> Ah, yes. In the manpage macros, this works similarly: all > paragraph macros reset the indent to what it "should" be > (so that any ".in" invocations within a paragraph will be > undone at the beginning of the next paragraph). That is, > ".TP" absolutely sets the indent to "something" + "extra", > and ".PP" sets it back to "something". > > The biggest difference is that ".TP" does not get the tag > as an argument, but instead reads it from the next line of > input: an input-line-count trap of one line is set and text > read for the tag is temporarily diverted, for the purpose of > determining whether the tag is wider than the extra indent > (the tag is set on a line by itself if it is). > > Since the input-line-count trap only counts "real" lines of > input, you can do fancy stuff such as special formatting of > the tag:
Thank you. I think I am beginning to understand this macro. I got a connected question about traps. The .SH macro can handle the section head- ing both as a parameter and the next input line, and in both cases the an-trap trap is invoked afted that line has been typeset. The trap is set by .it 1 an-trap, so I why is it fired after the section text even is it was passed to .SH as parameter? Are macro parameters handled as input lines? Anton
