Handlers — handlers • mark

Catch and report handlers

Usage

has_warning(x, FUN, ...)

has_error(x, FUN, ...)

has_message(x, FUN, ...)

get_warning(x, FUN, ..., .null = TRUE)

get_message(x, FUN, ..., .null = TRUE)

get_error(x, FUN, ..., .null = TRUE)

Arguments

x: A vector
FUN: A function
...: Additional params passed to FUN
.null: Logical, if FALSE will drop NULL results (for get_*())

Value

The has_*() functions will return TRUE/FALSE for if the handler is found in the execution of the code. The get_*() functions provide the text of the message

Details

These functions can be used to catch whether an evaluation will return an error or warning without raising.

References

Function for catching has been adapted from https://stackoverflow.com/a/4952908/12126576

Examples

has_warning(c(1, "no"), as.integer)
#>     1    no 
#> FALSE  TRUE 
#     1    no
# FALSE  TRUE

get_warning(c(1, "no"), as.integer)
#> $`1`
#> NULL
#> 
#> $no
#> [1] "NAs introduced by coercion"
#> 

# drop NULLs
get_warning(c(1, "no"), as.integer, .null = FALSE)
#> $no
#> [1] "NAs introduced by coercion"
#> 

foo <- function(x) {
  stopifnot(x > 0)
  x
}

has_error(c(1, 0, 2), foo)
#>     1     0     2 
#> FALSE  TRUE FALSE 
#     1     0     2
# FALSE  TRUE FALSE

get_error(c(1, 0, 2), foo)
#> $`1`
#> NULL
#> 
#> $`0`
#> [1] "x > 0 is not TRUE"
#> 
#> $`2`
#> NULL
#> 

# drop NULLs
get_error(c(1, 0, 2), foo, .null = FALSE)
#> $`0`
#> [1] "x > 0 is not TRUE"
#>