branch: externals/parser-generator
commit 71f03cc5a02ac9173bf176ec543abd92965a8cab
Author: Christian Johansson <christ...@cvj.se>
Commit: Christian Johansson <christ...@cvj.se>
Updated example
---
.../Deterministic-Right-Parser-for-LRk-Grammars.md | 54 +++++++++-------------
1 file changed, 22 insertions(+), 32 deletions(-)
diff --git a/docs/Deterministic-Right-Parser-for-LRk-Grammars.md
b/docs/Deterministic-Right-Parser-for-LRk-Grammars.md
index 4837347..65f7fb5 100644
--- a/docs/Deterministic-Right-Parser-for-LRk-Grammars.md
+++ b/docs/Deterministic-Right-Parser-for-LRk-Grammars.md
@@ -1,5 +1,9 @@
# Deterministic Right Parser for LR(k) Grammars
+This library contains functions to parse and translate grammar as well as
validate grammars.
+
+## LR Item
+
A valid LR-item for a viable prefix has this structure:
``` emacs-lisp
@@ -57,46 +61,32 @@ Calculate the set of LR items valid for any viable prefix S.
Perform a right-parse of input-stream.
```emacs-lisp
+(require 'parser-generator-lr)
(require 'ert)
(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)
+(parser-generator-lr-generate-parser-tables)
(setq
- parser-generator-lex-analyzer--function
- (lambda (index length)
- (let* ((string '((a 1 . 2) (a 2 . 3) (b 3 . 4) (b 4 . 5) (b 5 . 6)))
- (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)))
-
+ parser-generator-lex-analyzer--function
+ (lambda (index)
+ (let* ((string '((a 1 . 2) (a 2 . 3) (b 3 . 4) (b 4 . 5)))
+ (string-length (length string))
+ (max-index index)
+ (tokens))
+ (while (and
+ (< (1- index) string-length)
+ (< (1- index) max-index))
+ (push (nth (1- index) string) tokens)
+ (setq index (1+ index)))
+ (nreverse tokens))))
-(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))
+(should
+ (equal
+ '(2 2 2 1 1)
+ (parser-generator-lr-parse)))
```
[Back to start](../../../)
