Issue in man page regex.7

Issue in man page regex.7

[Helge Kreutzmann]

Without further ado, the following was found:

Issue:    I<egrep> → B<egrep>(1)

"Regular expressions (\"RE\"s), as defined in POSIX.2, come in two forms: "
"modern REs (roughly those of I<egrep>; POSIX.2 calls these \"extended\" "
"REs)  and obsolete REs (roughly those of B<ed>(1); POSIX.2 \"basic\" REs).  "
"Obsolete REs mostly exist for backward compatibility in some old programs; "
"they will be discussed at the end.  POSIX.2 leaves some aspects of RE syntax "
"and semantics open; \"\\*(dg\" marks decisions on these aspects that may not "
"be fully portable to other POSIX.2 implementations."

Issue in man page regex.7

[Helge Kreutzmann]

Without further ado, the following was found:

Issue 1:  alphabetic?
Issue 2:  multiple cases → both cases?

"If case-independent matching is specified, the effect is much as if all case "
"distinctions had vanished from the alphabet.  When an alphabetic that exists "
"in multiple cases appears as an ordinary character outside a bracket "
"expression, it is effectively transformed into a bracket expression "
"containing both cases, for example, \\[aq]x\\[aq] becomes \"I<[xX]>\".  When "
"it appears inside a bracket expression, all case counterparts of it are "
"added to the bracket expression, so that, for example, \"I<[x]>\" becomes "
"\"I<[xX]>\" and \"I<[\\[ha]x]>\" becomes \"I<[\\[ha]xX]>\"."

Re: Issue in man page regex.7

[Alejandro Colomar]

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Hi Helge,

On Wed, Nov 01, 2023 at 02:02:12PM +0000, Helge Kreutzmann wrote:
> Without further ado, the following was found:
> 
> Issue 1:  alphabetic?
> Issue 2:  multiple cases → both cases?

Depending on the locale, more than 2 are possible, AFAIK, so multiple
would be more accurate in that context, I think.

Cheers,
Alex

> 
> "If case-independent matching is specified, the effect is much as if all case "
> "distinctions had vanished from the alphabet.  When an alphabetic that exists "
> "in multiple cases appears as an ordinary character outside a bracket "
> "expression, it is effectively transformed into a bracket expression "
> "containing both cases, for example, \\[aq]x\\[aq] becomes \"I<[xX]>\".  When "
> "it appears inside a bracket expression, all case counterparts of it are "
> "added to the bracket expression, so that, for example, \"I<[x]>\" becomes "
> "\"I<[xX]>\" and \"I<[\\[ha]x]>\" becomes \"I<[\\[ha]xX]>\"."

-- 
<https://www.alejandro-colomar.es/>

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Re: Issue in man page regex.7

[Alejandro Colomar]

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On Wed, Nov 01, 2023 at 02:02:12PM +0000, Helge Kreutzmann wrote:
> Without further ado, the following was found:
> 
> Issue:    I<egrep> → B<egrep>(1)

Fixed:
<https://www.alejandro-colomar.es/src/alx/linux/man-pages/man-pages.git/commit/?h=contrib&id=f43a9ed0f80c18ca8a033883d726bfa78fa5c7d6>

Thanks,
Alex

> 
> "Regular expressions (\"RE\"s), as defined in POSIX.2, come in two forms: "
> "modern REs (roughly those of I<egrep>; POSIX.2 calls these \"extended\" "
> "REs)  and obsolete REs (roughly those of B<ed>(1); POSIX.2 \"basic\" REs).  "
> "Obsolete REs mostly exist for backward compatibility in some old programs; "
> "they will be discussed at the end.  POSIX.2 leaves some aspects of RE syntax "
> "and semantics open; \"\\*(dg\" marks decisions on these aspects that may not "
> "be fully portable to other POSIX.2 implementations."

-- 
<https://www.alejandro-colomar.es/>

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Issue in man page regex.7

[Helge Kreutzmann]

Without further ado, the following was found:

Issue:    alphabetic? Do you mean alphabet?

"If case-independent matching is specified, the effect is much as if all case "
"distinctions had vanished from the alphabet.  When an alphabetic that exists "
"in multiple cases appears as an ordinary character outside a bracket "
"expression, it is effectively transformed into a bracket expression "
"containing both cases, for example, \\[aq]x\\[aq] becomes \"I<[xX]>\".  When "
"it appears inside a bracket expression, all case counterparts of it are "
"added to the bracket expression, so that, for example, \"I<[x]>\" becomes "
"\"I<[xX]>\" and \"I<[\\[ha]x]>\" becomes \"I<[\\[ha]xX]>\"."

Re: Issue in man page regex.7

[Alejandro Colomar]

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Hi Helge,

On Sun, Nov 17, 2024 at 10:46:22AM GMT, Helge Kreutzmann wrote:
> Without further ado, the following was found:
> 
> Issue:    alphabetic? Do you mean alphabet?

No, it means "alphabetic character", but character was omitted.  As in,
anything that isalpha(c).

Cheers,
Alex

> 
> "If case-independent matching is specified, the effect is much as if all case "
> "distinctions had vanished from the alphabet.  When an alphabetic that exists "
> "in multiple cases appears as an ordinary character outside a bracket "
> "expression, it is effectively transformed into a bracket expression "
> "containing both cases, for example, \\[aq]x\\[aq] becomes \"I<[xX]>\".  When "
> "it appears inside a bracket expression, all case counterparts of it are "
> "added to the bracket expression, so that, for example, \"I<[x]>\" becomes "
> "\"I<[xX]>\" and \"I<[\\[ha]x]>\" becomes \"I<[\\[ha]xX]>\"."

-- 
<https://www.alejandro-colomar.es/>

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