stdlib_io: add Python-like input() function Fixes #259

Author: Brijesh-Thakkar

doc/specs/stdlib_io.md

@@ -268,14 +268,17 @@ No numeric conversion is performed.
 ### Arguments
 
 `prompt` (optional):  
-A character expression containing a prompt to be displayed before reading input.
+A character expression containing a prompt to be displayed before reading input.  
+This argument is `intent(in)`.
 
 `iostat` (optional):  
 Default integer, contains status of reading from standard input.
 Zero indicates success.
+This argument is `intent(out)`.
 
 `iomsg` (optional):  
 Deferred-length character variable containing an error message if `iostat` is non-zero.
+This argument is `intent(out)`.
 
 ### Return value
 

example/io/example_input.f90

@@ -1,2 +1,10 @@
-name = input("Enter your name: ")
-print *, "Hello:", name
+program example_input
+  use stdlib_io, only : input
+  implicit none
+
+  character(len=:), allocatable :: name
+
+  name = input("Enter your name: ")
+  print *, "Hello:", name
+
+end program example_input

src/stdlib_io.fypp

@@ -16,7 +16,7 @@ module stdlib_io
   implicit none
   private
   ! Public API
-  public :: loadtxt, savetxt, open, get_line, get_file , input
+  public :: loadtxt, savetxt, open, get_line, get_file, input
 
   !! version: experimental 
   !!
@@ -637,7 +637,6 @@ contains
     end if
   end function input_char
 
-
   !> Version: experimental
   !>
   !> Read a whole line from the standard input into a string variable

test/io/test_input.f90

@@ -1,3 +1,85 @@
-call write_test_input("  abc  ")
-s = input()
-call assert_equal(s, "  abc  ")
+module test_input
+  use testdrive, only : new_unittest, unittest_type, error_type, assert_equal
+  use stdlib_io, only : input
+  use stdlib_test_utils, only : write_test_input
+  implicit none
+  private
+  public :: collect
+
+contains
+
+  subroutine collect(tests)
+    type(unittest_type), allocatable, intent(out) :: tests(:)
+
+    tests = [ &
+      new_unittest("input preserves whitespace", test_input_whitespace), &
+      new_unittest("input with prompt",           test_input_prompt), &
+      new_unittest("input with iostat",           test_input_iostat), &
+      new_unittest("input with iomsg",            test_input_iomsg), &
+      new_unittest("input without optional args", test_input_no_args) &
+    ]
+  end subroutine collect
+
+
+  subroutine test_input_whitespace(error)
+    type(error_type), allocatable, intent(out) :: error
+    character(len=:), allocatable :: s
+
+    call write_test_input("  abc  ")
+    s = input()
+    call assert_equal(error, s, "  abc  ")
+  end subroutine test_input_whitespace
+
+
+  subroutine test_input_prompt(error)
+    type(error_type), allocatable, intent(out) :: error
+    character(len=:), allocatable :: s
+
+    call write_test_input("abc")
+    s = input("Enter value: ")
+    call assert_equal(error, s, "abc")
+  end subroutine test_input_prompt
+
+
+  subroutine test_input_iostat(error)
+    type(error_type), allocatable, intent(out) :: error
+    character(len=:), allocatable :: s
+    integer :: ios
+
+    call write_test_input("abc")
+    s = input(iostat=ios)
+    call assert_equal(error, ios, 0)
+    call assert_equal(error, s, "abc")
+  end subroutine test_input_iostat
+
+
+  subroutine test_input_iomsg(error)
+    type(error_type), allocatable, intent(out) :: error
+    character(len=:), allocatable :: s
+    character(len=:), allocatable :: msg
+
+    call write_test_input("abc")
+    s = input(iomsg=msg)
+    call assert_equal(error, s, "abc")
+  end subroutine test_input_iomsg
+
+
+  subroutine test_input_no_args(error)
+    type(error_type), allocatable, intent(out) :: error
+    character(len=:), allocatable :: s
+
+    call write_test_input("abc")
+    s = input()
+    call assert_equal(error, s, "abc")
+  end subroutine test_input_no_args
+
+end module test_input
+
+
+program run_test_input
+  use testdrive, only : run_testsuite
+  use test_input, only : collect
+  implicit none
+
+  call run_testsuite(collect)
+end program run_test_input