branch: externals/parser-generator
commit ab0559de39fdf8aadd5732fda1fe1e3d84e866f0
Author: Christian Johansson <christ...@cvj.se>
Commit: Christian Johansson <christ...@cvj.se>
More work
---
parser.el | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/parser.el b/parser.el
index af5ac0d..6544898 100644
--- a/parser.el
+++ b/parser.el
@@ -586,11 +586,6 @@
(when (> first-length 0)
(push first first-list))))))
(setq first-list (sort first-list 'parser--sort-list))
- (when (and
- (not first-list)
- (= (length β) 1)
- (eq (car β) 'e))
- (setq first-list '((e))))
first-list))))
;; Definition at p. 343
@@ -685,13 +680,21 @@
(when (parser--valid-non-terminal-p rhs-first)
(let ((rhs-rest (append (cdr rhs) suffix)))
(let ((rhs-rest-first (parser--first rhs-rest)))
+ (parser--debug
+ (message "rhs-rest-first: %s" rhs-rest-first))
+ (unless rhs-rest-first
+ (setq rhs-rest-first (list nil)))
(let ((sub-production (parser--get-grammar-rhs
rhs-first)))
;; For each production with B as LHS
(dolist (sub-rhs sub-production)
+ (parser--debug
+ (message "sub-rhs: %s" sub-rhs))
;; For each x in FIRST(αu)
(dolist (f rhs-rest-first)
+ (parser--debug
+ (message "f: %s" f))
;; Add [B -> . β, x] to v-set(e), provided it
is not already there
(unless (gethash `(e ,rhs-first nil ,sub-rhs
,f) lr-item-exists)
@@ -740,6 +743,8 @@
(when (parser--valid-non-terminal-p lr-item-suffix-first)
(let ((lr-item-suffix-rest-first (parser--first
lr-item-suffix-rest)))
+ (unless lr-item-suffix-rest-first
+ (setq lr-item-suffix-rest-first (list nil)))
(let ((sub-production (parser--get-grammar-rhs
lr-item-suffix-first)))
;; For each production with B as LHS
