nil.to_? and ruby2.0

[Gergely Kontra]

Hi!

To the nil war:

Then what is the reason nil.to_i and friends exists?

Will it hide bugs?

I'm using 1.8, there nil.to_i exists,but
a=nil
b=2

b+a # nil cannot be coerced into Fixnum

So where to use nil.to_i?

ps: and how can I correctly reply to a message, if I don't get mails,
but read the mails from the archive?


Another question of mine: where can I read docs about ruby1.9/ruby2.0?
Shall I DL a snapshot and try it myself, or is there a good doc
somewhere?

thx
Gergo

 

[Austin Ziegler]

To the nil war:

Then what is the reason nil.to_i and friends exists?

Will it hide bugs?

I'm using 1.8, there nil.to_i exists, but
a = nil
b = 2
b+a # => nil cannot be coerced into Fixnum

So where to use nil.to_i?

b + a.to_i # I might have String, Fixnum, Float, or even nil here...

-austin

ps: and how can I correctly reply to a message, if I don't get
mails, but read the mails from the archive?

Either subscribe to the list, or go through the google groups
interface for comp.lang.ruby -- or maybe the gmane interface for the
same.

-austin

 

[mark sparshatt]

Hi!

To the nil war:

Then what is the reason nil.to_i and friends exists?

Will it hide bugs?

I'm using 1.8, there nil.to_i exists,but
a=nil
b=2

b+a # nil cannot be coerced into Fixnum

So where to use nil.to_i?

you'd use nil.to_i in a case like this

a = some_method
2 + a.to_i

if you knew that some_method could return nil and that treating it as
zero was the right thing to do. I.E. if you've made a concious desicion
to treat nil as zero

However if we allowed this

a = some_method
2 + a #=>

then whether or not it's reasonable for some_method to return a nil, it
would still be silently handled whether you want it to or not.

So to_i and friends are there so a developer can use them to hide nils
if the program warrants it, but this hiding isn't the default behaviour,
so unexpected nils don't get hidden.

Which seems a reasonable compromise between flexibility and error detection.

 

[Charles Mills]

Hi!

To the nil war:

Then what is the reason nil.to_i and friends exists?

Will it hide bugs?

I'm using 1.8, there nil.to_i exists,but
a=nil
b=2

b+a # nil cannot be coerced into Fixnum

So where to use nil.to_i?

Perhaps your thinking of to_int - which isn't defined for nil and why
the above raises an error.

ps: and how can I correctly reply to a message, if I don't get mails,

but read the mails from the archive?


Another question of mine: where can I read docs about ruby1.9/ruby2.0?
Shall I DL a snapshot and try it myself, or is there a good doc
somewhere?

Seems like there are some bits and pieces scattered accross the
internet, but nothing _complete_. Maybe start here:
http://www.rubygarden.org/ruby?Rite

-Charlie

thx
Gergo
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+-[ Gergely Kontra <[email protected]> http://www.mcl.hu/~kgergely ]------+
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