fix pattern constructor due to ifort behavior

src/regex.f90

@@ -111,8 +111,24 @@ module regex_module
         module procedure re_matchp_nolength_noback
     end interface regex
 
+    ! Override default constructor for ifort bug
+    interface regex_token
+        module procedure pat_from_char
+    end interface regex_token
+
+
     contains
 
+    ! Construct a regex pattern from a single character
+    elemental type(regex_token) function pat_from_char(type,ccl) result(this)
+       integer, intent(in) :: type
+       character(kind=RCK), intent(in) :: ccl
+       call pat_destroy(this)
+       this%type = type
+       allocate(character(len=1,kind=RCK) :: this%ccl)
+       this%ccl(1:1) = ccl
+    end function pat_from_char
+
     ! Check that a pattern matches the expected result
     logical function check_pattern(string,pattern,expected) result(success)
        character(len=*,kind=RCK), intent(in) :: string

test/tests.f90

@@ -32,6 +32,7 @@ program tests
     call add_test(test_bracket_space())
     call add_test(test_end_anchor())
     call add_test(test_end_anchor2())
+    call add_test(test_read_version())
 
     ! Test #2
     call add_test(run_test2())
@@ -122,4 +123,12 @@ logical function test_end_anchor2() result(success)
 
     end function test_end_anchor2
 
+    logical function test_read_version() result(success)
+       character(*), parameter :: &
+       text = 'Intel(R) MPI Library 2021.8 for Linux*Copyright Intel Corporation.ifort version 2021.8.0'
+
+       success = check_pattern(text,'\d+\.\d+\.\d+',expected="2021.8.0")
+
+    end function test_read_version
+
 end program tests