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ChrisDolan (2855)
Journal of ChrisDolan (2855)
Tuesday January 13, 2009
10:29 PM
Regex for floating hex
A couple days ago I wrote about Java syntax for hexadecimal representation of floating point numbers like this:
0x1.fffffeP+127f
Here are the Perl 6 grammar snippets I put together to parse this. Easy!
token HexLiteral {
'0' ['x'|'X'] [
| '.' <HexDigit>+ <HexExponent>? <FloatTypeSuffix>?
| <HexDigit>+ [
| '.' <HexDigit>* <HexExponent>? <FloatTypeSuffix>?
| <IntegerTypeSuffix>?
]
]
}
token HexDigit { [\d|<[a..f]>|<[A..F]>] }
token HexExponent { ['p'|'P'] ['+'|'-']? \d+ }
token FloatTypeSuffix { 'f'|'F'|'d'|'D' }
help them think they understand.
--Larry Wall
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