ECMAScript regular expressions are getting better (2017)

Re:ECMAScript regular expressions are getting better (2017) by couchand on Wednesday November 28, 2018 @10:54AM (#18552462)

This was one of the places CoffeeScript really innovated, IMO (though of course Perl did it first). The "Block Regular Expressions"[0] allow whitespace and comments:

    NUMBER     = ///
      ^ 0b[01]+    |              # binary
      ^ 0o[0-7]+   |              # octal
      ^ 0x[\da-f]+ |              # hex
      ^ \d*\.?\d+ (?:e[+-]?\d+)?  # decimal
    ///i

[0]: https://coffeescript.org/#regexes

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Re:ECMAScript regular expressions are getting better (2017) by pitaj on Wednesday November 28, 2018 @12:06PM (#18553243)

Rust allows this too:

    Regex::new(r"(?x)
      (?P<y>\d{4}) # the year
      -
      (?P<m>\d{2}) # the month
      -
      (?P<d>\d{2}) # the day
    ")

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Re:ECMAScript regular expressions are getting better (2017) by burntsushi on Wednesday November 28, 2018 @01:00PM (#18553856)

Yup! rust/regex has had this for a while. More recently, its error messages have also gotten a lot better, which I'm proud of!

    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    regex parse error:
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    1: (?x)
    2:       (?P<y>\d{4}) # the year
    3:       -
    4:       (?P<m>*\d{2} # the month
                   ^
    5:       -
    6:       (?P<d>\d{2}) # the day
    7:     
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    error: repetition operator missing expression
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Playground link: https://play.rust-lang.org/?version=stable&mode=debug&editio...

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Re:ECMAScript regular expressions are getting better (2017) by DFHippie on Wednesday November 28, 2018 @12:27PM (#18553436)

Another way to write more readable Rust regexen: https://crates.io/crates/pidgin

(I'm the author.)

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Re:ECMAScript regular expressions are getting better (2017) by scrollaway on Wednesday November 28, 2018 @01:15PM (#18554038)

CoffeeScript sourced a lot of its design from Python. This is one of those.

https://docs.python.org/3/library/re.html#re.X

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Re:ECMAScript regular expressions are getting better (2017) by skrause on Wednesday November 28, 2018 @05:22PM (#18556235)

Python version: https://docs.python.org/3/library/re.html#re.VERBOSE

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