Status:	Passed, Jan 89 X3J13
Forum:         Cleanup
Issue:         LCM-NO-ARGUMENTS

References:    CLtL p. 202

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

  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".
