Re^2: Misreading m// documentation (perlop =~ )

[QM]

=~ with a string implies regex m//atch

Documented in doc:/perlop#Binding-Operators:

If the right argument is an expression rather than a search pattern, substitution, or transliteration, it is interpreted as a search pattern at run time.

[LanX]

> If the right argument is an expression rather than a search pattern,

True, but this doesn't apply here, it's literal a search pattern (i.e. compile time), the m is just optional:

Both generate exactly the same opcodes:

<Reveal this spoiler or all in this thread>

"expressions evaluated at runtime" are things like variables or functions or do-blocks...

  DB<103> $x= '\w{3}'
 => "\\w{3}"

  DB<104> 'abc' =~ $x
 => 1

  DB<105> sub regex { '\w{3}' }

  DB<106> 'abc' =~ regex()
 => 1

[QM]

OK, I see the light now.

<pedantic>
There's m//, and =~. m// can be used without =~ to match against $_, or with =~ to match against something else.

Without the presence of =~, m// can omit the m if the delimiter is //, else it is required.

=~ expects to see a match, substitution, or translation on the RHS, and assumes a match without m//, s//, y//, or tr//.
</pedantic>

And since m//, and =~ are 2 separate entities (that slightly overlap), the documentation doesn't tie these together explicitly (IMHO).