But unlike real quanta, reading a Perl variable doesn't force it to collapse into only one state.

To make this more concrete, note that converting a number (either integer or floating point) to a string leaves both the numeric AND string values marked as valid: 

$ perl -MDevel::Peek -wle '$x=12345; print Dump $x; print "$x"; print 
+Dump $x'
SV = IV(0x1004f958) at 0x1004f958
  REFCNT = 1
  FLAGS = (IOK,pIOK)
  IV = 12345

12345
SV = PVIV(0x10023810) at 0x1004f958
  REFCNT = 1
  FLAGS = (IOK,POK,pIOK,pPOK)
  IV = 12345
  PV = 0x10040c08 "12345"\0
  CUR = 5
  LEN = 8

[download]
The same thing works for string to numeric conversions, so 
$x="12345.67"; $y=$x+1;

[download]
leaves $x with a floating point value and a string value which are both valid.

Not only is the Perl implementation Doing What I Mean, by caching the results before it even occurs to me that it would be a good idea it's Doing What I Should Have Meant!

In reply to Re^2: When does '123' become the number 123.0? by quester
in thread When does '123' become the number 123.0? by wa1ter

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