From 6720abd183047b09fc6e981d969a8157d4709480 Mon Sep 17 00:00:00 2001
From: Sebastian Ehlert <28669218+awvwgk@users.noreply.github.com>
Date: Thu, 4 Feb 2021 21:39:57 +0100
Subject: [PATCH 1/8] Extend stdlib_ascii module for handling character
 variables

- extend to_lower function to work on character strings
- extend to_upper function to work on character strings
- implement to_title function
- implement reverse function
---
 doc/specs/index.md             |   2 +-
 doc/specs/stdlib_ascii.md      | 149 +++++++++++++++++++++++++++++++++
 src/stdlib_ascii.f90           |  83 +++++++++++++++---
 src/tests/ascii/test_ascii.f90 |  75 ++++++++++++++++-
 4 files changed, 294 insertions(+), 15 deletions(-)
 create mode 100644 doc/specs/stdlib_ascii.md

diff --git a/doc/specs/index.md b/doc/specs/index.md
index 6ea78b52e..aaa841831 100644
--- a/doc/specs/index.md
+++ b/doc/specs/index.md
@@ -11,6 +11,7 @@ This is and index/directory of the specifications (specs) for each new module/fe
 
 ## Experimental Features & Modules
 
+ - [ascii](./stdlib_ascii.html) - Procedures for handling ASCII characters
  - [bitsets](./stdlib_bitsets.html) - Bitset data types and procedures
  - [error](./stdlib_error.html) - Catching and handling errors
  - [IO](./stdlib_io.html) - Input/output helper & convenience
@@ -22,7 +23,6 @@ This is and index/directory of the specifications (specs) for each new module/fe
 
 ## Missing specs
 
- - [ascii](https://github.com/fortran-lang/stdlib/blob/master/src/stdlib_ascii.f90)
  - [kinds](https://github.com/fortran-lang/stdlib/blob/master/src/stdlib_kinds.f90)
 
 ## Released/Stable Features & Modules
diff --git a/doc/specs/stdlib_ascii.md b/doc/specs/stdlib_ascii.md
new file mode 100644
index 000000000..1ec32c7f7
--- /dev/null
+++ b/doc/specs/stdlib_ascii.md
@@ -0,0 +1,149 @@
+---
+title: ASCII
+---
+
+# The `stdlib_ascii` module
+
+[TOC]
+
+## Introduction
+
+The `stdlib_ascii` module provides procedures for handling and manipulating
+intrinsic character variables and constants.
+
+
+## Constants provided by `stdlib_ascii`
+
+@note Specification of constants is currently incomplete.
+
+
+## Specification of the `stdlib_ascii` procedures
+
+@note Specification of procedures is currently incomplete.
+
+
+### `to_lower`
+
+#### Status
+
+Experimental
+
+#### Description
+
+Converts input character variable to all lowercase.
+
+#### Syntax
+
+```f90
+res = to_lower("HELLO!")
+! res == "hello!"
+```
+
+#### Class
+
+Pure function.
+
+#### Argument
+
+`string`: shall be an intrinsic character type. It is an `intent(in)` argument.
+
+#### Result value
+
+The result is an intrinsic character type of the same length as `string`.
+
+
+### `to_upper`
+
+#### Status
+
+Experimental
+
+#### Description
+
+Converts input character variable to all uppercase.
+
+#### Syntax
+
+```
+res = to_upper("hello!")
+! res == "HELLO!"
+```
+
+#### Class
+
+Pure function.
+
+#### Argument
+
+`string`: shall be an intrinsic character type. It is an `intent(in)` argument.
+
+#### Result value
+
+The result is an intrinsic character type of the same length as `string`.
+
+
+### `to_title`
+
+#### Status
+
+Experimental
+
+#### Description
+
+Returns capitalized version of input character variable.
+The first alphanumeric character is capitalized.
+
+#### Syntax
+
+```
+res = to_title("hello!")
+! res == "Hello!"
+res = to_title("'enquoted'")
+! res == "'Enquoted'"
+res = to_title("1st")
+! res == "1st"
+```
+
+#### Class
+
+Pure function.
+
+#### Argument
+
+`string`: shall be an intrinsic character type. It is an `intent(in)` argument.
+
+#### Result value
+
+The result is an intrinsic character type of the same length as `string`.
+
+
+### `reverse`
+
+#### Status
+
+Experimental
+
+#### Description
+
+Reverses the order of all characters in the input character type.
+
+#### Syntax
+
+```f90
+res = reverse("Hello, World!")
+! res == "!dlroW ,olleH"
+res = reverse(res)
+! res == "Hello, World!"
+```
+
+#### Class
+
+Pure function.
+
+#### Argument
+
+`string`: shall be an intrinsic character type. It is an `intent(in)` argument.
+
+#### Result value
+
+The result is an intrinsic character type of the same length as `string`.
diff --git a/src/stdlib_ascii.f90 b/src/stdlib_ascii.f90
index a05951fbc..a1d823916 100644
--- a/src/stdlib_ascii.f90
+++ b/src/stdlib_ascii.f90
@@ -12,7 +12,7 @@ module stdlib_ascii
     public :: is_lower, is_upper
 
     ! Character conversion functions
-    public :: to_lower, to_upper
+    public :: to_lower, to_upper, to_title, reverse
 
     ! All control characters in the ASCII table (see www.asciitable.com).
     character(len=1), public, parameter :: NUL = achar(int(z'00')) !! Null
@@ -60,9 +60,6 @@ module stdlib_ascii
     character(len=*), public, parameter :: lowercase = letters(27:) !! a .. z
     character(len=*), public, parameter :: whitespace = " "//TAB//VT//CR//LF//FF !! ASCII _whitespace
 
-    character(len=26), parameter, private :: lower_case = 'abcdefghijklmnopqrstuvwxyz'
-    character(len=26), parameter, private :: upper_case = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
-
 contains
 
     !> Checks whether `c` is an ASCII letter (A .. Z, a .. z).
@@ -179,34 +176,94 @@ pure logical function is_blank(c)
 
     !> Returns the corresponding lowercase letter, if `c` is an uppercase
     !  ASCII character, otherwise `c` itself.
-    pure function to_lower(c) result(t)
+    pure function char_to_lower(c) result(t)
         character(len=1), intent(in) :: c !! A character.
         character(len=1)             :: t
         integer :: k
 
-        k = index( upper_case, c )
+        k = index( uppercase, c )
 
         if ( k > 0 ) then
-            t = lower_case(k:k)
+            t = lowercase(k:k)
         else
             t = c
         endif
-    end function
+    end function char_to_lower
 
     !> Returns the corresponding uppercase letter, if `c` is a lowercase
     !  ASCII character, otherwise `c` itself.
-    pure function to_upper(c) result(t)
+    pure function char_to_upper(c) result(t)
         character(len=1), intent(in) :: c !! A character.
         character(len=1)             :: t
         integer :: k
 
-        k = index( lower_case, c )
+        k = index( lowercase, c )
 
         if ( k > 0 ) then
-            t = upper_case(k:k)
+            t = uppercase(k:k)
         else
             t = c
         endif
-    end function
+    end function char_to_upper
+
+    !> Convert character variable to lower case
+    pure function to_lower(string) result(lower_string)
+        character(len=*), intent(in) :: string
+        character(len=len(string)) :: lower_string
+        integer :: i
+
+        do i = 1, len(string)
+            lower_string(i:i) = char_to_lower(string(i:i))
+        end do
+
+    end function to_lower
+
+    !> Convert character variable to upper case
+    pure function to_upper(string) result(upper_string)
+        character(len=*), intent(in) :: string
+        character(len=len(string)) :: upper_string
+        integer :: i
+
+        do i = 1, len(string)
+            upper_string(i:i) = char_to_upper(string(i:i))
+        end do
+
+    end function to_upper
+
+    !> Convert character variable to title case
+    pure function to_title(string) result(title_string)
+        character(len=*), intent(in) :: string
+        character(len=len(string)) :: title_string
+        integer :: i, n
+
+        n = len(string)
+        do i = 1, len(string)
+            if (is_alphanum(string(i:i))) then
+                title_string(i:i) = char_to_upper(string(i:i))
+                n = i
+                exit
+            else
+                title_string(i:i) = string(i:i)
+            end if
+        end do
+
+        do i = n + 1, len(string)
+            title_string(i:i) = char_to_lower(string(i:i))
+        end do
+
+    end function to_title
+
+    !> Reverse the character order in the input character variable
+    pure function reverse(string) result(reverse_string)
+        character(len=*), intent(in) :: string
+        character(len=len(string)) :: reverse_string
+        integer :: i, n
+
+        n = len(string)
+        do i = 1, n
+            reverse_string(n-i+1:n-i+1) = string(i:i)
+        end do
+
+    end function reverse
 
-end module
+end module stdlib_ascii
diff --git a/src/tests/ascii/test_ascii.f90 b/src/tests/ascii/test_ascii.f90
index b4ef154ce..cfe4a938c 100644
--- a/src/tests/ascii/test_ascii.f90
+++ b/src/tests/ascii/test_ascii.f90
@@ -6,7 +6,7 @@ program test_ascii
         whitespace, letters, is_alphanum, is_alpha, is_lower, is_upper, &
         is_digit, is_octal_digit, is_hex_digit, is_white, is_blank, &
         is_control, is_punctuation, is_graphical, is_printable, is_ascii, &
-        to_lower, to_upper, LF, TAB, NUL, DEL
+        to_lower, to_upper, to_title, reverse, LF, TAB, NUL, DEL
 
     implicit none
 
@@ -68,6 +68,11 @@ program test_ascii
 
     ! call test_ascii_table
 
+    call test_to_upper_string
+    call test_to_lower_string
+    call test_to_title_string
+    call test_reverse_string
+
 contains
 
     subroutine test_is_alphanum_short
@@ -540,4 +545,72 @@ pure logical function validation_func_interface(c)
         write(*,'(5X,12(I4))') (count(table(:,i)),i=1,12)
     end subroutine test_ascii_table
 
+    subroutine test_to_lower_string
+        character(len=:), allocatable :: dlc
+        character(len=32), parameter :: input = "UPPERCASE"
+
+        dlc = to_lower("UPPERCASE")
+        call check(dlc == "uppercase")
+
+        dlc = to_lower(input)
+        call check(len(dlc) == 32)
+        call check(len_trim(dlc) == 9)
+        call check(trim(dlc) == "uppercase")
+
+        dlc = to_lower("0123456789ABCDE")
+        call check(dlc == "0123456789abcde")
+    end subroutine test_to_lower_string
+
+    subroutine test_to_upper_string
+        character(len=:), allocatable :: dlc
+        character(len=32), parameter :: input = "lowercase"
+
+        dlc = to_upper("lowercase")
+        call check(dlc == "LOWERCASE")
+
+        dlc = to_upper(input)
+        call check(len(dlc) == 32)
+        call check(len_trim(dlc) == 9)
+        call check(trim(dlc) == "LOWERCASE")
+
+        dlc = to_upper("0123456789abcde")
+        call check(dlc == "0123456789ABCDE")
+    end subroutine test_to_upper_string
+
+    subroutine test_to_title_string
+        character(len=:), allocatable :: dlc
+        character(len=32), parameter :: input = "tiTLe"
+
+        dlc = to_title("tiTLe")
+        call check(dlc == "Title")
+
+        dlc = to_title(input)
+        call check(len(dlc) == 32)
+        call check(len_trim(dlc) == 5)
+        call check(trim(dlc) == "Title")
+
+        dlc = to_title(" s P a C e D !")
+        call check(dlc == " S p a c e d !")
+
+        dlc = to_title("1st, 2nd, 3rd")
+        call check(dlc == "1st, 2nd, 3rd")
+
+        dlc = to_title("""quOTed""")
+        call check(dlc == """Quoted""")
+    end subroutine test_to_title_string
+
+    subroutine test_reverse_string
+        character(len=:), allocatable :: dlc
+        character(len=32), parameter :: input = "reversed"
+
+        dlc = reverse("reversed")
+        call check(dlc == "desrever")
+
+        dlc = reverse(input)
+        call check(len(dlc) == 32)
+        call check(len_trim(dlc) == 32)
+        call check(trim(dlc) == "                        desrever")
+        call check(trim(adjustl(dlc)) == "desrever")
+    end subroutine test_reverse_string
+
 end program test_ascii

From e47f02822ee10e27384235ffa4cf2a3eaa67e4b7 Mon Sep 17 00:00:00 2001
From: Sebastian Ehlert <28669218+awvwgk@users.noreply.github.com>
Date: Fri, 5 Feb 2021 23:34:18 +0100
Subject: [PATCH 2/8] Apply restructring of specs from review

Co-authored-by: Jeremie Vandenplas <jeremie.vandenplas@gmail.com>
---
 doc/specs/stdlib_ascii.md | 63 ++++++++++++++++++++++++++++-----------
 1 file changed, 46 insertions(+), 17 deletions(-)

diff --git a/doc/specs/stdlib_ascii.md b/doc/specs/stdlib_ascii.md
index 1ec32c7f7..4a47bc635 100644
--- a/doc/specs/stdlib_ascii.md
+++ b/doc/specs/stdlib_ascii.md
@@ -35,8 +35,7 @@ Converts input character variable to all lowercase.
 #### Syntax
 
 ```f90
-res = to_lower("HELLO!")
-! res == "hello!"
+res = [stdlib_asciii(module):to_lower(function)]](string)
 ```
 
 #### Class
@@ -51,6 +50,15 @@ Pure function.
 
 The result is an intrinsic character type of the same length as `string`.
 
+#### Example
+
+```fortran
+program demo_to_lower
+    use stdlib_ascii, only : to_lower
+    implicit none
+    print'(a)', to_lower("HELLo!") ! returns "hello!"
+ end program demo_to_lower
+``` 
 
 ### `to_upper`
 
@@ -64,9 +72,8 @@ Converts input character variable to all uppercase.
 
 #### Syntax
 
-```
-res = to_upper("hello!")
-! res == "HELLO!"
+```fortran
+res = [[stdlib_ascii(module):to_upper(function)]](string)
 ```
 
 #### Class
@@ -81,6 +88,15 @@ Pure function.
 
 The result is an intrinsic character type of the same length as `string`.
 
+#### Example
+
+```fortran
+program demo_to_upper
+    use stdlib_ascii, only : to_upper
+    implicit none
+    print'(a)', to_upper("hello!") ! returns "HELLO!"
+ end program demo_to_upper
+``` 
 
 ### `to_title`
 
@@ -90,18 +106,14 @@ Experimental
 
 #### Description
 
-Returns capitalized version of input character variable.
-The first alphanumeric character is capitalized.
+Returns a capitalized version of an input character variable.
+Only the first alphanumeric character is capitalized.
+All following characters will become lowercase.
 
 #### Syntax
 
 ```
-res = to_title("hello!")
-! res == "Hello!"
-res = to_title("'enquoted'")
-! res == "'Enquoted'"
-res = to_title("1st")
-! res == "1st"
+res = [[stdlib_ascii(module):to_title(interface)]](string)
 ```
 
 #### Class
@@ -116,6 +128,17 @@ Pure function.
 
 The result is an intrinsic character type of the same length as `string`.
 
+#### Example
+
+```fortran
+program demo_to_title
+    use stdlib_ascii, only : to_title
+    implicit none
+    print*, to_title("hello!") ! returns "Hello!"
+    print*, to_title("'enquoted'") ! returns "'Enquoted'"
+    print*, to_title("1st")  ! returns "1st"
+ end program demo_to_title
+``` 
 
 ### `reverse`
 
@@ -130,10 +153,7 @@ Reverses the order of all characters in the input character type.
 #### Syntax
 
 ```f90
-res = reverse("Hello, World!")
-! res == "!dlroW ,olleH"
-res = reverse(res)
-! res == "Hello, World!"
+res = [[stdlib_ascii(module):reverse(function)]](string)
 ```
 
 #### Class
@@ -147,3 +167,12 @@ Pure function.
 #### Result value
 
 The result is an intrinsic character type of the same length as `string`.
+
+#### Example
+
+```fortran
+program demo_reverse
+    use stdlib_ascii, only : reverse
+    implicit none
+    print'(a)', reverse("Hello, World!") ! returns "!dlroW ,olleH"
+end program demo_reverse

From 591678dcd4781f404f0e1bf6d3a46cc02827f655 Mon Sep 17 00:00:00 2001
From: Sebastian Ehlert <28669218+awvwgk@users.noreply.github.com>
Date: Fri, 5 Feb 2021 23:39:27 +0100
Subject: [PATCH 3/8] Update documentation comments in stdlib_ascii

---
 src/stdlib_ascii.f90 | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/src/stdlib_ascii.f90 b/src/stdlib_ascii.f90
index a1d823916..473a6ad02 100644
--- a/src/stdlib_ascii.f90
+++ b/src/stdlib_ascii.f90
@@ -1,3 +1,7 @@
+!> The `stdlib_ascii` module provides procedures for handling and manipulating
+!> intrinsic character variables and constants.
+!>
+!> The specification of this module is available [here](../page/specs/stdlib_ascii.html).
 module stdlib_ascii
 
     implicit none
@@ -76,7 +80,7 @@ pure logical function is_alphanum(c)
     end function
 
     !> Checks whether or not `c` is in the ASCII character set -
-    !  i.e. in the range 0 .. 0x7F.
+    !> i.e. in the range 0 .. 0x7F.
     pure logical function is_ascii(c)
         character(len=1), intent(in) :: c !! The character to test.
         is_ascii = iachar(c) <= int(z'7F')
@@ -110,8 +114,8 @@ pure logical function is_hex_digit(c)
     end function
 
     !> Checks whether or not `c` is a punctuation character. That includes
-    !  all ASCII characters which are not control characters, letters,
-    !  digits, or whitespace.
+    !> all ASCII characters which are not control characters, letters,
+    !> digits, or whitespace.
     pure logical function is_punctuation(c)
         character(len=1), intent(in) :: c !! The character to test.
         integer :: ic
@@ -121,7 +125,7 @@ pure logical function is_punctuation(c)
     end function
 
     !> Checks whether or not `c` is a printable character other than the
-    !  space character.
+    !> space character.
     pure logical function is_graphical(c)
         character(len=1), intent(in) :: c !! The character to test.
         integer :: ic
@@ -132,7 +136,7 @@ pure logical function is_graphical(c)
     end function
 
     !> Checks whether or not `c` is a printable character - including the
-    !  space character.
+    !> space character.
     pure logical function is_printable(c)
         character(len=1), intent(in) :: c !! The character to test.
         integer :: ic
@@ -156,8 +160,8 @@ pure logical function is_upper(c)
     end function
 
     !> Checks whether or not `c` is a whitespace character. That includes the
-    !  space, tab, vertical tab, form feed, carriage return, and linefeed
-    !  characters.
+    !> space, tab, vertical tab, form feed, carriage return, and linefeed
+    !> characters.
     pure logical function is_white(c)
         character(len=1), intent(in) :: c !! The character to test.
         integer :: ic
@@ -166,7 +170,7 @@ pure logical function is_white(c)
     end function
 
     !> Checks whether or not `c` is a blank character. That includes the
-    !  only the space and tab characters
+    !> only the space and tab characters
     pure logical function is_blank(c)
         character(len=1), intent(in) :: c !! The character to test.
         integer :: ic
@@ -175,7 +179,7 @@ pure logical function is_blank(c)
     end function
 
     !> Returns the corresponding lowercase letter, if `c` is an uppercase
-    !  ASCII character, otherwise `c` itself.
+    !> ASCII character, otherwise `c` itself.
     pure function char_to_lower(c) result(t)
         character(len=1), intent(in) :: c !! A character.
         character(len=1)             :: t
@@ -191,7 +195,7 @@ pure function char_to_lower(c) result(t)
     end function char_to_lower
 
     !> Returns the corresponding uppercase letter, if `c` is a lowercase
-    !  ASCII character, otherwise `c` itself.
+    !> ASCII character, otherwise `c` itself.
     pure function char_to_upper(c) result(t)
         character(len=1), intent(in) :: c !! A character.
         character(len=1)             :: t
@@ -207,6 +211,8 @@ pure function char_to_upper(c) result(t)
     end function char_to_upper
 
     !> Convert character variable to lower case
+    !>
+    !> Version: experimental
     pure function to_lower(string) result(lower_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: lower_string
@@ -219,6 +225,8 @@ pure function to_lower(string) result(lower_string)
     end function to_lower
 
     !> Convert character variable to upper case
+    !>
+    !> Version: experimental
     pure function to_upper(string) result(upper_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: upper_string
@@ -231,6 +239,8 @@ pure function to_upper(string) result(upper_string)
     end function to_upper
 
     !> Convert character variable to title case
+    !>
+    !> Version: experimental
     pure function to_title(string) result(title_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: title_string
@@ -254,6 +264,8 @@ pure function to_title(string) result(title_string)
     end function to_title
 
     !> Reverse the character order in the input character variable
+    !>
+    !> Version: experimental
     pure function reverse(string) result(reverse_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: reverse_string

From c92f414948eaa9944fc98cdfdfa0d517e3f8c761 Mon Sep 17 00:00:00 2001
From: Sebastian Ehlert <28669218+awvwgk@users.noreply.github.com>
Date: Sat, 6 Feb 2021 22:03:29 +0100
Subject: [PATCH 4/8] Fix link generation and code block issues with FORD

---
 doc/specs/stdlib_ascii.md | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/doc/specs/stdlib_ascii.md b/doc/specs/stdlib_ascii.md
index 4a47bc635..e9200fee9 100644
--- a/doc/specs/stdlib_ascii.md
+++ b/doc/specs/stdlib_ascii.md
@@ -34,9 +34,7 @@ Converts input character variable to all lowercase.
 
 #### Syntax
 
-```f90
-res = [stdlib_asciii(module):to_lower(function)]](string)
-```
+`res = [[stdlib_asciii(module):to_lower(function)]] (string)`
 
 #### Class
 
@@ -72,9 +70,7 @@ Converts input character variable to all uppercase.
 
 #### Syntax
 
-```fortran
-res = [[stdlib_ascii(module):to_upper(function)]](string)
-```
+`res = [[stdlib_ascii(module):to_upper(function)]] (string)`
 
 #### Class
 
@@ -112,9 +108,7 @@ All following characters will become lowercase.
 
 #### Syntax
 
-```
-res = [[stdlib_ascii(module):to_title(interface)]](string)
-```
+`res = [[stdlib_ascii(module):to_title(interface)]] (string)`
 
 #### Class
 
@@ -152,9 +146,7 @@ Reverses the order of all characters in the input character type.
 
 #### Syntax
 
-```f90
-res = [[stdlib_ascii(module):reverse(function)]](string)
-```
+`res = [[stdlib_ascii(module):reverse(function)]] (string)`
 
 #### Class
 
@@ -176,3 +168,4 @@ program demo_reverse
     implicit none
     print'(a)', reverse("Hello, World!") ! returns "!dlroW ,olleH"
 end program demo_reverse
+```

From 59b195e627b93a04697cc1a673f40dfce969f831 Mon Sep 17 00:00:00 2001
From: Sebastian Ehlert <28669218+awvwgk@users.noreply.github.com>
Date: Wed, 10 Feb 2021 17:35:08 +0100
Subject: [PATCH 5/8] Reword capitalization rules

---
 doc/specs/stdlib_ascii.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/specs/stdlib_ascii.md b/doc/specs/stdlib_ascii.md
index e9200fee9..252f73a25 100644
--- a/doc/specs/stdlib_ascii.md
+++ b/doc/specs/stdlib_ascii.md
@@ -103,8 +103,8 @@ Experimental
 #### Description
 
 Returns a capitalized version of an input character variable.
-Only the first alphanumeric character is capitalized.
-All following characters will become lowercase.
+The first alphabetical character is transformed to uppercase unless it follows a numeral.
+The rest of the character sequence is transformed to lowercase.
 
 #### Syntax
 

From e67026237c7cce2ea47cc2bcb6b68e94754782ee Mon Sep 17 00:00:00 2001
From: milancurcic <caomaco@gmail.com>
Date: Wed, 10 Feb 2021 12:49:28 -0500
Subject: [PATCH 6/8] promote public functions to elemental

---
 doc/specs/stdlib_ascii.md      | 8 ++++----
 src/stdlib_ascii.f90           | 8 ++++----
 src/tests/ascii/test_ascii.f90 | 8 ++++++++
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/doc/specs/stdlib_ascii.md b/doc/specs/stdlib_ascii.md
index 252f73a25..168fd78df 100644
--- a/doc/specs/stdlib_ascii.md
+++ b/doc/specs/stdlib_ascii.md
@@ -38,7 +38,7 @@ Converts input character variable to all lowercase.
 
 #### Class
 
-Pure function.
+Elemental function.
 
 #### Argument
 
@@ -74,7 +74,7 @@ Converts input character variable to all uppercase.
 
 #### Class
 
-Pure function.
+Elemental function.
 
 #### Argument
 
@@ -112,7 +112,7 @@ The rest of the character sequence is transformed to lowercase.
 
 #### Class
 
-Pure function.
+Elemental function.
 
 #### Argument
 
@@ -150,7 +150,7 @@ Reverses the order of all characters in the input character type.
 
 #### Class
 
-Pure function.
+Elemental function.
 
 #### Argument
 
diff --git a/src/stdlib_ascii.f90 b/src/stdlib_ascii.f90
index 473a6ad02..36a93b762 100644
--- a/src/stdlib_ascii.f90
+++ b/src/stdlib_ascii.f90
@@ -213,7 +213,7 @@ end function char_to_upper
     !> Convert character variable to lower case
     !>
     !> Version: experimental
-    pure function to_lower(string) result(lower_string)
+    elemental function to_lower(string) result(lower_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: lower_string
         integer :: i
@@ -227,7 +227,7 @@ end function to_lower
     !> Convert character variable to upper case
     !>
     !> Version: experimental
-    pure function to_upper(string) result(upper_string)
+    elemental function to_upper(string) result(upper_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: upper_string
         integer :: i
@@ -241,7 +241,7 @@ end function to_upper
     !> Convert character variable to title case
     !>
     !> Version: experimental
-    pure function to_title(string) result(title_string)
+    elemental function to_title(string) result(title_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: title_string
         integer :: i, n
@@ -266,7 +266,7 @@ end function to_title
     !> Reverse the character order in the input character variable
     !>
     !> Version: experimental
-    pure function reverse(string) result(reverse_string)
+    elemental function reverse(string) result(reverse_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: reverse_string
         integer :: i, n
diff --git a/src/tests/ascii/test_ascii.f90 b/src/tests/ascii/test_ascii.f90
index cfe4a938c..2915911b9 100644
--- a/src/tests/ascii/test_ascii.f90
+++ b/src/tests/ascii/test_ascii.f90
@@ -559,6 +559,8 @@ subroutine test_to_lower_string
 
         dlc = to_lower("0123456789ABCDE")
         call check(dlc == "0123456789abcde")
+
+        call check(all(to_lower(["ABC", "DEF"]) == ["abc", "def"]))
     end subroutine test_to_lower_string
 
     subroutine test_to_upper_string
@@ -575,6 +577,8 @@ subroutine test_to_upper_string
 
         dlc = to_upper("0123456789abcde")
         call check(dlc == "0123456789ABCDE")
+
+        call check(all(to_upper(["abc", "def"]) == ["ABC", "DEF"]))
     end subroutine test_to_upper_string
 
     subroutine test_to_title_string
@@ -597,6 +601,8 @@ subroutine test_to_title_string
 
         dlc = to_title("""quOTed""")
         call check(dlc == """Quoted""")
+
+        call check(all(to_title(["abc", "def"]) == ["Abc", "Def"]))
     end subroutine test_to_title_string
 
     subroutine test_reverse_string
@@ -611,6 +617,8 @@ subroutine test_reverse_string
         call check(len_trim(dlc) == 32)
         call check(trim(dlc) == "                        desrever")
         call check(trim(adjustl(dlc)) == "desrever")
+
+        call check(all(reverse(["abc", "def"]) == ["cba", "fed"]))
     end subroutine test_reverse_string
 
 end program test_ascii

From 546fece11a82ff85abb81e4421511057c1796ddc Mon Sep 17 00:00:00 2001
From: Sebastian Ehlert <28669218+awvwgk@users.noreply.github.com>
Date: Wed, 10 Feb 2021 21:20:09 +0100
Subject: [PATCH 7/8] Revert e67026237c7cce2ea47cc2bcb6b68e94754782ee

Change from pure to elemental requires extra discussion, therefore
inclusion of this patch is deferred.
---
 doc/specs/stdlib_ascii.md      | 8 ++++----
 src/stdlib_ascii.f90           | 8 ++++----
 src/tests/ascii/test_ascii.f90 | 8 --------
 3 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/doc/specs/stdlib_ascii.md b/doc/specs/stdlib_ascii.md
index 168fd78df..252f73a25 100644
--- a/doc/specs/stdlib_ascii.md
+++ b/doc/specs/stdlib_ascii.md
@@ -38,7 +38,7 @@ Converts input character variable to all lowercase.
 
 #### Class
 
-Elemental function.
+Pure function.
 
 #### Argument
 
@@ -74,7 +74,7 @@ Converts input character variable to all uppercase.
 
 #### Class
 
-Elemental function.
+Pure function.
 
 #### Argument
 
@@ -112,7 +112,7 @@ The rest of the character sequence is transformed to lowercase.
 
 #### Class
 
-Elemental function.
+Pure function.
 
 #### Argument
 
@@ -150,7 +150,7 @@ Reverses the order of all characters in the input character type.
 
 #### Class
 
-Elemental function.
+Pure function.
 
 #### Argument
 
diff --git a/src/stdlib_ascii.f90 b/src/stdlib_ascii.f90
index 36a93b762..473a6ad02 100644
--- a/src/stdlib_ascii.f90
+++ b/src/stdlib_ascii.f90
@@ -213,7 +213,7 @@ end function char_to_upper
     !> Convert character variable to lower case
     !>
     !> Version: experimental
-    elemental function to_lower(string) result(lower_string)
+    pure function to_lower(string) result(lower_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: lower_string
         integer :: i
@@ -227,7 +227,7 @@ end function to_lower
     !> Convert character variable to upper case
     !>
     !> Version: experimental
-    elemental function to_upper(string) result(upper_string)
+    pure function to_upper(string) result(upper_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: upper_string
         integer :: i
@@ -241,7 +241,7 @@ end function to_upper
     !> Convert character variable to title case
     !>
     !> Version: experimental
-    elemental function to_title(string) result(title_string)
+    pure function to_title(string) result(title_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: title_string
         integer :: i, n
@@ -266,7 +266,7 @@ end function to_title
     !> Reverse the character order in the input character variable
     !>
     !> Version: experimental
-    elemental function reverse(string) result(reverse_string)
+    pure function reverse(string) result(reverse_string)
         character(len=*), intent(in) :: string
         character(len=len(string)) :: reverse_string
         integer :: i, n
diff --git a/src/tests/ascii/test_ascii.f90 b/src/tests/ascii/test_ascii.f90
index 2915911b9..cfe4a938c 100644
--- a/src/tests/ascii/test_ascii.f90
+++ b/src/tests/ascii/test_ascii.f90
@@ -559,8 +559,6 @@ subroutine test_to_lower_string
 
         dlc = to_lower("0123456789ABCDE")
         call check(dlc == "0123456789abcde")
-
-        call check(all(to_lower(["ABC", "DEF"]) == ["abc", "def"]))
     end subroutine test_to_lower_string
 
     subroutine test_to_upper_string
@@ -577,8 +575,6 @@ subroutine test_to_upper_string
 
         dlc = to_upper("0123456789abcde")
         call check(dlc == "0123456789ABCDE")
-
-        call check(all(to_upper(["abc", "def"]) == ["ABC", "DEF"]))
     end subroutine test_to_upper_string
 
     subroutine test_to_title_string
@@ -601,8 +597,6 @@ subroutine test_to_title_string
 
         dlc = to_title("""quOTed""")
         call check(dlc == """Quoted""")
-
-        call check(all(to_title(["abc", "def"]) == ["Abc", "Def"]))
     end subroutine test_to_title_string
 
     subroutine test_reverse_string
@@ -617,8 +611,6 @@ subroutine test_reverse_string
         call check(len_trim(dlc) == 32)
         call check(trim(dlc) == "                        desrever")
         call check(trim(adjustl(dlc)) == "desrever")
-
-        call check(all(reverse(["abc", "def"]) == ["cba", "fed"]))
     end subroutine test_reverse_string
 
 end program test_ascii

From 6e9574bf209625c5c27f21462c828bf929a85ea2 Mon Sep 17 00:00:00 2001
From: Jeremie Vandenplas <jeremie.vandenplas@gmail.com>
Date: Mon, 15 Feb 2021 19:30:00 +0100
Subject: [PATCH 8/8] Apply suggestions from code review

---
 doc/specs/stdlib_ascii.md | 4 ++--
 src/stdlib_ascii.f90      | 4 ++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/doc/specs/stdlib_ascii.md b/doc/specs/stdlib_ascii.md
index 252f73a25..5a6653337 100644
--- a/doc/specs/stdlib_ascii.md
+++ b/doc/specs/stdlib_ascii.md
@@ -34,7 +34,7 @@ Converts input character variable to all lowercase.
 
 #### Syntax
 
-`res = [[stdlib_asciii(module):to_lower(function)]] (string)`
+`res = [[stdlib_ascii(module):to_lower(function)]] (string)`
 
 #### Class
 
@@ -108,7 +108,7 @@ The rest of the character sequence is transformed to lowercase.
 
 #### Syntax
 
-`res = [[stdlib_ascii(module):to_title(interface)]] (string)`
+`res = [[stdlib_ascii(module):to_title(function)]] (string)`
 
 #### Class
 
diff --git a/src/stdlib_ascii.f90 b/src/stdlib_ascii.f90
index 473a6ad02..a9111888a 100644
--- a/src/stdlib_ascii.f90
+++ b/src/stdlib_ascii.f90
@@ -211,6 +211,7 @@ pure function char_to_upper(c) result(t)
     end function char_to_upper
 
     !> Convert character variable to lower case
+    !> ([Specification](../page/specs/stdlib_ascii.html#to_lower))
     !>
     !> Version: experimental
     pure function to_lower(string) result(lower_string)
@@ -225,6 +226,7 @@ pure function to_lower(string) result(lower_string)
     end function to_lower
 
     !> Convert character variable to upper case
+    !> ([Specification](../page/specs/stdlib_ascii.html#to_upper))
     !>
     !> Version: experimental
     pure function to_upper(string) result(upper_string)
@@ -239,6 +241,7 @@ pure function to_upper(string) result(upper_string)
     end function to_upper
 
     !> Convert character variable to title case
+    !> ([Specification](../page/specs/stdlib_ascii.html#to_title))
     !>
     !> Version: experimental
     pure function to_title(string) result(title_string)
@@ -264,6 +267,7 @@ pure function to_title(string) result(title_string)
     end function to_title
 
     !> Reverse the character order in the input character variable
+    !> ([Specification](../page/specs/stdlib_ascii.html#reverse))
     !>
     !> Version: experimental
     pure function reverse(string) result(reverse_string)