ccan/ccan/ccan_tokenizer/number_constant.guppy

/*
guppy is a pattern-matching language by Joey Adams that's not implemented or formalized yet.
See http://www.funsitelots.com/pub/guppy.g for a near self-definition

This is a guppy representation of integer and floating point formatting in C.
It is based on http://c0x.coding-guidelines.com/6.4.4.1.html and http://c0x.coding-guidelines.com/6.4.4.2.html
*/

number_constant: [
	integer_constant()
	floating_constant()
]

integer_constant: [
	([1-9] [0-9]*)           //decimal
	(0 [0-7]*)               //octal
	(0 [X x] [0-9 A-F a-f]*) //hexadecimal
]

integer_suffix: [
	([U u] [L l]*0..2)
	([L l]*1..2 [U u]*0..1)
]

floating_constant: [
	decimal_floating_constant()
	hexadecimal_floating_constant()
]

decimal_floating_constant: [
	([0-9]* '.' [0-9]+ exponent_part()*0..1 floating_suffix())
	([0-9]+ '.' exponent_part()*0..1 floating_suffix())
	([0-9]+ exponent_part() floating_suffix())
]

exponent_part:
	([E e] ['+' '-']*0..1 [0-9]+)

hexadecimal_floating_constant:
	(0 [X x] [
		[0-9 A-F a-f]* '.' [0-9 A-F a-f]+
		[0-9 A-F a-f]+ '.'
		[0-9 A-F a-f]+
	] [P p] ['+' '-']*0..1 [0-9]+ floating_suffix())

floating_suffix: [F L f l]*0..1

scan_number:
(
	[
		(0 [X x] [0-9 A-F a-f '.']*)
		(0 [B b] [0-1] [0-9 '.']*)
		([0-9 '.']*)
	]
	( [E P e p] ['+' '-']*0..1 [0-9]* )*0..1
	[0-9 A-Z a-z '.' '_' '$']*
)

/*
Notes:

A numeric constant can begin with any of:
	0-9 '.'
and can contain any of:
	0-9 a-f e f l p u x '.' '+' '-'
along with capital equivalents.

If scanning finds something starting with a '.' but no decimal digit after it, it is the '.' operator and not a number.

*/