Add parser

[phdru.name/cgi-bin/blog-ru/search-tags.git] / parse_query.py

diff --git a/parse_query.py b/parse_query.py
index 4533413f783bd163efca15393822c4d38172cb0a..c74eb78d21a29a5d33ec85af523ed85266b41796 100644 (file)
--- a/parse_query.py
+++ b/parse_query.py
@@ -18,3 +18,35 @@ def t_error(t):
     """Avoid warnings on stderr"""
 
 lexer = lex.lex()
+
+def p_expression_name(p):
+    """expression : NAME"""
+    p[0] = ('NAME', p[1])
+
+def p_expression_and(p):
+    """expression : expression AND_OP expression"""
+    p[0] = ('AND', p[1], p[3])
+
+def p_expression_not(p):
+    """expression : NOT_OP expression"""
+    p[0] = ('NOT', p[2])
+
+def p_expression_or(p):
+    """expression : expression OR_OP expression"""
+    p[0] = ('OR', p[1], p[3])
+
+def p_expression_parens(p):
+    """expression : '(' expression ')'"""
+    p[0] = ('PARENS', p[2])
+
+def p_error(p):
+    """Avoid warnings on stderr"""
+    yacc.restart()
+
+precedence = (
+    ('left', 'OR_OP'),
+    ('left', 'AND_OP'),
+    ('right', 'NOT_OP'),
+)
+
+parser = yacc.yacc()