call_with: Evaluate a function while injecting some locals.
In syberia/tundra: Standardized container format for deployment of classifiers.

Description Usage Arguments Value Examples

Instead of modifying a closure's parent environment directly, sometimes it may be desirable to do a one-time injection that overrides what would normally be accessible through the closure. call_with allows this by extending the usual do.call to a third argument that is a list or environment temporarily injected during the course of the call.

1	call_with(fn, args, with)

`fn`	function.
`args`	list. The arguments to call the `fn` with.
`with`	list or environment. Additional locals to make available during the call.

The result of calling fn with the injection provided by the with parameter.

## Not run: 
fn <- local({ x <- 1; function(y) { x + y } })
stopifnot(fn(1) == 2)
stopifnot(call_with(fn, list(1), list(x = 2)) == 3)

## End(Not run)