Regex: how to extract function parameters

Question

I could not find similar question with what I am trying to get at.

I have a function:

Foo(int n, str b, Bar1(), Bar2(smth));

I am trying to write regex to get the following matches:

int n
str b
Bar()
Bar2(smth) // don't need recursion

I've managed to do it in 2 separate regexes:

(?<=\().*(?=\))

to get:

int n, str b, Bar1(), Bar2(smth)

then on that string, I 've used:

[^,\s*][a-zA-Z\s<>.()0-9]*

to get:

int n
str b
Bar()
Bar2(smth)

But I would really like to do it in a single regex statement, is it possible to somehow capture first regex in a group and then run second regex on that group in a single statement? I am still quite vague on using groups.

Please mention the tool/lang you're using.

bobble bubble
– bobble bubble

2022-06-08 09:48:20 +00:00
Commented Jun 8, 2022 at 9:48 — bobble bubble
– bobble bubble, Commented Jun 8, 2022 at 9:48

Tim Biegeleisen · Accepted Answer · 2022-06-08 03:27:15Z

1

For the function call you happened to post, the following regex seems to work:

(?:\w+ \w+|\w+\(\w*\))

This pattern matches, alternatively, a type followed by variable name, or a function name, with optional parameters. Here is a working demo.

answered Jun 8, 2022 at 3:27

Tim Biegeleisen

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4 Comments

Chebz Over a year ago

I am looking for something more generic sadly, it could be something like Foo(out int n)

Tim Biegeleisen Over a year ago

...then you asked the wrong question. Update your question with the generic problem. Most likely, you will need to write/use a parser here; regex alone won't help.

Chebz Over a year ago

yeah it's difficult to explain specific use case, as I am trying to parse any C# function basically... either function call or function definition, just trying to extract everything that is separated by commas inside (,,,,)

Chebz Over a year ago

another example would be public void Function(something here)

Wiktor Stribiżew · Accepted Answer · 2022-06-08 07:42:54Z

0

You can use

(?:\G(?!^)\s*,\s*|\()\K\w+(?:\s+\w+|\s*\([^()]*\))

See the regex demo. Details:

(?:\G(?!^)\s*,\s*|\() - either the end of the preceding match and then a comma enclosed with zero or more whitespaces, or a ( char
\K - omit the text matched so far
\w+ - one or more word chars
(?:\s+\w+|\s*\([^()]*\)) - a non-capturing group matching one of two alternatives
- \s+\w+ - one or more whitespaces and then one or more word chars
- | - or
- \s* - zero or more whitespaces
- \([^()]*\) - a ( char, then zero or more chars other than ( and ) and then a ) char.

answered Jun 8, 2022 at 7:42

Wiktor Stribiżew

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Comments

Alexey · Accepted Answer · 2022-06-08 09:10:31Z

0

Try this one

((?<=\(|,\s)((\w+\s)+\w+)|(\w+\((\w+(\,\s){0,1})*\)))

Check demo https://regex101.com/r/Bv1Y5L/1

answered Jun 8, 2022 at 9:10

Alexey

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