Question

I have a question regarding Antlr, I am building a simple parser with it but I can t traverse the tree. I have found many online tutorials and they use a getAst(); function of the Parser class. Does anyone have any experience with this? I have the feeling that the way of doing this differs per version.

grammar SimpleCalc;

options 
{
    output=AST; 
} 

tokens {
    PLUS    =  +  ;
    MINUS   =  -  ;
    MULT    =  *  ;
    DIV =  /  ;
    SEMICOLON =  ; ;
    EQUAL =  = ;
    COMMA =  , ;
    BRACKETL =  ( ;
    BRACKETR =  ) ;
}

没有人对如何以替代方式tra树有任何想法或建议?

Answer 1

www.un.org/Depts/DGACM/index_french.htm CommonAST, 用于ANTLR v2.x.

ANTLR v3.x use CommonTree. 在界定<代码>output=AST时,所有终端管理人的规则均退回了>>>> 编码如果有getTree(>)方法,你可以使用树苗。

另见前次Q&A,其中显示了在分配一些投入后如何持有AST:。 • 如何生产利用国家航空航天中心建造的AST?

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