branch: externals/parser-generator
commit bd0686383975652da8006f3f81f77af191ca4253
Author: Christian Johansson <[email protected]>
Commit: Christian Johansson <[email protected]>
LR-parser now uses lex-analyzer for parsing
---
parser-generator-lr.el | 41 +++++++++++++++++++---------------------
test/parser-generator-lr-test.el | 33 ++++++++++++++++++++++++++++++--
2 files changed, 50 insertions(+), 24 deletions(-)
diff --git a/parser-generator-lr.el b/parser-generator-lr.el
index 91a8e17..bb08abb 100644
--- a/parser-generator-lr.el
+++ b/parser-generator-lr.el
@@ -8,7 +8,7 @@
(require 'parser-generator)
-
+(require 'parser-generator-lex-analyzer)
;;; Variables:
@@ -490,35 +490,32 @@
;; TODO Add support for SDT
;; TODO Add support for semantic-actions
;; TODO Consider case with 2 character look-ahead
-(defun parser-generator-lr--parse (input-tape &optional input-tape-index
pushdown-list)
- "Perform a LR-parse of INPUT-TAPE optionally at INPUT-TAPE-INDEX with
PUSHDOWN-LIST."
+(defun parser-generator-lr--parse (&optional input-tape-index pushdown-list
output)
+ "Perform a LR-parse via lex-analyzer, optionally at INPUT-TAPE-INDEX with
PUSHDOWN-LIST and OUTPUT."
(unless input-tape-index
(setq input-tape-index 0))
(unless pushdown-list
(push 0 pushdown-list))
+ (if (and
+ input-tape-index
+ (> input-tape-index 0))
+ (setq parser-generator-lex-analyzer--index input-tape-index)
+ (parser-generator-lex-analyzer--reset))
+
;; Make sure tables exists
(parser-generator-lr--generate-goto-tables)
(parser-generator-lr--generate-action-tables)
- (let ((accept nil)
- (input-tape-length (length input-tape))
- (output))
+ (let ((accept))
(while (and
- (not accept)
- (<= input-tape-index input-tape-length))
+ (not accept))
;; (1) The lookahead string u, consisting of the next k input symbols,
is determined.
- (let ((look-ahead)
- (look-ahead-length 0)
- (look-ahead-input-tape-index input-tape-index))
+ (let ((look-ahead (parser-generator-lex-analyzer--peek-next-look-ahead))
+ (look-ahead-length 0))
- (while (and
- (< look-ahead-input-tape-index input-tape-length)
- (< look-ahead-length parser-generator--look-ahead-number))
- (push (nth look-ahead-input-tape-index input-tape) look-ahead)
- (setq look-ahead-length (1+ look-ahead-length))
- (setq look-ahead-input-tape-index (1+ look-ahead-input-tape-index)))
+ (setq look-ahead-length (length look-ahead))
;; If we reached end of input-tape and look-ahead is too small, append
e-identifiers
(while (< look-ahead-length parser-generator--look-ahead-number)
@@ -551,13 +548,13 @@
;; transfer to an error recovery routine).
(error (format
- "Invalid syntax! Expected one of %s found %s at
input-tape-index %s"
+ "Invalid syntax! Expected one of %s found %s at index
%s"
possible-look-aheads
look-ahead
- input-tape-index)
+ parser-generator-lex-analyzer--index)
possible-look-aheads
look-ahead
- input-tape-index))
+ parser-generator-lex-analyzer--index))
(cond
@@ -598,7 +595,7 @@
(push a pushdown-list)
(push next-index pushdown-list)
- (setq input-tape-index (1+ input-tape-index))))))
+ (parser-generator-lex-analyzer--pop-token)))))
((equal (car action-match) 'reduce)
;; (b) If f(u) = reduce i and production i is A -> a,
@@ -655,7 +652,7 @@
(t (error (format "Invalid action-match: %s!"
action-match)))))))))
(unless accept
- (error "Parsed entire string without getting accepting!"))
+ (error "Parsed entire string without getting accepting! Output: %s"
(nreverse output)))
(nreverse output)))
(provide 'parser-generator-lr)
diff --git a/test/parser-generator-lr-test.el b/test/parser-generator-lr-test.el
index 4252bbf..222d986 100644
--- a/test/parser-generator-lr-test.el
+++ b/test/parser-generator-lr-test.el
@@ -225,13 +225,42 @@
(parser-generator--set-grammar '((Sp S) (a b) ((Sp S) (S (S a S b)) (S e))
Sp))
(parser-generator--set-look-ahead-number 1)
(parser-generator--process-grammar)
+
+ (setq
+ parser-generator-lex-analyzer--function
+ (lambda (index length)
+ (let* ((string '(a a b b))
+ (string-length (length string))
+ (max-index (+ index length))
+ (tokens))
+ (while (and
+ (< index string-length)
+ (< index max-index))
+ (push (nth index string) tokens)
+ (setq index (1+ index)))
+ (nreverse tokens))))
+
(should
(equal
'(2 2 2 1 1)
- (parser-generator-lr--parse '(a a b b))))
+ (parser-generator-lr--parse)))
+
+ (setq
+ parser-generator-lex-analyzer--function
+ (lambda (index length)
+ (let* ((string '(a a b b b))
+ (string-length (length string))
+ (max-index (+ index length))
+ (tokens))
+ (while (and
+ (< index string-length)
+ (< index max-index))
+ (push (nth index string) tokens)
+ (setq index (1+ index)))
+ (nreverse tokens))))
(should-error
- (parser-generator-lr--parse '(a a b b b)))
+ (parser-generator-lr--parse))
(message "Passed tests for (parser-generator-lr--parse)"))
