func (g *nfa) ToDot(w io.Writer) {
tw := tabwriter.NewWriter(w, 4, 8, 1, '\t', 0)
w.Write([]byte("digraph {\n"))
for i, _ := range g.Nodes {
fmt.Fprintf(tw,
"\tn%d\t[label=\"%d\"",
i, i)
if i == g.Start {
fmt.Fprintf(tw, ",style=solid,fillcolor=green")
}
if _, ok := g.Accepting[i]; ok {
fmt.Fprintf(tw, ",color=red")
}
fmt.Fprintf(tw, "];\n")
}
for i, node := range g.Nodes {
for label, to_list := range node.Nodes {
for _, to := range to_list {
fmt.Fprintf(tw, "\tn%d -> n%d\t[label=%#v];\n",
i, to, strconv.Quote(string(byte(label))))
}
}
for _, to := range node.Epsilons {
fmt.Fprintf(tw, "\tn%d -> n%d\t[label=\"eps\"];\n", i, to)
}
}
tw.Flush()
fmt.Fprintf(w, "}\n")
}
// fprint implements Fprint and takes a nodesSizes map for setting up the printer state.
func (cfg *Config) fprint(output io.Writer, fset *token.FileSet, node interface{}, nodeSizes map[ast.Node]int) (written int, err error) {
// redirect output through a trimmer to eliminate trailing whitespace
// (Input to a tabwriter must be untrimmed since trailing tabs provide
// formatting information. The tabwriter could provide trimming
// functionality but no tabwriter is used when RawFormat is set.)
output = &trimmer{output: output}
// setup tabwriter if needed and redirect output
var tw *tabwriter.Writer
if cfg.Mode&RawFormat == 0 {
minwidth := cfg.Tabwidth
padchar := byte('\t')
if cfg.Mode&UseSpaces != 0 {
padchar = ' '
}
twmode := tabwriter.DiscardEmptyColumns
if cfg.Mode&TabIndent != 0 {
minwidth = 0
twmode |= tabwriter.TabIndent
}
tw = tabwriter.NewWriter(output, minwidth, cfg.Tabwidth, 1, padchar, twmode)
output = tw
}
// setup printer
var p printer
p.init(output, cfg, fset, nodeSizes)
defer func() {
written = p.written
if e := recover(); e != nil {
err = e.(osError).err // re-panics if it's not a local osError
}
}()
// print node
switch n := node.(type) {
case ast.Expr:
p.useNodeComments = true
p.expr(n, ignoreMultiLine)
case ast.Stmt:
p.useNodeComments = true
// A labeled statement will un-indent to position the
// label. Set indent to 1 so we don't get indent "underflow".
if _, labeledStmt := n.(*ast.LabeledStmt); labeledStmt {
p.indent = 1
}
p.stmt(n, false, ignoreMultiLine)
case ast.Decl:
p.useNodeComments = true
p.decl(n, ignoreMultiLine)
case ast.Spec:
p.useNodeComments = true
p.spec(n, 1, false, ignoreMultiLine)
case *ast.File:
p.comments = n.Comments
p.useNodeComments = n.Comments == nil
p.file(n)
default:
panic(osError{fmt.Errorf("printer.Fprint: unsupported node type %T", n)})
}
p.flush(token.Position{Offset: infinity, Line: infinity}, token.EOF)
// flush tabwriter, if any
if tw != nil {
tw.Flush() // ignore errors
}
return
}
// Fprint "pretty-prints" an AST node to output and returns the number
// of bytes written and an error (if any) for a given configuration cfg.
// Position information is interpreted relative to the file set fset.
// The node type must be *ast.File, or assignment-compatible to ast.Expr,
// ast.Decl, ast.Spec, or ast.Stmt.
//
func (cfg *Config) Fprint(output io.Writer, fset *token.FileSet, node interface{}) (int, os.Error) {
// redirect output through a trimmer to eliminate trailing whitespace
// (Input to a tabwriter must be untrimmed since trailing tabs provide
// formatting information. The tabwriter could provide trimming
// functionality but no tabwriter is used when RawFormat is set.)
output = &trimmer{output: output}
// setup tabwriter if needed and redirect output
var tw *tabwriter.Writer
if cfg.Mode&RawFormat == 0 {
minwidth := cfg.Tabwidth
padchar := byte('\t')
if cfg.Mode&UseSpaces != 0 {
padchar = ' '
}
twmode := tabwriter.DiscardEmptyColumns
if cfg.Mode&TabIndent != 0 {
minwidth = 0
twmode |= tabwriter.TabIndent
}
tw = tabwriter.NewWriter(output, minwidth, cfg.Tabwidth, 1, padchar, twmode)
output = tw
}
// setup printer and print node
var p printer
p.init(output, cfg, fset)
go func() {
switch n := node.(type) {
case ast.Expr:
p.nesting = 1
p.useNodeComments = true
p.expr(n, ignoreMultiLine)
case ast.Stmt:
p.nesting = 1
p.useNodeComments = true
// A labeled statement will un-indent to position the
// label. Set indent to 1 so we don't get indent "underflow".
if _, labeledStmt := n.(*ast.LabeledStmt); labeledStmt {
p.indent = 1
}
p.stmt(n, false, ignoreMultiLine)
case ast.Decl:
p.nesting = 1
p.useNodeComments = true
p.decl(n, ignoreMultiLine)
case ast.Spec:
p.nesting = 1
p.useNodeComments = true
p.spec(n, 1, false, ignoreMultiLine)
case *ast.File:
p.nesting = 0
p.comments = n.Comments
p.useNodeComments = n.Comments == nil
p.file(n)
default:
p.errors <- fmt.Errorf("printer.Fprint: unsupported node type %T", n)
runtime.Goexit()
}
p.flush(token.Position{Offset: infinity, Line: infinity}, token.EOF)
p.errors <- nil // no errors
}()
err := <-p.errors // wait for completion of goroutine
// flush tabwriter, if any
if tw != nil {
tw.Flush() // ignore errors
}
return p.written, err
}
func main() {
usage()
tabw := tabwriter.NewWriter(os.Stdout, 1, 8, '\t', 0)
io.Copy(tabw, os.Stdin)
}
// Expand all variables in Vars within the given string. This does
// not assume any prefix or suffix that sets off a variable from the
// rest of the text, so a var of A set to HI expanded into HAPPY will
// become HHIPPY.
func Expand(x string) string {
for k, v := range Vars {
x = strings.Join(strings.Split(x, k), v)
}
return x
}
// Override the way help is displayed (not recommended)
var Help = func() string {
h0 := new(bytes.Buffer)
h := tabwriter.NewWriter(h0, 0, 8, 2, ' ', 0)
if len(opts) > 1 {
fmt.Fprintln(h, "Options:")
}
for _, o := range opts {
fmt.Fprint(h, " ")
if len(o.shortnames) > 0 {
for _, sn := range o.shortnames[0 : len(o.shortnames)-1] {
fmt.Fprintf(h, "-%c, ", sn)
}
fmt.Fprintf(h, "-%c", o.shortnames[len(o.shortnames)-1])
if o.allowsArg != nil {
fmt.Fprintf(h, " %s", *o.allowsArg)
}
}
fmt.Fprintf(h, "\t")