2011

■ For real numbers less than one, enter all decimal values with a leading
zero; that is, enter .001 as 0.001.
■ When nil is a possible parameter, AutoCAD Map 3D uses zero.
■ The expression evaluator deals only in strings; it does not distinguish
between strings and numerics. The expression evaluator converts strings
to their numeric values for math operations and converts the results back
to strings.
■ If you use variables set using AutoLISP, you must precede the variable with
an exclamation point (!).
■ To keep a space within a string, enclose the string in quotation marks. For
example, "this string" evaluates as one string, with a space between the
two words. Without the quotation marks, this string evaluates as two
separate strings. The expression evaluator ignores quotation marks.
■ You must enclose named objects with spaces in the name in parentheses
when used in evaluator functions. These objects include layers, blocks,
hatches, and linetypes.
■ The following expressions handle a maximum of three arguments: +, –, *,
/, AND, OR, STRCAT, =, and /=. All other expressions handle one or two
arguments. If you use +, –, *, or /, you must supply more than one
argument. For example, (+ 5 6) evaluates to 11; (+ 5 3 2) evaluates to 10.
■ An expression evaluates numbers with scientific notation in compound
simple expressions. For example, (+ 1e+001 1) evaluates to 11.0000; 1e+001
evaluates to 10.0.
■ AutoCAD Map 3D evaluates pi only in compound expressions; the program
treats pi as a string in simple expressions. For example, (STRCAT pi "_%")
evaluates to 3.14%; pi by itself evaluates to "pi."
■ You can specify
color (page 1552) using ACI, True Color, or Color Book color
values.
1554 | Chapter 12 Expression Evaluator