Nil.to_? and ruby2.0

ruby-talk
1

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

···

--
+-[ Gergely Kontra <kgergely@mcl.hu> http://www.mcl.hu/~kgergely ]------+

PhD Student (Room:IB113) PGP ID: 0x7E3846BF Mobile:(+36 20)356 9656 |
Budapest University of Technology and Economics ICQ# 175564914 |

+------------- "Olyan langesz vagyok, hogy poroltoval kellene jarnom!" -+

2

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

···

On 5/6/05, Gergely Kontra <kgergely@mcl.hu> wrote:
--
Austin Ziegler * halostatue@gmail.com
               * Alternate: austin@halostatue.ca

3

Gergely Kontra wrote:

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.

···

--
Mark Sparshatt

4

Gergely Kontra wrote:

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:

-Charlie

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

]------+

> PhD Student (Room:IB113) PGP ID: 0x7E3846BF Mobile:(+36 20)356

9656 |

> Budapest University of Technology and Economics ICQ#

175564914 |

+------------- "Olyan langesz vagyok, hogy poroltoval kellene

jarnom!" -+