From f0881305402f3dff56f99fcc4cbc8b615581b780 Mon Sep 17 00:00:00 2001
From: Igor Pashev <pashev.igor@gmail.com>
Date: Sun, 28 Aug 2022 15:40:21 +0200
Subject: C, Haskell, Python, Fortran

---
 mendeleev.f90 | 200 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 200 insertions(+)
 create mode 100644 mendeleev.f90

(limited to 'mendeleev.f90')

diff --git a/mendeleev.f90 b/mendeleev.f90
new file mode 100644
index 0000000..3108b5e
--- /dev/null
+++ b/mendeleev.f90
@@ -0,0 +1,200 @@
+program mendeleev
+
+   implicit none
+
+   character(len=2), dimension(0:118), parameter :: ELEMENTS = (/ "? ", &
+     "Ac", "Ag", "Al", "Am", "Ar", "As", "At", "Au", "B ", "Ba", "Be", "Bh", &
+     "Bi", "Bk", "Br", "C ", "Ca", "Cd", "Ce", "Cf", "Cl", "Cm", "Cn", "Co", &
+     "Cr", "Cs", "Cu", "Db", "Ds", "Dy", "Er", "Es", "Eu", "F ", "Fe", "Fl", &
+     "Fm", "Fr", "Ga", "Gd", "Ge", "H ", "He", "Hf", "Hg", "Ho", "Hs", "I ", &
+     "In", "Ir", "K ", "Kr", "La", "Li", "Lr", "Lu", "Lv", "Mc", "Md", "Mg", &
+     "Mn", "Mo", "Mt", "N ", "Na", "Nb", "Nd", "Ne", "Nh", "Ni", "No", "Np", &
+     "O ", "Og", "Os", "P ", "Pa", "Pb", "Pd", "Pm", "Po", "Pr", "Pt", "Pu", &
+     "Ra", "Rb", "Re", "Rf", "Rg", "Rh", "Rn", "Ru", "S ", "Sb", "Sc", "Se", &
+     "Sg", "Si", "Sm", "Sn", "Sr", "Ta", "Tb", "Tc", "Te", "Th", "Ti", "Tl", &
+     "Tm", "Ts", "U ", "V ", "W ", "Xe", "Y ", "Yb", "Zn", "Zr" /)
+
+   type :: formula_t
+      integer :: tail = 1
+      integer :: n = 0
+      integer, dimension(:), allocatable :: elements
+      type(formula_t), pointer :: next => null()
+   end type formula_t
+
+   type(formula_t), pointer :: formula, f
+   character(len=:), allocatable :: word
+   integer :: length, argc, i, j
+
+   argc = command_argument_count()
+   do i = 1, argc
+      call get_command_argument(i, length=length)
+      allocate(character(len=length) :: word)
+      call get_command_argument(i, value=word)
+      write (*, "(A, ':')") word
+
+      formula => explode(word)
+
+      f => formula
+      do while (associated(f))
+         if (f%n > 0) then
+            do j = 1, f%n
+               write (*, "(' ', A)", advance="no") trim(ELEMENTS(f%elements(j)))
+            end do
+            write (*, "()")
+         end if
+         f => f%next
+      end do
+
+      call free_formula(formula)
+      deallocate(word)
+   end do
+
+
+contains
+
+   pure subroutine free_formula(formula)
+      type(formula_t), pointer, intent(in out) :: formula
+
+      type(formula_t), pointer :: next
+
+      do while (associated(formula))
+         next => formula%next
+         deallocate(formula%elements)
+         deallocate(formula)
+         formula => next
+      end do
+   end subroutine free_formula
+
+
+   pure integer function tolower(c)
+      character(len=1), intent(in) :: c
+
+      integer :: i
+
+      i = iachar(c)
+      if (i >= 65 .and. i < 90) then
+         tolower = i + 32
+      else
+         tolower = i
+      endif
+   end function tolower
+
+
+   pure subroutine search(start, length, sh, c)
+      integer, intent(in out) :: start, length
+      integer, intent(in) :: sh
+      character(len=1), intent(in) :: c
+
+      integer :: l, m, u, c_
+
+      c_ = tolower(c)
+
+      u = start + length
+      l = start
+      do while (l < u)
+         m = (u + l) / 2
+         if (tolower(ELEMENTS(m)(sh:sh)) < c_) then
+           l = m + 1
+         else
+           u = m
+        endif
+      end do
+
+      if (l == start + length) then
+        length = 0
+        return
+      end if
+
+      if (tolower(ELEMENTS(l)(sh:sh)) /= c_) then
+        length = 0
+        return
+      end if
+
+      u = start + length
+      start = l
+      do while (l < u)
+         m = (u + l) / 2
+         if (c_ < tolower(ELEMENTS(m)(sh:sh))) then
+           u = m
+         else
+           l = m + 1
+        endif
+      end do
+
+      length = u - start
+   end subroutine search
+
+
+   pure subroutine advance(word, f)
+      character(len=*), intent(in) :: word
+      type(formula_t), pointer, intent(in out) :: f
+
+      integer :: n, tail
+      integer :: start, length, sh, c
+      type(formula_t), pointer :: g
+
+      tail = f%tail
+      n = f%n
+
+      sh = 0
+      start = 1
+      length = ubound(ELEMENTS, 1)
+      do
+         c = tail + sh
+         if (len(word) < c) exit
+
+         sh = sh + 1
+         call search(start, length, sh, word(c:c))
+         if (length == 0) exit
+
+         if (sh == len_trim(ELEMENTS(start))) then
+            if (n /= f%n) then
+               allocate(g)
+               allocate(g%elements(len(word)))
+               g%n = n
+               g%elements(1:n) = f%elements(1:n)
+               g%next => f%next
+               f%next => g
+               f => g
+            end if
+
+            f%n = f%n + 1
+            f%elements(f%n) = start
+            f%tail = c + 1
+            start = start + 1
+            length = length - 1
+         end if
+      end do
+
+      if (n == f%n) then
+         f%tail = f%tail + 1
+         f%n = f%n + 1
+         f%elements(f%n) = 0
+      end if
+   end subroutine advance
+
+
+   pure function explode(word) result(formula)
+      character(len=*), intent(in) :: word
+      type(formula_t), pointer :: formula
+
+      logical :: has_tail
+      type(formula_t), pointer :: f
+
+      allocate(formula)
+      allocate(formula%elements(len(word)))
+
+      do
+         f => formula
+         has_tail = .false.
+         do while (associated(f))
+            if (f%tail <= len(word)) then
+               call advance(word, f)
+               if (.not. has_tail) has_tail = f%tail <= len(word)
+            end if
+            f => f%next
+         end do
+         if (.not. has_tail) exit
+      end do
+   end function explode
+end program mendeleev
-- 
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