Conversion
Functions
For instance. We are
working with an integer. And now we want to convert that integer into
a string. We need a conversion function.
AutoLISP has got eleven
conversion functions. Here they are:
(angtos
<angle> [<mode> [<precision>]])
This function converts an
angle into a string. The angle is a real number in radians. The
result depends on the mode and the precision.
Mode Description
0 Degrees
1 Degrees/minutes/seconds
2 Degrees (400)
3 Radians
4 Land units
The precision argument
give the number of decimals. The mode and precision argument are in
the system variables AUUNITS and AUPREC.
Examples:
(setq p1 (list 500 133))
(setq p2 (list 240 133))
(setq an (angle p1 p2))
(angtos an 0 0) "180"
(angtos an 0
4) "180.0000"
(angtos an 1 4) "180d0'0"
(angtos an 3 4) "3.1416r"
(angtos an 4 2) "W"
(rtos
<number> [<mode> [<precision>]])
Now a real number is
converted into a text. The units and precision depend on the
arguments for mode and precision.
Mode Description
1 Mathematical
2 Decimal
3 Feet and decimal inches
4 Feet and fractional
inches
5 Divisions
The mode and the precision
arguments can be found in the system variables LUNITS and LUPREC.
Examples:
(rtos 17.5 1
4) "1.7500E+01"
(rtos 17.5 2 2) "17.50"
(rtos 17.5 3 2) "1'-5.50"
(rtos 17.5 4 2) "1'-5
1/2"
(rtos 17.5 5 2) "17
1/2"
(itoa
<integer>)
Now an integer is
converted into a text.
Examples:
(itoa 33) "33"
(itoa -17) "-17"
(atoi
<text>)
A text is converted into
an integer.
Examples:
(atoi "97") 97
(atoi "-3") -3
(atoi "3.9") 3
(atof
<text>)
A text is converted into a
real number.
Examples:
(atof "97.1") 97.1
(atof "-3") -3.0
(fix
<number>)
This function translates a
number into an integer.
Examples:
(fix 3) 3
(fix 3.7) 3
(float
<number>)
Here a number is
translated into a real number.
Examples:
(float 3) 3.0
(float 3.75) 3.75
(list
<expression>)
A list is created with a
number of loose expressions. It is often used to create a 2D point or
3D point.
(list 'a 'b 'c) (A B C)
(list 'a '(b c)
"text") (A (B C) "text")
(list 3.9 6.7) (3.9
6.7)
(ascii
"text")
The ASCII value of the
first character of the text is given.
(ascii "a") 97
(ascii "A") 66
(ascii "all") 97
(chr
<number>)
The number is an ASCII
value. The corresponding character is givne back.
Examples:
(chr 65) "A"
(chr 66) "B"
(chr 97) "a"
(read
<text>)
This function gives back
what has been read. The text cannot contain spaces. What is after the
space is ignored.
(read "LISP") LISP
(read "A") A
Exercise:
Create an AutoLISP
program, that creates the following parking spot. Do you see? The
sizes for the length, width, and angle are given.
This is how the AutoLISP
program works:
Command: PRKSP
Width/Length/Angle/<starting
point>:W
Width <default>:
width is entered
Width/Length/Angle/<starting
point>:L
Length <default>:
length is entered
Width/Length/Angle/<starting
point>:A
Angle <default>:
angle is entered
Number of parking spots
<default>: number is entered
Take care. The AutoLISP
program is going to be very big. So make separate functions for
entering the width, length, and angle.
Exercise
Let's write an AutoLISP
program. This is the drawing that is created by the AutoLISP program.
Two points are picked. The
circle is drawn in one point. And as line goes to the other point,
starting in the first point.
The user enters what text
is to be drawn in the circle. And a box is drawn around the text. The
TEXTBOX function is used.
