英文:
Antlr4 - Get token name
问题
以下是您要翻译的代码部分：
// 差异化`complexType`和`builtinType`，可以查看哪个不为null。
// 但是，如果我想区分`bool`和`u8`，我该怎么做呢？
// 这个问题可以回答我的问题，但是它是针对Antlr3的。
请注意，这段代码是关于如何在ANTLR中区分bool和u8类型的问题。
英文:
I have following (reduced) grammar:
grammar Test;
IDENTIFIER: [a-z]+ [a-zA-Z0-9]*;
WS: [ \t\n] -> skip;
compilationUnit:
field* EOF;
field:
type IDENTIFIER;
type:
(builtinType|complexType) ('[' ']')*;
builtinType:
'bool' | 'u8';
complexType:
IDENTIFIER;
And following program:
import org.antlr.v4.runtime.CharStreams;
import org.antlr.v4.runtime.CommonTokenStream;
public class Main{
public static void main(String[] args){
TestLexer tl=new TestLexer(CharStreams.fromString("u8 foo bool bar complex baz complex[][] baz2"));
TestParser tp=new TestParser(new CommonTokenStream(tl));
TestParser.CompilationUnitContext cuc=tp.compilationUnit();
System.out.println("CompilationUnit:"+cuc);
for(var field:cuc.field()){
System.out.println("Field: "+field);
System.out.println("Field.type: "+ field.type());
System.out.println("Field.type.builtinType: "+field.type().builtinType());
System.out.println("Field.type.complexType: "+field.type().complexType());
if(field.type().complexType()!=null)
System.out.println("Field.type.complexType.IDENTIFIER: "+field.type().complexType().IDENTIFIER());
}
}
}
To differentiate complexType and builtinType, I can look, which is not-null.
But, if I want to distinguish between bool and u8, how can I do that?
This question would answer my question, but it is for Antlr3.
答案1
得分: 2
要么使用替代标签：
builtinType
: 'bool' #builtinTypeBool
| 'u8' #builtinTypeU8
;
和/或在词法分析器中定义这些标记：
builtinType
: BOOL
| U8
;
BOOL : 'bool';
U8 : 'u8';
这样，您可以更轻松地检查访问者/监听器中的标记类型：
YourParser.BuiltinTypeContext ctx = ...
if (ctx.start.getType() == YourLexer.BOOL) {
// 它是一个 BOOL 标记
}
英文:
Either use alternative labels:
builtinType
: 'bool' #builtinTypeBool
| 'u8' #builtinTypeU8
;
and/or define these tokens in the lexer:
builtinType
: BOOL
| U8
;
BOOL : 'bool';
U8 : 'u8';
so that you can more easily inspect the token's type in a visitor/listener:
YourParser.BuiltinTypeContext ctx = ...
if (ctx.start.getType() == YourLexer.BOOL) {
// it's a BOOL token
}
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