Module checkit {
      any=lambda (z$)->{=lambda z$ (a$)->instr(z$,a$)>0}
      one=lambda (z$)->{=lambda z$ (a$)->z$=a$}
      number$="0123456789"

      series=Lambda  -> {
                  func=Array([])
                  =lambda  func (&line$, &res$)->{
                        if line$="" then exit
                        k=each(func)
                        def p=0,ok as boolean
                        while k {
                              ok=false :  p++ :  f=array(k)
                              if not f(mid$(line$,p,1)) then exit
                              ok=true
                        }
                        if ok then res$=left$(line$, p) : line$=mid$(line$, p+1)
                        =ok
                  }
      }

      is_any=lambda series, any  (c$) ->series(any(c$))
      is_one=lambda series, one  (c$) ->series(one(c$))
      Is_Alpha=series(lambda (a$)-> a$ ~ "[a-zA-Z]")
      Is_digit=series(any(number$))
      Is_hex=any(number$+"abcdefABCDEF")

      optionals=Lambda  -> {
                  func=Array([])
                  =lambda  func (&line$, &res$)->{
                        k=each(func)
                        def ok as boolean
                        while k {
                              f=array(k)
                              if f(&line$,&res$) then ok=true : exit
                        }
                        =ok
                  }
      }
      repeated=Lambda  (func)-> {
                  =lambda  func (&line$, &res$)->{
                        def ok as boolean, a$
                        res$=""
                        do {
                              sec=len(line$)
                              if not func(&line$,&a$) then exit
                              res$+=a$
                              ok=true
                        } until line$="" or sec=len(line$)
                        =ok
                  }
      }

      oneAndoptional=lambda (func1, func2) -> {
            =lambda  func1, func2 (&line$, &res$)->{
                              def ok as boolean, a$
                              res$=""
                              if not func1(&line$,&res$) then exit
                              if func2(&line$,&a$) then res$+=a$
                              =True
                        }
      }
      many=Lambda  -> {
                  func=Array([])
                  =lambda  func (&line$, &res$)->{
                        k=each(func)
                        def p=0,ok as boolean, acc$
                        oldline$=line$
                        while k  {
                              ok=false
                              res$=""
                              if line$="" then exit
                              f=array(k)
                              if not f(&line$,&res$) then exit
                              acc$+=res$
                              ok=true
                         }
                        if not ok then {line$=oldline$}  else res$=acc$
                        =ok
                  }
      }
      is_safe=series(any("$-_@.&"))
      Is_extra=series(any("!*'(),"+chr$(34)))
      Is_Escape=series(any("%"), is_hex, is_hex)
      \\Is_reserved=series(any("=;/#?: "))
      is_xalpha=optionals(Is_Alpha, is_digit, is_safe, is_extra, is_escape)
      is_xalphas=oneAndoptional(is_xalpha,repeated(is_xalpha))
      is_xpalpha=optionals(is_xalpha, is_one("+"))
      is_xpalphas=oneAndoptional(is_xpalpha,repeated(is_xpalpha))
      Is_ialpha=oneAndoptional(Is_Alpha,repeated(is_xpalphas))
      is_fragmentid=lambda is_xalphas (&lines$, &res$) -> {
            =is_xalphas(&lines$, &res$)
      }
      is_search=oneAndoptional(is_xalphas, repeated(many(series(one("+")), is_xalphas)))
      is_void=lambda (f)-> {
            =lambda f (&oldline$, &res$)-> {
                  line$=oldline$
                  if f(&line$, &res$) then {oldline$=line$ } else res$=""
                  =true
            }
      }
      is_scheme=is_ialpha
      is_path=repeated(oneAndoptional(is_void(is_xpalphas), series(one("/"))))
      is_uri=oneAndoptional(many(is_scheme, series(one(":")), is_path), many(series(one("?")),is_search))
      is_fragmentaddress=oneAndoptional(is_uri, many(series(one("#")),is_fragmentid ))

      data "foo://example.com:8042/over/there?name=ferret#nose"
      data "urn:example:animal:ferret:nose"
      data "jdbc:mysql://test_user:ouupppssss@localhost:3306/sakila?profileSQL=true "
      data "ftp://ftp.is.co.za/rfc/rfc1808.txt"
      data "http://www.ietf.org/rfc/rfc2396.txt#header1"
      data "ldap://[2001:db8::7]/c=GB?objectClass=one&objectClass=two"
      data "mailto:John.Doe@example.com"
      data "tel:+1-816-555-1212"
      data "telnet://192.0.2.16:80/"
      data "urn:oasis:names:specification:docbook:dtd:xml:4.1.2"

      while not empty {
            read What$
            pen 15 {
                  Print What$
            }
            a$=""
            If is_scheme(&What$, &a$) Then  Print "Scheme=";a$ : What$=mid$(What$,2)
            If is_path(&What$, &a$) Then {
                  count=0
                  while left$(a$, 1)="/" { a$=mid$(a$,2): count++}
                  if count>1 then {
                        domain$=leftpart$(a$+"/", "/")
                        a$=rightpart$(a$,"/")
                        if domain$<>"" Then Print "Domain:";Domain$
                        if a$<>"" Then Print "Path:";a$
                  } else.if  left$(What$,1) =":" then {
                        Print "path:";a$+What$: What$=""
                  } Else Print  "Data:"; a$

            }

            if left$(What$,1) =":" then {
                  is_number=repeated(is_digit)
                  What$=mid$(What$,2): If is_number(&What$, &a$) Then Print "Port:";a$
                  if not left$(What$,1)="/" then  exit
                  If is_path(&What$, &a$) Then {
                        while left$(a$, 1)="/" { a$=mid$(a$,2)}
                        if a$<>"" Then Print "Path:";a$
                  }
            }
            if left$(What$, 1)="?" then {
                        What$=mid$(What$,2)
                        If is_search(&What$, &a$) Then  {
                        v$=""
                        if left$(What$, 1)="=" then {
                              What$=mid$(What$,2)
                              If is_search(&What$, &v$) Then  Print "Query:";a$;"=";v$
                        }  else Print "Query:";a$
                        }
            }
            While  left$(What$, 1)="#"  {
            What$=mid$(What$,2)
            if not is_xalphas(&What$, &a$) Then exit
            Print "fragment:";a$
            }
            if What$<>"" Then Print "Data:"; What$
      }
}
Checkit