feat(string_t): encapsulate deferred-length string

Author: rouson

src/string_m.f90

@@ -0,0 +1,41 @@
+module string_m
+  implicit none
+  
+  private
+  public :: string_t
+  public :: array_of_strings
+
+  type string_t
+    private
+    character(len=:), allocatable :: string_
+  contains
+    procedure :: string
+  end type
+
+  interface string_t
+
+    elemental module function construct(string) result(new_string)
+      implicit none
+      character(len=*), intent(in) :: string
+      type(string_t) new_string
+    end function
+
+  end interface
+
+  interface
+
+    pure module function string(self) result(raw_string)
+      implicit none
+      class(string_t), intent(in) :: self
+      character(len=:), allocatable :: raw_string
+    end function
+
+    pure module function array_of_strings(delimited_strings, delimiter) result(strings_array)
+      implicit none
+      character(len=*), intent(in) :: delimited_strings, delimiter
+      type(string_t), allocatable :: strings_array(:)
+    end function
+   
+  end interface
+  
+end module string_m

src/string_s.f90

@@ -0,0 +1,36 @@
+submodule(string_m) string_s
+  implicit none
+  
+contains
+
+    module procedure construct
+      new_string%string_ = string
+    end procedure
+
+    module procedure string
+      raw_string = self%string_
+    end procedure
+
+  module procedure array_of_strings
+    character(len=:), allocatable :: remainder, next_string
+    integer next_delimiter, string_end
+
+    remainder = trim(adjustl(delimited_strings))
+    allocate(strings_array(0))
+
+    do  
+      next_delimiter = index(remainder, delimiter)
+      string_end = merge(len(remainder), next_delimiter-1, next_delimiter==0)
+      next_string = trim(adjustl(remainder(:string_end)))
+      if (len(next_string)==0) exit
+      strings_array = [strings_array, string_t(next_string)]
+      if (next_delimiter==0) then
+        remainder = ""
+      else
+        remainder = trim(adjustl(remainder(next_delimiter+1:)))
+      end if
+    end do
+
+  end procedure
+
+end submodule string_s