List comprehensions: Difference between revisions

Content added Content deleted
m (→‎{{header|Haskell}}: (Added a type signature))
(→‎{{header|AppleScript}}: Updated primitives)
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{{trans|JavaScript}}
{{trans|JavaScript}}

<lang AppleScript>-- List comprehension by direct and unsugared use of list monad
<lang AppleScript>-- List comprehension by direct and unsugared use of list monad


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on pythagoreanTriples(maxInteger)
on pythagoreanTriples(maxInteger)
script X
script X
on lambda(X)
on |λ|(X)
script Y
script Y
on lambda(Y)
on |λ|(Y)
script Z
script Z
on lambda(Z)
on |λ|(Z)
if X * X + Y * Y = Z * Z then
if X * X + Y * Y = Z * Z then
unit([X, Y, Z])
unit([X, Y, Z])
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[]
[]
end if
end if
end lambda
end |λ|
end script
end script
bind(Z, range(1 + Y, maxInteger))
bind(Z, enumFromTo(1 + Y, maxInteger))
end lambda
end |λ|
end script
end script
bind(Y, range(1 + X, maxInteger))
bind(Y, enumFromTo(1 + X, maxInteger))
end lambda
end |λ|
end script
end script
bind(X, range(1, maxInteger))
bind(X, enumFromTo(1, maxInteger))
end pythagoreanTriples
end pythagoreanTriples


-- TEST -----------------------------------------------------------------------

on run
on run
-- Pythagorean triples drawn from integers in the range [1..n]
-- Pythagorean triples drawn from integers in the range [1..n]
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pythagoreanTriples(25)
pythagoreanTriples(25)
--> {{3, 4, 5}, {5, 12, 13}, {6, 8, 10}, {7, 24, 25}, {8, 15, 17}, {9, 12, 15}, {12, 16, 20}, {15, 20, 25}}
--> {{3, 4, 5}, {5, 12, 13}, {6, 8, 10}, {7, 24, 25}, {8, 15, 17},
-- {9, 12, 15}, {12, 16, 20}, {15, 20, 25}}
⚫
end run
end run


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-- concat :: a -> a -> [a]
-- concat :: a -> a -> [a]
script concat
script concat
on lambda(a, b)
on |λ|(a, b)
a & b
a & b
end lambda
end |λ|
end script
end script
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---------------------------------------------------------------------------
-- GENERIC FUNCTIONS ----------------------------------------------------------


⚫
-- enumFromTo :: Int -> Int -> [Int]
-- GENERIC LIBRARY FUNCTIONS
⚫
on enumFromTo(m, n)
⚫
if n < m then
⚫
set d to -1
⚫
else
⚫
set d to 1
⚫
end if
⚫
set lst to {}
⚫
repeat with i from m to n by d
⚫
set end of lst to i
⚫
end repeat
⚫
return lst
end enumFromTo


-- foldl :: (a -> b -> a) -> a -> [b] -> a
-- foldl :: (a -> b -> a) -> a -> [b] -> a
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set lng to length of xs
set lng to length of xs
repeat with i from 1 to lng
repeat with i from 1 to lng
set v to lambda(v, item i of xs, i, xs)
set v to |λ|(v, item i of xs, i, xs)
end repeat
end repeat
return v
return v
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set lst to {}
set lst to {}
repeat with i from 1 to lng
repeat with i from 1 to lng
set end of lst to lambda(item i of xs, i, xs)
set end of lst to |λ|(item i of xs, i, xs)
end repeat
end repeat
return lst
return lst
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else
else
script
script
property lambda : f
property |λ| : f
end script
end script
end if
end if
end mReturn
end mReturn</lang>

⚫
-- range :: Int -> Int -> [Int]
⚫
on range(m, n)
⚫
if n < m then
⚫
set d to -1
else
⚫
set d to 1
⚫
end if
⚫
set lst to {}
⚫
repeat with i from m to n by d
⚫
set end of lst to i
⚫
end repeat
⚫
return lst
end range</lang>

{{Out}}
{{Out}}
<lang AppleScript>{{3, 4, 5}, {5, 12, 13}, {6, 8, 10}, {7, 24, 25}, {8, 15, 17}, {9, 12, 15}, {12, 16, 20}, {15, 20, 25}}</lang>
<lang AppleScript>{{3, 4, 5}, {5, 12, 13}, {6, 8, 10}, {7, 24, 25}, {8, 15, 17}, {9, 12, 15}, {12, 16, 20}, {15, 20, 25}}</lang>
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