Re: LPeg indent/whitespace based grammar
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- Subject: Re: LPeg indent/whitespace based grammar
- From: Duncan Cross <duncan.cross@...>
- Date: Fri, 7 Jul 2017 22:21:41 +0100
On Fri, Jul 7, 2017 at 9:09 PM, Matthias Dörfelt <lists@mokafolio.de> wrote:
> Awesome, thanks that is super helpful!
> Haven’t looked at the “re” portion of lpeg, yet. I was initially gonna stick with pure LPeg, but let’s see!
>
> Is it pretty straight forward to express your re code in pure lua & LPeg?
>
> Thanks!
Sure, I think this should be the equivalent:
--
local hierarchy = lpeg.P {
'hierarchy';
hierarchy = initial_indent
*
lpeg.Ct(
lpeg.Cg(
lpeg.Ct(
(
lpeg.V('first_root')
*
lpeg.V('next_root')^0
)^-1
),
'children'
)
)
*
lpeg.P(-1);
first_root = lpeg.V('entry');
next_root = '\n' * lpeg.V('entry');
entry = lpeg.Ct(
lpeg.Cg(lpeg.V('name'), 'name')
*
lpeg.Cg(
lpeg.Ct(
(
lpeg.V('first_child')
*
lpeg.V('next_child')^0
)^-1
),
'children'
)
);
first_child = '\n' * capture_deeper_indent * lpeg.V('entry');
next_child = '\n' * match_same_indent * lpeg.V('entry');
name = (1 - lpeg.P('\n'))^0;
}
--
-Duncan