basics/integers/stepping.rb

tests/_examples/basics/integers/stepping.rb in the metorex repository.

# A step named by keyword walks the same ground as one given by position.
positional = 1.step 9, 4
p positional.to_a
named = 1.step to: 9, by: 4
p named.to_a
mixed = 1.step 9, by: 4
p mixed.to_a
endless = 1.step by: 4
p endless.first 3

# A walk with no end has no count, while an infinite step reaches its end in
# a single stride.
p endless.size
toward_infinity = 1.step to: Float::INFINITY, by: 42
p toward_infinity.size
in_one_stride = 1.step to: Float::INFINITY, by: Float::INFINITY
p in_one_stride.size
back_in_one_stride = 1.step to: -Float::INFINITY, by: -Float::INFINITY
p back_in_one_stride.size

# An end or a step given both by position and by keyword is refused, as is a
# keyword the method does not take.
begin
  1.step 5, 1, to: 5 do break end
rescue ArgumentError => error
  puts error.message
end

begin
  1.step 5, 1, by: 5 do break end
rescue ArgumentError => error
  puts error.message
end

begin
  1.step step: 2 do break end
rescue ArgumentError => error
  puts error.message
end

# A step that cannot be compared against zero is refused when the walk runs
# rather than when it is built, so asking for the walk alone hands back an
# ordinary Enumerator.
begin
  1.1.step 5.1, "foo" do end
rescue ArgumentError => error
  puts error.message
end

walk = 1.step 5, "foo"
p walk.class
begin
  walk.size
rescue ArgumentError => error
  puts error.message
end

# A walk from an infinity to the same infinity has a span that is no number,
# so it yields nothing and its count is refused.
collected = []
Float::INFINITY.step Float::INFINITY, 1 do |value|
  collected.push value
end
p collected

standstill = Float::INFINITY.step Float::INFINITY, 1
begin
  standstill.size
rescue FloatDomainError => error
  puts error.message
end

Output:

[1, 5, 9]
[1, 5, 9]
[1, 5, 9]
[1, 5, 9]
Infinity
Infinity
1
1
to is given twice
step is given twice
unknown keyword: :step
comparison of String with 0 failed
Enumerator
comparison of String with 0 failed
[]
NaN