obtained gcc-4.6.4.tar.bz2 from upstream website;upstream

verified gcc-4.6.4.tar.bz2.sig;
imported gcc-4.6.4 source tree from verified upstream tarball.

downloading a git-generated archive based on the 'upstream' tag
should provide you with a source tree that is binary identical
to the one extracted from the above tarball.

if you have obtained the source via the command 'git clone',
however, do note that line-endings of files in your working
directory might differ from line-endings of the respective
files in the upstream repository.

3 files changed, 1468 insertions, 0 deletions

diff --git a/libgo/go/exp/datafmt/datafmt.go b/libgo/go/exp/datafmt/datafmt.go
new file mode 100644
index 000000000..46c412342
--- /dev/null
+++ b/libgo/go/exp/datafmt/datafmt.go
@@ -0,0 +1,731 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*	The datafmt package implements syntax-directed, type-driven formatting
+	of arbitrary data structures. Formatting a data structure consists of
+	two phases: first, a parser reads a format specification and builds a
+	"compiled" format. Then, the format can be applied repeatedly to
+	arbitrary values. Applying a format to a value evaluates to a []byte
+	containing the formatted value bytes, or nil.
+
+	A format specification is a set of package declarations and format rules:
+
+		Format      = [ Entry { ";" Entry } [ ";" ] ] .
+		Entry       = PackageDecl | FormatRule .
+
+	(The syntax of a format specification is presented in the same EBNF
+	notation as used in the Go language specification. The syntax of white
+	space, comments, identifiers, and string literals is the same as in Go.)
+
+	A package declaration binds a package name (such as 'ast') to a
+	package import path (such as '"go/ast"'). Each package used (in
+	a type name, see below) must be declared once before use.
+
+		PackageDecl = PackageName ImportPath .
+		PackageName = identifier .
+		ImportPath  = string .
+
+	A format rule binds a rule name to a format expression. A rule name
+	may be a type name or one of the special names 'default' or '/'.
+	A type name may be the name of a predeclared type (for example, 'int',
+	'float32', etc.), the package-qualified name of a user-defined type
+	(for example, 'ast.MapType'), or an identifier indicating the structure
+	of unnamed composite types ('array', 'chan', 'func', 'interface', 'map',
+	or 'ptr'). Each rule must have a unique name; rules can be declared in
+	any order.
+
+		FormatRule  = RuleName "=" Expression .
+		RuleName    = TypeName | "default" | "/" .
+		TypeName    = [ PackageName "." ] identifier .
+
+	To format a value, the value's type name is used to select the format rule
+	(there is an override mechanism, see below). The format expression of the
+	selected rule specifies how the value is formatted. Each format expression,
+	when applied to a value, evaluates to a byte sequence or nil.
+
+	In its most general form, a format expression is a list of alternatives,
+	each of which is a sequence of operands:
+
+		Expression  = [ Sequence ] { "|" [ Sequence ] } .
+		Sequence    = Operand { Operand } .
+
+	The formatted result produced by an expression is the result of the first
+	alternative sequence that evaluates to a non-nil result; if there is no
+	such alternative, the expression evaluates to nil. The result produced by
+	an operand sequence is the concatenation of the results of its operands.
+	If any operand in the sequence evaluates to nil, the entire sequence
+	evaluates to nil.
+
+	There are five kinds of operands:
+
+		Operand     = Literal | Field | Group | Option | Repetition .
+
+	Literals evaluate to themselves, with two substitutions. First,
+	%-formats expand in the manner of fmt.Printf, with the current value
+	passed as the parameter. Second, the current indentation (see below)
+	is inserted after every newline or form feed character.
+
+		Literal     = string .
+
+	This table shows string literals applied to the value 42 and the
+	corresponding formatted result:
+
+		"foo"       foo
+		"%x"        2a
+		"x = %d"    x = 42
+		"%#x = %d"  0x2a = 42
+
+	A field operand is a field name optionally followed by an alternate
+	rule name. The field name may be an identifier or one of the special
+	names @ or *.
+
+		Field       = FieldName [ ":" RuleName ] .
+		FieldName   = identifier | "@" | "*" .
+
+	If the field name is an identifier, the current value must be a struct,
+	and there must be a field with that name in the struct. The same lookup
+	rules apply as in the Go language (for instance, the name of an anonymous
+	field is the unqualified type name). The field name denotes the field
+	value in the struct. If the field is not found, formatting is aborted
+	and an error message is returned. (TODO consider changing the semantics
+	such that if a field is not found, it evaluates to nil).
+
+	The special name '@' denotes the current value.
+
+	The meaning of the special name '*' depends on the type of the current
+	value:
+
+		array, slice types   array, slice element (inside {} only, see below)
+		interfaces           value stored in interface
+		pointers             value pointed to by pointer
+
+	(Implementation restriction: channel, function and map types are not
+	supported due to missing reflection support).
+
+	Fields are evaluated as follows: If the field value is nil, or an array
+	or slice element does not exist, the result is nil (see below for details
+	on array/slice elements). If the value is not nil the field value is
+	formatted (recursively) using the rule corresponding to its type name,
+	or the alternate rule name, if given.
+
+	The following example shows a complete format specification for a
+	struct 'myPackage.Point'. Assume the package
+
+		package myPackage  // in directory myDir/myPackage
+		type Point struct {
+			name string;
+			x, y int;
+		}
+
+	Applying the format specification
+
+		myPackage "myDir/myPackage";
+		int = "%d";
+		hexInt = "0x%x";
+		string = "---%s---";
+		myPackage.Point = name "{" x ", " y:hexInt "}";
+
+	to the value myPackage.Point{"foo", 3, 15} results in
+
+		---foo---{3, 0xf}
+
+	Finally, an operand may be a grouped, optional, or repeated expression.
+	A grouped expression ("group") groups a more complex expression (body)
+	so that it can be used in place of a single operand:
+
+		Group       = "(" [ Indentation ">>" ] Body ")" .
+		Indentation = Expression .
+		Body        = Expression .
+
+	A group body may be prefixed by an indentation expression followed by '>>'.
+	The indentation expression is applied to the current value like any other
+	expression and the result, if not nil, is appended to the current indentation
+	during the evaluation of the body (see also formatting state, below).
+
+	An optional expression ("option") is enclosed in '[]' brackets.
+
+		Option      = "[" Body "]" .
+
+	An option evaluates to its body, except that if the body evaluates to nil,
+	the option expression evaluates to an empty []byte. Thus an option's purpose
+	is to protect the expression containing the option from a nil operand.
+
+	A repeated expression ("repetition") is enclosed in '{}' braces.
+
+		Repetition  = "{" Body [ "/" Separator ] "}" .
+		Separator   = Expression .
+
+	A repeated expression is evaluated as follows: The body is evaluated
+	repeatedly and its results are concatenated until the body evaluates
+	to nil. The result of the repetition is the (possibly empty) concatenation,
+	but it is never nil. An implicit index is supplied for the evaluation of
+	the body: that index is used to address elements of arrays or slices. If
+	the corresponding elements do not exist, the field denoting the element
+	evaluates to nil (which in turn may terminate the repetition).
+
+	The body of a repetition may be followed by a '/' and a "separator"
+	expression. If the separator is present, it is invoked between repetitions
+	of the body.
+
+	The following example shows a complete format specification for formatting
+	a slice of unnamed type. Applying the specification
+
+		int = "%b";
+		array = { * / ", " };  // array is the type name for an unnamed slice
+
+	to the value '[]int{2, 3, 5, 7}' results in
+
+		10, 11, 101, 111
+
+	Default rule: If a format rule named 'default' is present, it is used for
+	formatting a value if no other rule was found. A common default rule is
+
+		default = "%v"
+
+	to provide default formatting for basic types without having to specify
+	a specific rule for each basic type.
+
+	Global separator rule: If a format rule named '/' is present, it is
+	invoked with the current value between literals. If the separator
+	expression evaluates to nil, it is ignored.
+
+	For instance, a global separator rule may be used to punctuate a sequence
+	of values with commas. The rules:
+
+		default = "%v";
+		/ = ", ";
+
+	will format an argument list by printing each one in its default format,
+	separated by a comma and a space.
+*/
+package datafmt
+
+import (
+	"bytes"
+	"fmt"
+	"go/token"
+	"io"
+	"os"
+	"reflect"
+	"runtime"
+)
+
+
+// ----------------------------------------------------------------------------
+// Format representation
+
+// Custom formatters implement the Formatter function type.
+// A formatter is invoked with the current formatting state, the
+// value to format, and the rule name under which the formatter
+// was installed (the same formatter function may be installed
+// under different names). The formatter may access the current state
+// to guide formatting and use State.Write to append to the state's
+// output.
+//
+// A formatter must return a boolean value indicating if it evaluated
+// to a non-nil value (true), or a nil value (false).
+//
+type Formatter func(state *State, value interface{}, ruleName string) bool
+
+
+// A FormatterMap is a set of custom formatters.
+// It maps a rule name to a formatter function.
+//
+type FormatterMap map[string]Formatter
+
+
+// A parsed format expression is built from the following nodes.
+//
+type (
+	expr interface{}
+
+	alternatives []expr // x | y | z
+
+	sequence []expr // x y z
+
+	literal [][]byte // a list of string segments, possibly starting with '%'
+
+	field struct {
+		fieldName string // including "@", "*"
+		ruleName  string // "" if no rule name specified
+	}
+
+	group struct {
+		indent, body expr // (indent >> body)
+	}
+
+	option struct {
+		body expr // [body]
+	}
+
+	repetition struct {
+		body, separator expr // {body / separator}
+	}
+
+	custom struct {
+		ruleName string
+		fun      Formatter
+	}
+)
+
+
+// A Format is the result of parsing a format specification.
+// The format may be applied repeatedly to format values.
+//
+type Format map[string]expr
+
+
+// ----------------------------------------------------------------------------
+// Formatting
+
+// An application-specific environment may be provided to Format.Apply;
+// the environment is available inside custom formatters via State.Env().
+// Environments must implement copying; the Copy method must return an
+// complete copy of the receiver. This is necessary so that the formatter
+// can save and restore an environment (in case of an absent expression).
+//
+// If the Environment doesn't change during formatting (this is under
+// control of the custom formatters), the Copy function can simply return
+// the receiver, and thus can be very light-weight.
+//
+type Environment interface {
+	Copy() Environment
+}
+
+
+// State represents the current formatting state.
+// It is provided as argument to custom formatters.
+//
+type State struct {
+	fmt       Format         // format in use
+	env       Environment    // user-supplied environment
+	errors    chan os.Error  // not chan *Error (errors <- nil would be wrong!)
+	hasOutput bool           // true after the first literal has been written
+	indent    bytes.Buffer   // current indentation
+	output    bytes.Buffer   // format output
+	linePos   token.Position // position of line beginning (Column == 0)
+	default_  expr           // possibly nil
+	separator expr           // possibly nil
+}
+
+
+func newState(fmt Format, env Environment, errors chan os.Error) *State {
+	s := new(State)
+	s.fmt = fmt
+	s.env = env
+	s.errors = errors
+	s.linePos = token.Position{Line: 1}
+
+	// if we have a default rule, cache it's expression for fast access
+	if x, found := fmt["default"]; found {
+		s.default_ = x
+	}
+
+	// if we have a global separator rule, cache it's expression for fast access
+	if x, found := fmt["/"]; found {
+		s.separator = x
+	}
+
+	return s
+}
+
+
+// Env returns the environment passed to Format.Apply.
+func (s *State) Env() interface{} { return s.env }
+
+
+// LinePos returns the position of the current line beginning
+// in the state's output buffer. Line numbers start at 1.
+//
+func (s *State) LinePos() token.Position { return s.linePos }
+
+
+// Pos returns the position of the next byte to be written to the
+// output buffer. Line numbers start at 1.
+//
+func (s *State) Pos() token.Position {
+	offs := s.output.Len()
+	return token.Position{Line: s.linePos.Line, Column: offs - s.linePos.Offset, Offset: offs}
+}
+
+
+// Write writes data to the output buffer, inserting the indentation
+// string after each newline or form feed character. It cannot return an error.
+//
+func (s *State) Write(data []byte) (int, os.Error) {
+	n := 0
+	i0 := 0
+	for i, ch := range data {
+		if ch == '\n' || ch == '\f' {
+			// write text segment and indentation
+			n1, _ := s.output.Write(data[i0 : i+1])
+			n2, _ := s.output.Write(s.indent.Bytes())
+			n += n1 + n2
+			i0 = i + 1
+			s.linePos.Offset = s.output.Len()
+			s.linePos.Line++
+		}
+	}
+	n3, _ := s.output.Write(data[i0:])
+	return n + n3, nil
+}
+
+
+type checkpoint struct {
+	env       Environment
+	hasOutput bool
+	outputLen int
+	linePos   token.Position
+}
+
+
+func (s *State) save() checkpoint {
+	saved := checkpoint{nil, s.hasOutput, s.output.Len(), s.linePos}
+	if s.env != nil {
+		saved.env = s.env.Copy()
+	}
+	return saved
+}
+
+
+func (s *State) restore(m checkpoint) {
+	s.env = m.env
+	s.output.Truncate(m.outputLen)
+}
+
+
+func (s *State) error(msg string) {
+	s.errors <- os.NewError(msg)
+	runtime.Goexit()
+}
+
+
+// TODO At the moment, unnamed types are simply mapped to the default
+//      names below. For instance, all unnamed arrays are mapped to
+//      'array' which is not really sufficient. Eventually one may want
+//      to be able to specify rules for say an unnamed slice of T.
+//
+
+func typename(typ reflect.Type) string {
+	switch typ.(type) {
+	case *reflect.ArrayType:
+		return "array"
+	case *reflect.SliceType:
+		return "array"
+	case *reflect.ChanType:
+		return "chan"
+	case *reflect.FuncType:
+		return "func"
+	case *reflect.InterfaceType:
+		return "interface"
+	case *reflect.MapType:
+		return "map"
+	case *reflect.PtrType:
+		return "ptr"
+	}
+	return typ.String()
+}
+
+func (s *State) getFormat(name string) expr {
+	if fexpr, found := s.fmt[name]; found {
+		return fexpr
+	}
+
+	if s.default_ != nil {
+		return s.default_
+	}
+
+	s.error(fmt.Sprintf("no format rule for type: '%s'", name))
+	return nil
+}
+
+
+// eval applies a format expression fexpr to a value. If the expression
+// evaluates internally to a non-nil []byte, that slice is appended to
+// the state's output buffer and eval returns true. Otherwise, eval
+// returns false and the state remains unchanged.
+//
+func (s *State) eval(fexpr expr, value reflect.Value, index int) bool {
+	// an empty format expression always evaluates
+	// to a non-nil (but empty) []byte
+	if fexpr == nil {
+		return true
+	}
+
+	switch t := fexpr.(type) {
+	case alternatives:
+		// append the result of the first alternative that evaluates to
+		// a non-nil []byte to the state's output
+		mark := s.save()
+		for _, x := range t {
+			if s.eval(x, value, index) {
+				return true
+			}
+			s.restore(mark)
+		}
+		return false
+
+	case sequence:
+		// append the result of all operands to the state's output
+		// unless a nil result is encountered
+		mark := s.save()
+		for _, x := range t {
+			if !s.eval(x, value, index) {
+				s.restore(mark)
+				return false
+			}
+		}
+		return true
+
+	case literal:
+		// write separator, if any
+		if s.hasOutput {
+			// not the first literal
+			if s.separator != nil {
+				sep := s.separator // save current separator
+				s.separator = nil  // and disable it (avoid recursion)
+				mark := s.save()
+				if !s.eval(sep, value, index) {
+					s.restore(mark)
+				}
+				s.separator = sep // enable it again
+			}
+		}
+		s.hasOutput = true
+		// write literal segments
+		for _, lit := range t {
+			if len(lit) > 1 && lit[0] == '%' {
+				// segment contains a %-format at the beginning
+				if lit[1] == '%' {
+					// "%%" is printed as a single "%"
+					s.Write(lit[1:])
+				} else {
+					// use s instead of s.output to get indentation right
+					fmt.Fprintf(s, string(lit), value.Interface())
+				}
+			} else {
+				// segment contains no %-formats
+				s.Write(lit)
+			}
+		}
+		return true // a literal never evaluates to nil
+
+	case *field:
+		// determine field value
+		switch t.fieldName {
+		case "@":
+			// field value is current value
+
+		case "*":
+			// indirection: operation is type-specific
+			switch v := value.(type) {
+			case *reflect.ArrayValue:
+				if v.Len() <= index {
+					return false
+				}
+				value = v.Elem(index)
+
+			case *reflect.SliceValue:
+				if v.IsNil() || v.Len() <= index {
+					return false
+				}
+				value = v.Elem(index)
+
+			case *reflect.MapValue:
+				s.error("reflection support for maps incomplete")
+
+			case *reflect.PtrValue:
+				if v.IsNil() {
+					return false
+				}
+				value = v.Elem()
+
+			case *reflect.InterfaceValue:
+				if v.IsNil() {
+					return false
+				}
+				value = v.Elem()
+
+			case *reflect.ChanValue:
+				s.error("reflection support for chans incomplete")
+
+			case *reflect.FuncValue:
+				s.error("reflection support for funcs incomplete")
+
+			default:
+				s.error(fmt.Sprintf("error: * does not apply to `%s`", value.Type()))
+			}
+
+		default:
+			// value is value of named field
+			var field reflect.Value
+			if sval, ok := value.(*reflect.StructValue); ok {
+				field = sval.FieldByName(t.fieldName)
+				if field == nil {
+					// TODO consider just returning false in this case
+					s.error(fmt.Sprintf("error: no field `%s` in `%s`", t.fieldName, value.Type()))
+				}
+			}
+			value = field
+		}
+
+		// determine rule
+		ruleName := t.ruleName
+		if ruleName == "" {
+			// no alternate rule name, value type determines rule
+			ruleName = typename(value.Type())
+		}
+		fexpr = s.getFormat(ruleName)
+
+		mark := s.save()
+		if !s.eval(fexpr, value, index) {
+			s.restore(mark)
+			return false
+		}
+		return true
+
+	case *group:
+		// remember current indentation
+		indentLen := s.indent.Len()
+
+		// update current indentation
+		mark := s.save()
+		s.eval(t.indent, value, index)
+		// if the indentation evaluates to nil, the state's output buffer
+		// didn't change - either way it's ok to append the difference to
+		// the current identation
+		s.indent.Write(s.output.Bytes()[mark.outputLen:s.output.Len()])
+		s.restore(mark)
+
+		// format group body
+		mark = s.save()
+		b := true
+		if !s.eval(t.body, value, index) {
+			s.restore(mark)
+			b = false
+		}
+
+		// reset indentation
+		s.indent.Truncate(indentLen)
+		return b
+
+	case *option:
+		// evaluate the body and append the result to the state's output
+		// buffer unless the result is nil
+		mark := s.save()
+		if !s.eval(t.body, value, 0) { // TODO is 0 index correct?
+			s.restore(mark)
+		}
+		return true // an option never evaluates to nil
+
+	case *repetition:
+		// evaluate the body and append the result to the state's output
+		// buffer until a result is nil
+		for i := 0; ; i++ {
+			mark := s.save()
+			// write separator, if any
+			if i > 0 && t.separator != nil {
+				// nil result from separator is ignored
+				mark := s.save()
+				if !s.eval(t.separator, value, i) {
+					s.restore(mark)
+				}
+			}
+			if !s.eval(t.body, value, i) {
+				s.restore(mark)
+				break
+			}
+		}
+		return true // a repetition never evaluates to nil
+
+	case *custom:
+		// invoke the custom formatter to obtain the result
+		mark := s.save()
+		if !t.fun(s, value.Interface(), t.ruleName) {
+			s.restore(mark)
+			return false
+		}
+		return true
+	}
+
+	panic("unreachable")
+	return false
+}
+
+
+// Eval formats each argument according to the format
+// f and returns the resulting []byte and os.Error. If
+// an error occurred, the []byte contains the partially
+// formatted result. An environment env may be passed
+// in which is available in custom formatters through
+// the state parameter.
+//
+func (f Format) Eval(env Environment, args ...interface{}) ([]byte, os.Error) {
+	if f == nil {
+		return nil, os.NewError("format is nil")
+	}
+
+	errors := make(chan os.Error)
+	s := newState(f, env, errors)
+
+	go func() {
+		for _, v := range args {
+			fld := reflect.NewValue(v)
+			if fld == nil {
+				errors <- os.NewError("nil argument")
+				return
+			}
+			mark := s.save()
+			if !s.eval(s.getFormat(typename(fld.Type())), fld, 0) { // TODO is 0 index correct?
+				s.restore(mark)
+			}
+		}
+		errors <- nil // no errors
+	}()
+
+	err := <-errors
+	return s.output.Bytes(), err
+}
+
+
+// ----------------------------------------------------------------------------
+// Convenience functions
+
+// Fprint formats each argument according to the format f
+// and writes to w. The result is the total number of bytes
+// written and an os.Error, if any.
+//
+func (f Format) Fprint(w io.Writer, env Environment, args ...interface{}) (int, os.Error) {
+	data, err := f.Eval(env, args...)
+	if err != nil {
+		// TODO should we print partial result in case of error?
+		return 0, err
+	}
+	return w.Write(data)
+}
+
+
+// Print formats each argument according to the format f
+// and writes to standard output. The result is the total
+// number of bytes written and an os.Error, if any.
+//
+func (f Format) Print(args ...interface{}) (int, os.Error) {
+	return f.Fprint(os.Stdout, nil, args...)
+}
+
+
+// Sprint formats each argument according to the format f
+// and returns the resulting string. If an error occurs
+// during formatting, the result string contains the
+// partially formatted result followed by an error message.
+//
+func (f Format) Sprint(args ...interface{}) string {
+	var buf bytes.Buffer
+	_, err := f.Fprint(&buf, nil, args...)
+	if err != nil {
+		var i interface{} = args
+		fmt.Fprintf(&buf, "--- Sprint(%s) failed: %v", fmt.Sprint(i), err)
+	}
+	return buf.String()
+}
diff --git a/libgo/go/exp/datafmt/datafmt_test.go b/libgo/go/exp/datafmt/datafmt_test.go
new file mode 100644
index 000000000..d7c70b21d
--- /dev/null
+++ b/libgo/go/exp/datafmt/datafmt_test.go
@@ -0,0 +1,351 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package datafmt
+
+import (
+	"fmt"
+	"testing"
+	"go/token"
+)
+
+
+var fset = token.NewFileSet()
+
+
+func parse(t *testing.T, form string, fmap FormatterMap) Format {
+	f, err := Parse(fset, "", []byte(form), fmap)
+	if err != nil {
+		t.Errorf("Parse(%s): %v", form, err)
+		return nil
+	}
+	return f
+}
+
+
+func verify(t *testing.T, f Format, expected string, args ...interface{}) {
+	if f == nil {
+		return // allow other tests to run
+	}
+	result := f.Sprint(args...)
+	if result != expected {
+		t.Errorf(
+			"result  : `%s`\nexpected: `%s`\n\n",
+			result, expected)
+	}
+}
+
+
+func formatter(s *State, value interface{}, rule_name string) bool {
+	switch rule_name {
+	case "/":
+		fmt.Fprintf(s, "%d %d %d", s.Pos().Line, s.LinePos().Column, s.Pos().Column)
+		return true
+	case "blank":
+		s.Write([]byte{' '})
+		return true
+	case "int":
+		if value.(int)&1 == 0 {
+			fmt.Fprint(s, "even ")
+		} else {
+			fmt.Fprint(s, "odd ")
+		}
+		return true
+	case "nil":
+		return false
+	case "testing.T":
+		s.Write([]byte("testing.T"))
+		return true
+	}
+	panic("unreachable")
+	return false
+}
+
+
+func TestCustomFormatters(t *testing.T) {
+	fmap0 := FormatterMap{"/": formatter}
+	fmap1 := FormatterMap{"int": formatter, "blank": formatter, "nil": formatter}
+	fmap2 := FormatterMap{"testing.T": formatter}
+
+	f := parse(t, `int=`, fmap0)
+	verify(t, f, ``, 1, 2, 3)
+
+	f = parse(t, `int="#"`, nil)
+	verify(t, f, `###`, 1, 2, 3)
+
+	f = parse(t, `int="#";string="%s"`, fmap0)
+	verify(t, f, "#1 0 1#1 0 7#1 0 13\n2 0 0foo2 0 8\n", 1, 2, 3, "\n", "foo", "\n")
+
+	f = parse(t, ``, fmap1)
+	verify(t, f, `even odd even odd `, 0, 1, 2, 3)
+
+	f = parse(t, `/ =@:blank; float64="#"`, fmap1)
+	verify(t, f, `# # #`, 0.0, 1.0, 2.0)
+
+	f = parse(t, `float64=@:nil`, fmap1)
+	verify(t, f, ``, 0.0, 1.0, 2.0)
+
+	f = parse(t, `testing "testing"; ptr=*`, fmap2)
+	verify(t, f, `testing.T`, t)
+
+	// TODO needs more tests
+}
+
+
+// ----------------------------------------------------------------------------
+// Formatting of basic and simple composite types
+
+func check(t *testing.T, form, expected string, args ...interface{}) {
+	f := parse(t, form, nil)
+	if f == nil {
+		return // allow other tests to run
+	}
+	result := f.Sprint(args...)
+	if result != expected {
+		t.Errorf(
+			"format  : %s\nresult  : `%s`\nexpected: `%s`\n\n",
+			form, result, expected)
+	}
+}
+
+
+func TestBasicTypes(t *testing.T) {
+	check(t, ``, ``)
+	check(t, `bool=":%v"`, `:true:false`, true, false)
+	check(t, `int="%b %d %o 0x%x"`, `101010 42 52 0x2a`, 42)
+
+	check(t, `int="%"`, `%`, 42)
+	check(t, `int="%%"`, `%`, 42)
+	check(t, `int="**%%**"`, `**%**`, 42)
+	check(t, `int="%%%%%%"`, `%%%`, 42)
+	check(t, `int="%%%d%%"`, `%42%`, 42)
+
+	const i = -42
+	const is = `-42`
+	check(t, `int  ="%d"`, is, i)
+	check(t, `int8 ="%d"`, is, int8(i))
+	check(t, `int16="%d"`, is, int16(i))
+	check(t, `int32="%d"`, is, int32(i))
+	check(t, `int64="%d"`, is, int64(i))
+
+	const u = 42
+	const us = `42`
+	check(t, `uint  ="%d"`, us, uint(u))
+	check(t, `uint8 ="%d"`, us, uint8(u))
+	check(t, `uint16="%d"`, us, uint16(u))
+	check(t, `uint32="%d"`, us, uint32(u))
+	check(t, `uint64="%d"`, us, uint64(u))
+
+	const f = 3.141592
+	const fs = `3.141592`
+	check(t, `float64="%g"`, fs, f)
+	check(t, `float32="%g"`, fs, float32(f))
+	check(t, `float64="%g"`, fs, float64(f))
+}
+
+
+func TestArrayTypes(t *testing.T) {
+	var a0 [10]int
+	check(t, `array="array";`, `array`, a0)
+
+	a1 := [...]int{1, 2, 3}
+	check(t, `array="array";`, `array`, a1)
+	check(t, `array={*}; int="%d";`, `123`, a1)
+	check(t, `array={* / ", "}; int="%d";`, `1, 2, 3`, a1)
+	check(t, `array={* / *}; int="%d";`, `12233`, a1)
+
+	a2 := []interface{}{42, "foo", 3.14}
+	check(t, `array={* / ", "}; interface=*; string="bar"; default="%v";`, `42, bar, 3.14`, a2)
+}
+
+
+func TestChanTypes(t *testing.T) {
+	var c0 chan int
+	check(t, `chan="chan"`, `chan`, c0)
+
+	c1 := make(chan int)
+	go func() { c1 <- 42 }()
+	check(t, `chan="chan"`, `chan`, c1)
+	// check(t, `chan=*`, `42`, c1);  // reflection support for chans incomplete
+}
+
+
+func TestFuncTypes(t *testing.T) {
+	var f0 func() int
+	check(t, `func="func"`, `func`, f0)
+
+	f1 := func() int { return 42 }
+	check(t, `func="func"`, `func`, f1)
+	// check(t, `func=*`, `42`, f1);  // reflection support for funcs incomplete
+}
+
+
+func TestMapTypes(t *testing.T) {
+	var m0 map[string]int
+	check(t, `map="map"`, `map`, m0)
+
+	m1 := map[string]int{}
+	check(t, `map="map"`, `map`, m1)
+	// check(t, `map=*`, ``, m1);  // reflection support for maps incomplete
+}
+
+
+func TestPointerTypes(t *testing.T) {
+	var p0 *int
+	check(t, `ptr="ptr"`, `ptr`, p0)
+	check(t, `ptr=*`, ``, p0)
+	check(t, `ptr=*|"nil"`, `nil`, p0)
+
+	x := 99991
+	p1 := &x
+	check(t, `ptr="ptr"`, `ptr`, p1)
+	check(t, `ptr=*; int="%d"`, `99991`, p1)
+}
+
+
+func TestDefaultRule(t *testing.T) {
+	check(t, `default="%v"`, `42foo3.14`, 42, "foo", 3.14)
+	check(t, `default="%v"; int="%x"`, `abcdef`, 10, 11, 12, 13, 14, 15)
+	check(t, `default="%v"; int="%x"`, `ab**ef`, 10, 11, "**", 14, 15)
+	check(t, `default="%x"; int=@:default`, `abcdef`, 10, 11, 12, 13, 14, 15)
+}
+
+
+func TestGlobalSeparatorRule(t *testing.T) {
+	check(t, `int="%d"; / ="-"`, `1-2-3-4`, 1, 2, 3, 4)
+	check(t, `int="%x%x"; / ="*"`, `aa*aa`, 10, 10)
+}
+
+
+// ----------------------------------------------------------------------------
+// Formatting of a struct
+
+type T1 struct {
+	a int
+}
+
+const F1 = `datafmt "datafmt";` +
+	`int = "%d";` +
+	`datafmt.T1 = "<" a ">";`
+
+func TestStruct1(t *testing.T) { check(t, F1, "<42>", T1{42}) }
+
+
+// ----------------------------------------------------------------------------
+// Formatting of a struct with an optional field (ptr)
+
+type T2 struct {
+	s string
+	p *T1
+}
+
+const F2a = F1 +
+	`string = "%s";` +
+	`ptr = *;` +
+	`datafmt.T2 = s ["-" p "-"];`
+
+const F2b = F1 +
+	`string = "%s";` +
+	`ptr = *;` +
+	`datafmt.T2 = s ("-" p "-" | "empty");`
+
+func TestStruct2(t *testing.T) {
+	check(t, F2a, "foo", T2{"foo", nil})
+	check(t, F2a, "bar-<17>-", T2{"bar", &T1{17}})
+	check(t, F2b, "fooempty", T2{"foo", nil})
+}
+
+
+// ----------------------------------------------------------------------------
+// Formatting of a struct with a repetitive field (slice)
+
+type T3 struct {
+	s string
+	a []int
+}
+
+const F3a = `datafmt "datafmt";` +
+	`default = "%v";` +
+	`array = *;` +
+	`datafmt.T3 = s  {" " a a / ","};`
+
+const F3b = `datafmt "datafmt";` +
+	`int = "%d";` +
+	`string = "%s";` +
+	`array = *;` +
+	`nil = ;` +
+	`empty = *:nil;` +
+	`datafmt.T3 = s [a:empty ": " {a / "-"}]`
+
+func TestStruct3(t *testing.T) {
+	check(t, F3a, "foo", T3{"foo", nil})
+	check(t, F3a, "foo 00, 11, 22", T3{"foo", []int{0, 1, 2}})
+	check(t, F3b, "bar", T3{"bar", nil})
+	check(t, F3b, "bal: 2-3-5", T3{"bal", []int{2, 3, 5}})
+}
+
+
+// ----------------------------------------------------------------------------
+// Formatting of a struct with alternative field
+
+type T4 struct {
+	x *int
+	a []int
+}
+
+const F4a = `datafmt "datafmt";` +
+	`int = "%d";` +
+	`ptr = *;` +
+	`array = *;` +
+	`nil = ;` +
+	`empty = *:nil;` +
+	`datafmt.T4 = "<" (x:empty x | "-") ">" `
+
+const F4b = `datafmt "datafmt";` +
+	`int = "%d";` +
+	`ptr = *;` +
+	`array = *;` +
+	`nil = ;` +
+	`empty = *:nil;` +
+	`datafmt.T4 = "<" (a:empty {a / ", "} | "-") ">" `
+
+func TestStruct4(t *testing.T) {
+	x := 7
+	check(t, F4a, "<->", T4{nil, nil})
+	check(t, F4a, "<7>", T4{&x, nil})
+	check(t, F4b, "<->", T4{nil, nil})
+	check(t, F4b, "<2, 3, 7>", T4{nil, []int{2, 3, 7}})
+}
+
+
+// ----------------------------------------------------------------------------
+// Formatting a struct (documentation example)
+
+type Point struct {
+	name string
+	x, y int
+}
+
+const FPoint = `datafmt "datafmt";` +
+	`int = "%d";` +
+	`hexInt = "0x%x";` +
+	`string = "---%s---";` +
+	`datafmt.Point = name "{" x ", " y:hexInt "}";`
+
+func TestStructPoint(t *testing.T) {
+	p := Point{"foo", 3, 15}
+	check(t, FPoint, "---foo---{3, 0xf}", p)
+}
+
+
+// ----------------------------------------------------------------------------
+// Formatting a slice (documentation example)
+
+const FSlice = `int = "%b";` +
+	`array = { * / ", " }`
+
+func TestSlice(t *testing.T) { check(t, FSlice, "10, 11, 101, 111", []int{2, 3, 5, 7}) }
+
+
+// TODO add more tests
diff --git a/libgo/go/exp/datafmt/parser.go b/libgo/go/exp/datafmt/parser.go
new file mode 100644
index 000000000..c6d140264
--- /dev/null
+++ b/libgo/go/exp/datafmt/parser.go
@@ -0,0 +1,386 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package datafmt
+
+import (
+	"container/vector"
+	"go/scanner"
+	"go/token"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// ----------------------------------------------------------------------------
+// Parsing
+
+type parser struct {
+	scanner.ErrorVector
+	scanner scanner.Scanner
+	file    *token.File
+	pos     token.Pos   // token position
+	tok     token.Token // one token look-ahead
+	lit     []byte      // token literal
+
+	packs map[string]string // PackageName -> ImportPath
+	rules map[string]expr   // RuleName -> Expression
+}
+
+
+func (p *parser) next() {
+	p.pos, p.tok, p.lit = p.scanner.Scan()
+	switch p.tok {
+	case token.CHAN, token.FUNC, token.INTERFACE, token.MAP, token.STRUCT:
+		// Go keywords for composite types are type names
+		// returned by reflect. Accept them as identifiers.
+		p.tok = token.IDENT // p.lit is already set correctly
+	}
+}
+
+
+func (p *parser) init(fset *token.FileSet, filename string, src []byte) {
+	p.ErrorVector.Reset()
+	p.file = fset.AddFile(filename, fset.Base(), len(src))
+	p.scanner.Init(p.file, src, p, scanner.AllowIllegalChars) // return '@' as token.ILLEGAL w/o error message
+	p.next()                                                  // initializes pos, tok, lit
+	p.packs = make(map[string]string)
+	p.rules = make(map[string]expr)
+}
+
+
+func (p *parser) error(pos token.Pos, msg string) {
+	p.Error(p.file.Position(pos), msg)
+}
+
+
+func (p *parser) errorExpected(pos token.Pos, msg string) {
+	msg = "expected " + msg
+	if pos == p.pos {
+		// the error happened at the current position;
+		// make the error message more specific
+		msg += ", found '" + p.tok.String() + "'"
+		if p.tok.IsLiteral() {
+			msg += " " + string(p.lit)
+		}
+	}
+	p.error(pos, msg)
+}
+
+
+func (p *parser) expect(tok token.Token) token.Pos {
+	pos := p.pos
+	if p.tok != tok {
+		p.errorExpected(pos, "'"+tok.String()+"'")
+	}
+	p.next() // make progress in any case
+	return pos
+}
+
+
+func (p *parser) parseIdentifier() string {
+	name := string(p.lit)
+	p.expect(token.IDENT)
+	return name
+}
+
+
+func (p *parser) parseTypeName() (string, bool) {
+	pos := p.pos
+	name, isIdent := p.parseIdentifier(), true
+	if p.tok == token.PERIOD {
+		// got a package name, lookup package
+		if importPath, found := p.packs[name]; found {
+			name = importPath
+		} else {
+			p.error(pos, "package not declared: "+name)
+		}
+		p.next()
+		name, isIdent = name+"."+p.parseIdentifier(), false
+	}
+	return name, isIdent
+}
+
+
+// Parses a rule name and returns it. If the rule name is
+// a package-qualified type name, the package name is resolved.
+// The 2nd result value is true iff the rule name consists of a
+// single identifier only (and thus could be a package name).
+//
+func (p *parser) parseRuleName() (string, bool) {
+	name, isIdent := "", false
+	switch p.tok {
+	case token.IDENT:
+		name, isIdent = p.parseTypeName()
+	case token.DEFAULT:
+		name = "default"
+		p.next()
+	case token.QUO:
+		name = "/"
+		p.next()
+	default:
+		p.errorExpected(p.pos, "rule name")
+		p.next() // make progress in any case
+	}
+	return name, isIdent
+}
+
+
+func (p *parser) parseString() string {
+	s := ""
+	if p.tok == token.STRING {
+		s, _ = strconv.Unquote(string(p.lit))
+		// Unquote may fail with an error, but only if the scanner found
+		// an illegal string in the first place. In this case the error
+		// has already been reported.
+		p.next()
+		return s
+	} else {
+		p.expect(token.STRING)
+	}
+	return s
+}
+
+
+func (p *parser) parseLiteral() literal {
+	s := []byte(p.parseString())
+
+	// A string literal may contain %-format specifiers. To simplify
+	// and speed up printing of the literal, split it into segments
+	// that start with "%" possibly followed by a last segment that
+	// starts with some other character.
+	var list vector.Vector
+	i0 := 0
+	for i := 0; i < len(s); i++ {
+		if s[i] == '%' && i+1 < len(s) {
+			// the next segment starts with a % format
+			if i0 < i {
+				// the current segment is not empty, split it off
+				list.Push(s[i0:i])
+				i0 = i
+			}
+			i++ // skip %; let loop skip over char after %
+		}
+	}
+	// the final segment may start with any character
+	// (it is empty iff the string is empty)
+	list.Push(s[i0:])
+
+	// convert list into a literal
+	lit := make(literal, list.Len())
+	for i := 0; i < list.Len(); i++ {
+		lit[i] = list.At(i).([]byte)
+	}
+
+	return lit
+}
+
+
+func (p *parser) parseField() expr {
+	var fname string
+	switch p.tok {
+	case token.ILLEGAL:
+		if string(p.lit) != "@" {
+			return nil
+		}
+		fname = "@"
+		p.next()
+	case token.MUL:
+		fname = "*"
+		p.next()
+	case token.IDENT:
+		fname = p.parseIdentifier()
+	default:
+		return nil
+	}
+
+	var ruleName string
+	if p.tok == token.COLON {
+		p.next()
+		ruleName, _ = p.parseRuleName()
+	}
+
+	return &field{fname, ruleName}
+}
+
+
+func (p *parser) parseOperand() (x expr) {
+	switch p.tok {
+	case token.STRING:
+		x = p.parseLiteral()
+
+	case token.LPAREN:
+		p.next()
+		x = p.parseExpression()
+		if p.tok == token.SHR {
+			p.next()
+			x = &group{x, p.parseExpression()}
+		}
+		p.expect(token.RPAREN)
+
+	case token.LBRACK:
+		p.next()
+		x = &option{p.parseExpression()}
+		p.expect(token.RBRACK)
+
+	case token.LBRACE:
+		p.next()
+		x = p.parseExpression()
+		var div expr
+		if p.tok == token.QUO {
+			p.next()
+			div = p.parseExpression()
+		}
+		x = &repetition{x, div}
+		p.expect(token.RBRACE)
+
+	default:
+		x = p.parseField() // may be nil
+	}
+
+	return x
+}
+
+
+func (p *parser) parseSequence() expr {
+	var list vector.Vector
+
+	for x := p.parseOperand(); x != nil; x = p.parseOperand() {
+		list.Push(x)
+	}
+
+	// no need for a sequence if list.Len() < 2
+	switch list.Len() {
+	case 0:
+		return nil
+	case 1:
+		return list.At(0).(expr)
+	}
+
+	// convert list into a sequence
+	seq := make(sequence, list.Len())
+	for i := 0; i < list.Len(); i++ {
+		seq[i] = list.At(i).(expr)
+	}
+	return seq
+}
+
+
+func (p *parser) parseExpression() expr {
+	var list vector.Vector
+
+	for {
+		x := p.parseSequence()
+		if x != nil {
+			list.Push(x)
+		}
+		if p.tok != token.OR {
+			break
+		}
+		p.next()
+	}
+
+	// no need for an alternatives if list.Len() < 2
+	switch list.Len() {
+	case 0:
+		return nil
+	case 1:
+		return list.At(0).(expr)
+	}
+
+	// convert list into a alternatives
+	alt := make(alternatives, list.Len())
+	for i := 0; i < list.Len(); i++ {
+		alt[i] = list.At(i).(expr)
+	}
+	return alt
+}
+
+
+func (p *parser) parseFormat() {
+	for p.tok != token.EOF {
+		pos := p.pos
+
+		name, isIdent := p.parseRuleName()
+		switch p.tok {
+		case token.STRING:
+			// package declaration
+			importPath := p.parseString()
+
+			// add package declaration
+			if !isIdent {
+				p.error(pos, "illegal package name: "+name)
+			} else if _, found := p.packs[name]; !found {
+				p.packs[name] = importPath
+			} else {
+				p.error(pos, "package already declared: "+name)
+			}
+
+		case token.ASSIGN:
+			// format rule
+			p.next()
+			x := p.parseExpression()
+
+			// add rule
+			if _, found := p.rules[name]; !found {
+				p.rules[name] = x
+			} else {
+				p.error(pos, "format rule already declared: "+name)
+			}
+
+		default:
+			p.errorExpected(p.pos, "package declaration or format rule")
+			p.next() // make progress in any case
+		}
+
+		if p.tok == token.SEMICOLON {
+			p.next()
+		} else {
+			break
+		}
+	}
+	p.expect(token.EOF)
+}
+
+
+func remap(p *parser, name string) string {
+	i := strings.Index(name, ".")
+	if i >= 0 {
+		packageName, suffix := name[0:i], name[i:]
+		// lookup package
+		if importPath, found := p.packs[packageName]; found {
+			name = importPath + suffix
+		} else {
+			var invalidPos token.Position
+			p.Error(invalidPos, "package not declared: "+packageName)
+		}
+	}
+	return name
+}
+
+
+// Parse parses a set of format productions from source src. Custom
+// formatters may be provided via a map of formatter functions. If
+// there are no errors, the result is a Format and the error is nil.
+// Otherwise the format is nil and a non-empty ErrorList is returned.
+//
+func Parse(fset *token.FileSet, filename string, src []byte, fmap FormatterMap) (Format, os.Error) {
+	// parse source
+	var p parser
+	p.init(fset, filename, src)
+	p.parseFormat()
+
+	// add custom formatters, if any
+	for name, form := range fmap {
+		name = remap(&p, name)
+		if _, found := p.rules[name]; !found {
+			p.rules[name] = &custom{name, form}
+		} else {
+			var invalidPos token.Position
+			p.Error(invalidPos, "formatter already declared: "+name)
+		}
+	}
+
+	return p.rules, p.GetError(scanner.NoMultiples)
+}