Patches item #469, was opened at 2006-01-12 02:39 You can respond by visiting: http://sarovar.org/tracker/?func=detail&atid=495&aid=469&group_id=106 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Morten Høgholm (morten) Assigned to: Nobody (None) Summary: \currentexpansionmode + \ifalignscanning - \ifinedef Initial Comment: Here's a patch made against pdftex-1.40.0-alpha-20060111. It removes the \ifinedef primitive for a different primitive, namely \currentexpansionmode. This read-only register is 0 when doing regular typesetting, 1 when inside \edef or \xdef and 2 in other cases of full expansion with scan_toks. It could possibly be extended to distinguish between \marks and \write etc. Comments more than welcome on this one! I have also added an \ifalignscanning test. It is true whenever TeX is looking for \noalign etc. so is most useful for a \stopalignscanning function defined as \def\stopalignscanning{\ifalignscanning\relax\fi} ----------------------------------------------------------------------

Comment By: Morten Høgholm (morten) Date: 2006-01-16 21:23

Message: Logged In: YES user_id=3333 @None: An \ifalignscanning primitive can also help macros like LaTeX's \multicolumn and other code that relies on seeing \noalign or \omit to recover gracefully with a comprehensible error message. ---------------------------------------------------------------------- Comment By: Morten Høgholm (morten) Date: 2006-01-13 05:50 Message: Logged In: YES user_id=3333 Yes, just ideas here, which is why I asked for comments. We can discuss this on the list (once my subscription is accepted). ---------------------------------------------------------------------- Comment By: Taco Hoekwater (taco) Date: 2006-01-12 11:22 Message: Logged In: YES user_id=1608 Like Hans, I also prefer separate if primitives, mainly because I do not want to have to remember the meanings of the possible integer values (for that reason, I'm not too happy about \currentgrouptype either). Taco ---------------------------------------------------------------------- Comment By: Nobody (None) Date: 2006-01-12 10:14 Message: Logged In: NO i wonder why we need \ifalignscanning or \stopalignscanner at all when eTeX already has this feature - any \protected macro stops the scanning. ---------------------------------------------------------------------- Comment By: Hans Hagen (hagen) Date: 2006-01-12 09:08 Message: Logged In: YES user_id=927 somehow i think that if's are a better idea than a register because in your case the register only registers one case at the same time (when i saw this patch the first time, i wondered why not a complete set was implemented) - ifincsname - ifinedef - ifinwrite - ifinspecial - ifinpdfliteral - ifinannotbody - ifinmessage (special case of write) - ifinalign - ifinmark probably some more (ok, normally all those conditions can comfortably be catched in a macro package but if we add them, we should be complete in addition to this there can be a register which keeps track of the innermost one (we can have ifcsname inside an edef inside an align concerning the \stopalignscanner i think it's better to have something primitive like \crcr, say \endalign because using if's can have its own problem (we should not worry to much about a name clash, since one can always let it to another one); so, we should wait with adding this patches till (1) we agree and (2) it is complete remark: also, it's dangerous to add patched before a decent decission/interface is dediced upon; once it's in, we cannot change it any more Hans ---------------------------------------------------------------------- You can respond by visiting: http://sarovar.org/tracker/?func=detail&atid=495&aid=469&group_id=106