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.