To: J3                                                     J3/26-217
From: Dan Bonachea & Lorri Menard
Subject: Interp F23/023 on REDUCE OPERATION associativity
Date: 2026-October-23
References: 26-198

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NUMBER: F23/023
TITLE: REDUCE OPERATION associativity
KEYWORDS: REDUCE, ORDERED, associative
DEFECT TYPE: Erratum
STATUS: J3 consideration in progress
REFERENCES: 24-007

QUESTION:
On a REDUCE invocation where ORDERED has the value true, must the OPERATION
argument be mathematically associative?

ANSWER:
No, it was not intended to recommend associativity when ORDERED is present with
the value true.
When ORDERED is present with the value true the order of evaluations is fully
specified, therefore a lack of associativity would not affect the result.

An edit is provided to correct this oversight.

EDITS to 24-007:

[436:17-18] 16.9.1.73 REDUCE, para 3, OPERATION argument

Before "OPERATION", insert:

 "If ORDERED is absent or false, then "

Such that the entire sentence reads:

 "If ORDERED is absent or false, then OPERATION should implement a
  mathematically associative operation.


SUBMITTED BY: Dan Bonachea, Lorri Menard

HISTORY: 26-nnn   m241  Submitted

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