regex101: PTN Ply Matching

Explanation

Pro

Positive Lookbehind(?<=^|\n)

1st Alternative^

^start of string

2nd Alternative\n

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

Group spacer(?P<spacer>[[:blank:]]*(?:\{[^{]*(?&spacer)[^}]*\}[[:blank:]]*)[[:blank:]]*|[[:blank:]]+)

1st Alternative[[:blank:]]*(?:\{[^{]*(?&spacer)[^}]*\}[[:blank:]]*)[[:blank:]]*

Character Class[[:blank:]]*

*matches any number of characters from the set below:

[:blank:]a whitespace character, excluding line breaks [ \t]

Non-Capturing Group(?:\{[^{]*(?&spacer)[^}]*\}[[:blank:]]*)

\{the literal { (123₁₀ / 173₈ / 7B₁₆)

Negated Character Class[^{]*

*matches any number of characters outside the set below:

{the literal { (123₁₀ / 173₈ / 7B₁₆)

(?&spacer)calls group spacer as a subroutine

Negated Character Class[^}]*

*matches any number of characters outside the set below:

}the literal } (125₁₀ / 175₈ / 7D₁₆)

\}the literal } (125₁₀ / 175₈ / 7D₁₆)

Character Class[[:blank:]]*

*matches any number of characters from the set below:

[:blank:]a whitespace character, excluding line breaks [ \t]

Character Class[[:blank:]]*

*matches any number of characters from the set below:

[:blank:]a whitespace character, excluding line breaks [ \t]

2nd Alternative[[:blank:]]+

Character Class[[:blank:]]+

+matches at least one character from the set below:

[:blank:]a whitespace character, excluding line breaks [ \t]

Group 2(\d+)

\d+a digit, repeated at least once

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

(?&spacer)calls group spacer as a subroutine

Non-Capturing Group(?:([1-8])?([a-h])([1-8])([+-<>])([1-8]*)|([FSC])?([a-h])([1-8]))

1st Alternative([1-8])?([a-h])([1-8])([+-<>])([1-8]*)

Group 3([1-8])?

?repeats the group contents below at most once:

Character Class[1-8]

1-8one character from 1 (49₁₀) to 8 (56₁₀)

Group 4([a-h])

Character Class[a-h]

a-hone character from a (97₁₀) to h (104₁₀) (case sensitive)

Group 5([1-8])

Character Class[1-8]

1-8one character from 1 (49₁₀) to 8 (56₁₀)

Group 6([+-<>])

Character Class[+-<>]

+-<one character from + (43₁₀) to < (60₁₀)

>the literal > (62₁₀ / 76₈ / 3E₁₆)

Group 7([1-8]*)

Character Class[1-8]*

2nd Alternative([FSC])?([a-h])([1-8])

Non-Capturing Group(?:(?&spacer)(?:([1-8])?([a-h])([1-8])([+-<>])([1-8]*)|([FSC])?([a-h])([1-8])))?

(?&spacer)?optionally calls group spacer as a subroutine

Positive Lookahead(?=$|\n)

Global pattern flags

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

Quick Reference

25 tokens

Regular Expression

(?<=^|\n)(?P<spacer>[[:blank:]]*(?:\{[^{]*(?&spacer)[^}]*\}[[:blank:]]*)[[:blank:]]*|[[:blank:]]+)(\d+)\.(?&spacer)(?:([1-8])?([a-h])([1-8])([+-<>])([1-8]*)|([FSC])?([a-h])([1-8]))(?:(?&spacer)(?:([1-8])?([a-h])([1-8])([+-<>])([1-8]*)|([FSC])?([a-h])([1-8])))?(?&spacer)?(?=$|\n)

Unit Tests

There are no unit tests.