[REBOL] Re: REBOL/View 1.3 - invalid word datatype
From: rebol-list2:seznam:cz at: 16-Dec-2003 18:14
Tuesday, December 16, 2003, 8:45:56 AM, you wrote:
CR> On 16-Dec-03, rebOldes wrote:
>> Hello Carl,
>> As you are preparing new build of Rebol, I would like to ask you, If
>> it would be possible to change somehow handling of "invalid
>> As I'm working on a probably the largest known dialect using Rebol -
>> the Rebol/Flash dialect ( http://oldes.multimedia.cz/swf/ ), I
>> still feel very limited because of impossibility to use some words.
>> For example I would like to have in my dialect code words like this
>> ** Syntax Error: Invalid decimal -- 1._x
>> ** Near: (line 1) objects/1._x
>> As you can see, it's recognized as an invalid decimal. So here comes
>> the question. Would it be possible to change this behavior to
>> something which we could use? There were already some discussions on
>> mailing list about this issue months ago, but I still don't know
>> your opinion.
>> I think the best way would be to handle these 'invalid' words as a
>> special word which would not be able to hold some values but I would
>> be able to parse this word as a normal string.
>> If it will be a problem maybe it would help to use some refinement
>> in the 'load function not to throw these "invalid datatype" errors
>> and convert these "invalid datatypes".
>> If you would make this change, I would be able to make for example
>> functions as are known in other languages for example:
>> myFunc(a, 2, a + b)
>> because loading such a dialect would not throw error like:
>>>> load [myFunc(a, 2, a + b)]
>> ** Syntax Error: Invalid word -- a,
>> ** Near: (line 1) load [myFunc(a, 2, a + b)]
CR> The problem would be that real errors wouldn't be caught. Maybe we
CR> need a special type of block that would allow this? (Which would
CR> require a new datatype - well, two new datatypes - the special block
CR> and an unknown! datatype.)
CR> Which is non-trivial I suspect.
unknown! is a good name. For me it would be enough if such a datatype
would be recognized during 'load function - so it seems not to be such
a problem to me. Now we have a name as well:)
CR> For your Flash dialect Oldes, have you thought about a two-pass
CR> approach? The first pass would parse the file as a string,
CR> converting your myFunc(a, 2, a + b)s and so on to strings (or what
CR> datatypes or group of datatypes best suit them), with the second pass
CR> performing the main parse.
It's not a solution for something like objects/:i._x which I would
like to parse as _x possition of object i from array of objects.
Something what's not possible even in Rebol, but something, what could
be parsed in dialect easily if I would be able to load such a code.
Now I need to write:
CR> Carl Read
rebOldes -----------------[ http://oldes.multimedia.cz/ ]