Re: Newbie Dynamic Data Typing Help

[Hans Aberg]

[Please try to quote just relevant material.]

On 7 Oct 2005, at 21:13, Gill,Michael J wrote:

> Thanks for the tips, I'm trying the %union approach but am hung up on
> how to differentiate data types in the grammar.  I need to initialize
> VARs to either NUM or CHR types but only want to allow operations  
> (+, -,
> *, etc.) on NUM types, hoe do I differentiate VAR types in the  
> grammar?

It looks as though you are mixing the dynamically typed VAR with the  
statically typed CHR and NUM. If that is how it should be, one has to  
do what you are doing: in the actions, check for the dynamic type of  
VAR, impose a suitable conversion, or make an YYERROR. If VAR can be  
made statically typed, then you van use the Bison type system,  
without checks in the actions.

  Hans Aberg