Symbol.Type 在 Antlr4 中无法识别

Question

我目前正在学习 Antlr4。我尝试运行:

文档中有一个示例

DefPhase.java.

import org.antlr.v4.runtime.ParserRuleContext;
import org.antlr.v4.runtime.Token;
import org.antlr.v4.runtime.tree.ParseTreeProperty;

public class DefPhase extends CymbolBaseListener {
    ParseTreeProperty<Scope> scopes = new ParseTreeProperty<Scope>();
    GlobalScope globals;
    Scope currentScope; // define symbols in this scope
    public void enterFile(CymbolParser.FileContext ctx) {
        globals = new GlobalScope(null);
        currentScope = globals;
    }
    
    public void exitFile(CymbolParser.FileContext ctx) {
        System.out.println(globals);
    }

    public void enterFunctionDecl(CymbolParser.FunctionDeclContext ctx) {
        String name = ctx.ID().getText();
        int typeTokenType = ctx.type().start.getType();
        Symbol.Type type = CheckSymbols.getType(typeTokenType);
        
        // push new scope by making new one that points to enclosing scope
        FunctionSymbol function = new FunctionSymbol(name, type, currentScope);
        currentScope.define(function); // Define function in current scope
        saveScope(ctx, function);      // Push: set function's parent to current
        currentScope = function;       // Current scope is now function scope
    }

    void saveScope(ParserRuleContext ctx, Scope s) { scopes.put(ctx, s); }

    public void exitFunctionDecl(CymbolParser.FunctionDeclContext ctx) {
        System.out.println(currentScope);
        currentScope = currentScope.getEnclosingScope(); // pop scope
    }

    public void enterBlock(CymbolParser.BlockContext ctx) {
        // push new local scope
        currentScope = new LocalScope(currentScope);
        saveScope(ctx, currentScope);
    }

    public void exitBlock(CymbolParser.BlockContext ctx) {
        System.out.println(currentScope);
        currentScope = currentScope.getEnclosingScope(); // pop scope
    }

    public void exitFormalParameter(CymbolParser.FormalParameterContext ctx) {
        defineVar(ctx.type(), ctx.ID().getSymbol());
    }

    public void exitVarDecl(CymbolParser.VarDeclContext ctx) {
        defineVar(ctx.type(), ctx.ID().getSymbol());
    }

    void defineVar(CymbolParser.TypeContext typeCtx, Token nameToken) {
        int typeTokenType = typeCtx.start.getType();
        Symbol.Type type = CheckSymbols.getType(typeTokenType);
        VariableSymbol var = new VariableSymbol(nameToken.getText(), type);
        currentScope.define(var); // Define symbol in current scope
    }
}

由于某种原因 Symbol.Type 无法识别。翻了一下好像之前的Antlr有个库叫symtab。最新的是 1.0.8。该库包含所有相关定义，但仍不包含 Symbol.Type。 Anltr4 是否有专门的符号表？

关于这个问题我真的需要一些帮助

Answer 1

我想你说的这个例子是这个：https://github.com/remenska/Grammars/blob/master/book-examples/listeners/DefPhase.java

如果您查看它所在的包，您会发现类型 Symbol (https://github.com/remenska/Grammars/blob/master/book-examples/listeners/Symbol.java) 并且它具有字段类型。也许你可以以某种方式使用它。所以它似乎真的来自这本书的例子。

Symbol.Type 在 Antlr4 中无法识别

Symbol.Type unrecognized in Antlr4

java

antlr

antlr4

antlr3