module stdlib_error
!! Provides support for catching and handling errors
!! ([Specification](../page/specs/stdlib_error.html))
use, intrinsic :: iso_fortran_env, only: stderr => error_unit
use stdlib_optval, only: optval
implicit none
private
interface ! f{08,18}estop.f90
module subroutine error_stop(msg, code)
!! version: experimental
!!
!! Provides a call to `error stop` and allows the user to specify a code and message
!! ([Specification](..//page/specs/stdlib_error.html#description_1))
character(*), intent(in) :: msg
integer, intent(in), optional :: code
end subroutine error_stop
end interface
public :: check, error_stop
contains
subroutine check(condition, msg, code, warn)
!! version: experimental
!!
!! Checks the value of a logical condition
!! ([Specification](../page/specs/stdlib_error.html#description))
!!
!!##### Behavior
!!
!! If `condition == .false.` and:
!!
!! * No other arguments are provided, it stops the program with the default
!! message and exit code `1`;
!! * `msg` is provided, it prints the value of `msg`;
!! * `code` is provided, it stops the program with the given exit code;
!! * `warn` is provided and `.true.`, it doesn't stop the program and prints
!! the message.
!!
!!##### Examples
!!
!!* If `a /= 5`, stops the program with exit code `1`
!! and prints `Check failed.`
!!``` fortran
!! call check(a == 5)
!!```
!!
!!* As above, but prints `a == 5 failed`.
!!``` fortran
!! call check(a == 5, msg='a == 5 failed.')
!!```
!!
!!* As above, but doesn't stop the program.
!!``` fortran
!! call check(a == 5, msg='a == 5 failed.', warn=.true.)
!!```
!!
!!* As example #2, but stops the program with exit code `77`
!!``` fortran
!! call check(a == 5, msg='a == 5 failed.', code=77)
!!```
!
! Arguments
! ---------
logical, intent(in) :: condition
character(*), intent(in), optional :: msg
integer, intent(in), optional :: code
logical, intent(in), optional :: warn
character(*), parameter :: msg_default = 'Check failed.'
if (.not. condition) then
if (optval(warn, .false.)) then
write(stderr,*) optval(msg, msg_default)
else
call error_stop(optval(msg, msg_default), optval(code, 1))
end if
end if
end subroutine check
end module stdlib_error
