Opened 7 years ago

Closed 5 years ago

#51 closed defect (fixed)

support for cyclic structures in primitives

Reported by: alexshinn Owned by: alexshinn
Priority: major Milestone:
Component: WG1 - Core Keywords:
Cc:

Description

list?, length, equal? and other fundamental
primitives may diverge when given cyclic
data. In the former two cases, avoiding this
is simple and not inefficient, and the equivalents
already provided in SRFI-1, in the latter case
a proposal was made and rejected on the R6RS list.

Do we want to specify the behavior when these
primitives encounter cyclic data?

Change History (9)

comment:1 Changed 7 years ago by arcfide

What a reason given for the rejection? Was there any rationale given for this behavior? I'd like to see what the previous editor's thought about this, and why it was chosen to be this way.

comment:2 Changed 7 years ago by cowan

  • Resolution set to fixed
  • Status changed from new to closed

The WG voted to accept the SRFI-1 rules, and to require that equal? MUST NOT terminate on a cyclic list.

comment:3 Changed 7 years ago by cowan

Correction: The WG voted to make no change to R5RS.

comment:4 Changed 6 years ago by cowan

WG1 voted:

equal? is required to do proper checks for cyclic structure to not diverge
list? should return #f and length raise an error for cyclic lists

comment:5 Changed 6 years ago by alexshinn

  • Resolution fixed deleted
  • Status changed from closed to reopened

comment:6 Changed 6 years ago by alexshinn

  • Owner alexshinn deleted
  • Status changed from reopened to assigned

comment:7 Changed 6 years ago by alexshinn

  • Status changed from assigned to decided

comment:8 Changed 6 years ago by alexshinn

  • Owner set to alexshinn
  • Status changed from decided to writing

comment:9 Changed 5 years ago by cowan

  • Resolution set to fixed
  • Status changed from writing to closed
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