In the latter two examples, the hex has already been interpreted as a hex value before the hex function is called. So what gets passed to the hex function is the decimal string representation of the number. This may clarify: 

$n = 0xaf;;
print $n;;
175

print hex $n;;
373

print oct $n;;
125

print hex '175';;
373

print oct '175';;
125

[download]

Ie. both hex & oct take strings which they then interpret as numbers in a default base (16 or 8) respectively. If you pass them a number, it is converted to a string first.

But it also gets more confusing as they will also interpret number is each others bases if that is indicated by a prefix in their arguments:

print hex '0x' . '175';;
373

print hex '0' . '175';;
373

print oct '0x' . '175';;
373

print oct '0' . '175';;
125

[download]
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
RIP an inspiration; A true Folk's Guy

In reply to Re: To hex EXPR or 'EXPR' is my question by BrowserUk
in thread To hex EXPR or 'EXPR' is my question by biohisham

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