Input from Parameter

[scottmaccal]

Greetings,

I am trying to come up with a way to get user input in the form of (circle number1 number2) where circle is a defined function and the number1 and number2 are input from the user. I would like number1 and number2 input to go into a (write-line) function that already has characters in it. Here is some of the code I have written thus far.

(define (circle)
(set 'out-file (open "c:/users/name/desktop/circle" "write"))
(write-line "circle number1 number2 " out-file)
(close out-file))

(circle)

Any help would be greatly appreciated.

[cormullion]

Hi Scott...

Do you mean this sort of thing:

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(define (circle x y) 
  (set 'out-file (open "circle" "write")) 
  (write-line (string "circle " x " " y)  out-file) 
  (close out-file)) 

> (circle 1 2)
true
> (circle 3 4)
true
> (read-file "circle")
"circle 3 4\n"
>

Only the most recent values were stored. If you want to keep a history, use append-file.

[lithper]

the standard way to do variable interpolation inside a given string, as far as I understand, is by using the "format" function.

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(write-line (format "blablabla %s blabla %d" string_var decimal_num_var))

[scottmaccal]

the standard way to do variable interpolation inside a given string, as far as I understand, is by using the "format" function.

Code: Select all

(write-line (format "blablabla %s blabla %d" string_var decimal_num_var))

Thanks for the response cormullion and lithper!

My question now is how do I go about getting input from the user to fill num_var in a defined function?

What would such a function look like?

[Lutz]

You can use (read-line) to get input from stdin/keyboard. This will work only in a command shell/terminal window, not in the console window of the newLISP-GS Java front-end installed on Windows or Mac OS X.

[scottmaccal]

You can use (read-line) to get input from stdin/keyboard. This will work only in a command shell/terminal window, not in the console window of the newLISP-GS Java front-end installed on Windows or Mac OS X.

Thank you.

That gets me heading in the right direction.

[Jeff]

You will also want to cast them to integers or floats using (int foo) or (float foo).

[scottmaccal]

You will also want to cast them to integers or floats using (int foo) or (float foo).

How would I go about handling things that are not digits?

My latest challenge is writing code that will call a defined function after the user has inputed a certain sting. This is the code I have so far:

Code: Select all

(print "What shape: ")
(set 'answer (read-line))

(if
  (answer "draw-circle")
  (circle))

Could you point me in the right direction?

[Jeff]

Code: Select all

(print "What shape: ")
(set 'answer (read-line))

(if (= answer "draw-circle")
  (circle))

That would make *that* work properly. What I was talking about was that read-line interns strings. After (set 'answer (read-line)), answer now contains a string. If you were accepting, for example, a radius for a circle that would get used as a float, you would do:

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(print "What radius: ")
(set 'answer (read-line))

(if (set 'answer (float answer))
  (do-something-with answer)
  (begin
    (print "What *float* radius: ")
    (set 'answer (read-line))))

[cormullion]

Just for fun, here's a gui version of a circle-drawing routine. I was reminded by your posts of the fun we had typing responses to commands, and how complicated the business of getting the right information from a user on the command line could be (decimal commas, exponents, ranges and limits, etc.)

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(load (append (env "NEWLISPDIR") "/guiserver.lsp")) 
(gs:init)
(gs:frame 'f 50 50 550 600) ; a window
(gs:set-flow-layout 'f) ; layout type
(gs:canvas 'a-canvas) ; a canvas
(gs:set-background 'a-canvas gs:white)
(gs:set-size 'a-canvas 500 500)

(gs:slider 'radius-slider 'radius-slider-handler "horizontal" 0 800 100) ; a slider
(gs:label 'radius-label {radius}) ; a label

(define (radius-slider-handler id value) ; handler
   (cond 
     ((= id "MAIN:radius-slider")
        (set 'scale (div (float value) 100))
        (gs:set-scale scale scale)
        (gs:set-text 'radius-label (string (int (div value 2)) { pixels}))
        (gs:update))))

; assemble
(gs:add-to 'f 'a-canvas 'radius-slider 'radius-label)

(gs:set-translation 250 250) 
(set 'circle-radius 30)
(gs:draw-circle 'circle 0 0 circle-radius)
(gs:set-visible 'f true)

; run
(gs:listen)

[scottmaccal]

Jeff,

Thank you! That info was a big help.

Cormullion,

Thanks for sharing the GUI code. Even though it looks quite complex, it is remarkable to me how readable it is.