LispForum

Posted: **Fri Apr 10, 2015 10:05 pm**

Hi,

As far is I understand the "if" construct of common lisp (and that is not that far

you
can only put ONE expression in each branch like this:

(if (> x 1 )
 (print "true")
 (print "false))

I searched google and hyperpsec but only found examples like that above.

Is it possible to put more than one form (correct terminus???) into each branch of
the "if" (WARNING! WRONG SYNTAX AHEAD! ONLY AN EXAMPLE!):

Code: Select all

(if (> x 1 )
 ((print "true")
 (print "also true"))
 ((print "false)
  (print "also false)))

?

Thanks you very much in advance for any help!
Best regards,
mcc

Posted: **Sat Apr 11, 2015 2:11 am**

See PROGN and use it like this:

Code: Select all

(if (test-form ...)
    (progn
      (first-then-form ...)
      (second-then-form ...))
    (progn
      (first-else-form ...)
      (second-else-form ...)))

Posted: **Sat Apr 11, 2015 7:37 am**

Hi edgar-rft,

thanks again for your valuable help!

Best regards,
mcc

Posted: **Fri Apr 17, 2015 5:33 am**

And don't forget progn's lookalikes prog1 and prog2. I've found them useful once or twice.

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