partial: Partial evaluation of a function

In JSzitas/recovery: Recover From Failures and Perform Partial Tests

Description

Partially evaluates a function, returning only the objects which exist after the last line of partial evaluation.

Usage

partial(fun, args, eval_point = NULL, full_scope = FALSE, fix_pattern = FALSE)

Arguments

fun	A function to partially evaluate.
args	A list of the arguments necessary for the function to execute. See details.
eval_point	The function line from which to return the result. A line number in the body of the function, or a character string quoting a part of the function. See details.
full_scope	Whether to return everything that was in scope at the partial evaluation point, defaults to **FALSE**.
fix_pattern	Whether to used **fixed** for regex matching on **eval_point**, defaults to **FALSE**.

Details

Parameter **args** can be safely ignored for functions which take no arguments explicitly, or for functions that have all their arguments set. **eval_point** stands for the line in the function body to be replaced with a return - this line is temporarily overwritten so a return can be made from it. See examples for usage.

Value

A result of partial evaluations - the full environment containing every object in scope at that evaluation if **full_scope** is **TRUE**, the last **call** otherwise.

Note

If regex matching fails and your expression does not evaluate to anything valid, please try shortening it or supplying a different part of it.

Examples

# create a dummy function
dummy_function <- function( x,     y = 2,    z,
                            a = 5, b = TRUE, c = 10 )
{
 x_2 <- x + y - z
 TRUTHFULLY <- b
 negative <- (c-a) > 0

return(y)
}

# works with function body line number
partial( fun = dummy_function,
         args = list(x = 10,z = FALSE, b = FALSE),
         eval_point = 1 )
partial( fun = dummy_function,
         args = list(x = 10,z = FALSE, b = FALSE),
         eval_point = 3 )

# works with partial string matching
partial( fun = dummy_function,
         args = list(x = 10,z = FALSE, b = FALSE),
         eval_point = "negat" )
# and semi-full string matching
partial( fun = dummy_function,
         args = list(x = 10,z = FALSE, b = FALSE),
         eval_point = "negative <- " )

JSzitas/recovery documentation built on April 3, 2021, 3:16 p.m.