[elpa] externals/parser-generator 65d9ce2 106/434: Fixed a bug with E-FREE-FIRST function and function that validates a set of LR-items

[ELPA Syncer]

branch: externals/parser-generator
commit 65d9ce2d5161c70b6c1ae861a57919dffbc84672
Author: Christian Johansson <christian@cvj.se>
Commit: Christian Johansson <christian@cvj.se>

    Fixed a bug with E-FREE-FIRST function and function that validates a set of 
LR-items
---
 parser-lr.el        |  4 +++-
 parser.el           | 21 ++++++++++++++++++---
 test/parser-test.el |  8 ++++++++
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/parser-lr.el b/parser-lr.el
index b46fb9d..9a33364 100644
--- a/parser-lr.el
+++ b/parser-lr.el
@@ -269,7 +269,9 @@
          (message "a-look-ahead: %s" a-look-ahead))
 
         ;; The only sets of LR items which need to be tested are those that 
contain a dot at the right end of a production
-        (unless a-look-ahead
+        (when (and
+               (nth 1 a)
+               (not a-look-ahead))
           (setq a-follow (nth 3 a))
 
           (parser--debug
diff --git a/parser.el b/parser.el
index 61df8fd..d4a110b 100644
--- a/parser.el
+++ b/parser.el
@@ -29,6 +29,10 @@
   nil
   "Generated F-sets for grammar.")
 
+(defvar parser--f-free-sets
+  nil
+  "Generated e-free F-sets for grammar.")
+
 (defvar parser--look-ahead-number
   nil
   "Current look-ahead number used.")
@@ -68,7 +72,8 @@
 
 (defun parser--clear-cache ()
   "Clear cache."
-  (setq parser--f-sets nil))
+  (setq parser--f-sets nil)
+  (setq parser--f-free-sets nil))
 
 (defun parser--distinct (elements)
   "Return distinct of ELEMENTS."
@@ -658,8 +663,13 @@
   (let ((productions (parser--get-grammar-productions))
         (k parser--look-ahead-number))
     (let ((i-max (length productions)))
+
       ;; Generate F-sets only once per grammar
-      (unless parser--f-sets
+      (unless (or
+               (and (not disallow-e-first)
+                    parser--f-sets)
+               (and disallow-e-first
+                    parser--f-free-sets))
         (let ((f-sets (make-hash-table :test 'equal))
               (i 0))
           (while (< i i-max)
@@ -695,6 +705,8 @@
                     (puthash production-lhs (nreverse f-p-set) f-set))))
               (puthash i f-set f-sets)
               (setq i (+ i 1))))
+          (if disallow-e-first
+              (setq parser--f-free-sets f-sets))
           (setq parser--f-sets f-sets)))
 
       (parser--debug
@@ -723,7 +735,10 @@
                      ((parser--valid-non-terminal-p symbol)
                       (parser--debug
                        (message "non-terminal symbol: %s" symbol))
-                      (let ((symbol-f-set (gethash symbol (gethash (1- i-max) 
parser--f-sets))))
+                      (let ((symbol-f-set))
+                        (if disallow-e-first
+                            (setq symbol-f-set (gethash symbol (gethash (1- 
i-max) parser--f-free-sets)))
+                          (setq symbol-f-set (gethash symbol (gethash (1- 
i-max) parser--f-sets))))
                         (parser--debug
                          (message "symbol-f-set: %s" symbol-f-set))
                         (when (> (length symbol-f-set) 1)
diff --git a/test/parser-test.el b/test/parser-test.el
index 7cb3ee8..681709c 100644
--- a/test/parser-test.el
+++ b/test/parser-test.el
@@ -313,6 +313,14 @@
     (parser--e-free-first 'S)))
   (message "Passed empty-free-first 2 with complex grammar")
 
+  (parser--set-look-ahead-number 1)
+  (parser--process-grammar)
+  (should
+   (equal
+    '((c))
+    (parser--e-free-first '(S b a))))
+  (message "Passed empty-free-first 1 with complex grammar")
+
   (message "Passed tests for (parser--empty-free-first)"))
 
 (defun parser-test--valid-grammar-p ()