wrapr (version 2.1.0)

DebugFnW: Wrap a function for debugging.

Description

Wrap fn, so it will save arguments on failure.

Usage

DebugFnW(saveDest, fn)

Value

wrapped function that saves state on error.

Arguments

saveDest

where to write captured state (determined by type): NULL random temp file, character temp file, name globalenv() variable, and function triggers callback.

fn

function to call

See Also

dump.frames, DebugFn, DebugFnW, DebugFnWE, DebugPrintFn, DebugFnE, DebugPrintFnE Operator idea from: https://gist.github.com/nassimhaddad/c9c327d10a91dcf9a3370d30dff8ac3d . Please see: vignette("DebugFnW", package="wrapr").

Examples

saveDest <- paste0(tempfile('debug'),'.RDS')
f <- function(i) { (1:10)[[i]] }
df <- DebugFnW(saveDest,f)
# correct run
df(5)
# now re-run
# capture error on incorrect run
tryCatch(
   df(12),
   error = function(e) { print(e) })
# examine details
situation <- readRDS(saveDest)
str(situation)
# fix and re-run
situation$args[[1]] <- 6
do.call(situation$fn,situation$args)
# clean up
file.remove(saveDest)


f <- function(i) { (1:10)[[i]] }
curEnv <- environment()
writeBack <- function(sit) {
   assign('lastError', sit, envir=curEnv)
}
attr(writeBack,'name') <- 'writeBack'
df <- DebugFnW(writeBack,f)
tryCatch(
   df(12),
   error = function(e) { print(e) })
str(lastError)