Test Functions

Test Functions


AutoLISP has got two text functions. They are:


- IF function
- COND function


IF Function


(if <expression> <then> <else>)


The expression is evaluated. If it is true, then the THEN part is performed. If not, then the ELSE part is performed.


Examples:


Function: Gives:


(if (= 1 3) "Yes" "No") "No"
(if (= 2 (+ 1 1) "Yes") "Yes"
(if (= 2 (+ 3 4) "Yes") nil


The THEN part or the ELSE part of the IF function can only contain one expression. If more there are more expressions, then PROGN is used.


Example:


(if (= a b)
(progn
(setq a (+ a 10))
(setq b (+ b 10))
)
(progn
(setq a (- a 10))
(setq b (- b 10))
)
)


Here is another example of how the IF function can be used. Now we have an AutoLISP program. A line is drawn and a circle and a text.


(defun c:ball1 (/ p1 p2 an tx aw ht)
(setq p1 (getpoint "\nFirst point:")
p2 (getpoint p1 "\nSecond point:")
an (angle p1 p2)
)
(initget 1 "Yes" No")
(setq aw (getkword "Text (Yes/No)? "))
(if (= aw "Yes")
(setq ht (getdist "\nHeight: ")
tx (getstring "\nText: ")
)
(setq ht (getdist p1 "\nRadius: "))
)
(command "line" (polar p1 an ht) p2 ""
"circle" p1 ht
)
(if (= aw "Yes")
(command "text" "m" p1 ht 0 tx)
)
)


COND Function


(cond (<text1> <result1> …)


This function is used to perform an action depending on the value of a variable. Here is an AutoLISP program that shows it.


If is the program from before. But now you can draw a circle, a square, or a triangle. You choose in the beginning.


(defun c:ball2 (/ p1 p2 an ht tx aw)
(setq p1 (getpoint "\nFirst point: ")
p2 (getpoint p1 "\nSecond point: ")
an (angle p1 p2)
ht (getdist "\nHeight text: ")
tx (getstring "\nText: ")
)
(initget "Cir Tri Quadr")
(setq aw (getkword "\nTriangle/Quadrant/
<Circle>: ")
)
(command "line" (polar p1 an ht) p2 "")
(cond
((= aw "Tri")
(command "polygon" 3
p1
"c"
(polar p1 an ht)
)
)
((= aw "Quadr")
(command "polygon" 4
p1
"c"
ht
)
)
(T
(command "circle" p1 ht)
)
)
(command "text" "m" p1 ht 0 txt)
)