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Diffstat (limited to 'doc')
-rw-r--r-- | doc/groff.texi | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/doc/groff.texi b/doc/groff.texi index 5c4af4fc9..7e300dbef 100644 --- a/doc/groff.texi +++ b/doc/groff.texi @@ -12571,8 +12571,19 @@ certain other @code{troff} implementations.@footnote{This refers to @code{vtroff}, a translator that would convert the C/A/T output from early-vintage @acronym{AT&T} @code{troff} to a form suitable for Versatec and Benson-Varian plotters.} +@end table + +If the first argument to an @code{if}, @code{ie}, or @code{while} +request begins with a non-alphanumeric character apart from @code{!} +(see below); it performs an @slanted{output comparison test}. +@footnote{Strictly, letters not otherwise recognized @emph{are} treated +as output comparison delimiters. For portability, it is wise to avoid +using letters not in the list above; for example, Plan@tie{}9 +@code{troff} uses @samp{h} to test a mode it calls @code{htmlroff}, and +GNU @code{troff} may provide additional operators in the future.} @cindex output comparison operator +@table @code @item @code{'}@var{xxx}@code{'}@var{yyy}@code{'} True if formatting the comparands @var{xxx} and @var{yyy} produces the same output commands. The delimiter need not be a neutral apostrophe: |