CLHS: Issue LCM-NO-ARGUMENTS Writeup

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## Issue LCM-NO-ARGUMENTS Writeup

    Issue:         LCM-NO-ARGUMENTS

    References:    CLtL p. 202

    Related issues: none

    Category:      ADDITION

    Edit history:  Version 1, Guy Steele 10/17/88

    Problem description:

       CLtL incorrectly states that (lcm) should return infinity, and
       therefore specifies that giving lcm no arguments is an error.

       In point of mathematical fact, 1 is the identity for the lcm operation.

    Proposal (LCM-NO-ARGUMENTS:1):  Define (lcm) to return the integer 1.

    Examples:   (lcm) => 1

    Test Cases:  (lcm) => 1

       Currently the behavior in this case is implementation-dependent.

    Rationale:  Doing what is mathematically right.

    Current practice:
       KCL signals an error.
       Lucid Lisp returns 1.
       Symbolics Common Lisp returns 1.

    Cost to Implementors:  Pretty small (one-line fix).

    Cost to Users:  None.

    Cost of non-adoption:  Continued embarassment for Steele.

    Performance impact:  Negligible.

    Benefits:  Correct handling of a seldom-used boundary case.

    Esthetics:  Mild improvement.

    Discussion:  Mentioned in Steele's December 1985 "clarifications".

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