program demo_regcomp use M_regex, only: regex_type, regcomp, regexec, regfree use M_regex, only: regmatch implicit none type(regex_type) :: regex integer :: matches(2,1) character(len=:),allocatable :: input_line character(len=:),allocatable :: output_line character(len=:),allocatable :: expression logical :: match integer :: ipass integer :: istart expression= "[-0-9.*/+]+" ! define extended regular expression input_line= "30*0 250*1 5 AND 6 7:and some text8 999" ! define an input line to search for the expression call regcomp(regex,expression,'x') ! compile the regex ipass=1 ! initialize pass counter INFINITE: do ! find match, then look again in remainder of line till all matches found match=regexec(regex,input_line,matches) ! look for a match in (remaining) string if(.not.match)exit INFINITE ! if no match found exit output_line=regmatch(1,input_line,matches) ! use bounds in MATCHES to select the matching substring write(*,'(8x,*(a))') 'match="',output_line,'"' ! show match istart=matches(2,1)+1 ! find beginning of remainder of string if(istart.gt.len(input_line))exit INFINITE ! reached end of string input_line=input_line(istart:) ! reduce string by any previous match ipass=ipass+1 ! increment count of passes made enddo INFINITE ! free memory used for compiled regular expression call regfree(regex) end program demo_regcomp