bink@aplcen.apl.jhu.edu (Ubben Greg) (08/15/89)
What are the advantages and disadvantages of using .if \w'\\$1' ... instead of .if !'\\$1'' ... in DWB 2.0 DiTroff macros? Although the latter seems more readable, I've seen the former used enough times to wonder about it. I apologize for the trivial nature of this question, but I want my macros to be as robust as possible. You TROFF wizards might offer your E-mail address if you object to this posting (it's much too low-level to be covered in any references I know of). -- Greg Ubben bink@aplcen.apl.jhu.edu !mimsy!aplcen!bink (I think)
henry@utzoo.uucp (Henry Spencer) (08/16/89)
In article <2658@aplcen.apl.jhu.edu> bink@aplcen.apl.jhu.edu (Ubben Greg) writes: >What are the advantages and disadvantages of using > .if \w'\\$1' ... >instead of > .if !'\\$1'' ... >in DWB 2.0 DiTroff macros? ... They're two different things. The first asks if the width of the string is non-zero. The second asks whether there are any characters in it. Remember that there are such things as zero-width characters. People who use the first form to test for an empty string have goofed. -- V7 /bin/mail source: 554 lines.| Henry Spencer at U of Toronto Zoology 1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu