Regular Expressions 101

Non-Capturing Group(?:^|\n)

1st Alternative^

^start of string

2nd Alternative\n

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

Group 1([^\n]*options:[^\n]*(?=\n?)(?:\n+[ \t].*?(?=\n|$))*)

Negated Character Class[^\n]*

*matches any number of characters outside the set below:

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

options:the literal text options: (case insensitive)

Negated Character Class[^\n]*

*matches any number of characters outside the set below:

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

Positive Lookahead(?=\n?)

\n?optionally matches a line-feed (newline) character (ASCII 10)

Non-Capturing Group(?:\n+[ \t].*?(?=\n|$))*

*repeats the group contents below any number of times:

\n+a line-feed (newline) character (ASCII 10), repeated at least once

Character Class[ \t]

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

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

Positive Lookahead(?=\n|$)

1st Alternative\n

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

2nd Alternative$

$end of string, or before its final line terminator

Global pattern flags

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

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

(?:^|\n)([^\n]*options:[^\n]*(?=\n?)(?:\n+[ \t].*?(?=\n|$))*)

New

Usage:
  diagrammer [--debug] [--output=<file>] <input-file>
  diagrammer --help


Options:
  --debug, -d      Draw the diagram upon a grid.

  --help           Show this message and exit.

  --output=<file>  Place output in file 'file'. [default: output.png]


Copyright Evgeny Gagauz, 2016.