weird keyword parameters in rails

[robbie]

Hi, I'm very new to Ruby, and to Ruby on Rails.
I'm halfway through the pickaxe book, past all of the stuff on syntax,
and I haven't seen anything explaining the keyword parameter syntax
used extensively in rails. The syntax I mean is:

method( :keyword => "value" )

I understand how to use this, I'm just not sure where it comes from.
Am I being docile, or is this slightly weird?
Thanks

robbie

 

[robbie]

just wanted to add, can't google it as google doesn't seem to search on
non alphanumeric characters. If anyone knows how to do that in google I
would also much appreciate it (sorry this is off topic).

 

[Austin Ziegler]

Hi, I'm very new to Ruby, and to Ruby on Rails.
I'm halfway through the pickaxe book, past all of the stuff on syntax,
and I haven't seen anything explaining the keyword parameter syntax
used extensively in rails. The syntax I mean is:
=20
method( :keyword =3D> "value" )
=20
I understand how to use this, I'm just not sure where it comes from.
Am I being docile, or is this slightly weird?

It's a hash with a Symbol as a parameter.

Try it in irb.

def foo(bar)
puts bar.class
puts bar.inspect
end

fookeyword =3D> 'value')

-austin
--=20
Austin Ziegler * (e-mail address removed)
* Alternate: (e-mail address removed)

 

[rmagick]

Check out p. 361 in the Pickaxe 2nd Ed. In a method call, the initial
parameters may be followed by "a list of key => value pairs. These
pairs are collected into a single new Hash object and passed as a
single parameter." In your example, "method" would get a hash argument
with 1 key-value pair.

 

[robbie]

thanks guys.
That's a clever trick.