ANTLR:如何使用ANTLR 4根据索引位置解析定长文本文件? [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

以上各行的固定长度为94个字符.

Above lines are 94 char fixed length.

预期的输出:基于此输入，Antlr语法应基于索引位置进行解析.

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标识为"1".它应将整行识别为 HEADER1 作为单独的字符串.

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

就像解析器在第二行的起始索引中找到"5"一样.它应将整行识别为 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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