LOGO-L> Re: LOGO-L> John Wood's problem with RUN
jlwo...@my-deja.com
Thanks for some of your ideas. They have been very helpful, but a lot of the
results were created by a similar problem I dealt with trying to work with
making a chess game. As somebody below indicated the RUN :PLAY needs 2
adjustments. First PLAY is a primitive and secondly the syntax needs to be
changed for PC LOGO 2.0 for WINDOWS. I needed to use either the word
SENTENCE or LIST written as follows:
RUN (SE :RUN_PLAY)
Again thank you for your help, and it appears that several similar LOGO
programs have varying syntax. My reference manual that came with the
program does not show, or suggest this solution. It shows using [] 's.
In article <7m01eq$gdh$1...@agate.berkeley.edu>,
b...@anarres.CS.Berkeley.EDU (Brian Harvey) wrote:
> "John Hayes" <jah...@xtra.co.nz> writes:
> >First, Bill Glass reminds us that PLAY is a primitive, so use another name,
> >perhaps PLAY.IT.
>
> This should not be necessary; in Logo, variable names and procedure names are
> independent. The fact that there is a procedure named PLAY (primitive or
> otherwise) doesn't interfere with saying
> MAKE "PLAY whatever
> ... :PLAY ...
>
> >Now you need to have a list for RUN, so the contents of PLAY.IT need to be
> >enclosed within brackets. To bring that about PLAY.IT must initially be an
> >empty list, so MAKE "PLAY.IT [].
>
> You are confusing two issues here. The input to RUN must (in some versions of
> Logo) be a list, but that doesn't mean you have to use brackets to create it.
>
> Brackets are used when you want a *literal* (a/k/a *constant*) list:
> MAKE "SUITS [HEARTS SPADES DIAMONDS CLUBS]
> But you can also create lists using constructor procedures such as LIST
> or SENTENCE:
> MAKE "COLORS LIST "RED "BLACK
> or
> MAKE "INPUT READLIST
>
> >make "play.it []
> >if equal? :CH_FORM 1 [make "play.it fput "POWER :play.it] else [make
> >"play.it fput "SLOT :play.it]
> >if equal? :CH_SIDE "L [make "play.it word first:play.it "_LEFT] else [make
> >"play.it word first :play.it "_RIGHT]
>
> The last line above undoes the list-ness of :PLAY.IT! You said
> MAKE "PLAY.IT WORD ... ...
> ^^^^
>
> The output of the WORD procedure is, as you might guess, a word, *not* a list.
> Just because you previously gave PLAY.IT a list as its value doesn't mean that
> future values will automatically be lists.
>
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