Cleanup

Signed-off-by: Matthew Hayes <matthewha853@gmail.com>

Author: mhayes853

cactus-engine/src/engine.h

@@ -286,6 +286,7 @@ class GrammarVocabulary {
 class Grammar {
 public:
     Grammar();
+    Grammar(xgrammar::Grammar raw_grammar);
     ~Grammar() = default;
 
     static Grammar ebnf(const std::string& ebnf, const std::string& start_symbol = "root");
@@ -316,9 +317,6 @@ class Grammar {
     const xgrammar::Grammar& raw_value() const;
 
 private:
-    friend class GrammarMatcher;
-    Grammar(xgrammar::Grammar raw_grammar);
-
     xgrammar::Grammar grammar;
     bool is_universal_ = false;
 };

cactus-engine/src/grammar.cpp

@@ -88,18 +88,8 @@ Grammar Grammar::ebnf(const std::string& ebnf, const std::string& start_symbol)
 }
 
 Grammar Grammar::epsilon() {
-    return Grammar::structural_tag(R"({
-        "type": "structural_tag",
-        "format": {
-            "type": "repeat",
-            "min": 0,
-            "max": 0,
-            "content": {
-                "type": "const_string",
-                "value": "x"
-            }
-        }
-    })");
+    static auto grammar = Grammar::ebnf("root ::= \"\"");
+    return grammar;
 }
 
 Grammar Grammar::json() {