fix(command_line_m): arbritrary-length flag values

Author: rouson

example/get-flag-value.f90

@@ -1,20 +1,19 @@
 program get_flag_value
   !! Demonstrate how to find the value of a command-line flag 
+  !! Running this program as follows with the command
+  !!
+  !! fpm run --example get-flag-value -- --input-file foo
+  !!
+  !! result in normal termination.
+  use assert_m, only : assert
   use command_line_m, only : command_line_t
   implicit none
 
   type(command_line_t) command_line
   character(len=:), allocatable :: input_file_name
+  character(len=*), parameter :: expected_name="some_file_name"
 
   input_file_name = command_line%flag_value("--input-file")
 
-  ! Running this program as follows with the command
-  !
-  ! fpm run --example get-flag-value -- --input-file foo
-  !
-  ! result in normal termination.
-
-  print *,"input file: ",input_file_name
-  
-  if (input_file_name/="foo") error stop "example/get-flag-value: expected flag value 'foo' not receieved"
+  call assert(input_file_name==expected_name,"get_flag_value: input_file_name==expected_name",diagnostic_data=input_file_name )
 end program

src/command_line_m.f90

@@ -23,11 +23,11 @@ module function argument_present(acceptable_argument) result(found)
       logical found
     end function
 
-    module function flag_value(flag) result(flag_val)
+    module function flag_value(flag)
       !! result is the value passed adjacent to a command-line flag
       implicit none
       character(len=*), intent(in) :: flag
-      character(len=:), allocatable :: flag_val
+      character(len=:), allocatable :: flag_value
     end function
 
   end interface

src/command_line_s.f90

@@ -1,5 +1,4 @@
 submodule(command_line_m) command_line_s
-  use assert_m, only : assert
   implicit none
 
 contains
@@ -37,16 +36,21 @@
 
   module procedure flag_value
 
-    integer argnum, arglen
-    character(len=64) arg
+    integer argnum, arglen, flag_value_length
+    character(len=:), allocatable :: arg
+
 
     flag_search: &
     do argnum = 1,command_argument_count()
-      call get_command_argument(argnum, arg, arglen)
+
+      call get_command_argument(argnum, length=arglen)
+      allocate(character(len=arglen) :: arg)
+      call get_command_argument(argnum, arg)
+
       if (arg==flag) then
-        call assert(arglen<=len(arg), "flag_value: arglen<=len(arg)")
-        allocate(character(len=arglen) :: flag_val)
-        call get_command_argument(argnum+1, flag_val)
+        call get_command_argument(argnum+1, length=flag_value_length)
+        allocate(character(len=flag_value_length) :: flag_value)
+        call get_command_argument(argnum+1, flag_value)
         exit flag_search
       end if
     end do flag_search

test/command_line_test.f90

@@ -34,8 +34,9 @@ function check_flag_value() result(test_passes)
     integer exit_status, command_status
     character(len=132) command_message
 
+    ! command = "fpm run --example get-flag-value -- --input-file ni_weights_iter131072 > /dev/null 2>&1", &
     call execute_command_line( &
-      command = "fpm run --example get-flag-value -- --input-file foo > /dev/null 2>&1", &
+      command = "fpm run --example get-flag-value -- --input-file some_file_name", &
       wait = .true., exitstat = exit_status, cmdstat = command_status, cmdmsg = command_message &
     )   
     test_passes = exit_status == 0