describe “should_not == vs. should !=”
it do
5.should_not == 6
end # passes
it do
5.should != 6
end # fails
end
On Jan 18, 2008 10:47 PM, David J. [email protected] wrote:
I’m running the rspec 1.1.2 gem with the corresponding Textmate bundle
The second failure surprises me.
Is != not supported?
Sadly, yes. It is not supported. Because Ruby does not support it.
When you say 5 == 3, what that is really saying is 5.==(3), which is
how we’re able to support 5.should == 3 (becomes 5.should.==(3)).
No such luck w/ !=.
C’est la vie.
Cheers,
David
On 19/01/2008, at 17:36 , David C. wrote:
When you say 5 == 3, what that is really saying is 5.==(3), which is
how we’re able to support 5.should == 3 (becomes 5.should.==(3)).
Would it be true to say that the reason “5.should != 3” won’t work is
that somewhere inside Ruby the x != y comparison is remapped to !(x
== y), and thus the “5.should != 3” is remapped to “not (5.should.==
3)”, with rspec generating a failure when “should” sees false coming
back from the “==” method?
Or am I barking up the wrong tree and potentially misleading dozens
of programmers down the garden path?
Alex
On Jan 20, 2008 8:01 PM, Alex S. [email protected] wrote:
Or am I barking up the wrong tree and potentially misleading dozens
of programmers down the garden path?
I’m 99 44/100% sure that you have it right. The expression x != y is
syntactic sugar for !(x == y) much like x += y is syntactic sugar for
x = (x +y)
The parser turns these into an internal representation (abstract
syntax tree for 1.8, byte-codes for 1.9) which is identical to the
second form.
–
Rick DeNatale
My blog on Ruby
http://talklikeaduck.denhaven2.com/
I’m 99 44/100% sure that you have it right. The expression x != y is
syntactic sugar for !(x == y) much like x += y is syntactic sugar for
x = (x +y)The parser turns these into an internal representation (abstract
syntax tree for 1.8, byte-codes for 1.9) which is identical to the
second form.
In 1.8 it’s just syntactic sugar. But 1.9 provides actual != and !~
methods so that you can override it in situations like this.
(from Ruby-Core: http://www.ruby-forum.com/topic/134608 )
On Jan 21, 2008 8:22 AM, Jim L. [email protected] wrote:
methods so that you can override it in situations like this.
Oooooh. Good to know. We’re not 1.9 compatible yet, but when we get
there we’ll definitely add this!