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Help with simple grammar [message #985956]

Fri, 16 November 2012 20:58

Andrew A

Messages: 9
Registered: June 2012

Junior Member

I have a grammar:

Model: statements+=Statement*;
	
Statement: Var | Macro | WS;

Var: '{' '#' value=ID '}' ;
	
Macro: '#macro' '{' value=ID'}';

This parsed succesfull

#macro{x}
{#v}

but this not:

#macro{x}
{#m}

and this is not:

#macro{x}
{#mac}

It seems to be that parser expects #macro (where #m or #mac)

I don't understand why. Could you help me, please?

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Re: Help with simple grammar [message #985965 is a reply to message #985956]

Fri, 16 November 2012 21:11

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi,

the problem is: keywords are terminals. and the lexer that reads terminals eats as much as it can

=>

Var: '{' '#' value=ID '}' ;

Macro: '#''macro' '{' value=ID'}';

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Help with simple grammar [message #986097 is a reply to message #985956]

Sun, 18 November 2012 19:22

Martin Mising name

Messages: 32
Registered: July 2009

Member

I keep getting caught out with this type of issue. To help me think it through I created Example1 and Example2 on this page.

Martin

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