[antlr-interest] Lexer - length/position as token delimiter?

[angrymongoose]

Hello all,

I need to be able to parse messages of the form:

message : headers tag+ trailer;

tag : tag_id tag_body;

<< begin of file omitted>>
:23B:CRED
:32A:000612USD5443,99
:33B:USD5443,99
<< end of file omitted>>

The problem I am having is that the tag body uses position as the
element delimiter rather than a clearly defined character. For example
looking at the 32A line:

":32A:" is the tag id and "000612USD5443,99" is the
tag_body. 

The tag body in turn breaks down into a date "000612" (6), a
currency
code "USD"  (3), and an amount (1-15).

Is it possible to somehow parse the tag body using ANTLR using one
lexer/parser or I am stuck writing tag parsers by hand. I guess an
alternative is to use ANTLR to write parsers for each tag and have a
master parser invoke the subparsers?

Thanks in advance for any help/suggestions.

-Norman




 
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