From: Markus <markus@...>
Date: 2004-10-05T23:13:37+09:00
Subject: Re: [RCR] New [] Semantics

On Tue, 2004-10-05 at 01:33, trans. (T. Onoma) wrote:

> Hmm... a bit of a touch up (btw unbound can be represented by it's own object, 
> so no special syntax required):

     If there is no special syntax, but how do create them?  I'll admit
I like the idea of Infinity posted on the next thread over, but that
came up after I started.

>   r = 0<..<43
>   r = 0<..<=42
>   r = 0<=..<43
>   r = 0<=..<=42

>   r = 0<..+<42
>   r = 0<..+<=42
>   r = 0<=..+<42
>   r = 0<=..+<=42

     I'm not sure what distinction you are making here with the '+'.  

> Basically tie-fighter ranges ( and x-wing ranges ;)  F'ugly! :( Alhtough I 
> like your direction. 

     The core idea is actually peripheral to this (or visa versa); I'm
modifying parse.y to extend the idea of tOP_ASGN ( +=, -=, etc.) to
include (as user redefinable methods like <=> is presently) _all_
combinations of operator characters.

> Alternative is just to use standard-like notation:
> 
>   0 < r < 43
>   0 < r <= 42
>   0 <= r < 43
>   0 <= r <= 42
> 
>   0 < r +< 43
>   0 < r +<= 42
>   0 <= r +< 43
>   0 <= r +<= 42

> Who said assignment always had to be 'r =' ? Of course it would be nice if we 
> could just do like:

     Yikes!   I don't think that would be easy to parse at all,
especially since all three non-terminals could be syntactical complex. 
And what if you wanted to pass a range as an actual parameter?

>   r = :(0,43)
>   r = :(0,42]
>   r = :[0,43)
>   r = :[0,42]
> 
>   r = :(0:43)
>   r = :(0:42]
>   r = :[0:43)
>   r = :[0:42]

     Hmmm.  That would be a little harder--or at least, I don't quite
see how to bend the parser to handle it.

-- Markus