Re: [Groff] condition: OR of two string comparisons

[Ralph Corderoy]

Hi Werner,

> Having `.if x' instead of a new keyword `.ifx' is appealing to me.
> Assuming that we have a global register to activate a novel
> interpretation of expressions (as suggested by Colin), we could indeed
> simply stay with the currently available keywords.  A similar approach
> is already used by Heirloom troff to define various extensions.
> 
> Note, however, that it gets tricky if groff tries to execute `modern'
> macros in compatibility mode (.cp 0), cf. `.de1' and friends.

I'd like to read `.nr i 3+4*6' and know if that's 27 or 42 without
having to know the value of a `new expression syntax' register;  code is
often read by jumping in at a point and not following from the start of
execution.  Altering the syntax, with a new request or invalid old
expression syntax, gives me that knowledge on the spot.

Cheers, Ralph.