Reorder handling: AND - OR - NOT

[phdru.name/cgi-bin/blog-ru/search-tags.git] / parser / grammar

diff --git a/parser/grammar b/parser/grammar
index 5a0c3d53a1a9c8d5f5d270804ed7f3150e0637bc..b88b9eddfa5fcada98134fe649558c167fd93a85 100644 (file)
--- a/parser/grammar
+++ b/parser/grammar
@@ -8,8 +8,8 @@
 # Parentheses are allowed to group expressions; for example:
 #  TAG & (TAG | TAG)
 #  !(TAG | TAG)
-# Allowed operators: conjunction - & &&
-#                    disjunction - | ||
+# Allowed operators: conjunction - & && AND and
+#                    disjunction - | || OR or
 #                    negation    - !
 # This  is a simple version of the grammar and it allows
 # rather stupid expressions, like !!TAG or ((TAG)); in the future
@@ -26,9 +26,33 @@ NOT_OP : '!'
 SP1 : '[ \t]+'
 
 expression : NAME
-           | expression AND_OP AND_OP expression
-           | expression AND_OP expression
-           | expression OR_OP OR_OP expression
-           | expression OR_OP expression
-           | NOT_OP expression
-           | '(' expression ')'
+           | expression SP0 AND_OP AND_OP SP0 expression
+           | expression SP0 AND_OP SP0 expression
+           | l_expression and_word r_expression
+           | expression SP0 OR_OP OR_OP SP0 expression
+           | expression SP0 OR_OP SP0 expression
+           | l_expression or_word r_expression
+           | NOT_OP SP0 expression
+           | expression_parens
+
+l_expression : expression_parens
+             | expression_sp
+
+r_expression : expression_parens
+             | sp_expression
+
+expression_parens : '(' SP0 expression SP0 ')'
+
+sp_expression : SP1 expression
+
+expression_sp : expression SP1
+
+and_word : 'A' 'N' 'D'
+         | 'a' 'n' 'd'
+
+or_word : 'O' 'R'
+        | 'o' 'r'
+
+SP0 : SP1 | empty
+
+empty :