x_to_monad: Conversions to monads

In rmonad: A Monadic Pipeline System

Description

These functions convert possibly non-monadic inputs into monads.

Usage

as_monad(expr, desc = NULL, tag = NULL, doc = .default_doc(),
  key = NULL, env = parent.frame(), lossy = FALSE)

funnel(..., env = parent.frame(), keep_history = TRUE)

combine(xs, keep_history = TRUE, desc = .default_code())

Arguments

expr	An expression
desc	A description of the monad (usually the producing code)
tag	Character vector specifying the tag to associate with a node
doc	A docstring to associate with the monad
key	16 byte raw vector
env	Evaluation environment
lossy	logical Should unnesting with record be done?
...	multiple expressions
keep_history	merge the histories of all monads
xs	A list of elements to join into a monad

Details

For each of these functions, failure of any part causes failure of the whole. Any non-monadic inputs will be converted to monads. Any exceptions raised in the inputs will be caught.

as_monad evaluate a single expression into an Rmonad. If the value is already an Rmonad, it will be nested.

funnel evaluates multiple arguments into one Rmonad. It can be used within pipelines to create multi-input nodes (works well with %*>%).

combine takes a list of Rmonads and joins the elements into one Rmonad. The values of the original monadic containers joined into a list in the child Rmonad. The list Rmonads are recorded as the new Rmonad's parents.

Examples

as_monad(stop(1))
as_monad(1:10)
as_monad(5 %>>% sqrt)

## merge failing inputs 
funnel( 1:10, stop(1), sqrt(-3:3) )

## join pipelines
b2 <- letters[1:10] %>>% sqrt
b3 <- -3:6 %>>% log
1:10 %>% funnel(b2,b3) %>>%
  {data.frame(b1=.[[1]], b2=.[[2]], b3=.[[3]])}

z <- list(
  x = rnorm(10) %>>% sqrt,
  y = 1 %>>% colSums
)
combine(z)

rmonad documentation built on March 26, 2020, 7:31 p.m.