Oliver Zeigermann wrote:
> OK, so you need a tree grammar that can parse complex boolean
> expressions, right?
>
> expression
> : ^((AND|OR) expression expression)
> | ^(('<'|'>'|'='|'!=') expression expression)
> | ^(('+'|'-'|'*'|'/') expression expression)
> | ID
> | literal
> ;
>
> Would that work?
>
> -Oliver
>
>
This grammar is not syntactically restrictive since it allows ^(AND 3
4). This will cause problems if you want to evaluate the tree since you
won't know the type of the return value of expression. It is better to
separate out arithmetic and logical expressions. Care must be taken to
establish if ID is arithmetic or logical.
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