Functional

compose#

(let compose (fun (_f _g) (...))) Compose function calls

Parameters#

• _f: the first function
• _g: the second function

Author#

@rstefanic

Example#

(let foo (fun (a) (* a a)))
(let bar (fun (b) (+ b b)))
(let composed (compose foo bar))
(print (composed 12))  # return value is (12 + 12) * (12 + 12)

left#

(let left (fun (_x) (...))) Take a value as its argument and return a function taking 2 arguments which will call the first function on the value

Parameter#

• _x: the value

Author#

@SuperFola

Example#

(let val (left 12))
(val (fun (x) (print x " i am called")) (fun (x) (print x " i am NOT called")))

right#

(let right (fun (_y) (...))) Take a value as its argument and return a function taking 2 arguments which will call the second function on the value

Parameter#

• _y: the value

Author#

@SuperFola

Example#

(let val (right 12))
(val (fun (x) (print x " i am NOT called")) (fun (x) (print x " i am called")))

flip#

(let flip (fun (_f) (...))) Flip the arguments of a function

Note: Returns a function taking 2 arguments a and b, calling (f b a)

Parameter#

• _f: the function

Author#

@rstefanic

Example#

(let foo (fun (a b) (- a b)))
((flip foo) 14 12) # will call (foo 12 14) instead of (foo 14 12)

identity#

(let identity (fun (_x) (...))) No-op, return the value as-is

Parameter#

• _x: the value

Author#

@SuperFola

Example#

(let maybeAbs (if shouldNormalizeNegatives math:abs identity))
(let data (list:map nums maybeAbs))

recombine#

(let recombine (fun (_f _g _h) (...))) Generic form for functions that need to reuse their arguments

Note: Returns a function taking one argument x, calling (f (g x) (h x))

Parameters#

• _f: function called with two arguments
• _g: first unary function
• _h: second unary function

Author#

@SuperFola

Example#

(let mean (recombine (fun (a b) (/ a b)) list:sum list:size))
(print (mean [0 1 1 2 3 5 8 13]))  # 4.125