newlispfanclub.alh.net

Posted: **Fri Apr 14, 2006 12:06 am**

why doesn't the following work?

(define (addcustomer )
(set 'namee (read-line))
(set 'street (read-line))
(push '((namee) (street)))customer)

The part that isn't working is: (push '((namee) (street)))customer)

Posted: **Fri Apr 14, 2006 2:39 am**

Try this program:

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; test
(define (addcustomer)
        (set 'namee (read-line))
        (set 'street (read-line))
        (push (list namee street)  customer))

now execute it:

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~> newlisp test
newLISP v.8.8.0 on OSX UTF-8, execute 'newlisp -h' for more info.

> (addcustomer)
John Doe 
123 Main Street, Anytown    
("John Doe" "123 Main Street, Anytown")
>

Lutz

Posted: **Fri Apr 14, 2006 7:28 am**

As for why. First:

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(namee)

is trying unsuccessfully to evaluate the first item in this list as the function namee.

But:

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'(namee street)

will produce (namee street), because the quote prevents these symbols from being evaluated.

So your original code:

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'((namee) (street)))

is doing two things that you don't want: preventing evaluation of a list of lists, and trying to evaluate those lists and failing to find useful functions.

WIthout the doubled parentheses:

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(push '(namee street) customer)

you would have a nice unevaluated list of symbols:

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> (push '(namee street) customer)
(namee street)

Since namee contains information you want, evaluate it.

newlispfanclub.alh.net

why don't this work?

why don't this work?