Exemplo n.º 1
0
//  details responds to an inspection request for a single expression
func details(w http.ResponseWriter, r *http.Request) {
	field := fmt.Sprintf("v%d", baseExpr)
	expr := r.FormValue(field)     // must read before any writing
	expr = strings.TrimSpace(expr) // trim leading/trailing blanks
	putheader(w, r, "Inspect Expression")
	tree, err := rx.Parse(expr)
	if err == nil {
		fmt.Fprintf(w, "<P>Regular Expression: %s\n", hx(expr))
		// must print (or at least stringize) tree before augmenting
		fmt.Fprintf(w, "<P>Initial Parse Tree: %s\n", hx(tree))

		augt := rx.Augment(tree, 0)
		dfa := rx.BuildDFA(augt)
		dmin := dfa.Minimize()

		fmt.Fprintf(w, "<P>Augmented Tree: %s\n", hx(augt))
		fmt.Fprintf(w, "<h2>Examples</h2>\n<P>")
		genexamples(w, tree, 0)
		genexamples(w, tree, 1)
		genexamples(w, tree, 2)
		genexamples(w, tree, 3)
		genexamples(w, tree, 5)
		genexamples(w, tree, 8)

		showaut(w, dmin, []string{expr})
	} else {
		fmt.Fprint(w, "<P>")
		showerror(w, err)
	}

	fmt.Fprint(w, "<h2>Try another?</h2>")
	putform(w, "/details", "Enter a regular expression:",
		1, []string{expr}, 0, nil)
	putfooter(w, r)
}
Exemplo n.º 2
0
//  multaut displays a multi-NFA and multi-DFA
func multaut(w http.ResponseWriter, r *http.Request) {

	// must read all input before writing anything
	exprlist := getexprs(r)
	nx := len(exprlist)

	// parse and echo the input
	treelist := make([]rx.Node, 0, nx)
	putheader(w, r, "Multi-expression Automata")
	fmt.Fprintf(w, "<P class=xleading>%d expressions:\n", nx)
	for i, s := range exprlist {
		fmt.Fprintf(w, "<BR><B>%c:</B> &nbsp; %s\n",
			rx.AcceptLabels[i], hx(s))
		tree, err := rx.Parse(s)
		if !showerror(w, err) {
			treelist = append(treelist, rx.Augment(tree, i))
		}
	}

	if nx > 0 && len(treelist) == nx { // if no errors
		dfa := rx.MultiDFA(treelist) // build combined DFA
		dmin := dfa.Minimize()
		showaut(w, dmin, exprlist)
	}
	putfooter(w, r)
}
Exemplo n.º 3
0
//  lpxc -- list and parse expressions for comparison, returning augtree list
func lpxc(w http.ResponseWriter, exprlist []string) []rx.Node {
	treelist := make([]rx.Node, 0)

	for i, s := range exprlist {
		fmt.Fprintf(w,
			"<SPAN class=%s><BR><B>%c:</B> &nbsp; %s</SPAN>\n",
			colorname(i), rx.AcceptLabels[i], hx(s))
		tree, err := rx.Parse(s)
		if !showerror(w, err) {
			treelist = append(treelist, rx.Augment(tree, i))
		}
	}
	return treelist
}
Exemplo n.º 4
0
//  draw produces a Dot file for rendering a DFA or NFA in the user's browser.
func draw(w http.ResponseWriter, r *http.Request, which string) {

	exprlist := getexprs(r) // must load data before writing anything
	nx := len(exprlist)

	putheader(w, r, which+" Graph") // write page header
	fmt.Fprintln(w, "<P class=xleading>")

	treelist := make([]rx.Node, 0)
	for i, e := range exprlist {
		if nx > 1 {
			fmt.Fprintf(w, "%c. &nbsp; ", rx.AcceptLabels[i])
		}
		fmt.Fprintf(w, "%s<BR>\n", hx(e))
		tree, err := rx.Parse(e)
		if !showerror(w, err) {
			treelist = append(treelist, rx.Augment(tree, i))
		}
	}

	if nx > 0 && len(treelist) == nx { // if no errors
		dfa := rx.MultiDFA(treelist) // build combined DFA
		dmin := dfa.Minimize()       // minimize it

		fmt.Fprintln(w, `<script type="text/vnd.graphviz" id="graph">`)
		if which == "NFA" {
			dmin.GraphNFA(w, "")
		} else if nx == 1 {
			dmin.ToDot(w, "", "")
		} else {
			which = "Multi"
			dmin.ToDot(w, "", rx.AcceptLabels)
		}
		fmt.Fprintln(w, `</script>`)

		tDraw.Execute(w, which)
	}
	putfooter(w, r)
}
Exemplo n.º 5
0
// refexamine advertises the Examine page
func refexamine(w http.ResponseWriter) {
	fmt.Fprint(w, `
<P> On the <A HREF="/examine">Examine</A> page you can enter
a regular expression to generate several kinds of data:
parse trees, synthetic examples, and the automata state lists.
Links from there produce diagrams of either the
<A HREF="http://en.wikipedia.org/wiki/Nondeterministic_finite_automaton">NFA</A>
or
<A HREF="http://en.wikipedia.org/wiki/Deterministic_finite_automaton">DFA</A>
for the language.
`)
	tree, _ := rx.Parse(HomeExample)
	augt := rx.Augment(tree, 0)
	fmt.Fprintf(w, `
<DIV CLASS=inblock>Regular Expression: %s
<BR>Augmented Parse Tree: %s
<BR class=xleading>Examples:<BR>`, hx(HomeExample), hx(augt))
	genexamples(w, augt, 0)
	genexamples(w, augt, 2)
	genexamples(w, augt, 4)
	fmt.Fprintln(w, `<DIV class="rside smaller">`)
	genexam(w, "submit this example to see full output", HomeExample)
	fmt.Fprintln(w, `</DIV></DIV>`)
}