Re: Re: LOGO-L> Re: Punctuation (was: what is logo useful for anyways?)

["Dreyfuss Pierre-Andre" <p.a.dreyfuss@mailexcite.com>]

The same message but tested and bugfree.

If you want to use variables without :

It is very easy  Logo is powerfull enough to let you do everything you want.



If you want to use a b c as variable without :   then 
writes.

to a 
op :a
end

to b 
op :b
end

to c
op :c
end


And you don't need : any more

make  "a 5
make "b 6
pr a * b

and if you want to get rid of " then.


to c_IS :value
make "c  :value
end


to a_is :value
make "a :value
end

to b_is :value
make "b :value
end

Now try.

a_is 5
b_is 6
c_is a + b
pr c

Or more general:

to defvar :name
define word :name "_is ~
list [value] (list "make word "" :name ":value)
define :name list [] list "op word ": :name
end

This program should have no bugs I tested it.

(Yesterday I was using a computer without MSWLOGO on it.)

Just declare your variables with defvar.

You need once a quote to do that.

defvar "x

And then you can use x_is and x

 But you still have a notation for affectation and a notation for extracting the
value.


a works like cap or pos, it is a function just outputing its value. 


Regards.


P-A Dreyfuss
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>This is answer to :
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>> Brian Harvey wrote: 
>> > Is this worth pursuing?  How much of a problem are quotes and
>> > colons, really?
>>
>>To the serious computer scientist who needs a tool for list manipulation
>>and lambda calculus, Logo is under-powered.   To an amateur programmer and
>>to kids, I believe that the complications introduced by the "quotes and
>>colons" are detrimental, and the benefit is marginal.  
>>
>>In an unscientific survey that I made, not even one kid knew what these
>>"quotes and colons" are for, even if they knew when to use them.  At best,
>>kids could get used to these marks because "that's how things are done".  I
>>am sure that none of the readers of this group thinks that kids should be
>>educated to do things without understanding why.  
>>
>>My guess is that 99 out of 100 Logo users will not be able to explain why
>>these signs are needed.  I could be wrong.  But if I'm not wrong, then, to
>>answer your question - this is well worth pursuing.
>>
>>I remember a post by Olga Tuzova a few months ago about a student of hers
>>who got stuck with the Logo syntax when she wanted to use the Pythagorean
>>theorem in a program.  What she wanted to express was
>>    C = A^2 + B^2;
>>The above equation is a legal C statement, with a clear beginning and end.
>>Now translate it to Logo and compare.
>>
>>Chuck Shavit
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