[elpa] externals/parser-generator 44eb5a3 062/434: Passing unit test for V(e) and V(S)

[ELPA Syncer]

branch: externals/parser-generator
commit 44eb5a3eb66550edf275e9a3d0e9dea2de9c7e3c
Author: Christian Johansson <christian@cvj.se>
Commit: Christian Johansson <christian@cvj.se>

    Passing unit test for V(e) and V(S)
---
 parser.el           | 18 ++++++++++++++----
 test/parser-test.el | 12 +++++-------
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/parser.el b/parser.el
index f33c556..fb09c89 100644
--- a/parser.el
+++ b/parser.el
@@ -11,7 +11,7 @@
 
 
 (defvar parser--debug
-  t
+  nil
   "Whether to print debug messages or not.")
 
 (defvar parser--table-non-terminal-p
@@ -677,6 +677,8 @@
 
                   ;; Check if RHS starts with a non-terminal
                   (let ((rhs-first (car rhs)))
+                    (parser--debug
+                     (message "rhs-first: %s" rhs-first))
                     (when (parser--valid-non-terminal-p rhs-first)
                       (let ((rhs-rest (append (cdr rhs) suffix)))
                         (let ((rhs-rest-first (parser--first rhs-rest)))
@@ -685,9 +687,18 @@
                           (unless rhs-rest-first
                             (setq rhs-rest-first '((e))))
                           (let ((sub-production (parser--get-grammar-rhs 
rhs-first)))
+                            (parser--debug
+                               (message "sub-production: %s" sub-production))
 
                             ;; For each production with B as LHS
                             (dolist (sub-rhs sub-production)
+
+                              ;; Set follow to nil if it's the e-identifier
+                              (when (and
+                                     (= (length sub-rhs) 1)
+                                     (eq (car sub-rhs) 'e))
+                                (setq sub-rhs nil))
+
                               (parser--debug
                                (message "sub-rhs: %s" sub-rhs))
 
@@ -707,11 +718,10 @@
          (message "V(e) = %s" lr-items-e))
         (puthash '(e) lr-items-e lr-items))
 
-      ;; Do step 2 only if prefix is not the e identifier
+      ;; 2 Suppose that we have constructed V(X1,X2,...,Xi-1) we construct 
V(X1,X2,...,Xi) as follows:
       (unless (and
                (= (length γ) 1)
                (eq (car γ) 'e))
-        ;; 2 Suppose that we have constructed V(X1,X2,...,Xi-1) we construct 
V(X1,X2,...,Xi) as follows:
         (let ((prefix-acc)
               (prefix-previous (gethash '(e) lr-items)))
           (dolist (prefix γ)
@@ -776,7 +786,7 @@
               (puthash prefix-acc lr-new-item lr-items)))))
 
       (parser--debug
-         (message "γ: %s" γ))
+       (message "γ: %s" γ))
       (gethash γ lr-items))))
 
 
diff --git a/test/parser-test.el b/test/parser-test.el
index fa0517f..87189e1 100644
--- a/test/parser-test.el
+++ b/test/parser-test.el
@@ -231,15 +231,13 @@
   (parser--set-grammar '((Sp S) (a b) ((Sp S) (S (S a S b)) (S e)) Sp))
   (parser--set-look-ahead-number 1)
 
-  '((S (e) nil (e)) (S (e) nil (a)))
-
   (should
    (equal
-    '((Sp nil (S) (e))
-      (S nil (S a S b) (e))
-      (S nil (S a S b) (a))
-      (S nil nil (e))
-      (S nil nil (a)))
+    '((S nil nil (a))
+    (S nil (S a S b) (a))
+    (S nil nil (e))
+    (S nil (S a S b) (e))
+    (Sp nil (S) (e)))
     (parser--lr-items 'e)))
   (message "Passed V(e)")