Re: Can LPeg do basic arithmetic?

[Sean Conner <sean@...>]

It was thus said that the Great Soni L. once stated:
> 
> 
> On 05/07/16 05:18 PM, Sean Conner wrote:
> >It was thus said that the Great Soni L. once stated:
> >>As you may or may not know by now, regex can do basic arithmetic, with
> >>unary integers.[1] Can LPeg do better, say with binary integers, or
> >>binary floats, or even full-blown decimal?
> > 
> >   Yup.  You can do the regex approach with a substitution capture
> >(lpeg.Cs()) or even a full blown calculator (there's an example on the LPeg
> >web page).
> 
> Too bad it's not pure LPeg, instead deferring to a Lua function for it.

  What?  Is not lpeg.Cf() LPeg, just because it accepts a Lua function as a
parameter?  So,

	lpeg.R"09" / { ['o'] = 0 , ['1'] = 1 , ['2'] = 2 ... }

is fine, but not?

	lpeg.R"09" / tonumber

  If LPeg allows it, it's LPeg.

  But okay, fine!  If you restrict the domain to single digits, then:

	  lpeg.P"0+0" * lpeg.Cc(0)
	+ lpeg.P"0+1" * lpeg.Cc(1)
	+ lpeg.P"0+2" * lpeg.Cc(2)
	+ lpeg.P"0+3" * lpeg.Cc(3) 
	... and so on.  Go crazy with this.

  -spc (Stop moving the goal posts!)