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Versions: 6
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Stored size: 1.42 KB
Contents
class Object
def false? ; nil ; end
def true? ; yield ; end
end
class FalseClass
def false? ; yield ; end
def true? ; nil ; end
end
class NilClass
def false? ; yield ; end
def true? ; nil ; end
end
module Kernel
def _if(exp, &block)
else_block = callcc { |cont|
@condition = cont
return exp.true?(&block)
}
@condition = nil
exp.false?(&else_block)
end
def _unless(exp, &block)
else_block = callcc { |cont|
@condition = cont
return exp.false?(&block)
}
@condition = nil
exp.true?(&else_block)
end
def _else(&block)
@condition.call(block) if @condition
end
end
# --- Test ---
a = nil
b = 2
c = false
_if(a != b) {
puts "a!=b"
}
_else {
puts "a==b"
}
_unless(b) {
puts "b is false"
}
_else {
puts "b is true"
}
# I was thinking of allowing for a multi block scenario.
module Kernel
alias fn lambda
def iff( *exp_blks )
r = nil
exp_blks.each_with_index{ |e,i|
if i % 2 == 0
r = e.true?(&exp_blks[i+1]); break if e
end
}
r
end
def unles( *exp_blks )
r = nil
exp_blks.each_with_index{ |e,i|
if i % 2 == 0
r = e.false?(&exp_blks[i+1]); break if ! e
end
}
r
end
end
# --- test ---
a = nil
b = 2
c = false
iff(
(a != b), fn{
puts "a!=b"
},
(true), fn{
puts "a==b"
}
)
unles(
(b), fn{
puts "b is false"
},
(false), fn{
puts "b is true"
}
)
Version data entries
6 entries across 6 versions & 2 rubygems