fix strings and conditions redefinition and grammar

avast · Jan 29, 2024 · 9623d2b · 9623d2b
1 parent 22eedaf
commit 9623d2b
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Showing 3 changed files with 23 additions and 6 deletions.
diff --git a/src/parser/grammar/expressions.rs b/src/parser/grammar/expressions.rs
@@ -15,11 +15,28 @@ pub(crate) fn block_expr(p: &mut Parser) {
 }
 
 pub(super) fn rule_body(p: &mut Parser) {
+    let mut has_strings = false;
+    let mut has_condition = false;
     while !p.at(EOF) && !p.at(RBRACE) {
         match p.current() {
             // add metadata later
-            STRINGS => strings(p),
-            CONDITION => condition(p),
+            STRINGS => {
+                if has_strings {
+                    p.error("only one strings block is allowed");
+                }
+                if has_condition {
+                    p.error("strings block must come before condition block");
+                }
+                strings(p);
+                has_strings = true;
+            }
+            CONDITION => {
+                if has_condition {
+                    p.error("only one condition block is allowed");
+                }
+                condition(p);
+                has_condition = true;
+            }
             _ => {
                 p.err_and_bump("expected strings or condition");
             }

diff --git a/src/parser/parser.rs b/src/parser/parser.rs
@@ -112,7 +112,6 @@ impl<'t> Parser<'t> {
 
     pub(crate) fn err_recover(&mut self, message: &str, recovery: TokenSet) {
         if self.at_ts(recovery) {
-            println!("recovery: {:?}", self.current());
             self.error(message);
             return;
         }

diff --git a/yara_subset.grammar b/yara_subset.grammar
@@ -1,12 +1,13 @@
 SOURCE -> RULE | eps.
 RULE -> rule identifier lbrace RULEBODY rbrace.
-RULEBODY -> STRINGS RULEBODY | CONDITION RULEBODY | eps.
+RULEBODY -> STRINGS CONDITION | CONDITION .
 STRINGS -> string colon STRINGSBODY.
 CONDITION -> condition colon CONDITIONBODY.
 STRINGSBODY -> variable assign string STRINGSBODY | eps.
-CONDITIONBODY -> LITERAL CONDITIONBODY | OPERATOR CONDITIONBODY | eps.
+CONDITIONBODY -> LITERAL EXPRESSION | OPERATOR EXPRESSION .
+EXPRESSION -> LITERAL EXPRESSION | OPERATOR EXPRESSION | eps.
 LITERAL -> variable | BOOLEAN.
 BOOLEAN -> true | false.
 OPERATOR -> and | or | 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+%7C+CONDITION+%7C+eps.%0D%0ASTRINGS+-%3E+string+colon+STRINGSBODY.%0D%0ACONDITION+-%3E+condition+colon+CONDITIONBODY.%0D%0ASTRINGSBODY+-%3E+variable+assign+string+STRINGSBODY+%7C+eps.%0D%0ACONDITIONBODY+-%3E+LITERAL+EXPRESSION+%7C+OPERATOR+EXPRESSION+%7C+eps.%0D%0ALITERAL+-%3E+variable+%7C+BOOLEAN.%0D%0ABOOLEAN+-%3E+true+%7C+false.%0D%0AOPERATOR+-%3E+and+%7C+or+%7C+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+CONDITIONBODY.%0D%0ASTRINGSBODY+-%3E+variable+assign+string+STRINGSBODY+%7C+eps.%0D%0ACONDITIONBODY+-%3E+LITERAL+EXPRESSION+%7C+OPERATOR+EXPRESSION+.%0D%0AEXPRESSION+-%3E+LITERAL+EXPRESSION+%7C+OPERATOR+EXPRESSION+%7C+eps.%0D%0ALITERAL+-%3E+variable+%7C+BOOLEAN.%0D%0ABOOLEAN+-%3E+true+%7C+false.%0D%0AOPERATOR+-%3E+and+%7C+or+%7C+not.