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Size: 891 Bytes
Versions: 7
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Stored size: 891 Bytes
Contents
module DR
module Lambda
extend self
#standard ruby: col.map(&f) for one variable
#Here: Lambda.map(f,col1,col2,...) for several variables
#Other implementation:
#(shift cols).zip(cols).map {|a| f.call(*a)}
#but our implementation stops as soon as a collection is empty
#whereas the zip implementation use the length of the first collection
#and pads with nil
def map(f,*cols)
cols=cols.map(&:each)
r=[]
loop do
r<<f.call(*cols.map(&:next))
end
r
rescue StopIteration
end
#like map but return an enumerator
def enum_map(f,*cols)
cols=cols.map(&:each)
Enumerator.new do |y|
loop do
y<<f.call(*cols.map(&:next))
end
end
end
#compose a list of functions
def compose(*f)
f.reverse!
first=f.shift
return lambda do |*args,&b|
v=first.call(*args,&b)
f.reduce(v) {|v,fun| fun.call(v)}
end
end
end
end
Version data entries
7 entries across 7 versions & 1 rubygems