branch: externals/parser-generator
commit cfc687a66263fda07ddad43365604e80f9ecef8d
Author: Christian Johansson <[email protected]>
Commit: Christian Johansson <[email protected]>
More work on refactoring lexer to handle states and using a buffer
---
docs/Lexical-Analysis.md | 8 +-
parser-generator-lex-analyzer.el | 259 ++++++++++++++++-------------
test/parser-generator-lex-analyzer-test.el | 1 +
3 files changed, 144 insertions(+), 124 deletions(-)
diff --git a/docs/Lexical-Analysis.md b/docs/Lexical-Analysis.md
index ac17c11e00..842c19a02f 100644
--- a/docs/Lexical-Analysis.md
+++ b/docs/Lexical-Analysis.md
@@ -4,7 +4,7 @@ Set lexical analysis function by setting variable
`parser-generator-lex-analyzer
The lexical analysis is internally indexed on a local variable
`parser-generator-lex-analyzer--index` and has it optional state in the local
variable `parser-generation-lex-analyzer--state`. The initial values for the
index and state can be set in variables
`parser-generation-lex-analyzer--index-init` and
`parser-generator-lex-analyzer--state-init`.
-All parsers expect a list as response from lexical-analysis, the first item in
the list should be a list of one or more tokens. The second is "move
index"-flag, if it is non-nil it is expected to be a integer representing the
index to move the lex-analyzer to and perform a new lex. Third item is the new
index after the lex. The fourth item is the new state after the lex.
+All parsers expect a list as response from lexical-analysis, the first item in
the list should be a list of one or more tokens. The second is "move
index"-flag, if it is non-nil it is expected to be a integer representing the
index to temporarily move the index to and perform a new lex. Third item is not
used. The fourth item is the new state after the lex.
To enable exporting, the functions need to be specified in a way that the
entire body is within the same block, do that using `(let)` or `(progn)` for
example.
@@ -21,7 +21,7 @@ To enable exporting, the functions need to be specified in a
way that the entire
(< (1- index) max-index))
(push (nth (1- index) string) tokens)
(setq index (1+ index)))
- (list tokens nil index nil))))
+ (list tokens nil nil nil))))
```
## Token
@@ -62,7 +62,7 @@ Returns the look-ahead number of next terminals in stream, if
end of stream is r
(setq new-index (cdr (cdr (nth (1- index) string))))
(push next-token tokens)
(setq index (1+ index)))
- (list (nreverse tokens) nil new-index nil))))
+ (list (nreverse tokens) nil nil nil))))
(parser-generator-lex-analyzer--reset)
(setq parser-generator--look-ahead-number 1)
@@ -104,7 +104,7 @@ Returns the next token in stream and moves the lexical
analyzer index one point
(setq new-index (cdr (cdr (nth (1- index) string))))
(push (nth (1- index) string) tokens)
(setq index (1+ index)))
- (list (nreverse tokens) nil new-index nil))))
+ (list (nreverse tokens) nil nil nil))))
(parser-generator-lex-analyzer--reset)
(setq parser-generator--look-ahead-number 1)
diff --git a/parser-generator-lex-analyzer.el b/parser-generator-lex-analyzer.el
index 7edbf1df4f..f4ef62fa68 100644
--- a/parser-generator-lex-analyzer.el
+++ b/parser-generator-lex-analyzer.el
@@ -25,30 +25,45 @@
nil
"Get next token like \='(a b . c) or nil, expects signal if input-tape is
invalid.")
-(defvar-local
- parser-generator-lex-analyzer--index
+(defvar
+ parser-generator-lex-analyzer--state-init
nil
- "Index in lex-analyzer.")
+ "Initial value of state.")
+
+(defvar
+ parser-generator-lex-analyzer--reset-function
+ nil
+ "Function used when resetting lex-analyzer.")
(defvar
parser-generator-lex-analyzer--index-init
1
"Initial value of index.")
+
+;;; Buffer-Local Variables:
+
+
+(defvar-local
+ parser-generator-lex-analyzer--index
+ nil
+ "Index in lex-analyzer.")
+
(defvar-local
parser-generator-lex-analyzer--state
nil
"State of lex-analyzer.")
-(defvar
- parser-generator-lex-analyzer--state-init
+(defvar-local
+ parser-generator-lex-analyzer--state
nil
- "Initial value of state.")
+ "State of lex-analyzer.")
-(defvar
- parser-generator-lex-analyzer--reset-function
+(defvar-local
+ parser-generator-lex-analyzer--buffered-response
nil
- "Function used when resetting lex-analyzer.")
+ "Buffered tokens of lex-analyzer.")
+
;; Functions
@@ -92,8 +107,6 @@
"Peek next look-ahead number of tokens via lex-analyzer."
(unless parser-generator-lex-analyzer--index
(error "Missing lex-analyzer index when peeking!"))
- (unless parser-generator-lex-analyzer--function
- (error "Missing lex-analyzer function when peeking!"))
(unless parser-generator--look-ahead-number
(error "Missing look-ahead-number when peeking!"))
(let ((look-ahead)
@@ -107,129 +120,69 @@
(max
1
parser-generator--look-ahead-number)))
+
(while (<
look-ahead-length
k)
- (condition-case error
- (progn
- (let* ((result-list
- (funcall
- parser-generator-lex-analyzer--function
- index
- state))
- (token
- (nth 0 result-list))
- (move-to-index-flag
- (nth 1 result-list))
- (new-index
- (nth 2 result-list))
- (new-state
- (nth 3 result-list)))
- (if move-to-index-flag
- (progn
- (setq
- index
- move-to-index-flag)
- (setq
- state
- new-state))
- (if token
- (progn
- (setq index new-index)
- (unless (listp (car token))
- (setq token (list token)))
- (let ((token-count (length token))
- (token-index 0))
- (while
- (and
- (<
- look-ahead-length
- k)
- (<
- token-index
- token-count))
- (let ((next-look-ahead-item
- (nth token-index token)))
- (push
- next-look-ahead-item
- look-ahead)
- (setq
- look-ahead-length
- (1+ look-ahead-length))
- (setq
- token-index
- (1+ token-index))))))
-
- ;; Fill up look-ahead with EOF-identifier if we found nothing
- (push (list parser-generator--eof-identifier) look-ahead)
- (setq look-ahead-length (1+ look-ahead-length))
- (setq index (1+ index))))))
-
- (error
- (error
- "Lex-analyze failed to peek next look-ahead at %s, error: %s,
look-ahead: %S"
- index
- error
- look-ahead))))
+
+ (let* ((result-list
+ (parser-generator-lex-analyzer--get-buffered-lex
+ index
+ state))
+ (token
+ (nth 0 result-list))
+ (new-index
+ (nth 2 result-list)))
+ (if token
+ (progn
+ (push
+ token
+ look-ahead)
+ (setq
+ look-ahead-length
+ (1+ look-ahead-length))
+ (setq
+ index
+ new-index))
+
+ ;; Fill up look-ahead with EOF-identifier if we found nothing
+ (push (list parser-generator--eof-identifier) look-ahead)
+ (setq look-ahead-length (1+ look-ahead-length))
+ (setq index (1+ index)))))
+
(nreverse look-ahead)))
(defun parser-generator-lex-analyzer--pop-token ()
"Pop next token via lex-analyzer."
(unless parser-generator-lex-analyzer--index
(error "Missing lex-analyzer index when popping!"))
- (unless parser-generator-lex-analyzer--function
- (error "Missing lex-analyzer function when popping!"))
(unless parser-generator--look-ahead-number
(error "Missing look-ahead-number when popping!"))
- (let ((continue t)
- (tokens))
- (while continue
- (condition-case error
- (progn
- (let* ((result-list
- (funcall
- parser-generator-lex-analyzer--function
- parser-generator-lex-analyzer--index
- parser-generator-lex-analyzer--state))
- (token
- (nth 0 result-list))
- (move-to-index-flag
- (nth 1 result-list))
- (new-index
- (nth 2 result-list))
- (new-state
- (nth 3 result-list)))
- (if move-to-index-flag
- (progn
- (setq-local
- parser-generator-lex-analyzer--index
- move-to-index-flag)
- (setq-local
- parser-generator-lex-analyzer--state
- new-state))
- (setq
- parser-generator-lex-analyzer--index
- new-index)
- (when token
- (unless (listp (car token))
- (setq token (list token)))
- (let ((first-token (car token)))
- (push
- first-token
- tokens)))
- (setq
- continue
- nil))))
- (error
- (error
- "Lex-analyze failed to pop token at %s %s, error: %s"
- parser-generator-lex-analyzer--index
- parser-generator-lex-analyzer--state
- (car (cdr error))))))
- (nreverse tokens)))
+ (let* ((result-list
+ (parser-generator-lex-analyzer--get-buffered-lex
+ parser-generator-lex-analyzer--index
+ parser-generator-lex-analyzer--state))
+ (token
+ (nth 0 result-list))
+ (new-index
+ (nth 2 result-list))
+ (new-state
+ (nth 3 result-list)))
+ (setq-local
+ parser-generator-lex-analyzer--index
+ new-index)
+ (setq-local
+ parser-generator-lex-analyzer--state
+ new-state)
+ (if token
+ (list token)
+ nil)))
(defun parser-generator-lex-analyzer--reset ()
"Reset lex-analyzer."
+ (setq
+ parser-generator-lex-analyzer--buffered-response
+ (make-hash-table :test 'equal))
(setq
parser-generator-lex-analyzer--index
parser-generator-lex-analyzer--index-init)
@@ -239,6 +192,72 @@
(when parser-generator-lex-analyzer--reset-function
(funcall parser-generator-lex-analyzer--reset-function)))
+(defun parser-generator-lex-analyzer--get-buffered-lex (index state)
+ "Get next token in stream, use buffer to only call function when needed."
+
+ (unless (gethash
+ index
+ parser-generator-lex-analyzer--buffered-response)
+ (let ((continue t)
+ (tmp-index index)
+ (tmp-state state))
+ (unless parser-generator-lex-analyzer--function
+ (error "Missing lex-analyzer function!"))
+ (while continue
+ (condition-case error
+ (progn
+ (let* ((result-list
+ (funcall
+ parser-generator-lex-analyzer--function
+ tmp-index
+ tmp-state))
+ (tokens
+ (nth 0 result-list))
+ (move-to-index-flag
+ (nth 1 result-list))
+ (new-state
+ (nth 3 result-list)))
+ (if move-to-index-flag
+ (progn
+ (setq
+ tmp-index
+ move-to-index-flag)
+ (setq
+ tmp-state
+ new-state))
+
+ (if tokens
+
+ (unless (listp (car tokens))
+ (setq tokens (list tokens)))
+
+ ;; Fill up look-ahead with EOF-identifier if we found
nothing
+ (push
+ (list parser-generator--eof-identifier)
+ tokens))
+
+ (dolist (token tokens)
+ (let ((token-start (car (cdr token)))
+ (token-end (cdr (cdr token))))
+ (puthash
+ token-start
+ (list token nil token-end new-state)
+ parser-generator-lex-analyzer--buffered-response)))
+
+ (setq
+ continue
+ nil))))
+ (error
+ (error
+ "Lex-analyze failed to get next token at: %s in state: %s, error:
%s"
+ index
+ state
+ (car (cdr error))))))))
+
+ (gethash
+ index
+ parser-generator-lex-analyzer--buffered-response))
+
(provide 'parser-generator-lex-analyzer)
diff --git a/test/parser-generator-lex-analyzer-test.el
b/test/parser-generator-lex-analyzer-test.el
index 44ee9a7ad3..43bbd7a89a 100644
--- a/test/parser-generator-lex-analyzer-test.el
+++ b/test/parser-generator-lex-analyzer-test.el
@@ -86,6 +86,7 @@
(setq index (1+ index)))
(list (nreverse tokens) nil new-index nil))))
+ (parser-generator-lex-analyzer--reset)
(should-error
(parser-generator-lex-analyzer--peek-next-look-ahead))
