john@basho.uucp (John Lacey) (03/28/91)
I have a problem with OzTeX 1.3. If I say `\def\foo#1\par{...}',
and then say `\foo text\par', I get #1 as four tokens, `t',
`e', `x', and `t'.
BUT, if instead I say `\foo text^^M^^M' (either just like that
or by actually pressing two returns), I get five tokens---the
obvious four and a trailing blank space.
What's the matter?
--
John Lacey 614 436 3773 73730,2250
john@basho.uucp or basho!john@cis.ohio-state.eduraymond@math.berkeley.edu (Raymond Chen) (03/30/91)
In article <1991Mar28.071310.26773@basho.uucp>, john@basho (John Lacey) writes: >If I say `\def\foo#1\par{...}' ... [and] `\foo text^^M^^M'... >I get five tokens---the obvious four and a trailing blank space. Read the TeXbook, page 46f very carefully. Especially the double-dangerous bend on page 47 that begins `If TeX sees an end-of-line character'. The first ^^M TeX sees is in state M, so it gets converted to a space. It is the second one that TeX sees in state N and which is converted into a \par.
eijkhout@s41.csrd.uiuc.edu (Victor Eijkhout) (03/30/91)
john@basho.uucp (John Lacey) writes: >I have a problem with OzTeX 1.3. If I say `\def\foo#1\par{...}', >and then say `\foo text\par', I get #1 as four tokens, `t', >`e', `x', and `t'. How would you want it otherwise? There are two kinds of tokens: character tokens and control sequence tokens (oh well. parameter tokens is the third kind), and you didn't say \foo\text\par, so you get four character tokens. >BUT, if instead I say `\foo text^^M^^M' (either just like that >or by actually pressing two returns), I get five tokens---the >obvious four and a trailing blank space. Now I think you're holding something back here. If you write \foo text^^M^^M \nextmacros.... \againsomehting \par you will get #1 <- text \nextmacros\againsomething so I suspect that you left an empty line after the ^^M^^M call. Explanation: the first ^^M is the end of the line so the second one is never seen. Contrary to popular misconceptions, a \par is not the result of two ^^M's in a row, it is the effect of an ^^M while TeX is still in state N, that is, if there were at most space characters on the line so far. Exercise for the reader: do you get a \par in the following cases: --- \space --- --- \expandafter\relax \space --- --- \catcode`Q=10 Q --- ??? Victor.