regex101: LDraw valid numbers and invalid formats capture

Pro

Positive Lookbehind(?<=[ \t])

Character Class[ \t]

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

-?optionally matches the literal - (45₁₀ / 55₈ / 2D₁₆)

Non-Capturing Group(?: (?: \d |[1-9]\d+ |[1-9]\d*\.\d{1,3}(?<!0) |\.\d{1,3}(?<!0) )|(?: (\.0*)0 |(0+)\.\d{0,2}[1-9] |(0+)(?:0|[1-9]\d*)\.?\d* |\d+(\.0*) |\d*\.(?:[1-9]|\d[1-9])?(0+) |\d*\.\d{3}(\d+) ) )

1st Alternative (?: \d |[1-9]\d+ |[1-9]\d*\.\d{1,3}(?<!0) |\.\d{1,3}(?<!0) )

Non-Capturing Group(?: \d |[1-9]\d+ |[1-9]\d*\.\d{1,3}(?<!0) |\.\d{1,3}(?<!0) )

1st Alternative \d

\da digit

2nd Alternative[1-9]\d+

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

\d+a digit, repeated at least once

3rd Alternative[1-9]\d*\.\d{1,3}(?<!0)

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

\d*a digit, repeated any number of times

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d{1,3}a digit, repeated between 1 and 3 times

Negative Lookbehind(?<!0)

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

4th Alternative\.\d{1,3}(?<!0)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d{1,3}a digit, repeated between 1 and 3 times

Negative Lookbehind(?<!0)

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

2nd Alternative(?: (\.0*)0 |(0+)\.\d{0,2}[1-9] |(0+)(?:0|[1-9]\d*)\.?\d* |\d+(\.0*) |\d*\.(?:[1-9]|\d[1-9])?(0+) |\d*\.\d{3}(\d+) )

Non-Capturing Group(?: (\.0*)0 |(0+)\.\d{0,2}[1-9] |(0+)(?:0|[1-9]\d*)\.?\d* |\d+(\.0*) |\d*\.(?:[1-9]|\d[1-9])?(0+) |\d*\.\d{3}(\d+) )

1st Alternative (\.0*)0

Group 1(\.0*)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

0*the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated any number of times

0 the literal text 0

2nd Alternative(0+)\.\d{0,2}[1-9]

Group 2(0+)

0+the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated at least once

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d{0,2}a digit, repeated between 0 and 2 times

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

3rd Alternative(0+)(?:0|[1-9]\d*)\.?\d*

Group 3(0+)

0+the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated at least once

Non-Capturing Group(?:0|[1-9]\d*)

1st Alternative0

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

2nd Alternative[1-9]\d*

Character Class[1-9]

\d*a digit, repeated any number of times

\.?optionally matches the literal . (46₁₀ / 56₈ / 2E₁₆)

\d*a digit, repeated any number of times

4th Alternative\d+(\.0*)

5th Alternative\d*\.(?:[1-9]|\d[1-9])?(0+)

6th Alternative\d*\.\d{3}(\d+)

Positive Lookahead(?=[ \t]|$)

Character Class[ \t]?

Global pattern flags

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

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

25 tokens

Regular Expression

(?<=[ \t])-?
(?:
(?:
	\d
	|[1-9]\d+
	|[1-9]\d*\.\d{1,3}(?<!0)
	|\.\d{1,3}(?<!0)
)|(?:
	(\.0*)0
	|(0+)\.\d{0,2}[1-9]
	|(0+)(?:0|[1-9]\d*)\.?\d*
	|\d+(\.0*)
	|\d*\.(?:[1-9]|\d[1-9])?(0+)
	|\d*\.\d{3}(\d+)
)
)
(?=[ \t]|$)[ \t]?

Unit Tests

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