--state-label state)))))
- (push (tNFA--state-create
- (tNFA--state-next state)
- (tNFA--tags-copy (tNFA--state-tags state)))
- state-list)))
- (dolist (state (tNFA--DFA-state-list DFA-state))
- (when (or (and (eq (tNFA--state-type state) 'literal)
- (eq chr (tNFA--state-label state)))
- (and (eq (tNFA--state-type state) 'char-alt)
- (memq chr (tNFA--state-label state)))
- (and (eq (tNFA--state-type state) 'neg-char-alt)
- (not (memq chr (tNFA--state-label state))))
- (eq (tNFA--state-type state) 'wildcard))
- (push (tNFA--state-create
- (tNFA--state-next state)
- (tNFA--tags-copy (tNFA--state-tags state)))
- state-list))))
-
- ;; if state list is empty, return empty, failure DFA state
- (when state-list
- ;; otherwise, construct new DFA state and add it to the pool if
- ;; it's not already there
- (setq state-list (tNFA--epsilon-boundary state-list (1+ pos)))
- (setq state
- (or (gethash state-list (tNFA--DFA-state-pool DFA-state))
- (tNFA--DFA-state-create
- state-list
- (tNFA--DFA-state-pool DFA-state)
- :test (tNFA--DFA-state-test DFA-state))))
- ;; return next state
- state)))
-
-
-
-(defun tNFA--epsilon-boundary (state-set pos)
- ;; Return the tagged epsilon-boundary of the NFA states listed in
- ;; STATE-SET, that is the set of all states that can be reached via
- ;; epsilon transitions from some state in STATE-SET (not including
- ;; states in STATE-SET itself).
- (let ((queue (queue-create))
- (result '())
- (reset '())
- state next tags)
- ;; temporarily link the NFA states to their corresponding tNFA
- ;; states, and add them to the queue
- (dolist (t-state state-set)
- (setf state (tNFA--state-NFA-state t-state)
- (tNFA--NFA-state-tNFA-state state) t-state)
- (push state reset)
- (queue-enqueue queue state))
-
- (while (setq state (queue-dequeue queue))
- (cond
- ;; branch or epsilon: add next states as necessary, copying tags
- ;; across
- ((or (eq (tNFA--NFA-state-type state) 'branch)
- (eq (tNFA--NFA-state-type state) 'epsilon))
- (dolist (next (if (eq (tNFA--NFA-state-type state) 'epsilon)
- (list (tNFA--NFA-state-next state))
- (tNFA--NFA-state-next state)))
- (unless (tNFA--NFA-state-tNFA-state next)
- (setf (tNFA--NFA-state-tNFA-state next)
- (tNFA--state-create
- next (tNFA--tags-copy (tNFA--NFA-state-tags state))))
- (push next reset)
- ;; if next state hasn't already been seen in-degree times,
- ;; add it to the end of the queue
- (if (/= (decf (tNFA--NFA-state-count next)) 0)
- (queue-enqueue queue next)
- ;; if it has now been seen in-degree times, reset count
- ;; and add it back to the front of the queue
- (setf (tNFA--NFA-state-count next)
- (tNFA--NFA-state-in-degree next))
- (queue-prepend queue next)))))
-
- ;; tag: add next state if necessary, updating tags if necessary
- ((eq (tNFA--NFA-state-type state) 'tag)
- (setq next (tNFA--NFA-state-next state))
- ;; if next state is not already in results list, or it is
- ;; already in results but new tag value takes precedence...
- (when (or (not (tNFA--NFA-state-tNFA-state next))
- (tNFA--tags< pos (tNFA--NFA-state-tag state)
- (tNFA--NFA-state-tags next)))
- ;; if next state is already in results, update tag value
- (if (tNFA--NFA-state-tNFA-state next)
- (tNFA--tags-set (tNFA--NFA-state-tags next)
- (tNFA--NFA-state-tag state) pos)
- ;; if state is not already in results, copy tags, updating
- ;; tag value, and add next state to results list
- (setq tags (tNFA--tags-copy (tNFA--NFA-state-tags state)))
- (tNFA--tags-set tags (tNFA--NFA-state-tag state) pos)
- (setf (tNFA--NFA-state-tNFA-state next)
- (tNFA--state-create next tags))
- (push next reset))
- ;; if next state hasn't already been seen in-degree times, add
- ;; it to the end of the queue
- (if (/= (decf (tNFA--NFA-state-count next)) 0)
- (queue-enqueue queue next)
- ;; if it has now been seen in-degree times, reset count and
- ;; add it back to the front of the queue
- (setf (tNFA--NFA-state-count next)
- (tNFA--NFA-state-in-degree next))
- (queue-prepend queue next))))
-
- ;; anything else is a non-epsilon-transition state, so add it to
- ;; result
- (t (push (tNFA--NFA-state-tNFA-state state) result))
- ))
-
- ;; reset temporary NFA state link and count
- (dolist (state reset)
- (setf (tNFA--NFA-state-tNFA-state state) nil
- (tNFA--NFA-state-count state)
- (tNFA--NFA-state-in-degree state)))
- ;; sort result states
- (sort result
- (lambda (a b) (< (tNFA--state-id a) (tNFA--state-id b))))
- ))
-
-
-
-;;; ================================================================
-;;; tNFA matching
-
-;;;###autoload
-(defun* tNFA-regexp-match (regexp string &key (test 'eq))
- "Return non-nil if STRING matches REGEXP, nil otherwise.
-Sets the match data if there was a match; see `match-beginning',
-`match-end' and `match-string'.
-
-REGEXP and STRING can be any sequence type (vector, list, or
-string); they need not be actual strings. Special characters in
-REGEXP are still just that: elements of the sequence that are
-characters which have a special meaning in regexps.
-
-The :test keyword argument specifies how to test whether two
-individual elements of STRING are identical. The default is `eq'.
-
-Only a subset of the full Emacs regular expression syntax is
-supported. There is no support for regexp constructs that are
-only meaningful for strings (character ranges and character
-classes inside character alternatives, and syntax-related
-backslash constructs). Back-references and non-greedy postfix
-operators are not supported, so `?' after a postfix operator
-loses its special meaning. Also, matches are always anchored, so
-`$' and `^' lose their special meanings (use `.*' at the
-beginning and end of the regexp to get an unanchored match)."
-
- (let ((tNFA (tNFA-from-regexp regexp :test test))
- (i -1) tags match-data group-stack (grp 0))
-
- ;; evolve tNFA according to characters of STRING
- (catch 'fail
- (dolist (chr (append string nil))
- (unless (setq tNFA (tNFA-next-state tNFA chr (incf i)))
- (throw 'fail nil)))
-
- ;; if REGEXP matched...
- (when (setq tags (tNFA--DFA-state-match tNFA))
- (setq match-data (make-list (+ (length tags) 2) nil))
- ;; set match data
- (setf (nth 0 match-data) 0
- (nth 1 match-data) (length string))
- ;; set group match data if there were any groups
- (dotimes (i (length tags))
- (if (eq (tNFA--tags-type tags i) 'max)
- (unless (= (tNFA--tags-get tags i) -1)
- (setf (nth (1+ (* 2 (pop group-stack))) match-data)
- (tNFA--tags-get tags i)))
- (incf grp)
- (unless (= (tNFA--tags-get tags i) -1)
- (push grp group-stack)
- (setf (nth (* 2 grp) match-data)
- (tNFA--tags-get tags i)))))
- (set-match-data match-data)
- tags))))
-
-
-(defun tNFA-group-data (tNFA)
- "Return the group match data associated with a tNFA state."
- (tNFA--tags-to-groups (tNFA--DFA-state-match tNFA)))
-
-
-
-(provide 'tNFA)
-
-;;; tNFA.el ends here
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Stefan Monnier <=