Post-Condition if Statements And NameErrors

[MaggotChild]

I thought this was odd:

def bs
1
end

print y + 1 if y = bs

NameError: undefined local variable or method `y' for main:Object

And, of course, the multi-line if works:

if x = bs
print x + 1
end

 

[Eric Christopherson]

I thought this was odd:

def bs
=A01
end

=A0print y + 1 if y =3D bs

NameError: undefined local variable or method `y' for main:Object

And, of course, the multi-line if works:

if x =3D bs
=A0print x + 1
end

Something like this came up a few weeks ago. I think the parser is the
one generating the NameError, because the parser only consider a
variable to be defined if it sees an assignment to it, and such
assignment has to come *before* any use of the variable. Even though
the interpreter actually would actually execute y =3D bs first, the
parser doesn't see it at the point where its value is used.

 

[Benoit Daloze]

[Note: parts of this message were removed to make it a legal post.]

Something like this came up a few weeks ago. I think the parser is the
one generating the NameError, because the parser only consider a
variable to be defined if it sees an assignment to it, and such
assignment has to come *before* any use of the variable. Even though
the interpreter actually would actually execute y = bs first, the
parser doesn't see it at the point where its value is used.

Yeah, that's a bit annoying and considerably reduce while-one-liners
possibilities:

lines = IO.read('mac.txt').lines.to_a

puts line while line = lines.pop

but that works if you assign anything to line before ...