Lisp acessing value (new to Lisp)

Question

I'm new to Lisp and don't know how to access the :DIM value! Here's the code:

(defstruct peca 
  dim 
  val)

(setf exemple #S(PECA :DIM 2 :VAL 1))

How can I get the value of :DIM from exemple? When I try exemple-dim it says variable -DIM has no value.

jwmc · Accepted Answer · 2012-11-16 12:06:16Z

4

The macro defstruct defines reader functions, among other things. The default names for these are of the form structname-slotname, in your case giving peca-dim and peca-val.

There is further information in the HyperSpec, here.

edited Nov 16, 2012 at 12:06

answered Nov 16, 2012 at 11:56

jwmc

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1 Comment

Michael H. Over a year ago

jwmc has answered the direct question of how you access those values. You should know that if you don't like the default style of "classname + hyphen + slot-name", you can use the :conc-name option to specify something nicer for the initial portion (usually something shorter). Now, I would recommend against typing #S(...) yourself. Lisp prints it that way, but you should use the automatically defined (make-peca :dim ... :val ...) constructor instead.

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