* bug#8935: 24.0.50; `substitute-command-keys' doc @ 2011-06-25 21:29 Drew Adams 2011-07-15 14:32 ` Lars Magne Ingebrigtsen 2011-07-15 15:33 ` Andreas Schwab 0 siblings, 2 replies; 17+ messages in thread From: Drew Adams @ 2011-06-25 21:29 UTC (permalink / raw) To: 8935 Both the doc string and the doc in the Elisp manual (node `Keys in Documentation') are unnecessarily confusing wrt `\='. They both correctly say that `\=' "quotes the following character and is discarded". However, they then say this to illustrate what is meant: "thus, `\=\[' puts `\[' into the output, and `\=\=' puts `\=' into the output." This is uncessarily complex and misleading. All the `\=' does is quote/escape the (single) next character, whatever it is. Nothing more. It has no special effect on special character combinations such as `\[' and `\='. If you really want to say something about escaping `\' as the next character then I suppose you could: "In particular, `\=\' produces `\' in the output. The character following the escaped character does not enter into (i.e., affect) the behavior at all. In GNU Emacs 24.0.50.1 (i386-mingw-nt5.1.2600) of 2011-06-20 on 3249CTO Windowing system distributor `Microsoft Corp.', version 5.1.2600 configured using `configure --with-gcc (4.5) --no-opt --cflags -Ic:/build/include' ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-06-25 21:29 bug#8935: 24.0.50; `substitute-command-keys' doc Drew Adams @ 2011-07-15 14:32 ` Lars Magne Ingebrigtsen 2011-07-15 15:33 ` Andreas Schwab 1 sibling, 0 replies; 17+ messages in thread From: Lars Magne Ingebrigtsen @ 2011-07-15 14:32 UTC (permalink / raw) To: Drew Adams; +Cc: 8935 "Drew Adams" <drew.adams@oracle.com> writes: > It has no special effect on special character combinations such as `\[' > and `\='. If you really want to say something about escaping `\' as > the next character then I suppose you could: "In particular, `\=\' > produces `\' in the output. The character following the escaped > character does not enter into (i.e., affect) the behavior at all. I've now done this. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog http://lars.ingebrigtsen.no/ ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-06-25 21:29 bug#8935: 24.0.50; `substitute-command-keys' doc Drew Adams 2011-07-15 14:32 ` Lars Magne Ingebrigtsen @ 2011-07-15 15:33 ` Andreas Schwab 2011-07-15 16:00 ` Drew Adams ` (3 more replies) 1 sibling, 4 replies; 17+ messages in thread From: Andreas Schwab @ 2011-07-15 15:33 UTC (permalink / raw) To: Drew Adams; +Cc: 8935 "Drew Adams" <drew.adams@oracle.com> writes: > It has no special effect on special character combinations such as `\[' > and `\='. If you really want to say something about escaping `\' as > the next character then I suppose you could: "In particular, `\=\' > produces `\' in the output. This is wrong, because \ by itself has no special meaning, so you don't need to precede it by \=. Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different." ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 15:33 ` Andreas Schwab @ 2011-07-15 16:00 ` Drew Adams 2011-07-15 16:35 ` Lars Magne Ingebrigtsen ` (2 subsequent siblings) 3 siblings, 0 replies; 17+ messages in thread From: Drew Adams @ 2011-07-15 16:00 UTC (permalink / raw) To: 'Andreas Schwab'; +Cc: 8935 > > It has no special effect on special character combinations > > such as `\[' and `\='. If you really want to say something > > about escaping `\' as the next character then I suppose you > > could: "In particular, `\=\' produces `\' in the output. > > This is wrong, because \ by itself has no special meaning, so > you don't need to precede it by \=. It's not wrong. \ by itself has no special meaning, so it need not be escaped when by itself - agreed. But \ followed by these particular chars (e.g. `[') does have special meaning for `substitute-command-keys', so when followed by such a char it does need to be escaped, if you want `\' in the output. It is nevertheless the \ and only the \ that is escaped. The escaping code takes no look past the \ to see what follows it. It is you, the programmer, who decides whether a particular \ needs escaping, and yes, you do that by looking at the following char (e.g. `['). But _you_ do that - that is not part of what `substitute-command-keys' does or `\=' does. ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 15:33 ` Andreas Schwab 2011-07-15 16:00 ` Drew Adams @ 2011-07-15 16:35 ` Lars Magne Ingebrigtsen 2011-07-15 16:35 ` Lars Magne Ingebrigtsen 2011-07-18 13:55 ` Stefan Monnier 3 siblings, 0 replies; 17+ messages in thread From: Lars Magne Ingebrigtsen @ 2011-07-15 16:35 UTC (permalink / raw) To: 8935 Andreas Schwab <schwab@linux-m68k.org> writes: > "Drew Adams" <drew.adams@oracle.com> writes: > >> It has no special effect on special character combinations such as `\[' >> and `\='. If you really want to say something about escaping `\' as >> the next character then I suppose you could: "In particular, `\=\' >> produces `\' in the output. > > This is wrong, because \ by itself has no special meaning, so you don't > need to precede it by \=. I see. I thought it worked the normal way, in that "\e" would be "e". Thanks for correcting this. Did you do the manual, too? If not I can take care of that. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog http://lars.ingebrigtsen.no/ ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 15:33 ` Andreas Schwab 2011-07-15 16:00 ` Drew Adams 2011-07-15 16:35 ` Lars Magne Ingebrigtsen @ 2011-07-15 16:35 ` Lars Magne Ingebrigtsen 2011-07-15 17:23 ` Drew Adams 2011-07-18 13:55 ` Stefan Monnier 3 siblings, 1 reply; 17+ messages in thread From: Lars Magne Ingebrigtsen @ 2011-07-15 16:35 UTC (permalink / raw) To: Andreas Schwab; +Cc: 8935 Andreas Schwab <schwab@linux-m68k.org> writes: > "Drew Adams" <drew.adams@oracle.com> writes: > >> It has no special effect on special character combinations such as `\[' >> and `\='. If you really want to say something about escaping `\' as >> the next character then I suppose you could: "In particular, `\=\' >> produces `\' in the output. > > This is wrong, because \ by itself has no special meaning, so you don't > need to precede it by \=. I see. I thought it worked the normal way, in that "\e" would be "e". Thanks for correcting this. Did you do the manual, too? If not I can take care of that. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog http://lars.ingebrigtsen.no/ ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 16:35 ` Lars Magne Ingebrigtsen @ 2011-07-15 17:23 ` Drew Adams 2011-07-15 17:28 ` Lars Magne Ingebrigtsen 0 siblings, 1 reply; 17+ messages in thread From: Drew Adams @ 2011-07-15 17:23 UTC (permalink / raw) To: 'Lars Magne Ingebrigtsen', 'Andreas Schwab'; +Cc: 8935 > > This is wrong, because \ by itself has no special meaning, > > so you don't need to precede it by \=. > > I see. I thought it worked the normal way, in that "\e" would be "e". It does. That is correct. Andreas was wrong in saying it is wrong. What is true is that \ by itself (not followed by [, =, etc.) does not _NEED_ to be escaped. But it is certainly true that \= escapes \, whether it needs to in any given context (e.g. \[) or not (e.g. \ abc). If it escapes a \ that does not need escaping, the effect is a no-op. ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 17:23 ` Drew Adams @ 2011-07-15 17:28 ` Lars Magne Ingebrigtsen 2011-07-15 18:38 ` Andreas Schwab 2011-07-15 19:18 ` Drew Adams 0 siblings, 2 replies; 17+ messages in thread From: Lars Magne Ingebrigtsen @ 2011-07-15 17:28 UTC (permalink / raw) To: Drew Adams; +Cc: 8935, 'Andreas Schwab' "Drew Adams" <drew.adams@oracle.com> writes: > What is true is that \ by itself (not followed by [, =, etc.) does not > _NEED_ to be escaped. But it is certainly true that \= escapes \, > whether it needs to in any given context (e.g. \[) or not (e.g. \ > abc). If it escapes a \ that does not need escaping, the effect is a > no-op. Uhm. Now I'm even more confused. "\=\e" will print as "\e"? Right? So it's not a noop, and the fix I applied was correct. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog http://lars.ingebrigtsen.no/ ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 17:28 ` Lars Magne Ingebrigtsen @ 2011-07-15 18:38 ` Andreas Schwab 2011-07-15 19:17 ` Drew Adams 2011-07-15 19:18 ` Drew Adams 1 sibling, 1 reply; 17+ messages in thread From: Andreas Schwab @ 2011-07-15 18:38 UTC (permalink / raw) To: Lars Magne Ingebrigtsen; +Cc: 8935 Lars Magne Ingebrigtsen <larsi@gnus.org> writes: > "\=\e" will print as "\e"? Right? So it's not a noop, and the fix I > applied was correct. No. The *only* special sequences processed by substitute-command-keys' are '\=', '\[', '\<' and '\{'. Nothing else. The sentence is about how to write these special sequences in the doc string so that they are not treated specially, so the examples should talk about '\=' and '\[', not about '\'. Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different." ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 18:38 ` Andreas Schwab @ 2011-07-15 19:17 ` Drew Adams 2011-07-15 20:09 ` Andreas Schwab 0 siblings, 1 reply; 17+ messages in thread From: Drew Adams @ 2011-07-15 19:17 UTC (permalink / raw) To: 'Andreas Schwab', 'Lars Magne Ingebrigtsen'; +Cc: 8935 > > "\=\e" will print as "\e"? Right? So it's not a noop, and the fix I > > applied was correct. > > No. The *only* special sequences processed by > substitute-command-keys' are '\=', '\[', '\<' and '\{'. > Nothing else. Correct. > The sentence is about how to write these special sequences in > the doc string so that they are not treated specially, Correct. > so the examples should talk about '\=' and '\[', not about '\'. It's OK to mention that in "\=\[" the \= escapes the \ so that \[ appears in the output. But it is only the \ that is being escaped here. Escaping a character means making it act normally, not specially. Only the \ acts specially, and it does so only when it precedes [, {, etc. So yes, this escaping of \ only has an effect when the \ precedes [, {, etc. But strictly speaking it is only the \ that gets escaped in these contexts. The =, [, etc. does not need to be escaped because those are not treated specially unless preceded by an unescaped \. So only one character needs to be escaped: the \. Anyway, it's a minor point (bug). I really don't care what you do with it. When I read the doc string, I found it confusing. I looked at the code and understood. It is _enough_ to say that \= escapes a \, preventing it from introducing a substitution when followed by =, [, etc. Or as I said in the beginning: > This is uncessarily complex and misleading. All the `\=' does is > quote/escape the (single) next character, whatever it is. Nothing > more. ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 19:17 ` Drew Adams @ 2011-07-15 20:09 ` Andreas Schwab 0 siblings, 0 replies; 17+ messages in thread From: Andreas Schwab @ 2011-07-15 20:09 UTC (permalink / raw) To: Drew Adams; +Cc: 'Lars Magne Ingebrigtsen', 8935 "Drew Adams" <drew.adams@oracle.com> writes: > Escaping a character means making it act normally, not specially. Only the \ > acts specially, Wrong. > and it does so only when it precedes [, {, etc. Right. And only this is of interest. > It is _enough_ to say that \= escapes a \, preventing it from > introducing a substitution when followed by =, [, etc. No, this is the wrong thing to do. The doc string should say how to produce a value that contains the two character sequences '\=' or '\['. That's the *whole* point of the examples (and these are *examples*, not specification). You don't need '\=' to produce a backslash in the value. So that is useless to say so. A doc string needs to get to the point, not be technically correct. Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different." ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 17:28 ` Lars Magne Ingebrigtsen 2011-07-15 18:38 ` Andreas Schwab @ 2011-07-15 19:18 ` Drew Adams 2011-07-15 19:22 ` Lars Magne Ingebrigtsen 1 sibling, 1 reply; 17+ messages in thread From: Drew Adams @ 2011-07-15 19:18 UTC (permalink / raw) To: 'Lars Magne Ingebrigtsen'; +Cc: 8935, 'Andreas Schwab' > > What is true is that \ by itself (not followed by [, =, > > etc.) does not _NEED_ to be escaped. But it is certainly true > > that \= escapes \, whether it needs to in any given context > > (e.g. \[) or not (e.g. \abc). If it escapes a \ that does not > > need escaping, the effect is a no-op. > > Uhm. Now I'm even more confused. > > "\=\e" will print as "\e"? Right? Right. > So it's not a noop, It's a no-op in the sense that it does nothing. Of course, it is still the case that, as the doc string says, the \= itself "is discarded". What remains is the \ that was escaped. Not sure what your confusion is. \= escapes the char that follows it. What does escaping mean in this context? Preventing \ from having any special behavior when it precedes =, [, etc. The point is that it is not the pair of characters \=, \[, etc. that is escaped. \ is the only char escaped: it is prevented from doing anything special; it just appears in the output as is. Because \ gets escaped, it has no special `substitute-command-keys' effect on what follows it, whatever that might be. > and the fix I applied was correct. Dunno what it was. What I described is a proper fix, IMO. ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 19:18 ` Drew Adams @ 2011-07-15 19:22 ` Lars Magne Ingebrigtsen 2011-07-15 19:25 ` Drew Adams 0 siblings, 1 reply; 17+ messages in thread From: Lars Magne Ingebrigtsen @ 2011-07-15 19:22 UTC (permalink / raw) To: Drew Adams; +Cc: 8935, 'Andreas Schwab' "Drew Adams" <drew.adams@oracle.com> writes: >> and the fix I applied was correct. > > Dunno what it was. > > What I described is a proper fix, IMO. You don't read the emacs-diffs mailing list? :-) I implemented what you described. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog http://lars.ingebrigtsen.no/ ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 19:22 ` Lars Magne Ingebrigtsen @ 2011-07-15 19:25 ` Drew Adams 0 siblings, 0 replies; 17+ messages in thread From: Drew Adams @ 2011-07-15 19:25 UTC (permalink / raw) To: 'Lars Magne Ingebrigtsen'; +Cc: 8935, 'Andreas Schwab' > > Dunno what it was. > > You don't read the emacs-diffs mailing list? :-) Nope. Sorry. > I implemented what you described. Thank you. ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-15 15:33 ` Andreas Schwab ` (2 preceding siblings ...) 2011-07-15 16:35 ` Lars Magne Ingebrigtsen @ 2011-07-18 13:55 ` Stefan Monnier 2011-07-18 14:27 ` Andreas Schwab 3 siblings, 1 reply; 17+ messages in thread From: Stefan Monnier @ 2011-07-18 13:55 UTC (permalink / raw) To: Andreas Schwab; +Cc: 8935 >> It has no special effect on special character combinations such as `\[' >> and `\='. If you really want to say something about escaping `\' as >> the next character then I suppose you could: "In particular, `\=\' >> produces `\' in the output. > This is wrong, because \ by itself has no special meaning, so you don't > need to precede it by \=. Actually \ does have a special meaning, which depends on the following char (just like \ in regexps). The difference between that and regexps is that in regexp \<char> turns into just <char> when \<char> has no special meaning, where it turns into \<char> here. Stefan ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-18 13:55 ` Stefan Monnier @ 2011-07-18 14:27 ` Andreas Schwab 2011-07-18 16:20 ` Stefan Monnier 0 siblings, 1 reply; 17+ messages in thread From: Andreas Schwab @ 2011-07-18 14:27 UTC (permalink / raw) To: Stefan Monnier; +Cc: 8935 Stefan Monnier <monnier@iro.umontreal.ca> writes: > Actually \ does have a special meaning, which depends on the following > char (just like \ in regexps). The difference between that and regexps > is that in regexp \<char> turns into just <char> when \<char> has no > special meaning, where it turns into \<char> here. If you want a \ in a regexp you must write \\, always. But if you want to have a \ from substitute-command-keys you just write \, and if you want \\= you must write \\=\=. Thus \ by itself is not special here. Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different." ^ permalink raw reply [flat|nested] 17+ messages in thread
* bug#8935: 24.0.50; `substitute-command-keys' doc 2011-07-18 14:27 ` Andreas Schwab @ 2011-07-18 16:20 ` Stefan Monnier 0 siblings, 0 replies; 17+ messages in thread From: Stefan Monnier @ 2011-07-18 16:20 UTC (permalink / raw) To: Andreas Schwab; +Cc: 8935 >> Actually \ does have a special meaning, which depends on the following >> char (just like \ in regexps). The difference between that and regexps >> is that in regexp \<char> turns into just <char> when \<char> has no >> special meaning, where it turns into \<char> here. > If you want a \ in a regexp you must write \\, always. But if you want > to have a \ from substitute-command-keys you just write \, and if you > want \\= you must write \\=\=. Thus \ by itself is not special here. The "by itself" doesn't mean much, and \ is special because it changes the meaning of the subsequent character. I agree it's not special in the same way as it is in regexps, but it is still special. Stefan ^ permalink raw reply [flat|nested] 17+ messages in thread
end of thread, other threads:[~2011-07-18 16:20 UTC | newest] Thread overview: 17+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2011-06-25 21:29 bug#8935: 24.0.50; `substitute-command-keys' doc Drew Adams 2011-07-15 14:32 ` Lars Magne Ingebrigtsen 2011-07-15 15:33 ` Andreas Schwab 2011-07-15 16:00 ` Drew Adams 2011-07-15 16:35 ` Lars Magne Ingebrigtsen 2011-07-15 16:35 ` Lars Magne Ingebrigtsen 2011-07-15 17:23 ` Drew Adams 2011-07-15 17:28 ` Lars Magne Ingebrigtsen 2011-07-15 18:38 ` Andreas Schwab 2011-07-15 19:17 ` Drew Adams 2011-07-15 20:09 ` Andreas Schwab 2011-07-15 19:18 ` Drew Adams 2011-07-15 19:22 ` Lars Magne Ingebrigtsen 2011-07-15 19:25 ` Drew Adams 2011-07-18 13:55 ` Stefan Monnier 2011-07-18 14:27 ` Andreas Schwab 2011-07-18 16:20 ` Stefan Monnier
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