6 ms·

If only more languages supported quote operators like Perl. They really do make certain things like this so much easier. Non interpolating quotes: q/I wasn

If only more languages supported quote operators like Perl. They really do make certain things like this so much easier. Non interpolating quotes: q/I wasn't surprised when he said "boo" and game me $5/; q@I wasn't surprised when he said "boo" and game me $5@; q!I wasn't surprised when he said "boo" and game me $5!; q(I wasn't surprised when he said "boo" and game me $5); q[I wasn't surprised when he said "boo" and game me $5]; Interpolating quotes: qq/Hello, $name!/; qq!Hello, $name\!!; qq@Hello, $name!@; qq(Hello, $name!); qq[Hello, $name!]; qq'Hello, $name!'; Rule of thumb, single q for single quote string (non-interpolating normally), and two q's for a double quote string (normally interpolates).

twic 6y ago
Lifted directly from sed, one of Perl's inspirations: s/replace #/with $/ s#replace /#with _#
- mycl 6y ago
  I think it was in ed already. The POSIX ed spec says: "Any character other than <space> or <newline> can be used instead of a slash to delimit the RE and the replacement."
  - codesnik 6y ago
    and, AFAIR, in perl space and enter could be delimiters too! I think I've used it in some perlgolf task which didn't count whitespace.
    - codesnik 6y ago
      and memory tricked me. Whitespace doesn't work for regex and quoting terminators.
      - kbp 6y ago
        Works in Ruby: irb(main):001:1/ puts(%r irb(main):002:1* a+ irb(main):003:0> .match? %q aaa ) true
asicsp 6y ago
I'm not sure if Ruby borrowed the full range of q and qq operators, but it offers Percent strings: https://ruby-doc.org/core-2.7.1/doc/syntax/literals_rdoc.html#label-Percent+Strings https://ruby-doc.org/core-2.7.1/doc/syntax/literals_rdoc.htm...
- tasogare 6y ago
  This is just string interpolation.
  - asicsp 6y ago
    %q allows different delimiters to represent single quoted strings, which doesn't have string interpolation. For ex: $ ruby -e 'a=5; puts "[#{a}]"' [5] $ ruby -e 'a=5; puts %q/[#{a}]/' [#{a}]
    - byroot 6y ago
      %Q or just % does interpolation: $ ruby -e 'a=5; puts %Q/[#{a}]/' [5] $ ruby -e 'a=5; puts %/[#{a}]/' [5]
eCa 6y ago
q and qq are fantastic. And qw too: # ['this', 'is', 'a', 'list'] qw/this is a list/;
- toxik 6y ago
  ... but boy am I glad I don’t have to read stuff like that.
  - drran 6y ago
    ['but', 'boy', 'am', 'I', 'glad', 'I', 'don\'t', 'have', 'to', 'read', 'stuff', 'like', 'that'] qw/but boy am I glad I don’t have to read stuff like that/ But why?
    - toxik 6y ago
      Or as it is written in mostly any other language: split("but boy am I glad I don't have to read stuff like that") But I guess you saved three bytes, so that's nice.
      - drran 6y ago
        Split works at run time, while qw// is just shorthand for array initialization syntax, so it works at compile time.
        toxik 6y ago
        If splitting a string is an important optimization point in your program, neither language is a good choice. You fail to explain why other languages do not grow these vestiges. I can only assume the implicit explanation is that you believe them to be incompetently designed, whereas I believe the exact complement: it looks like a good idea, but it isn’t.
        b2gills 6y ago
        There are many good ideas that aren't in one programming language or another. Does that actually mean they are bad ideas? No. It only means that particular language didn't copy that particular idea. There may be bad ideas that are in many languages, that doesn't somehow make them good. --- Quote-words are used regularly in Perl because they are clear and useful. for (qw' alpha beta charlie ') { say } for (split '', 'alpha beta charlie') { say } for ( 'alpha', 'beta', 'charlie' ) { say } The `qw` emphasizes that we are dealing with `alpha`, `beta`, and 'charlie`. The other ones have extra noise that is only there to satisfy the compiler. Now imagine you have to add `delta` to the list. With the `qw` you only have to press the spacebar and the letters `d e l t a`. You don't have to worry if you accidently left off a `'`, because you didn't need to add one. To be fair, the `split` would have the same benefit. But it is still more error-prone. For example I wonder how many people didn't notice that the first argument to `split` was an empty string when it should have been a string with one space in it. I didn't even notice it, and I've been programming in Perl for decades.
nialv7 6y ago
D does: https://dlang.org/spec/lex.html#delimited_strings https://dlang.org/spec/lex.html#delimited_strings Rust does too, to some degree: https://github.com/rust-lang/rust/pull/9674 https://github.com/rust-lang/rust/pull/9674
- bachmeier 6y ago
  Unfortunately D doesn't allow substitutions like Perl.
RJIb8RBYxzAMX9u 6y ago
I do generally prefer Perl's q and qq, though Python's triple-quote and its raw form are often good enough. Python also inherited C's (mis-)feature of concatenating consecutive string literals automatically, which comes in handy in some cases.
sergeykish 6y ago
%q/ruby/ %q@is@ %q!strongly! %q(inspired) %q[by] %q<perl> %Q~#{"interpolating quotes"}~ %&non interpolating by default&
gsliepen 6y ago
Raw string literals in C++ allow this as well: R"/(I wasn't surprised when he said "boo" and game me $5)/" R"@(I wasn't surprised when he said "boo" and game me $5)@" R"|(I wasn't surprised when he said "boo" and game me $5)|" https://en.cppreference.com/w/cpp/language/string_literal https://en.cppreference.com/w/cpp/language/string_literal
bdmatatu 6y ago
I also like how Raku has extended this with the Q operator, allowing one to specify what should be interpolated (scalars, escape sequences, closures, etc) also with arbitrary delimiters -- Q/I got $5 \sigh / # literal Q:s/Hello $name/ # just scalars Q:b/hello world\n/ # just backslash escape sequences https://docs.raku.org/syntax/Q https://docs.raku.org/syntax/Q
- kbenson 6y ago
  That may be a good candidate of something to port back when Perl 7 gets to the stage of adding new features.
deleted 6y ago
[deleted]
ISL 6y ago
Wouldn't that fall over for common usages of the shell (presuming it acts like sed)? Suppose you have an executable "queue". you'd generally run it as ./queue With this rule, wouldn't that be parsed as ./q'e'e ?
- kbenson 6y ago
  It's the idea, rather than the implementation, which I'm advocating for. For a shell, it would likely be best to trigger with a reserved character (or two) that's much less likely to be encountered in normal usage.
  - ISL 6y ago
    Understood. Finding a reserved character (or even sequence) that doesn't have collisions or unintended behavior beyond what the semi-reserved ' and " can do will be hard (but not necessarily impossible :)! ).
- a1369209993 6y ago
  In addition to what kbenson said, word characters [a-zA-Z0-9] usually aren't eligible as quotes anyway, otherwise how would qq'this has a q in it' parse (versus q/'this has a /).
ChrisSD 6y ago
Powershell has "here-strings". For example: @" For help, type "get-help" "@ https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_quoting_rules?view=powershell-7#here-strings https://docs.microsoft.com/en-us/powershell/module/microsoft...
- desktopninja 6y ago
  BASH too. Example: SILLY_VAR=" My silly username is "$USER" " echo ${SILLY_VAR}
jrockway 6y ago
It does look nice, and I kind of miss the feature in other programming languages. I also maintained cperl-mode for many years, and honestly the editor support for this functionality never quite worked right. It is hard to parse, and even harder when you are doing a heuristic-based incremental parse. (The challenge with text editors is that you have to provide correct syntax highlighting even when the document contains parse errors that the compiler would have bailed out on.) Because editor tooling is important to me, I'm willing to see an ugly "\"quoted\" string" from time to time, if it means that I get better tools as a result.

twic 6y ago

Lifted directly from sed, one of Perl's inspirations: s/replace #/with $/ s#replace /#with _#

mycl 6y ago
I think it was in ed already. The POSIX ed spec says: "Any character other than <space> or <newline> can be used instead of a slash to delimit the RE and the replacement."
- codesnik 6y ago
  and, AFAIR, in perl space and enter could be delimiters too! I think I've used it in some perlgolf task which didn't count whitespace.
  - codesnik 6y ago
    and memory tricked me. Whitespace doesn't work for regex and quoting terminators.
    - kbp 6y ago
      Works in Ruby: irb(main):001:1/ puts(%r irb(main):002:1* a+ irb(main):003:0> .match? %q aaa ) true

asicsp 6y ago

I'm not sure if Ruby borrowed the full range of q and qq operators, but it offers Percent strings: https://ruby-doc.org/core-2.7.1/doc/syntax/literals_rdoc.html#label-Percent+Strings https://ruby-doc.org/core-2.7.1/doc/syntax/literals_rdoc.htm...

tasogare 6y ago
This is just string interpolation.
- asicsp 6y ago
  %q allows different delimiters to represent single quoted strings, which doesn't have string interpolation. For ex: $ ruby -e 'a=5; puts "[#{a}]"' [5] $ ruby -e 'a=5; puts %q/[#{a}]/' [#{a}]
  - byroot 6y ago
    %Q or just % does interpolation: $ ruby -e 'a=5; puts %Q/[#{a}]/' [5] $ ruby -e 'a=5; puts %/[#{a}]/' [5]

eCa 6y ago

q and qq are fantastic. And qw too: # ['this', 'is', 'a', 'list'] qw/this is a list/;

toxik 6y ago
... but boy am I glad I don’t have to read stuff like that.
- drran 6y ago
  ['but', 'boy', 'am', 'I', 'glad', 'I', 'don\'t', 'have', 'to', 'read', 'stuff', 'like', 'that'] qw/but boy am I glad I don’t have to read stuff like that/ But why?
  - toxik 6y ago
    Or as it is written in mostly any other language: split("but boy am I glad I don't have to read stuff like that") But I guess you saved three bytes, so that's nice.
    - drran 6y ago
      Split works at run time, while qw// is just shorthand for array initialization syntax, so it works at compile time.
      - toxik 6y ago
        If splitting a string is an important optimization point in your program, neither language is a good choice. You fail to explain why other languages do not grow these vestiges. I can only assume the implicit explanation is that you believe them to be incompetently designed, whereas I believe the exact complement: it looks like a good idea, but it isn’t.
        b2gills 6y ago
        There are many good ideas that aren't in one programming language or another. Does that actually mean they are bad ideas? No. It only means that particular language didn't copy that particular idea. There may be bad ideas that are in many languages, that doesn't somehow make them good. --- Quote-words are used regularly in Perl because they are clear and useful. for (qw' alpha beta charlie ') { say } for (split '', 'alpha beta charlie') { say } for ( 'alpha', 'beta', 'charlie' ) { say } The `qw` emphasizes that we are dealing with `alpha`, `beta`, and 'charlie`. The other ones have extra noise that is only there to satisfy the compiler. Now imagine you have to add `delta` to the list. With the `qw` you only have to press the spacebar and the letters `d e l t a`. You don't have to worry if you accidently left off a `'`, because you didn't need to add one. To be fair, the `split` would have the same benefit. But it is still more error-prone. For example I wonder how many people didn't notice that the first argument to `split` was an empty string when it should have been a string with one space in it. I didn't even notice it, and I've been programming in Perl for decades.

nialv7 6y ago

D does: https://dlang.org/spec/lex.html#delimited_strings https://dlang.org/spec/lex.html#delimited_strings Rust does too, to some degree: https://github.com/rust-lang/rust/pull/9674 https://github.com/rust-lang/rust/pull/9674

bachmeier 6y ago
Unfortunately D doesn't allow substitutions like Perl.

RJIb8RBYxzAMX9u 6y ago

I do generally prefer Perl's q and qq, though Python's triple-quote and its raw form are often good enough. Python also inherited C's (mis-)feature of concatenating consecutive string literals automatically, which comes in handy in some cases.

sergeykish 6y ago

%q/ruby/ %q@is@ %q!strongly! %q(inspired) %q[by] %q<perl> %Q~#{"interpolating quotes"}~ %&non interpolating by default&

gsliepen 6y ago

Raw string literals in C++ allow this as well: R"/(I wasn't surprised when he said "boo" and game me $5)/" R"@(I wasn't surprised when he said "boo" and game me $5)@" R"|(I wasn't surprised when he said "boo" and game me $5)|" https://en.cppreference.com/w/cpp/language/string_literal https://en.cppreference.com/w/cpp/language/string_literal

bdmatatu 6y ago

I also like how Raku has extended this with the Q operator, allowing one to specify what should be interpolated (scalars, escape sequences, closures, etc) also with arbitrary delimiters -- Q/I got $5 \sigh / # literal Q:s/Hello $name/ # just scalars Q:b/hello world\n/ # just backslash escape sequences https://docs.raku.org/syntax/Q https://docs.raku.org/syntax/Q

kbenson 6y ago
That may be a good candidate of something to port back when Perl 7 gets to the stage of adding new features.

deleted 6y ago

[deleted]

ISL 6y ago

Wouldn't that fall over for common usages of the shell (presuming it acts like sed)? Suppose you have an executable "queue". you'd generally run it as ./queue With this rule, wouldn't that be parsed as ./q'e'e ?

kbenson 6y ago
It's the idea, rather than the implementation, which I'm advocating for. For a shell, it would likely be best to trigger with a reserved character (or two) that's much less likely to be encountered in normal usage.
- ISL 6y ago
  Understood. Finding a reserved character (or even sequence) that doesn't have collisions or unintended behavior beyond what the semi-reserved ' and " can do will be hard (but not necessarily impossible :)! ).
a1369209993 6y ago
In addition to what kbenson said, word characters [a-zA-Z0-9] usually aren't eligible as quotes anyway, otherwise how would qq'this has a q in it' parse (versus q/'this has a /).

ChrisSD 6y ago

Powershell has "here-strings". For example: @" For help, type "get-help" "@ https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_quoting_rules?view=powershell-7#here-strings https://docs.microsoft.com/en-us/powershell/module/microsoft...

desktopninja 6y ago
BASH too. Example: SILLY_VAR=" My silly username is "$USER" " echo ${SILLY_VAR}

jrockway 6y ago

It does look nice, and I kind of miss the feature in other programming languages. I also maintained cperl-mode for many years, and honestly the editor support for this functionality never quite worked right. It is hard to parse, and even harder when you are doing a heuristic-based incremental parse. (The challenge with text editors is that you have to provide correct syntax highlighting even when the document contains parse errors that the compiler would have bailed out on.) Because editor tooling is important to me, I'm willing to see an ugly "\"quoted\" string" from time to time, if it means that I get better tools as a result.