Merge stdlib_ascii(module):to_string(interface) to stdlib_strings(module):format_to_string(interface).

#### Works
1. merge `to_string` and `format_to_string` to `stdlib_strings`, make the name `to_string`
2. redrect the used keyword `to_string` in `stdlib_string_type`
3. add `stdlib_string_type_constructor.fypp` to avoid the ring dependence in `stdlib_strings` and `stdlib_string_type`.
4. other clean works.

Author: zoziha

doc/specs/stdlib_ascii.md

@@ -212,42 +212,4 @@ program demo_reverse
     implicit none
     print'(a)', reverse("Hello, World!") ! returns "!dlroW ,olleH"
 end program demo_reverse
-```
-
-### `to_string`
-
-#### Status
-
-Experimental
-
-#### Description
-
-Create a character string representing the value of the provided variable.
-
-#### Syntax
-
-`res = [[stdlib_ascii(module):to_string(interface)]] (string)`
-
-#### Class
-
-Pure function.
-
-#### Argument
-
-`val`: shall be an intrinsic integer or logical type. It is an `intent(in)` argument.
-
-#### Result value
-
-The result is an intrinsic character type.
-
-#### Example
-
-```fortran
-program demo_string_value
-    use stdlib_ascii, only : to_string
-    implicit none
-    print'(a)', to_string(-3) ! returns "-3"
-    print'(a)', to_string(.true.) ! returns "T"
-    print'(a)', to_string(42) ! returns "42"
-end program demo_string_value
-```
+```

doc/specs/stdlib_strings.md

@@ -436,7 +436,7 @@ end program demo_count
 ```
 
 <!-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -->
-### `format_to_string`
+### `to_string`
 
 #### Description
 
@@ -445,15 +445,15 @@ Input a wrong `format` that cause the internal-IO to fail, the result value is a
 
 #### Syntax
 
-`format_to_string = [[stdlib_strings(module):format_to_string(interface)]] (value [, format])`
+`string = [[stdlib_strings(module):to_string(interface)]] (value [, format])`
 
 #### Status
 
 Experimental
 
 #### Class
 
-Pure function
+Pure function.
 
 #### Argument
 
@@ -464,38 +464,38 @@ Pure function
 
 #### Result value
 
-The result is an allocatable length `character` scalar with up to 512 `character` length.
+The result is an allocatable length `character` scalar with up to 128 cached `character` length.
 
 #### Example
 
 ```fortran
-program demo_format_to_string
-    use :: stdlib_strings, only: format_to_string
+program demo_to_string
+    use :: stdlib_strings, only: to_string
     implicit none
 
-    print *, 'format_to_string(complex) : '
-        print *, format_to_string((1, 1))              ! (1.00000000,1.00000000)
-        print *, format_to_string((1, 1), '(F6.2)')    ! (  1.00,  1.00)
-        print *, format_to_string((1000, 1), '(ES0.2)'), format_to_string((1000, 1), '(SP,F6.3)')     ! (1.00E+3,1.00)(******,+1.000)
+    print *, 'to_string(complex) : '
+        print *, to_string((1, 1))              ! (1.00000000,1.00000000)
+        print *, to_string((1, 1), '(F6.2)')    ! (  1.00,  1.00)
+        print *, to_string((1000, 1), '(ES0.2)'), to_string((1000, 1), '(SP,F6.3)')     ! (1.00E+3,1.00)(******,+1.000)
                         !! Too narrow formatter for real number
                         !! Normal demonstration(`******` from Fortran Standard)
 
-    print *, 'format_to_string(integer) : '
-        print *, format_to_string(1)                   ! 1
-        print *, format_to_string(1, '(I4)')           !     1
-        print *, format_to_string(1, '(I0.4)'), format_to_string(2, '(B4)')           ! 0001  10  
+    print *, 'to_string(integer) : '
+        print *, to_string(1)                   ! 1
+        print *, to_string(1, '(I4)')           !     1
+        print *, to_string(1, '(I0.4)'), to_string(2, '(B4)')           ! 0001  10  
 
-    print *, 'format_to_string(real) : '
-        print *, format_to_string(1.)                  ! 1.00000000
-        print *, format_to_string(1., '(F6.2)')        !   1.00 
-        print *, format_to_string(1., '(SP,ES9.2)'), format_to_string(1, '(F7.3)')    ! +1.00E+00[*]
-                        !! 1 wrong demonstration(`*` from `format_to_string`)
+    print *, 'to_string(real) : '
+        print *, to_string(1.)                  ! 1.00000000
+        print *, to_string(1., '(F6.2)')        !   1.00 
+        print *, to_string(1., '(SP,ES9.2)'), to_string(1, '(F7.3)')    ! +1.00E+00[*]
+                        !! 1 wrong demonstration(`*` from `to_string`)
 
-    print *, 'format_to_string(logical) : '
-        print *, format_to_string(.true.)              ! T
-        print *, format_to_string(.true., '(L2)')      !  T
-        print *, format_to_string(.true., 'L2'), format_to_string(.false., '(I5)')    ! [*][*]
-                        !! 2 wrong demonstrations(`*` from `format_to_string`)
+    print *, 'to_string(logical) : '
+        print *, to_string(.true.)              ! T
+        print *, to_string(.true., '(L2)')      !  T
+        print *, to_string(.true., 'L2'), to_string(.false., '(I5)')    ! [*][*]
+                        !! 2 wrong demonstrations(`*` from `to_string`)
 
-end program demo_format_to_string
+end program demo_to_string
 ```

src/CMakeLists.txt

@@ -30,7 +30,8 @@ set(fppFiles
     stdlib_stats_distribution_PRNG.fypp
     stdlib_math.fypp
     stdlib_string_type.fypp
-    stdlib_string_format_to_string.fypp
+    stdlib_string_type_constructor.fypp
+    stdlib_string_to_string.fypp
     stdlib_strings.fypp
 )
 

src/Makefile.manual

@@ -27,8 +27,9 @@ SRCFYPP =\
         stdlib_math.fypp \
         stdlib_stats_distribution_PRNG.fypp \
         stdlib_string_type.fypp \
+        stdlib_string_type_constructor.fypp \
         stdlib_strings.fypp \
-        stdlib_string_format_to_string.fypp
+        stdlib_string_to_string.fypp
 
 SRC = f18estop.f90 \
       stdlib_error.f90 \
@@ -139,10 +140,13 @@ stdlib_stats_distribution_PRNG.o: \
 	stdlib_error.o
 stdlib_string_type.o: stdlib_ascii.o \
     stdlib_kinds.o
+stdlib_string_type_constructor.o: stdlib_string_type.o \
+    stdlib_string_to_string.o \
+    stdlib_strings.o
 stdlib_strings.o: stdlib_ascii.o \
     stdlib_string_type.o \
 	stdlib_optval.o \
     stdlib_kinds.o
 stdlib_math.o: stdlib_kinds.o
-stdlib_string_format_to_string.o: stdlib_strings.o
+stdlib_string_to_string.o: stdlib_strings.o
 stdlib_linalg_outer_product.o: stdlib_linalg.o

src/stdlib_ascii.fypp

@@ -20,19 +20,6 @@ module stdlib_ascii
 
     ! Character conversion functions
     public :: to_lower, to_upper, to_title, to_sentence, reverse
-    public :: to_string
-
-    !> Version: experimental
-    !>
-    !> Create a character string representing the value of the provided variable.
-    interface to_string
-    #:for kind in INT_KINDS
-        module procedure :: to_string_integer_${kind}$
-    #:endfor
-    #:for kind in LOG_KINDS
-        module procedure :: to_string_logical_${kind}$
-    #:endfor
-    end interface to_string
 
     ! All control characters in the ASCII table (see www.asciitable.com).
     character(len=1), public, parameter :: NUL = achar(int(z'00')) !! Null
@@ -362,51 +349,4 @@ contains
 
     end function reverse
 
-    #:for kind in INT_KINDS
-    !> Represent an integer of kind ${kind}$ as character sequence
-    pure function to_string_integer_${kind}$(val) result(string)
-        integer, parameter :: ik = ${kind}$
-        integer(ik), intent(in) :: val
-        character(len=:), allocatable :: string
-        integer, parameter :: buffer_len = range(val)+2
-        character(len=buffer_len) :: buffer
-        integer :: pos
-        integer(ik) :: n
-        character(len=1), parameter :: numbers(0:9) = &
-            ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]
-
-        if (val == 0_ik) then
-            string = numbers(0)
-            return
-        end if
-
-        n = abs(val)
-        buffer = ""
-
-        pos = buffer_len + 1
-        do while (n > 0_ik)
-            pos = pos - 1
-            buffer(pos:pos) = numbers(mod(n, 10_ik))
-            n = n/10_ik
-        end do
-        if (val < 0_ik) then
-            pos = pos - 1
-            buffer(pos:pos) = '-'
-        end if
-
-        string = buffer(pos:)
-    end function to_string_integer_${kind}$
-    #:endfor
-
-    #:for kind in LOG_KINDS
-    !> Represent an logical of kind ${kind}$ as character sequence
-    pure function to_string_logical_${kind}$(val) result(string)
-        integer, parameter :: ik = ${kind}$
-        logical(ik), intent(in) :: val
-        character(len=1) :: string
-
-        string = merge("T", "F", val)
-    end function to_string_logical_${kind}$
-    #:endfor
-
 end module stdlib_ascii