D:\>perl -MO=Deparse -E"say 02.5"
use feature 'current_sub', 'evalbytes', 'fc', 'postderef_qq', 'say', '
+state', 'switch', 'unicode_strings', 'unicode_eval';
say '25';
-e syntax OK
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With hindsight, the fact that 25 is a quoted string is a hint.

Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond

true, I haven't noticed :)

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}

Both operators work though.

say '==' if 02.5 == 25;
say 'eq' if 02.5 eq 25;
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prints both == and eq

Yes - though making assumptions about equivalence based on the output of perl's print() function is not a good practice.
For example:

C:\>perl -le "print sqrt(2);"
1.4142135623731

C:\>perl -le "print 'WTF' unless sqrt(2) == 1.4142135623731;"
WTF
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Cheers,
Rob

Sigh! I use . to concatenate strings so infrequently that I just didn't think of it in that role. :-(

Using Perl to drive moderately high power electronics (400W) does give "smoke testing" a whole other meaning - perhaps closer the the original meaning?

It's probably overkill, but I'll give it a plug, anyway:

C:\>perl -MMath::MPFR -le "print Math::MPFR->new('2.5', 8);"
2.625
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Math::GMPf is another perl module that can convert octal floating point values to decimal.
Are there any other modules doing that ? (I would expect so, but I haven't checked.)
I couldn't spot any built-in perl functions that will readily do this.

Cheers,
Rob