Re^7: Transform ASCII into UniCode (escape

Sorry I'm too tired now, I'll check tomorrow.

Multiple levels of escaping are often kind of brainf*ck.

> would expect the strings coming in to contain the characters to operate on, not strings that Perl can turn into the characters to operate on by evaluating them.

this escape_metas can also be used with a character class [METAS] for with multiple metas.

> The \b is tricky, as I can use it to get three different results from my three subroutines:

exactly, as I said, it depends what the intended behavior is.

FWIW

my intention was to implement a sub tri = "transliterate interpolated" which allowed to write tri($input,$left,$right) and implemented $input =~ tr/LEFT/RIGHT/ while sticking close to tr's behaviour but without breaking.

I'll try again ~~tomorrow.~~ after GPW. :)

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

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Re^8: Transform ASCII into UniCode (escape_metas) by LanX (Saint) on Mar 23, 2021 at 23:27 UTC
> my intention was to implement a sub tri = "transliterate interpolated" which allowed to write tri($input,$left,$right) and implemented $input =~ tr/LEFT/RIGHT/ while sticking close to tr's behaviour but without breaking. That's more complicated than I thought because of the special nature of tr's arguments. :( double-quotes allow interpolation and escape codes, single-quotes don't `DB<76> p "a\bc" c DB<77> p length "a\bc" 3 DB<78> p 'a\bc' a\bc DB<79> p length 'a\bc' 4 DB<80> p 'a\b' eq 'a\\b' 1` [download] But tr forbids interpolation while allowing escape codes `DB<80> say '$l' =~ tr/$l/xyz/r # no interpolation xy DB<81> say "a\b" =~ tr/a\b/xyz/r # but escape codes xy` [download] This makes evaling tr in a predictable way far too complicated. Just escaping delimiters won't do, if escape codes are involved. I think it's wise to give it up here. Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply] [d/l] [select]

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Re^8: Transform ASCII into UniCode (escape_metas)
by LanX (Saint) on Mar 23, 2021 at 23:27 UTC

> my intention was to implement a sub tri = "transliterate interpolated" which allowed to write tri($input,$left,$right) and implemented $input =~ tr/LEFT/RIGHT/ while sticking close to tr's behaviour but without breaking.

That's more complicated than I thought because of the special nature of tr's arguments. :(

double-quotes allow interpolation and escape codes, single-quotes don't

  DB<76> p "a\bc"
c
  DB<77> p length "a\bc"
3
  DB<78> p 'a\bc'
a\bc
  DB<79> p length 'a\bc'
4
  DB<80> p 'a\b' eq 'a\\b'
1
[download]

But tr forbids interpolation while allowing escape codes

  DB<80> say '$l' =~ tr/$l/xyz/r    # no interpolation
xy

  DB<81> say "a\b" =~ tr/a\b/xyz/r  # but escape codes
xy
[download]

This makes evaling tr in a predictable way far too complicated.

Just escaping delimiters won't do, if escape codes are involved.

I think it's wise to give it up here.

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

[reply]
[d/l]
[select]