ANTLR:如何使用 ANTLR 4 根据索引位置解析固定长度的文本文件? [英] ANTLR : How to parse fixed length text file based on index position using ANTLR 4?

问题描述

输入:

101 04200001312345678981107291600A094101US FORD NA             TEST COMPANY101                
5225TEST COMPANY                       11234567898PPDTEST BUYS 110801110801   1098765430000001

以上各行是 94 个字符的固定长度.

Above lines are 94 char fixed length.

预期输出:基于此输入，Antlr 语法应根据索引位置进行解析.

Expected output: Based on this input , Antlr grammar should parse based on index positions.

例如:如果解析器在第一行的起始字符中识别出1".它应该将整行识别为一个单独的字符串，如 HEADER1.

For Example: If parser identify '1' in starting char of line one. It should recognize entire line as a separate string as HEADER1.

与解析器在第二行的起始索引中找到5"一样.它应该将整行识别为一个单独的字符串，如 HEADER2.

Same as if parser finds '5' in starting index of line two. It should recognize entire line as a separate string as HEADER2.

推荐答案

fragment Digit: '0'..'9' ;
fragment Alpha: '_' | 'A'..'Z';

Number: Digit+ ;
Alphanumeric: (Letter | Digit)+ ;

header1: '1' Alphanumeric+
header2: '5' Alphanumeric+

WS
  : (' ' | '\t') -> skip //channel (HIDDEN) 
  ;

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