diff options
Diffstat (limited to 'doc/groff.texinfo')
| -rw-r--r-- | doc/groff.texinfo | 41 |
1 files changed, 26 insertions, 15 deletions
diff --git a/doc/groff.texinfo b/doc/groff.texinfo index 190b801d..cbfb5589 100644 --- a/doc/groff.texinfo +++ b/doc/groff.texinfo @@ -6829,7 +6829,7 @@ The following example defines strings to begin and end a superscript: @Example -.ds @{ \v'-.3m'\s'\Es[.s]*60/100' +.ds @{ \v'-.3m'\s'\En[.s]*60/100' .ds @} \s0\v'.3m' @endExample @@ -10683,7 +10683,7 @@ Note that a page can't be ejected if @code{vpt} is set to zero. @endDefreq @Defreq {wh, dist [@Var{macro}]} -Set a page location trap. Positive values for @var{dist} set +Set a page location trap. Non-negative values for @var{dist} set the trap relative to the top of the page; negative values set the trap relative to the bottom of the page. Default scaling indicator is @samp{v}. @@ -10724,7 +10724,8 @@ It is possible to have more than one trap at the same location; to do so, the traps must be defined at different locations, then moved together with the @code{ch} request; otherwise the second trap would replace the first one. Earlier defined traps hide later defined traps if moved to the same -position (the many empty lines caused by the @code{bp} request are omitted): +position (the many empty lines caused by the @code{bp} request are omitted +in the following example): @Example .de a @@ -10774,9 +10775,9 @@ traps. Change the location of a trap. The first argument is the name of the macro to be invoked at the trap, and the second argument is the new location for the trap -(note that the parameters are specified the opposite of the @code{wh} -request). This is useful for building up footnotes in a diversion to -allow more space at the bottom of the page for them. +(note that the parameters are specified in opposite order as in the +@code{wh} request). This is useful for building up footnotes in a +diversion to allow more space at the bottom of the page for them. Default scaling indicator for @var{dist} is @samp{v}. If @var{dist} is missing, the trap is removed. @@ -10844,6 +10845,16 @@ Another line. @endExample @endDefreg +@cindex diversions, and traps +@cindex traps, and diversions +An important fact to consider while designing macros is that diversions and +traps do not interact normally. For example, if a trap invokes a header +macro (while outputting a diversion) which tries to change the font on the +current page, the effect will not be visible before the diversion has +completely been printed (except for input protected with @code{\!} or +@code{\?}) since the data in the diversion is already formatted. In most +cases, this is not the expected behaviour. + @c --------------------------------------------------------------------- @node Diversion Traps, Input Line Traps, Page Location Traps, Traps @@ -10858,7 +10869,7 @@ Another line. @cindex trap, diversion, setting (@code{dt}) Set a trap @emph{within} a diversion. @var{dist} is the location of the trap -(identical to the @code{.wh} request; default scaling indicator is +(identical to the @code{wh} request; default scaling indicator is @samp{v}) and @var{macro} is the name of the macro to be invoked. The number register @code{.t} still works within diversions. @xref{Diversions}, for more information. @@ -10899,9 +10910,9 @@ next @var{n}@tie{}lines in a bold font. @cindex interrupted lines and input line traps (@code{itc}) @cindex traps, input line, and interrupted lines (@code{itc}) @cindex lines, interrupted, and input line traps (@code{itc}) -The @code{itc} request is identical, -except that a line interrupted with @code{\c} -counts as one input line. +The @code{itc} request is identical +except that an interrupted text line (ending with @code{\c}) +is not counted as a separate line. Both requests are associated with the current environment (@pxref{Environments}); switching to another environment disables the @@ -11047,7 +11058,7 @@ Diversions may be nested. The read-only number register @code{.z} contains the name of the current diversion (this is a string-valued register). The read-only number register @code{.d} contains the current vertical place in the diversion. If not in a diversion it is the same -as the register @code{nl}. +as register @code{nl}. @endDefreg @Defreg {.h} @@ -11125,15 +11136,15 @@ and @code{dl} contain the vertical and horizontal size of the diversion. @cindex transparent output (@code{\!}, @code{\?}) @cindex output, transparent (@code{\!}, @code{\?}) Prevent requests, macros, and escapes from being -interpreted when read into a diversion. This takes the given text -and @dfn{transparently} embeds it into the diversion. This is useful for +interpreted when read into a diversion. Both escapes take the given text +and @dfn{transparently} embed it into the diversion. This is useful for macros which shouldn't be invoked until the diverted text is actually output. The @code{\!} escape transparently embeds text up to and including the end of the line. The @code{\?} escape transparently embeds text until the next -occurrence of the @code{\?} escape. For example: +occurrence of the @code{\?} escape. Example: @Example \?@var{anything}\? @@ -11185,7 +11196,7 @@ at all; its argument is simply ignored. @cindex @code{output} request, and @code{\!} @Defreq {output, string} Emit @var{string} directly to the @code{gtroff} intermediate output -(subject to copy-mode interpretation); this is similar to @code{\!} used +(subject to copy-mode interpretation); this is similar to @code{\!} used at the top level. An initial double quote in @var{string} is stripped off to allow initial blanks. |