Regular Expressions 101

Explanation
Pro

1st Alternative(?<topro>$[^)]*?\bpro +)(?<afterpro>.*?$)

Group topro(?<topro>\([^)]*?\bpro +)

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

Negated Character Class[^)]*?

*?matches any number of characters outside the set below:

)the literal ) (41₁₀ / 51₈ / 29₁₆)

\ban ASCII word boundary

prothe literal text pro (case sensitive)

+the literal (32₁₀ / 40₈ / 20₁₆) , repeated at least once

Group afterpro(?<afterpro>.*?\))

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

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

2nd Alternative(?<withoutpro>$.*?$)

Group withoutpro(?<withoutpro>$.*?$)

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

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

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

Global pattern flags

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

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

Ready to run

25 tokens

(?<topro>\([^)]*?\bpro +)(?<afterpro>.*?\))|(?<withoutpro>\(.*?\))