regex101: parsing ini files

Explanation

Pro

^start of line

Negative Lookahead(?!\s*$)

\s*any whitespace character, repeated any number of times

$end of line

\s*any whitespace character, repeated any number of times

Negative Lookahead(?!\s)

\sany whitespace character

Group 1([^#\n\[=]+?)

Negated Character Class[^#\n\[=]+?

+?matches at least one character outside the set below:

#the literal # (35₁₀ / 43₈ / 23₁₆)

\na line-feed (newline) character (ASCII 10)

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

=the literal = (61₁₀ / 75₈ / 3D₁₆)

\s*?any whitespace character, repeated any number of times

Atomic Group(?>#.*?$|(?>=\s*$|=\s*?(?:#?|(".*?"|[^\s].*?)\s*?)(?:\s*#.*?$)*?$)?$)

1st Alternative#.*?$

#the literal # (35₁₀ / 43₈ / 23₁₆)

.*?any character (except for line terminators), repeated any number of times

$end of line

2nd Alternative(?>=\s*$|=\s*?(?:#?|(".*?"|[^\s].*?)\s*?)(?:\s*#.*?$)*?$)?$

Atomic Group(?>=\s*$|=\s*?(?:#?|(".*?"|[^\s].*?)\s*?)(?:\s*#.*?$)*?$)?

?repeats the group contents below at most once:

1st Alternative=\s*$

=the literal = (61₁₀ / 75₈ / 3D₁₆)

\s*any whitespace character, repeated any number of times

$end of line

2nd Alternative=\s*?(?:#?|(".*?"|[^\s].*?)\s*?)(?:\s*#.*?$)*?$

=the literal = (61₁₀ / 75₈ / 3D₁₆)

\s*?any whitespace character, repeated any number of times

Non-Capturing Group(?:#?|(".*?"|[^\s].*?)\s*?)

1st Alternative#?

#?optionally matches the literal # (35₁₀ / 43₈ / 23₁₆)

2nd Alternative(".*?"|[^\s].*?)\s*?

Group 2(".*?"|[^\s].*?)

1st Alternative".*?"

"the literal " (34₁₀ / 42₈ / 22₁₆)

.*?any character (except for line terminators), repeated any number of times

"the literal " (34₁₀ / 42₈ / 22₁₆)

2nd Alternative[^\s].*?

Negated Character Class[^\s]

\sany whitespace character

.*?any character (except for line terminators), repeated any number of times

\s*?any whitespace character, repeated any number of times

Non-Capturing Group(?:\s*#.*?$)*?

*?repeats the group contents below any number of times:

\s*any whitespace character, repeated any number of times

#the literal # (35₁₀ / 43₈ / 23₁₆)

.*?any character (except for line terminators), repeated any number of times

$end of line

Global pattern flags

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

g modifier: global. Finds all matches instead of stopping after the first

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

Quick Reference

25 tokens

Regular Expression

^(?!\s*$)\s*(?!\s)([^#\n\[=]+?)\s*?(?>#.*?$|(?>=\s*$|=\s*?(?:#?|(".*?"|[^\s].*?)\s*?)(?:\s*#.*?$)*?$)?$)

Unit Tests

There are no unit tests.