| Type: | Package |
| Encoding: | UTF-8 |
| Title: | Curry, Compose, and Other Higher-Order Functions |
| Version: | 0.7 |
| Date: | 2026-06-23 |
| Description: | Provides a small collection of higher-order functions for functional-style programming in R, including 'Curry' (partial application), 'CurryL' (lazy partial application), 'Compose' (function composition, including a multi-argument variant), 'Identity', 'Negate' and 'Swap'. |
| License: | GPL-2 | GPL-3 [expanded from: GPL (≥ 2)] |
| URL: | https://github.com/klutometis/R-functional |
| BugReports: | https://github.com/klutometis/R-functional/issues |
| LazyLoad: | yes |
| Imports: | lisp (≥ 0.2) |
| NeedsCompilation: | no |
| Packaged: | 2026-06-24 05:59:43 UTC; danenberg |
| Author: | Peter Danenberg [aut, cre] |
| Maintainer: | Peter Danenberg <pcd@roxygen.org> |
| Repository: | CRAN |
| Date/Publication: | 2026-06-24 07:00:02 UTC |
Compose an arbitrary number of functions.
Description
My Happy Hacking keyboard gave out during the writing of this procedure; moment of silence, please.
Usage
Compose(...)
Arguments
... |
the functions to be composed |
Details
Had to make this slightly more complex to handle the nullary case; also included a fast-path for the trivial case.
Value
A composed function
Examples
car <- function(list) list[[1]]
cdr <- function(list) list[2:length(list)]
cadr <- Compose(cdr, car)
stopifnot(cadr(c(1,2,3)) == 2)
Pre-specify a procedures named parameters, returning a new procedure.
Description
Thanks, Byron Ellis; and Aaron McDaid modified it to preserve names across invocation.
Usage
Curry(FUN, ...)
Arguments
FUN |
the function to be curried |
... |
the determining parameters |
Details
https://stat.ethz.ch/pipermail/r-devel/2007-November/047318.html
Value
A new function partially determined
Examples
double <- Curry(`*`, e1=2)
stopifnot(double(4) == 8)
Lazy curry; thanks, Jamie! <https://github.com/klutometis/R-functional/issues/1>
Description
Lazy curry; thanks, Jamie! <https://github.com/klutometis/R-functional/issues/1>
Usage
CurryL(FUN, ...)
Arguments
FUN |
the function to be curried |
... |
the determining parameters |
Value
A new function that, when called, lazily evaluates FUN with the
pre-specified and subsequent arguments.
Examples
# day is not defined; thanks, Jamie Folson.
CurryL(function(...) match.call(),
x=5,
y=as.Date(day))(z=as.Date(day,"%Y"))
Identity function.
Description
Is concatenation benign?
Usage
Identity(...)
Arguments
... |
tautological arguments |
Value
The tautologized arguments, concatenated
Examples
list.copy <- function(list)
Reduce(Identity, list)
list <- c(1, 2, 3)
stopifnot(list.copy(list) == list)
Negate a function; borrowed from src/library/base/R/funprog.R for pre-2.7 Rs.
Description
Negate a function; borrowed from src/library/base/R/funprog.R for pre-2.7 Rs.
Usage
Negate(f)
Arguments
f |
the function to be negated |
Value
The negated function
Examples
is.even <- function(a) a%%2 == 0
is.odd <- Negate(is.even)
stopifnot(Reduce(`&&`, Map(is.odd, c(1, 3, 5))))
Thanks, Gabor; see <http://stackoverflow.com/a/23726989>: swaps the first two arguments in a function.
Description
Thanks, Gabor; see <http://stackoverflow.com/a/23726989>: swaps the first two arguments in a function.
Usage
Swap(f)
Arguments
f |
The function whose arguments to swap |
Value
A function with swapped arguments
Composition with multiple arguments.
Description
Thanks, Alexander Davis!
Usage
multi.argument.Compose(...)
Arguments
... |
the functions to be composed |
Value
A composed function
Examples
f <- function(x, y) x+y
g <- function(x) x*2
stopifnot(multi.argument.Compose(f, g)(1,1) == 4)