Function Entry: EQUAL

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Function Entry: EQUAL

Name

equal

Class

Function

Syntax

(equal expr1 expr2 [fuzz])

Arguments and Values

  • expr1, expr2: integer, real, string, list, ename, T, or nil.
  • fuzz (optional): integer or real tolerance value used for inexact numeric comparison.

Description

Determines whether two expressions evaluate to the same value. Unlike eq, equal compares structurally: two distinct but element-wise equal lists are equal. The optional fuzz argument controls tolerance for real-number comparison and for lists of reals such as point coordinates; two reals computed by different methods can differ slightly, and fuzz lets such values compare equal when the absolute difference is within tolerance.

Return Values

Returns T if the expressions are equal under the rules above, otherwise nil.

Side Effects

None.

Examples

  • Structural equality on lists: (equal '(a b c) '(a b c)) returns T.
  • Numeric tolerance: with (setq a 1.123456) and (setq b 1.123457), (equal a b) returns nil, while (equal a b 0.000001) returns T.

Availability

  • AutoCAD 2026: documented.
  • BricsCAD V26: presumed compatible (no contradicting page found).
  • Status: AutoCAD documented; BricsCAD presumed-both pending Phase 4 verification.