anonymous class, body defined by Proc.new vs. lambda

[Thomas Hafner]

Hello,

this is OK for both, Ruby 1.8 and 1.9:
f = Proc.new{}; Class.new(&f)

But why is that valid for Ruby 1.8 only?
f = lambda{}; Class.new(&f)

Ruby 1.9 complains
`initialize': wrong number of arguments (1 for 0) (ArgumentError)
from ./now.rb:21:in `new'
from ./now.rb:21:in `<main>'

Regards
Thomas

 

[Phlip]

Ruby 1.9 complains
`initialize': wrong number of arguments (1 for 0) (ArgumentError)
from ./now.rb:21:in `new'
from ./now.rb:21:in `<main>'

Just a guess does this fix it?

f = lambda{|o| }; Class.new(&f)

Something to do with lambdas defend their arity...

 

[Ryan Davis]

this is OK for both, Ruby 1.8 and 1.9:
f = Proc.new{}; Class.new(&f)

But why is that valid for Ruby 1.8 only?
f = lambda{}; Class.new(&f)

Ruby 1.9 complains
`initialize': wrong number of arguments (1 for 0) (ArgumentError)
from ./now.rb:21:in `new'
from ./now.rb:21:in `<main>'

the error message tells you why. it isn't hard to figure out what the
arg is either:
#<Class:0x428ec>