Made format constants public

CHANGELOG.md

@@ -47,6 +47,9 @@ Changes to existing modules
     [#562](https://github.com/fortran-lang/stdlib/pull/562)
 - support for quadruple precision made optional
   [#565](https://github.com/fortran-lang/stdlib/pull/565)
+- change in module `stdlib_io`
+  - Modified format constants, and made public
+  [#617](https://github.com/fortran-lang/stdlib/pull/617)
 
 
 # Version 0.1.0

doc/specs/stdlib_io.md

@@ -273,3 +273,45 @@ program demo_getline
     end do
 end program demo_getline
 ```
+
+## Formatting constants
+
+### Status
+
+Experimental
+
+### Description
+
+Formatting constants for printing out integer, floating point, and complex numbers at their full precision.
+Provides formats for all kinds as defined in the `stdlib_kinds` module.
+
+### Example
+
+```fortran
+program demo_fmt_constants
+    use, stdlib_kinds, only : int32, int64, sp, dp 
+    use stdlib_io,     only : FMT_INT, FMT_REAL_SP, FMT_REAL_DP, FMT_COMPLEX_SP, FMT_COMPLEX_DP
+    implicit none
+
+    integer(kind=int32) :: i32
+    integer(kind=int64) :: i64
+    real(kind=sp)       :: r32
+    real(kind=dp)       :: r64
+    complex(kind=sp)    :: c32
+    complex(kind=dp)    :: c64
+
+    i32 = 100_int32
+    i64 = 100_int64
+    r32 = 100.0_sp
+    r64 = 100.0_dp
+    c32 = cmplx(100.0_sp, kind=sp)
+    c64 = cmplx(100.0_dp, kind=dp)
+
+    print "(2("//FMT_INT//",1x))", i32, i64 ! outputs: 100 100
+    print FMT_REAL_SP, r32                  ! outputs: 1.00000000E+02
+    print FMT_REAL_DP, r64                  ! outputs: 1.0000000000000000E+002
+    print FMT_COMPLEX_SP, c32               ! outputs: 1.00000000E+02  0.00000000E+00
+    print FMT_COMPLEX_DP, c64               ! outputs: 1.0000000000000000E+002  0.0000000000000000E+000
+
+end program demo_fmt_constants
+```

src/stdlib_io.fypp

@@ -21,17 +21,32 @@ module stdlib_io
   ! Private API that is exposed so that we can test it in tests
   public :: parse_mode
 
-  ! Format strings with edit descriptors for each type and kind
+  !> Version: experimental
+  !>
+  !> Format strings with edit descriptors for each type and kind
+  !> ([Specification](../page/specs/stdlib_io.html))
   character(*), parameter :: &
-    FMT_INT = '(*(i0,1x))', &
-    FMT_REAL_SP = '(*(es15.8e2,1x))', &
-    FMT_REAL_DP = '(*(es24.16e3,1x))', &
-    FMT_REAL_XDP = '(*(es26.18e3,1x))', &
-    FMT_REAL_QP = '(*(es44.35e4,1x))', &
-    FMT_COMPLEX_SP = '(*(es15.8e2,1x,es15.8e2))', &
-    FMT_COMPLEX_DP = '(*(es24.16e3,1x,es24.16e3))', &
-    FMT_COMPLEX_XDP = '(*(es26.18e3,1x,es26.18e3))', &
-    FMT_COMPLEX_QP = '(*(es44.35e4,1x,es44.35e4))'
+    !> Format string for integers
+    FMT_INT = '(i0)', &
+    !> Format string for single precision real numbers
+    FMT_REAL_SP = '(es15.8e2)', &
+    !> Format string for souble precision real numbers
+    FMT_REAL_DP = '(es24.16e3)', &
+    !> Format string for extended double precision real numbers
+    FMT_REAL_XDP = '(es26.18e3)', &
+    !> Format string for quadruple precision real numbers
+    FMT_REAL_QP = '(es44.35e4)', &
+    !> Format string for single precision complex numbers
+    FMT_COMPLEX_SP = '(es15.8e2,1x,es15.8e2)', &
+    !> Format string for double precision complex numbers
+    FMT_COMPLEX_DP = '(es24.16e3,1x,es24.16e3)', &
+    !> Format string for extended double precision complex numbers
+    FMT_COMPLEX_XDP = '(es26.18e3,1x,es26.18e3)', &
+    !> Format string for quadruple precision complex numbers
+    FMT_COMPLEX_QP = '(es44.35e4,1x,es44.35e4)'
+
+  public :: FMT_INT, FMT_REAL_SP, FMT_REAL_DP, FMT_REAL_XDP, FMT_REAL_QP
+  public :: FMT_COMPLEX_SP, FMT_COMPLEX_DP, FMT_COMPLEX_XDP, FMT_COMPLEX_QP
 
   !> Version: experimental
   !>
@@ -112,9 +127,9 @@ contains
       allocate(d(nrow, ncol))
       do i = 1, nrow
         #:if 'real' in t1
-          read(s, FMT_REAL_${k1}$) d(i, :)
+          read(s, "(*"//FMT_REAL_${k1}$(1:len(FMT_REAL_${k1}$)-1)//",1x))") d(i, :)
         #:elif 'complex' in t1
-          read(s, FMT_COMPLEX_${k1}$) d(i, :)
+          read(s, "(*"//FMT_COMPLEX_${k1}$(1:len(FMT_COMPLEX_${k1}$)-1)//",1x))") d(i, :)
         #:else
           read(s, *) d(i, :)
         #:endif
@@ -150,11 +165,11 @@ contains
       s = open(filename, "w")
       do i = 1, size(d, 1)
         #:if 'real' in t1
-          write(s, FMT_REAL_${k1}$) d(i, :)
+          write(s, "(*"//FMT_REAL_${k1}$(1:len(FMT_REAL_${k1}$)-1)//",1x))") d(i, :)
         #:elif 'complex' in t1
-          write(s, FMT_COMPLEX_${k1}$) d(i, :)
+          write(s, "(*"//FMT_COMPLEX_${k1}$(1:len(FMT_COMPLEX_${k1}$)-1)//",1x))") d(i, :)
         #:elif 'integer' in t1
-          write(s, FMT_INT) d(i, :)
+          write(s, "(*"//FMT_INT(1:len(FMT_INT)-1)//",1x))") d(i, :)
         #:else
           write(s, *) d(i, :)
         #:endif