从令牌创建语法树 [英] Creating a syntax tree from tokens

问题描述

我正在尝试为 TI-BASIC 语法创建一个微型解释器。 / p>

这是我要解释的TI-BASIC片段

  A->（2+（3 * 3））
  

我已经标记了代码

  Token {type = VARIABLE，content ='A'} 
 Token {type = ASSIGN，content ='null'} 
令牌{type = L_PAREN，content ='null'} 
 Token {type = NUM​​，content ='2'} 
 Token {type = ADD ，content ='null'} 
令牌{type = L_PAREN，content ='null'} 
令牌{type = NUM​​，content ='3'} 
令牌{type = MULT，content ='null'} 
令牌{type = NUM​​，内容='3'} 
令牌{type = R_PAREN，内容='null'} 
令牌{type = R_PAREN，content =' null'} 
令牌{type = EOS，内容='null'}（语句结尾）
令牌{type = EOF，内容='null'}（文件结尾）
  

如果我没记错的话，我认为下一步是将这些表示为kens作为语句树（抽象语法树？）

 分配（->）
 / \ 
 / \ 
 A加
 / \ 
 / \ 
 2乘以
 / \ 
 / \ 
 3 3 
  

我想知道如何创建该树，或者这是否正确要做的事。谢谢！

解决方案

简单的答案是，您需要为TI-Basic编写一个解析器。您已经编写了词法分析器（词法分析器），现在需要编写语法分析器。

有很多方法可以执行此操作，但是解析器的Wikipedia页面是一个不错的起点：解析器示例。

I'm trying to create a tiny interpreter for TI-BASIC syntax.

This is a snippet of TI-BASIC I'm trying to interpret

A->(2+(3*3))

I've tokenized the code above into this sequence of tokens:

Token{type=VARIABLE, content='A'}
Token{type=ASSIGN, content='null'}
Token{type=L_PAREN, content='null'}
Token{type=NUM, content='2'}
Token{type=ADD, content='null'}
Token{type=L_PAREN, content='null'}
Token{type=NUM, content='3'}
Token{type=MULT, content='null'}
Token{type=NUM, content='3'}
Token{type=R_PAREN, content='null'}
Token{type=R_PAREN, content='null'}
Token{type=EOS, content='null'} (end of statement)
Token{type=EOF, content='null'} (end of file)

If I'm not mistaken, I think the next step from here is to represent these tokens as a tree of statements (Abstract Syntax Tree?)

 Assignment (->)
    / \
   /   \
  A    Add
       /\
      /  \
     2  Multiply
           /\
          /  \
         3    3

I'm wondering how I should go about creating this tree, or if that's even the correct thing to do. Thanks!

解决方案

The simple answer is that you need to write a parser for TI-Basic. You've already written your lexer (lexical analyzer) and now you need to write your syntax analyzer.

There are many ways of doing this, but the Wikipedia page on parsers is a good place to start: examples of parsers.

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