Data commit

Task/Call-a-function/Racket/call-a-function.rkt

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+#lang racket
+
+;; Calling a function that requires no arguments
+(foo)
+
+;; Calling a function with a fixed number of arguments
+(foo 1 2 3)
+
+;; Calling a function with optional arguments
+;; Calling a function with a variable number of arguments
+(foo 1 2 3) ; same in both cases
+
+;; Calling a function with named arguments
+(foo 1 2 #:x 3) ; using #:keywords for the names
+
+;; Using a function in statement context
+;; Using a function in first-class context within an expression
+;; Obtaining the return value of a function
+;; -> Makes no sense for Racket, as well as most other functional PLs
+
+;; Distinguishing built-in functions and user-defined functions
+(primitive? foo)
+;; but this is mostly useless, since most of Racket is implemented in
+;; itself
+
+;; Distinguishing subroutines and functions
+;; -> No difference, though `!' is an idiomatic suffix for names of
+;;    side-effect functions, and they usually return (void)
+
+;; Stating whether arguments are passed by value or by reference
+
+;; -> Always by value, but it's possible to implement languages with
+;;    other argument passing styles, including passing arguments by
+;;    reference (eg, there is "#lang algol60")
+
+;; Is partial application possible and how
+(curry foo 1 2)    ; later apply this on 3
+(λ(x) (foo 1 2 x)) ; a direct way of doing the same