How should I use sublime text regex engine (PCRE) to delete all latex comments?

Question

I followed the question in another post: Regex to capture LaTeX comments

The provided answer is awesome. However, it seems like it can only be used in the .net engine, but I want to use the PCRE engine. That is because I'm using sublime text and it seems like this engine is used by default. I tried many times, but without success.

The latex is

\usepackage{test}%COMMENT1

TEXT
%COMMENT2
TEXT

Value is 10\%, this should not be removed. %COMMENT3

begin{tikz}[
important 1,
%COMMENT4
important 2, %COMMENT5
]

TEXT
%COMMENT 6

TEXT

Table: value1&value2\\%COMMENT7
Table: value1&value2\\      %COMMENT8
Table: value1&value2            \\%COMMENT 9
Table: value1&value2\\%            COMMENT 10
Table: value1&value2\\%COMMENT11

I tried (?m)(?<=(?<!\\)(?:\\{0}))%.*(?:\r?\n(?!\r?$))?. Only works on comment 1-6,8.

The online results can be found https://regex101.com/r/zSIBMu/3

How should I modify it?

@Thefourthbird Probably not. Because "\\" will start a new line and '\%' will print out '%' itself. So, this is not a comment in latex. — stackname, Dec 17 '21 at 23:39
Does this answer your question? [Sublime text 2 how to delete comments only](https://stackoverflow.com/a/44572917/4473405) — Keith Hall, Dec 18 '21 at 06:11
@KeithHall Thanks a lot. I never thought of it in this way. This is pretty useful and can be used for all types of comments without using any new regex. Thanks. — stackname, Dec 18 '21 at 21:59

Casimir et Hippolyte · Answer 1 · 2021-12-17T23:24:54.593

4

With a capture group:

((?<!\\)(?:\\\\)*)%.*

and with $1 as replacement.

demo

Or perhaps, if \K is supported:

(?<!\\)(?:\\\\)*\K%.*

with an empty string as replacement.

demo

Notice: I don't see any reason to remove the newline sequence even if the comment takes all the line.

edited Dec 17 '21 at 23:24

answered Dec 17 '21 at 23:13

Casimir et Hippolyte

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Thanks. This is working. But I'm not sure if I understand the meaning of your notice. – stackname Dec 17 '21 at 23:24
@whatsname: That means that if a comment is at the start of the line, the replacement doesn't delete the line (only the comment). – Casimir et Hippolyte Dec 17 '21 at 23:49
Thanks for the explanation. I think this is needed when there are multiple consecutive single lines of comments. Then, deleting them would make it look better than replacing them with white space. – stackname Dec 18 '21 at 01:32

The fourth bird · Accepted Answer · 2021-12-18T00:11:28.757

4

You might also make use of a SKIP FAIL approach:

\\(?<!\\.)(?>\\\\)*%(*SKIP)(*F)|%.*

The pattern matches:

\\(?<!\\.) Match \ not preceded with \
(?>\\\\)* Match optional pairs of \\
%(*SKIP)(*FAIL) Match % and skip the match
| Or
%.* Match % and the rest of the line

Regex demo

Edit

A non lookaround solution suggested by Casimir et Hippolyte to skip the match for \\ or \%

\\[\\%](*SKIP)(*F)|%.*

\\[\\%] Match either \\ or \% using a character class
(*SKIP)(*FAIL) Skip the match
| Or
%.* Match % and the rest of the line

Regex demo

edited Dec 18 '21 at 00:11

answered Dec 17 '21 at 23:41

The fourth bird

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If I were you, for a SKIP/FAIL approach with two branches, I will write something like `\\\\(*SKIP)(*F)|%.*` that blindly skips all escaped backslash whatever the location. (less complicated, and the two branches start with a literal string too.) – Casimir et Hippolyte Dec 17 '21 at 23:47
@CasimiretHippolyte I started with an easier approach, but `\\\\(*SKIP)(*F)|%.*` will still have a match in `\%, this should not be removed. %COMMENT3` – The fourth bird Dec 17 '21 at 23:51
You are right, but I'm sure there's something more simple to do (avoiding lookarounds). – Casimir et Hippolyte Dec 17 '21 at 23:53
@CasimiretHippolyte Let me fiddle around with it a bit more, your feedback is appreciated :-) – The fourth bird Dec 17 '21 at 23:53
1

Perhaps this one, but I'm not sure: https://regex101.com/r/eDGQjR/1 – Casimir et Hippolyte Dec 17 '21 at 23:56
@CasimiretHippolyte I think a fuse just popped in my head, that looks beautiful. Can I add it, or do you want to add it to your answer? – The fourth bird Dec 18 '21 at 00:02
1

No, It's for you, you rightly suggested the SKIP/FAIL approach. – Casimir et Hippolyte Dec 18 '21 at 00:03
@CasimiretHippolyte Brilliant, thanks! I have read a lot of your answers (and still do), always a good read :-) – The fourth bird Dec 18 '21 at 00:15
1

Thanks, but don't read too old answers (especially some that I haven't edited yet <°)))))>). – Casimir et Hippolyte Dec 18 '21 at 00:22

How should I use sublime text regex engine (PCRE) to delete all latex comments?

2 Answers2