Mark many functions as pure (no side effects)

fortran/problem_linker.sh

@@ -72,7 +72,7 @@ cat <<EOF3 >> $OUTPUT_FILE
         end select
     end function run_problem
 
-    logical function is_slow(id)
+    pure logical function is_slow(id)
         integer(i4t), intent(in) :: id
         select case (id)
 EOF3

fortran/src/include/math.f90

@@ -4,7 +4,7 @@ module math
 
 contains
 
-    integer(i18t) function factorial(n) result(answer)
+    pure integer(i18t) function factorial(n) result(answer)
         integer, intent(in) :: n
         integer :: i
         answer = 1

fortran/src/include/primes.f90

@@ -78,7 +78,7 @@ subroutine clear_prime_bit(num)
     end subroutine clear_prime_bit
 
     ! Function to check if a bit is set
-    logical function get_prime_bit(num) result(bit)
+    pure logical function get_prime_bit(num) result(bit)
         integer(i18t), intent(in) :: num
         bit = logical(btest(prime_sieve(num / bits_per_int + 1), mod(num, bits_per_int)))
     end function get_prime_bit

fortran/src/include/ranges.f90

@@ -4,12 +4,12 @@ module ranges
 
 contains
 
-    integer function range_entry3(start, step, idx) result(answer)
+    pure integer function range_entry3(start, step, idx) result(answer)
         integer, intent(in) :: start, step, idx
         answer = start + (step * idx)
     end function
 
-    integer function range_entry4(start, end, step, idx) result(answer)
+    pure integer function range_entry4(start, end, step, idx) result(answer)
         integer, intent(in) :: start, end, step, idx
         integer :: length, l_idx
 

fortran/src/p0001.f90

@@ -12,7 +12,7 @@
 module Problem0001
     implicit none
 contains
-    integer function p0001() result(answer)
+    pure integer function p0001() result(answer)
         integer :: i
         answer = 0
 

fortran/src/p0002.f90

@@ -15,7 +15,7 @@
 module Problem0002
     implicit none
 contains
-    integer function p0002() result(answer)
+    pure integer function p0002() result(answer)
         integer :: a = 1, b = 2, i, tmp
         answer = 0
 

fortran/src/p0004.f90

@@ -8,7 +8,7 @@
 module Problem0004
     implicit none
 contains
-    integer function p0004() result(answer)
+    pure integer function p0004() result(answer)
         integer :: i, j, k, n, prod, length
         logical :: is_palindrome
         character(len=8) :: string

fortran/src/p0006.f90

@@ -19,7 +19,7 @@
 module Problem0006
     implicit none
 contains
-    integer function p0006() result(answer)
+    pure integer function p0006() result(answer)
         integer :: sum = 1, sum_of_squares = 1, i
         answer = 0
 

fortran/src/p0008.f90

@@ -33,7 +33,7 @@ module Problem0008
     use constants
     implicit none
 contains
-    integer(i18t) function p0008() result(answer)
+    pure integer(i18t) function p0008() result(answer)
         integer :: i, j
         integer(i18t) :: tmp
         integer(i1t), dimension(1000) :: digits

fortran/src/p0009.f90

@@ -15,7 +15,7 @@
 module Problem0009
     implicit none
 contains
-    integer function p0009() result(answer)
+    pure integer function p0009() result(answer)
         integer :: a, b, c = 3, a_square, b_square, c_square
 
         do

fortran/src/p0011.f90

@@ -34,7 +34,7 @@ module Problem0011
     use constants
     implicit none
 contains
-    integer(i18t) function p0011() result(answer)
+    pure integer(i18t) function p0011() result(answer)
         integer(i2t), dimension(20, 20) :: grid
         integer(i18t) :: tmp
         integer :: i, j

fortran/src/p0013.f90

@@ -108,7 +108,7 @@ module Problem0013
     use constants
     implicit none
 contains
-    integer(i18t) function p0013() result(answer)
+    pure integer(i18t) function p0013() result(answer)
         integer(i18t), dimension(3, 100) :: numbers
         integer(i18t), dimension(3) :: arr = (/ 0, 0, 0 /)
         integer(i18t) :: ten18 = 1000000000000000000_8

fortran/src/p0017.f90

@@ -18,7 +18,7 @@
 module Problem0017
     implicit none
 contains
-    integer recursive function to_string_len(n) result(answer)
+    pure integer recursive function to_string_len(n) result(answer)
         integer, intent(in) :: n
         integer :: tmp
         answer = 0
@@ -71,7 +71,7 @@ integer recursive function to_string_len(n) result(answer)
         end if
     end function
 
-    integer function p0017() result(answer)
+    pure integer function p0017() result(answer)
         integer :: x
 
         answer = 0

fortran/src/p0028.f90

@@ -49,7 +49,7 @@ module Problem0028
     use ranges
     implicit none
 contains
-    integer function p0028() result(answer)
+    pure integer function p0028() result(answer)
         integer :: i, start
 
         answer = 1

fortran/src/p0034.f90

@@ -18,7 +18,7 @@ module Problem0034
     use math
     implicit none
 contains
-    integer(i18t) function p0034() result(answer)
+    pure integer(i18t) function p0034() result(answer)
         integer :: i, j
         integer(i18t) tmp
         character(len=5) string

fortran/src/p0076.f90

@@ -41,7 +41,7 @@ module Problem0076
     use constants
     implicit none
 contains
-    integer function p0076() result(answer)
+    pure integer function p0076() result(answer)
         integer :: idx, i, sum = 100
         integer, dimension(100) :: counts
         answer = 0

fortran/src/p0836.f90

@@ -17,7 +17,7 @@ module Problem0836
     implicit none
     integer, parameter :: p0836_len = 14
 contains
-    character(p0836_len) function p0836()
+    pure character(p0836_len) function p0836()
         p0836 = 'aprilfoolsjoke'
     end function p0836
 end module Problem0836