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[REBOL] Re: relative expressions

From: ingo:h-o-h at: 1-Apr-2003 20:24

Hi Gabriele, Gabriele Santilli wrote: <...>
> Now imagine if we had types of values that were designed > specifically for our problem domain. In such a case, you would not > even need PARSE rules, but only something that makes the correct > actions for these values. (Notice that in REBOL the "methods" for > datatypes are called "actions". I wonder if this is a > coincidence.) This would solve the reusability problem, because > you just have to change the actions. > > However, you still don't have an easy way to "write down" the > values; this is where PARSE comes. You design a dialect with the > rules to parse it and translate it to a (sequence of) (custom) > value(s). It is like VID, that just translates to a FACE, which is > then used by View.
<...> You are right, I wrote a webbased calendar using pliant. I wanted to be able to write dates, but with some added sugar. 2003-01-01 would be the first of January 2003 01-01 First of january in whatever year 03/-1 the lasst of february in whatever year and some more like this. I missed my 'parse badly, but then I found the possibility to create new types, along with the to/from string rules - in a way it's even more powerfull then parse, because it is saved in the corresponding variable _as_this_new_datatype_. Having real userdefinable datatypes on the Rebol level would be great. Kind regards, Ingo