• kdevel (17/17) Dec 12 2020 In some situations a ] must be escaped as in
• Tobias Pankrath (4/23) Dec 12 2020 As I understand it, the statement is indeed true and a regex
• Tobias Pankrath (3/5) Dec 12 2020 This [1] is how I would word it.

kdevel <kdevel vogtner.de> writes:

In some situations a ] must be escaped as in

    auto re = regex(`^[a\]]$`); // match a and ] only

Unfortunately dmd/phobos does not warn if you forget the 
backslash:

    auto re = regex(`^[a]]$`); // match a]

This leads me to the documentation [1] which says

    \c where c is one of [|*+?() 	Matches the character c itself.

] must be added to this list since \] obviously matches ]. 
Additionally
the statement

    any character except [{|*+?()^$     Matches the character 
itself.

is not true since ] does not match itself when ] denotes the end 
of
a character class. I don't have a suggestion for better wording 
yet.

[1] https://dlang.org/phobos/std_regex.html

Tobias Pankrath <tobias+dlang pankrath.net> writes:

On Saturday, 12 December 2020 at 12:03:49 UTC, kdevel wrote:
 In some situations a ] must be escaped as in

    auto re = regex(`^[a\]]$`); // match a and ] only

 Unfortunately dmd/phobos does not warn if you forget the 
 backslash:

    auto re = regex(`^[a]]$`); // match a]

 This leads me to the documentation [1] which says

    \c where c is one of [|*+?() 	Matches the character c itself.

 ] must be added to this list since \] obviously matches ]. 
 Additionally
 the statement

    any character except [{|*+?()^$     Matches the character 
 itself.

 is not true since ] does not match itself when ] denotes the 
 end of
 a character class. I don't have a suggestion for better wording 
 yet.

 [1] https://dlang.org/phobos/std_regex.html

As I understand it, the statement is indeed true and a regex 
`]]]` would match and only match the string `]]]`. What should be 
added somewhere is

   Inside character classes the character ']' has to be written 
 as '\]'.

Tobias Pankrath <tobias+dlang pankrath.net> writes:

On Saturday, 12 December 2020 at 12:03:49 UTC, kdevel wrote:
 I don't have a suggestion for better wording yet.

 [1] https://dlang.org/phobos/std_regex.html

This [1] is how I would word it.

[1] https://github.com/dlang/phobos/pull/7724