Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!ucbvax!TAMVM1.BITNET!X066TR From: X066TR@TAMVM1.BITNET ("Thomas J. Reid") Newsgroups: comp.text.tex Subject: Re: \the \baselineskip Message-ID: <39B8979880015BC3@post-office.uh.edu> Date: 17 Feb 91 23:03:33 GMT References: Sender: daemon@ucbvax.BERKELEY.EDU Organization: Texas A&M University Computing Services Center Lines: 33 On Sun, 17 Feb 91 16:48:31 EST Michael Barr said: > ... For some reason, it doesn't do this if instead of \the you >execute \showthe\baselineskip. I don't understand why the two behave >differently; I can only assume one takes place in the stomach and the >other in the esophagous, or something like that. TeX's digestive tract >is something of a black hole, at least to me. Michael, You must have tried the same thing I did when I saw the first note: run TeX substituting \showthe for \the. I noticed the same thing you did, but did not think anything of it at the time. After getting your note, I studied the problem again. It turns out that \the and \showthe are getting processed in different parts of TeX's "digestive tract"; \the in its "mouth," and \showthe in its "stomach." This explains why the two are different. The original poster asked me off-list for a pointers on understanding when and where expansions take place. The best place that I've found in _The_TeXbook_ is on page 373: "TeX's control sequences are divided into two main categories, 'expandable' and 'unexpandable'; the former category includes all macros and \if...\fi tests, as well as special operations like \the and \input, while the latter category includes the primitive commands listed in Chapter 24. The expansion of expandable tokens takes place in TeX's 'mouth,' but primitive commands (including assignments) are done in TeX's 'stomach.'" The \showthe primitive is among those listed in Chapter 24 (on page 279). ---Tom Reid