how to create additional to CST attribute in AST ?

[Viktor Suvorov <viksuv@xxxxxxxxx>]

Hello,

I want to add attribute into AST class, which have no
relation to grammar. This attribute will be filled
during semantic analyses stage. 

For example, i want to add "error" attribute to AST
classes. Or I might wnat to add "id" attribute for
some classes.

I can, of cource, modify generated AST classes. But I
hope there is workaround, which allows to avoid such
step.

As example, consider following valid grammar.

/*-----------------------------------*/
Productions
/*-----------------------------------*/

lib_elem {-> lib_elem} = tk_program
[name]:tk_identifier tk_endprogram {-> New
lib_elem.program(name)}
;

/*-----------------------------------------*/
Abstract Syntax Tree
/*-----------------------------------------*/

lib_elem = {program} [name]:tk_identifier
;

I would like to add additional field "id" which can
store "tk_identifier" to production lib_elem in AST:

lib_elem = {program} [name]:tk_identifier
[id]:tk_identifier
;

Is it possible to modify CST production lib_elem in
such way, that grammar would be valid ? Constructions
like 

lib_elem {-> lib_elem} = tk_program
[name]:tk_identifier tk_endprogram {-> New
lib_elem.program(name, Null)}
;

are not working for me ... .

I attached valid and "would like to be" grammars.

Thank you,
Viktor


 
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Package parsers.aspect;

/*--------------------------------------------------*/
Helpers
/*--------------------------------------------------*/

	hlp_program = 'PROGRAM';
	hlp_endprogram = 'END_PROGRAM';

	hlp_tab 	= 9;
	hlp_cr 		= 13;
	hlp_lf 		= 10;
	hlp_eol 	= (hlp_cr hlp_lf) | hlp_cr | hlp_lf; 
	hlp_space	= ' ';
	hlp_letter 	= ['A' .. 'Z'] | ['a' .. 'z'];
	hlp_digit 	= ['0' .. '9'];
	hlp_id_head	= (hlp_letter | ('_' (hlp_letter | hlp_digit)));
	hlp_id_tail	= (('_')? (hlp_letter | hlp_digit))*;
	hlp_identifier = hlp_id_head hlp_id_tail;
/*----------------------------------------------------*/
Tokens
/*----------------------------------------------------*/

tk_program = hlp_program;
tk_endprogram = hlp_endprogram;

tk_ignore = hlp_tab | hlp_eol | hlp_space;

tk_identifier = hlp_identifier;

/*-------------------------------------------------*/
Ignored Tokens
/*-------------------------------------------------*/

tk_ignore;

/*---------------------------------------------------*/
Productions
/*----------------------------------------------------*/

aspect {-> aspect} = 
	lib_elem*	{-> New aspect([lib_elem.lib_elem])}
;

lib_elem {-> lib_elem} = tk_program [name]:tk_identifier tk_endprogram {-> New lib_elem.program(name)}
;

/*-----------------------------------------*/
Abstract Syntax Tree
/*-----------------------------------------*/

aspect = [lib_elems]:lib_elem*
;

lib_elem =	{program} [name]:tk_identifier
;

Package parsers.aspect;

/*--------------------------------------------------*/
Helpers
/*--------------------------------------------------*/

	hlp_program = 'PROGRAM';
	hlp_endprogram = 'END_PROGRAM';

	hlp_tab 	= 9;
	hlp_cr 		= 13;
	hlp_lf 		= 10;
	hlp_eol 	= (hlp_cr hlp_lf) | hlp_cr | hlp_lf; 
	hlp_space	= ' ';
	hlp_letter 	= ['A' .. 'Z'] | ['a' .. 'z'];
	hlp_digit 	= ['0' .. '9'];
	hlp_id_head	= (hlp_letter | ('_' (hlp_letter | hlp_digit)));
	hlp_id_tail	= (('_')? (hlp_letter | hlp_digit))*;
	hlp_identifier = hlp_id_head hlp_id_tail;
/*----------------------------------------------------*/
Tokens
/*----------------------------------------------------*/

tk_program = hlp_program;
tk_endprogram = hlp_endprogram;

tk_ignore = hlp_tab | hlp_eol | hlp_space;

tk_identifier = hlp_identifier;

/*-------------------------------------------------*/
Ignored Tokens
/*-------------------------------------------------*/

tk_ignore;

/*---------------------------------------------------*/
Productions
/*----------------------------------------------------*/

aspect {-> aspect} = 
	lib_elem*	{-> New aspect([lib_elem.lib_elem])}
;

lib_elem {-> lib_elem} = tk_program [name]:tk_identifier tk_endprogram {-> New lib_elem.program(name, Null)}
;

/*-----------------------------------------*/
Abstract Syntax Tree
/*-----------------------------------------*/

aspect = [lib_elems]:lib_elem*
;

lib_elem =	{program} [name]:tk_identifier [id]:identifier
;