Watching this discussion and thinking about the various contexts which
should or should not trigger σ → ς substitution are surely the Greek
number signs:
- U+0374 GREEK NUMERAL SIGN:'ʹ'
- U+0375 GREEK LOWER NUMERAL SIGN:'͵'
I have just been fortunate to not run into -- or unfortunate not
to notice! -- that yet.
So my substitution regular expression, which defines the following
context negatively,
should rather be
s/(?<= \p{Script=Greek} ) (?<= \pL ) ( \pM* ) σ (?! \pL |
[-ʹ͵] )/$1ς/gx
There certainly are edge cases which this doesn't handle. The one
which immediately comes to mind is `(s)` and similar, which should
be sensitive to what comes before and after the parentheses.
on Thu, 07 May 2015 I wrote:
Den 2015-05-07 16:02, Jonathan Kew skrev:
> Would it be feasible to define this negatively instead --
> something like "a sigma is final if it is NOT followed by another
> letter"?
>
> A possible refinement is that a lone sigma, neither preceded nor
> followed by another letter, should probably be lowercased as σ
> rather than ς.
I have used this Perl regular expression substitution to change σ into
ς for some years, with satisfactory results so far,
s/(?<= \p{Script=Greek} ) (?<= \pL ) σ (?! \pL | - )/ς/gx
That is: change a σ into ς if it is preceded by a Greek letter
and not followed by a letter or a hyphen. NB that this
substitution as written above only works with NFC text. For NFD
you would need to use the following, since the perl regex engine
doesn't support variable-length lookbehind:
s/(?<= \p{Script=Greek} ) (?<= \pL ) ( \pM* ) σ (?! \pL | - )/$1ς/gx
I guess that when intersection character classes are possible one
should change the negative lookahead into "when not followed by a
Greek letter or a hyphen.
(?! (?[ \p{Script=Greek} & \pL ]) | - )
/bpj
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