fix left recursion

avast · Jan 29, 2024 · 528b1f5 · 528b1f5
1 parent 77d208d
commit 528b1f5
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/yara_subset.grammar b/yara_subset.grammar
@@ -4,10 +4,11 @@ RULEBODY -> STRINGS CONDITION | CONDITION .
 STRINGS -> string colon STRINGSBODY.
 CONDITION -> condition colon EXPRESSION.
 STRINGSBODY -> variable assign string STRINGSBODY | eps.
-EXPRESSION -> EXPRESSION OPERATOR EXPRESSION | NOTOPERATOR EXPRESSION | LITERAL.
+EXPRESSION -> LITERAL EXPRESSION_2 | NOTOPERATOR EXPRESSION.
+EXPRESSION_2 -> OPERATOR EXPRESSION EXPRESSION_2 | eps.
 LITERAL -> variable | BOOLEAN.
 BOOLEAN -> true | false.
 OPERATOR -> and | or.
 NOTOPERATOR -> not.
 
-// https://smlweb.cpsc.ucalgary.ca/vital-stats.php?grammar=SOURCE+-%3E+RULE+%7C+eps.%0D%0ARULE+-%3E+rule+identifier+lbrace+RULEBODY+rbrace.%0D%0ARULEBODY+-%3E+STRINGS+CONDITION+%7C+CONDITION+.%0D%0ASTRINGS+-%3E+string+colon+STRINGSBODY.%0D%0ACONDITION+-%3E+condition+colon+EXPRESSION.%0D%0ASTRINGSBODY+-%3E+variable+assign+string+STRINGSBODY+%7C+eps.%0D%0AEXPRESSION+-%3E+EXPRESSION+OPERATOR+EXPRESSION+%7C+NOTOPERATOR+EXPRESSION+%7C+LITERAL.%0D%0ALITERAL+-%3E+variable+%7C+BOOLEAN.%0D%0ABOOLEAN+-%3E+true+%7C+false.%0D%0AOPERATOR+-%3E+and+%7C+or.%0D%0ANOTOPERATOR+-%3E+not.
+// https://smlweb.cpsc.ucalgary.ca/vital-stats.php?grammar=SOURCE+-%3E+RULE+%7C+eps.%0D%0ARULE+-%3E+rule+identifier+lbrace+RULEBODY+rbrace.%0D%0ARULEBODY+-%3E+STRINGS+CONDITION+%7C+CONDITION+.%0D%0ASTRINGS+-%3E+string+colon+STRINGSBODY.%0D%0ACONDITION+-%3E+condition+colon+EXPRESSION.%0D%0ASTRINGSBODY+-%3E+variable+assign+string+STRINGSBODY+%7C+eps.%0D%0AEXPRESSION+-%3E+LITERAL+EXPRESSION_2+%7C+NOTOPERATOR+EXPRESSION.%0D%0AEXPRESSION_2+-%3E+OPERATOR+EXPRESSION+EXPRESSION_2+%7C+eps.%0D%0ALITERAL+-%3E+variable+%7C+BOOLEAN.%0D%0ABOOLEAN+-%3E+true+%7C+false.%0D%0AOPERATOR+-%3E+and+%7C+or.%0D%0ANOTOPERATOR+-%3E+not.