Consider the following program:

perl -MDevel::Peek -le 'my @nonempty = (1); my @empty = (); print Dump
+(scalar @nonempty); print Dump(scalar @empty)'
SV = IV(0x563dfe2d16f0) at 0x563dfe2d1700
  REFCNT = 1
  FLAGS = (TEMP,IOK,pIOK)
  IV = 1

SV = PVNV(0x563dfe2d0200) at 0x563dfe2ce410
  REFCNT = 2147483647
  FLAGS = (PADTMP,IOK,NOK,POK,READONLY,PROTECT,pIOK,pNOK,pPOK)
  IV = 0
  NV = 0
  PV = 0x7fb0f957d3c2 "0"
  CUR = 1
  LEN = 0

[download]

Which is to say, scalar returns a PV if the array is empty, and an IV if it is not. This can be a problem, because most serializers, including JSON modules, will encode the PV as "0" and the IV as 1, which will cause a problem if the consumer of the resulting JSON expects strict type conformance.

Is there a logical reason for this discrepancy?

(Yes, I know that I could just do 0+scalar @array - my point is that that shouldn't be necessary.)

In reply to Reason for this discrepancy with scalar? by kikuchiyo

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