[ruby-core:69743] [Ruby trunk - Feature #11309] [Open] Iterator over string matches

[ruby-core:69743] [Ruby trunk - Feature #11309] [Open] Iterator over string matches

[sawadatsuyoshi]

Issue #11309 has been reported by Tsuyoshi Sawada.

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Feature #11309: Iterator over string matches
https://bugs.ruby-lang.org/issues/11309

* Author: Tsuyoshi Sawada
* Status: Open
* Priority: Normal
* Assignee: 
----------------------------------------
This was hinted from a problem in stackoverflow (http://stackoverflow.com/questions/31074050/build-list-of-strings-containing-substrings-separated-by-an-from-a-string/31075511#31075511).

Suppose there is a string:

    s = "a_b_c_d_e"

To get an array of pre-matches that result from matching `s` with `"_"`, I can do this:

    a = []
    s.scan("_"){a.push($`)}
    a # => ["a", "a_b", "a_b_c", "a_b_c_d"]

But this looks too Perlish. I thought it would be nice if there is a method on `String` that creates an enumerator over matches so that I can do something like this:

    "a_b_c_d_e".some_method("_").with_object([]){|m, a| a.push(m.post_match)}
    # => ["a", "a_b", "a_b_c", "a_b_c_d"]

where `m` is the last matchdata instance at that point. I believe such method would have wider application.



-- 
https://bugs.ruby-lang.org/

[ruby-core:69744] [Ruby trunk - Feature #11309] Iterator over string matches

[sawadatsuyoshi]

Issue #11309 has been updated by Tsuyoshi Sawada.


Oops, I meant `pre_match`, not `post_match`. Sorry.

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Feature #11309: Iterator over string matches
https://bugs.ruby-lang.org/issues/11309#change-53125

* Author: Tsuyoshi Sawada
* Status: Open
* Priority: Normal
* Assignee: 
----------------------------------------
This was hinted from a problem in stackoverflow (http://stackoverflow.com/questions/31074050/build-list-of-strings-containing-substrings-separated-by-an-from-a-string/31075511#31075511).

Suppose there is a string:

    s = "a_b_c_d_e"

To get an array of pre-matches that result from matching `s` with `"_"`, I can do this:

    a = []
    s.scan("_"){a.push($`)}
    a # => ["a", "a_b", "a_b_c", "a_b_c_d"]

But this looks too Perlish. I thought it would be nice if there is a method on `String` that creates an enumerator over matches so that I can do something like this:

    "a_b_c_d_e".some_method("_").with_object([]){|m, a| a.push(m.post_match)}
    # => ["a", "a_b", "a_b_c", "a_b_c_d"]

where `m` is the last matchdata instance at that point. I believe such method would have wider application.



-- 
https://bugs.ruby-lang.org/

[ruby-core:69822] [Ruby trunk - Feature #11309] Iterator over string matches

[duerst]

Issue #11309 has been updated by Martin Dürst.


What do you think looks too Perlish? Is it just the $`?

In that case, having something like $MATCH (as an alias to $~) might help:

"a_b_c_d_e".scan("_").with_object([]) { |_, a| a.push $MATCH.post_match }

Even without that,

"a_b_c_d_e".scan("_").with_object([]) { |_, a| a.push $~.post_match }

is quite readable, because "post_match" makes it easy to understand that $~ must be the current match.


----------------------------------------
Feature #11309: Iterator over string matches
https://bugs.ruby-lang.org/issues/11309#change-53220

* Author: Tsuyoshi Sawada
* Status: Open
* Priority: Normal
* Assignee: 
----------------------------------------
This was hinted from a problem in stackoverflow (http://stackoverflow.com/questions/31074050/build-list-of-strings-containing-substrings-separated-by-an-from-a-string/31075511#31075511).

Suppose there is a string:

    s = "a_b_c_d_e"

To get an array of pre-matches that result from matching `s` with `"_"`, I can do this:

    a = []
    s.scan("_"){a.push($`)}
    a # => ["a", "a_b", "a_b_c", "a_b_c_d"]

But this looks too Perlish. I thought it would be nice if there is a method on `String` that creates an enumerator over matches so that I can do something like this:

    "a_b_c_d_e".some_method("_").with_object([]){|m, a| a.push(m.post_match)}
    # => ["a", "a_b", "a_b_c", "a_b_c_d"]

where `m` is the last matchdata instance at that point. I believe such method would have wider application.



-- 
https://bugs.ruby-lang.org/

[ruby-core:69824] [Ruby trunk - Feature #11309] Iterator over string matches

[sawadatsuyoshi]

Issue #11309 has been updated by Tsuyoshi Sawada.


Martin Dürst wrote:
> What do you think looks too Perlish? Is it just the $`?

That is one. But a more severe one is that (I thought) I had to initialize `a = []` in a separate line.

> "a_b_c_d_e".scan("_").with_object([]) { |_, a| a.push $MATCH.post_match }
> "a_b_c_d_e".scan("_").with_object([]) { |_, a| a.push $~.post_match }

These are better. But I still don't like the fact that I have to access a global variable.

----------------------------------------
Feature #11309: Iterator over string matches
https://bugs.ruby-lang.org/issues/11309#change-53223

* Author: Tsuyoshi Sawada
* Status: Open
* Priority: Normal
* Assignee: 
----------------------------------------
This was hinted from a problem in stackoverflow (http://stackoverflow.com/questions/31074050/build-list-of-strings-containing-substrings-separated-by-an-from-a-string/31075511#31075511).

Suppose there is a string:

    s = "a_b_c_d_e"

To get an array of pre-matches that result from matching `s` with `"_"`, I can do this:

    a = []
    s.scan("_"){a.push($`)}
    a # => ["a", "a_b", "a_b_c", "a_b_c_d"]

But this looks too Perlish. I thought it would be nice if there is a method on `String` that creates an enumerator over matches so that I can do something like this:

    "a_b_c_d_e".some_method("_").with_object([]){|m, a| a.push(m.post_match)}
    # => ["a", "a_b", "a_b_c", "a_b_c_d"]

where `m` is the last matchdata instance at that point. I believe such method would have wider application.



-- 
https://bugs.ruby-lang.org/