branch: externals/parser-generator
commit d14d4277c5e35da6ab34683ee30c6a265a4eccdd
Author: Christian Johansson <[email protected]>
Commit: Christian Johansson <[email protected]>
Moved more about lex-analysis to separate document
---
README.md | 68 ------------------------------------------------
docs/Lexical-Analysis.md | 68 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 68 insertions(+), 68 deletions(-)
diff --git a/README.md b/README.md
index fa23e93..438ecd7 100644
--- a/README.md
+++ b/README.md
@@ -11,74 +11,6 @@ This is just started, so most stuff are *WIP*.
We use a regular-language based lexical analyzer that can be implemented by a
finite-state-machine (FSM). Read more [here](docs/Lexical-Analysis.md).
-### Peek next look-ahead
-
-Returns the look-ahead number of next terminals in stream.
-
-``` emacs-lisp
-(require 'ert)
-(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))))
-(parser-generator-lex-analyzer--reset)
-(setq parser-generator--look-ahead-number 1)
- (should
- (equal
- '(a)
- (parser-generator-lex-analyzer--peek-next-look-ahead)))
-
- (setq parser-generator--look-ahead-number 2)
- (should
- (equal
- '(a b)
- (parser-generator-lex-analyzer--peek-next-look-ahead)))
-
-```
-
-### Pop token
-
-Returns the next token in stream and moves index one forward.
-
-``` emacs-lisp
-(require 'ert)
-(setq
- parser-generator-lex-analyzer--function
- (lambda (index length)
- (let* ((string '(a 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))))
-(parser-generator-lex-analyzer--reset)
-(should
- (equal
- '(a)
- (parser-generator-lex-analyzer--pop-token)))
- (should
- (equal
- '(b)
- (parser-generator-lex-analyzer--pop-token)))
- (should
- (equal
- nil
- (parser-generator-lex-analyzer--pop-token)))
-```
-
## Syntax Analysis / Parsing
We use push down transducer (PDT) based algorithms.
diff --git a/docs/Lexical-Analysis.md b/docs/Lexical-Analysis.md
index d648f87..ae71ff9 100644
--- a/docs/Lexical-Analysis.md
+++ b/docs/Lexical-Analysis.md
@@ -2,6 +2,74 @@
Set lexical analysis function by setting variable
`parser-generator-lex-analyzer--function`. Optionally set reset function by
setting variable `parser-generator-lex-analyzer--reset-function`. The lexical
analysis is indexed on variable `parser-generator-lex-analyzer--index`. All
parsers expect a list of tokens as response from lexical-analysis.
+### Peek next look-ahead
+
+Returns the look-ahead number of next terminals in stream.
+
+``` emacs-lisp
+(require 'ert)
+(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))))
+(parser-generator-lex-analyzer--reset)
+(setq parser-generator--look-ahead-number 1)
+ (should
+ (equal
+ '(a)
+ (parser-generator-lex-analyzer--peek-next-look-ahead)))
+
+ (setq parser-generator--look-ahead-number 2)
+ (should
+ (equal
+ '(a b)
+ (parser-generator-lex-analyzer--peek-next-look-ahead)))
+
+```
+
+### Pop token
+
+Returns the next token in stream and moves index one forward.
+
+``` emacs-lisp
+(require 'ert)
+(setq
+ parser-generator-lex-analyzer--function
+ (lambda (index length)
+ (let* ((string '(a 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))))
+(parser-generator-lex-analyzer--reset)
+(should
+ (equal
+ '(a)
+ (parser-generator-lex-analyzer--pop-token)))
+ (should
+ (equal
+ '(b)
+ (parser-generator-lex-analyzer--pop-token)))
+ (should
+ (equal
+ nil
+ (parser-generator-lex-analyzer--pop-token)))
+```
+
## Example
``` emacs-lisp
