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Line 183: F sin arc sin = compose(sin, arc sin); print((sin arc sin(0.5), (sin O arc sin)(0.5), new line))</syntaxhighlight> =={{header\|Amazing Hopper}}== VERSION 1: <syntaxhighlight lang="c"> #defn Compose(_FX_,_FY_) _FX_,_FY_ main: 0.5,Compose(sin,arcsin) "\n", print {0}return </syntaxhighlight> {{out}} <pre> $ hopper3 basica/compose1.hop 0.500000 </pre> VERSION 2: <syntaxhighlight lang="c"> #define-a «(_X_) _X_ ) #define Compose(_FX_,_FY_) _FC_(_FX_,_FY_, #define _FC_(_X_,_Y_,) ,_X_,_Y_ main: Compose(sin,arcsin)«( 0.5) "\n", print {0}return </syntaxhighlight> {{out}} <pre> $ hopper3 basica/compose2.hop 0.500000 </pre> VERSION 3: <syntaxhighlight lang="c"> #define «(_X_) _X_ ) #define Compose(_FX_,_FY_) _FC_(_FX_,_FY_, #define _FC_(_X_,_Y_,) ,_X_,_Y_ main: Compose(sin,arcsin)«( 0.5, mul by '2' ) "\n", print {0}return </syntaxhighlight> {{out}} <pre> $ hopper3 basica/compose2.hop 1.000000 </pre> <p>The power of macro-substitution, by Hopper!</p> =={{header\|AntLang}}== Line 550 ⟶ 603: {{out}} on Android phone: <syntaxhighlight lang="bori">0.500000000</syntaxhighlight> =={{header\|Binary Lambda Calculus}}== In lambda calculus, the compose functions happens to coincide with multiplication on Church numerals, namely <code>compose = \f \g \x. f (g x)</code> which in BLC is <pre>00 00 00 01 1110 01 110 10</pre> =={{header\|BQN}}== Line 610 ⟶ 669: b = compose(->double ->add1) p b 1 #should print 4</syntaxhighlight> =={{header\|Bruijn}}== Composition operators as defined in <code>std/Combinator</code>: <syntaxhighlight lang="bruijn"> :import std/Number . # 1x composition, bluebird combinator …∘… [[[2 (1 0)]]] :test (((inc ∘ (mul (+2))) (+3)) =? (+7)) ([[1]]) # 2x composition, blackbird combinator …∘∘… [[[[3 (2 1 0)]]]] :test (((inc ∘∘ mul) (+2) (+3)) =? (+7)) ([[1]]) # 3x composition, bunting combinator …∘∘∘… [[[[[4 (3 2 1 0)]]]]] :test (((inc ∘∘∘ (add ∘∘ mul)) (+1) (+2) (+4)) =? (+7)) ([[1]]) # reverse composition, queer bird combinator …→… [[[1 (2 0)]]] :test ((((mul (+2)) → inc) (+3)) =? (+7)) ([[1]]) </syntaxhighlight> =={{header\|C}}== Line 1,044 ⟶ 1,129: =={{header\|Elena}}== ELENA 46.x : <syntaxhighlight lang="elena">import extensions; Line 1,055 ⟶ 1,140: public program() { var fg := (x => x + 1).compose::(x => x * x); console.printLine(fg(3)) Line 1,336 ⟶ 1,421: {{FormulaeEntry\|page=https://formulae.org/?script=examples/Function_composition}} '''Solution''' [[File:Fōrmulæ - Function composition 01.png]] The compose function returns a lambda expression, containing the actual composition of its arguments, and hence it can be called applied with its argument(s): '''Test cases''' [[File:Fōrmulæ - Function composition 02.png]] [[File:Fōrmulæ - Function composition 03.png]] Arguments of the functions to compose can be the same symbol, they are not "scrambled": [[File:Fōrmulæ - Function composition 04.png]] [[File:Fōrmulæ - Function composition 05.png]] Because a function in Fōrmulæ is just a lambda expression, a lambda expression can be directly provided. [[File:Fōrmulæ - Function composition 06.png]] [[File:Fōrmulæ - Function composition 03.png]] [[File:Fōrmulæ - Function composition 07.png]] [[File:Fōrmulæ - Function composition 05.png]] Since the composition function returns a lambda expression, it is not required to be applied: [[File:Fōrmulæ - Function composition 08.png]] [[File:Fōrmulæ - Function composition 09.png]] [[File:Fōrmulæ - Function composition 10.png]] [[File:Fōrmulæ - Function composition 11.png]] =={{header\|GAP}}== Line 2,831 ⟶ 2,954: =={{header\|RPL}}== {{works with\|HP\|48G}} ~~RPL allows x to be a value or a variable. In this case, the function returns an expression.~~ « →STR SWAP →STR + ~~{{works with\|Halcyon Calc\|4.2.7}}~~ DUP "»«" POS " " REPL STR→ ~~≪ SWAP EVAL SWAP EVAL ≫~~ » '<span style="color:blue">FCOMP</span>' STO <span style="color:grey">@ ''( « f » « g » → « f o g » )''</span> ~~'FCOMP' STO~~ ≪ ALOG ≫ ≪ COS ≫ 0<span style="color:blue">FCOMP</span> ≪ ALOG ≫ ≪ COS ≫ ~~'x'~~<span style="color:blue">FCOMP</span> 0 EVAL ≪ ALOG ≫ ≪ COS ≫ <span style="color:blue">FCOMP</span> 'x' EVAL {{out}} <pre> 3: ≪ COS ALOG ≫ 2: 10 1: 'ALOG(COS(x))' </pre> =={{header\|Ruby}}== This <tt>compose</tt> method gets passed two Method objects or Proc objects Line 3,347 ⟶ 3,473: =={{header\|Wren}}== <syntaxhighlight lang="~~ecmascript~~wren">var compose = Fn.new { \|f, g\| Fn.new { \|x\| f.call(g.call(x)) } } var double = Fn.new { \|x\| 2 * x }