SRFI-26 — cut/cute: partial application via slot notation
SRFI-26 provides cut and cute, compact syntax for partial application: write a specialized procedure by marking the "holes" with <> instead of writing a full lambda.
(import (srfi 26))
(map (cut * 2 <>) '(1 2 3)) ;; => (2 4 6)
(map (cut cons <> '()) '(a b c)) ;; => ((a) (b) (c))
((cut + 1 <>) 10) ;; => 11<...> collects the rest of the arguments. cute is like cut but evaluates the non-hole subexpressions once, up front (useful when they're expensive or effectful).
2 bindings
Syntax: (cut f arg ...) Library: (srfi 26) Description: Specializes a procedure f by replacing some arguments with slots (<>). Returns a lambda that accepts the slot arguments in order. Use <...> as a rest slot. Non-<> arguments are re-evaluated on each call (unlike cute). Example: (define add5 (cut + <> 5)) (add5 3) => 8 (define cons-star (cut cons <> '())) (cons-star 1) => (1)
Syntax: (cute f arg ...) Library: (srfi 26) Description: Like cut, but non-slot expressions are evaluated once when cute is called, not at each invocation. Slots (<>) become lambda parameters; <...> is a rest slot. Example: (define add-n (cute + <> (begin (display "eval") 5))) (add-n 3) => 8 ; "eval" is printed only once