old/template: copy code from template

First step of moving exp/template into template: save the old code.
Code is unedited except for target name in Makefile.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/4893042

src/pkg/old/template/Makefile

+# 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.
+
+include ../../Make.inc
+
+TARG=old/template
+GOFILES=\
+	doc.go\
+	execute.go\
+	format.go\
+	parse.go\
+
+include ../../Make.pkg

src/pkg/old/template/doc.go

+// 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 template implements data-driven templates for generating textual
+	output such as HTML.
+
+	Templates are executed by applying them to a data structure.
+	Annotations in the template refer to elements of the data
+	structure (typically a field of a struct or a key in a map)
+	to control execution and derive values to be displayed.
+	The template walks the structure as it executes and the
+	"cursor" @ represents the value at the current location
+	in the structure.
+
+	Data items may be values or pointers; the interface hides the
+	indirection.
+
+	In the following, 'Field' is one of several things, according to the data.
+
+		- The name of a field of a struct (result = data.Field),
+		- The value stored in a map under that key (result = data["Field"]), or
+		- The result of invoking a niladic single-valued method with that name
+		  (result = data.Field())
+
+	If Field is a struct field or method name, it must be an exported
+	(capitalized) name.
+
+	Major constructs ({} are the default delimiters for template actions;
+	[] are the notation in this comment for optional elements):
+
+		{# comment }
+
+	A one-line comment.
+
+		{.section field} XXX [ {.or} YYY ] {.end}
+
+	Set @ to the value of the field.  It may be an explicit @
+	to stay at the same point in the data. If the field is nil
+	or empty, execute YYY; otherwise execute XXX.
+
+		{.repeated section field} XXX [ {.alternates with} ZZZ ] [ {.or} YYY ] {.end}
+
+	Like .section, but field must be an array or slice.  XXX
+	is executed for each element.  If the array is nil or empty,
+	YYY is executed instead.  If the {.alternates with} marker
+	is present, ZZZ is executed between iterations of XXX.
+
+		{field}
+		{field1 field2 ...}
+		{field|formatter}
+		{field1 field2...|formatter}
+		{field|formatter1|formatter2}
+
+	Insert the value of the fields into the output. Each field is
+	first looked for in the cursor, as in .section and .repeated.
+	If it is not found, the search continues in outer sections
+	until the top level is reached.
+
+	If the field value is a pointer, leading asterisks indicate
+	that the value to be inserted should be evaluated through the
+	pointer.  For example, if x.p is of type *int, {x.p} will
+	insert the value of the pointer but {*x.p} will insert the
+	value of the underlying integer.  If the value is nil or not a
+	pointer, asterisks have no effect.
+
+	If a formatter is specified, it must be named in the formatter
+	map passed to the template set up routines or in the default
+	set ("html","str","") and is used to process the data for
+	output.  The formatter function has signature
+		func(wr io.Writer, formatter string, data ...interface{})
+	where wr is the destination for output, data holds the field
+	values at the instantiation, and formatter is its name at
+	the invocation site.  The default formatter just concatenates
+	the string representations of the fields.
+
+	Multiple formatters separated by the pipeline character | are
+	executed sequentially, with each formatter receiving the bytes
+	emitted by the one to its left.
+
+	As well as field names, one may use literals with Go syntax.
+	Integer, floating-point, and string literals are supported.
+	Raw strings may not span newlines.
+
+	The delimiter strings get their default value, "{" and "}", from
+	JSON-template.  They may be set to any non-empty, space-free
+	string using the SetDelims method.  Their value can be printed
+	in the output using {.meta-left} and {.meta-right}.
+*/
+package template

src/pkg/old/template/execute.go

+// 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.
+
+// Code to execute a parsed template.
+
+package template
+
+import (
+	"bytes"
+	"io"
+	"reflect"
+	"strings"
+)
+
+// Internal state for executing a Template.  As we evaluate the struct,
+// the data item descends into the fields associated with sections, etc.
+// Parent is used to walk upwards to find variables higher in the tree.
+type state struct {
+	parent *state          // parent in hierarchy
+	data   reflect.Value   // the driver data for this section etc.
+	wr     io.Writer       // where to send output
+	buf    [2]bytes.Buffer // alternating buffers used when chaining formatters
+}
+
+func (parent *state) clone(data reflect.Value) *state {
+	return &state{parent: parent, data: data, wr: parent.wr}
+}
+
+// Evaluate interfaces and pointers looking for a value that can look up the name, via a
+// struct field, method, or map key, and return the result of the lookup.
+func (t *Template) lookup(st *state, v reflect.Value, name string) reflect.Value {
+	for v.IsValid() {
+		typ := v.Type()
+		if n := v.Type().NumMethod(); n > 0 {
+			for i := 0; i < n; i++ {
+				m := typ.Method(i)
+				mtyp := m.Type
+				if m.Name == name && mtyp.NumIn() == 1 && mtyp.NumOut() == 1 {
+					if !isExported(name) {
+						t.execError(st, t.linenum, "name not exported: %s in type %s", name, st.data.Type())
+					}
+					return v.Method(i).Call(nil)[0]
+				}
+			}
+		}
+		switch av := v; av.Kind() {
+		case reflect.Ptr:
+			v = av.Elem()
+		case reflect.Interface:
+			v = av.Elem()
+		case reflect.Struct:
+			if !isExported(name) {
+				t.execError(st, t.linenum, "name not exported: %s in type %s", name, st.data.Type())
+			}
+			return av.FieldByName(name)
+		case reflect.Map:
+			if v := av.MapIndex(reflect.ValueOf(name)); v.IsValid() {
+				return v
+			}
+			return reflect.Zero(typ.Elem())
+		default:
+			return reflect.Value{}
+		}
+	}
+	return v
+}
+
+// indirectPtr returns the item numLevels levels of indirection below the value.
+// It is forgiving: if the value is not a pointer, it returns it rather than giving
+// an error.  If the pointer is nil, it is returned as is.
+func indirectPtr(v reflect.Value, numLevels int) reflect.Value {
+	for i := numLevels; v.IsValid() && i > 0; i++ {
+		if p := v; p.Kind() == reflect.Ptr {
+			if p.IsNil() {
+				return v
+			}
+			v = p.Elem()
+		} else {
+			break
+		}
+	}
+	return v
+}
+
+// Walk v through pointers and interfaces, extracting the elements within.
+func indirect(v reflect.Value) reflect.Value {
+loop:
+	for v.IsValid() {
+		switch av := v; av.Kind() {
+		case reflect.Ptr:
+			v = av.Elem()
+		case reflect.Interface:
+			v = av.Elem()
+		default:
+			break loop
+		}
+	}
+	return v
+}
+
+// If the data for this template is a struct, find the named variable.
+// Names of the form a.b.c are walked down the data tree.
+// The special name "@" (the "cursor") denotes the current data.
+// The value coming in (st.data) might need indirecting to reach
+// a struct while the return value is not indirected - that is,
+// it represents the actual named field. Leading stars indicate
+// levels of indirection to be applied to the value.
+func (t *Template) findVar(st *state, s string) reflect.Value {
+	data := st.data
+	flattenedName := strings.TrimLeft(s, "*")
+	numStars := len(s) - len(flattenedName)
+	s = flattenedName
+	if s == "@" {
+		return indirectPtr(data, numStars)
+	}
+	for _, elem := range strings.Split(s, ".") {
+		// Look up field; data must be a struct or map.
+		data = t.lookup(st, data, elem)
+		if !data.IsValid() {
+			return reflect.Value{}
+		}
+	}
+	return indirectPtr(data, numStars)
+}
+
+// Is there no data to look at?
+func empty(v reflect.Value) bool {
+	v = indirect(v)
+	if !v.IsValid() {
+		return true
+	}
+	switch v.Kind() {
+	case reflect.Bool:
+		return v.Bool() == false
+	case reflect.String:
+		return v.String() == ""
+	case reflect.Struct:
+		return false
+	case reflect.Map:
+		return false
+	case reflect.Array:
+		return v.Len() == 0
+	case reflect.Slice:
+		return v.Len() == 0
+	}
+	return false
+}
+
+// Look up a variable or method, up through the parent if necessary.
+func (t *Template) varValue(name string, st *state) reflect.Value {
+	field := t.findVar(st, name)
+	if !field.IsValid() {
+		if st.parent == nil {
+			t.execError(st, t.linenum, "name not found: %s in type %s", name, st.data.Type())
+		}
+		return t.varValue(name, st.parent)
+	}
+	return field
+}
+
+func (t *Template) format(wr io.Writer, fmt string, val []interface{}, v *variableElement, st *state) {
+	fn := t.formatter(fmt)
+	if fn == nil {
+		t.execError(st, v.linenum, "missing formatter %s for variable", fmt)
+	}
+	fn(wr, fmt, val...)
+}
+
+// Evaluate a variable, looking up through the parent if necessary.
+// If it has a formatter attached ({var|formatter}) run that too.
+func (t *Template) writeVariable(v *variableElement, st *state) {
+	// Resolve field names
+	val := make([]interface{}, len(v.args))
+	for i, arg := range v.args {
+		if name, ok := arg.(fieldName); ok {
+			val[i] = t.varValue(string(name), st).Interface()
+		} else {
+			val[i] = arg
+		}
+	}
+	for i, fmt := range v.fmts[:len(v.fmts)-1] {
+		b := &st.buf[i&1]
+		b.Reset()
+		t.format(b, fmt, val, v, st)
+		val = val[0:1]
+		val[0] = b.Bytes()
+	}
+	t.format(st.wr, v.fmts[len(v.fmts)-1], val, v, st)
+}
+
+// Execute element i.  Return next index to execute.
+func (t *Template) executeElement(i int, st *state) int {
+	switch elem := t.elems[i].(type) {
+	case *textElement:
+		st.wr.Write(elem.text)
+		return i + 1
+	case *literalElement:
+		st.wr.Write(elem.text)
+		return i + 1
+	case *variableElement:
+		t.writeVariable(elem, st)
+		return i + 1
+	case *sectionElement:
+		t.executeSection(elem, st)
+		return elem.end
+	case *repeatedElement:
+		t.executeRepeated(elem, st)
+		return elem.end
+	}
+	e := t.elems[i]
+	t.execError(st, 0, "internal error: bad directive in execute: %v %T\n", reflect.ValueOf(e).Interface(), e)
+	return 0
+}
+
+// Execute the template.
+func (t *Template) execute(start, end int, st *state) {
+	for i := start; i < end; {
+		i = t.executeElement(i, st)
+	}
+}
+
+// Execute a .section
+func (t *Template) executeSection(s *sectionElement, st *state) {
+	// Find driver data for this section.  It must be in the current struct.
+	field := t.varValue(s.field, st)
+	if !field.IsValid() {
+		t.execError(st, s.linenum, ".section: cannot find field %s in %s", s.field, st.data.Type())
+	}
+	st = st.clone(field)
+	start, end := s.start, s.or
+	if !empty(field) {
+		// Execute the normal block.
+		if end < 0 {
+			end = s.end
+		}
+	} else {
+		// Execute the .or block.  If it's missing, do nothing.
+		start, end = s.or, s.end
+		if start < 0 {
+			return
+		}
+	}
+	for i := start; i < end; {
+		i = t.executeElement(i, st)
+	}
+}
+
+// Return the result of calling the Iter method on v, or nil.
+func iter(v reflect.Value) reflect.Value {
+	for j := 0; j < v.Type().NumMethod(); j++ {
+		mth := v.Type().Method(j)
+		fv := v.Method(j)
+		ft := fv.Type()
+		// TODO(rsc): NumIn() should return 0 here, because ft is from a curried FuncValue.
+		if mth.Name != "Iter" || ft.NumIn() != 1 || ft.NumOut() != 1 {
+			continue
+		}
+		ct := ft.Out(0)
+		if ct.Kind() != reflect.Chan ||
+			ct.ChanDir()&reflect.RecvDir == 0 {
+			continue
+		}
+		return fv.Call(nil)[0]
+	}
+	return reflect.Value{}
+}
+
+// Execute a .repeated section
+func (t *Template) executeRepeated(r *repeatedElement, st *state) {
+	// Find driver data for this section.  It must be in the current struct.
+	field := t.varValue(r.field, st)
+	if !field.IsValid() {
+		t.execError(st, r.linenum, ".repeated: cannot find field %s in %s", r.field, st.data.Type())
+	}
+	field = indirect(field)
+
+	start, end := r.start, r.or
+	if end < 0 {
+		end = r.end
+	}
+	if r.altstart >= 0 {
+		end = r.altstart
+	}
+	first := true
+
+	// Code common to all the loops.
+	loopBody := func(newst *state) {
+		// .alternates between elements
+		if !first && r.altstart >= 0 {
+			for i := r.altstart; i < r.altend; {
+				i = t.executeElement(i, newst)
+			}
+		}
+		first = false
+		for i := start; i < end; {
+			i = t.executeElement(i, newst)
+		}
+	}
+
+	if array := field; array.Kind() == reflect.Array || array.Kind() == reflect.Slice {
+		for j := 0; j < array.Len(); j++ {
+			loopBody(st.clone(array.Index(j)))
+		}
+	} else if m := field; m.Kind() == reflect.Map {
+		for _, key := range m.MapKeys() {
+			loopBody(st.clone(m.MapIndex(key)))
+		}
+	} else if ch := iter(field); ch.IsValid() {
+		for {
+			e, ok := ch.Recv()
+			if !ok {
+				break
+			}
+			loopBody(st.clone(e))
+		}
+	} else {
+		t.execError(st, r.linenum, ".repeated: cannot repeat %s (type %s)",
+			r.field, field.Type())
+	}
+
+	if first {
+		// Empty. Execute the .or block, once.  If it's missing, do nothing.
+		start, end := r.or, r.end
+		if start >= 0 {
+			newst := st.clone(field)
+			for i := start; i < end; {
+				i = t.executeElement(i, newst)
+			}
+		}
+		return
+	}
+}
+
+// A valid delimiter must contain no space and be non-empty.
+func validDelim(d []byte) bool {
+	if len(d) == 0 {
+		return false
+	}
+	for _, c := range d {
+		if isSpace(c) {
+			return false
+		}
+	}
+	return true
+}

src/pkg/old/template/format.go

+// 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.
+
+// Template library: default formatters
+
+package template
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+)
+
+// StringFormatter formats into the default string representation.
+// It is stored under the name "str" and is the default formatter.
+// You can override the default formatter by storing your default
+// under the name "" in your custom formatter map.
+func StringFormatter(w io.Writer, format string, value ...interface{}) {
+	if len(value) == 1 {
+		if b, ok := value[0].([]byte); ok {
+			w.Write(b)
+			return
+		}
+	}
+	fmt.Fprint(w, value...)
+}
+
+var (
+	esc_quot = []byte(""") // shorter than """
+	esc_apos = []byte("'") // shorter than "'"
+	esc_amp  = []byte("&")
+	esc_lt   = []byte("<")
+	esc_gt   = []byte(">")
+)
+
+// HTMLEscape writes to w the properly escaped HTML equivalent
+// of the plain text data s.
+func HTMLEscape(w io.Writer, s []byte) {
+	var esc []byte
+	last := 0
+	for i, c := range s {
+		switch c {
+		case '"':
+			esc = esc_quot
+		case '\'':
+			esc = esc_apos
+		case '&':
+			esc = esc_amp
+		case '<':
+			esc = esc_lt
+		case '>':
+			esc = esc_gt
+		default:
+			continue
+		}
+		w.Write(s[last:i])
+		w.Write(esc)
+		last = i + 1
+	}
+	w.Write(s[last:])
+}
+
+// HTMLFormatter formats arbitrary values for HTML
+func HTMLFormatter(w io.Writer, format string, value ...interface{}) {
+	ok := false
+	var b []byte
+	if len(value) == 1 {
+		b, ok = value[0].([]byte)
+	}
+	if !ok {
+		var buf bytes.Buffer
+		fmt.Fprint(&buf, value...)
+		b = buf.Bytes()
+	}
+	HTMLEscape(w, b)
+}

src/pkg/old/template/parse.go

+// 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.
+
+// Code to parse a template.
+
+package template
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"reflect"
+	"strconv"
+	"strings"
+	"unicode"
+	"utf8"
+)
+
+// Errors returned during parsing and execution.  Users may extract the information and reformat
+// if they desire.
+type Error struct {
+	Line int
+	Msg  string
+}
+
+func (e *Error) String() string { return fmt.Sprintf("line %d: %s", e.Line, e.Msg) }
+
+// checkError is a deferred function to turn a panic with type *Error into a plain error return.
+// Other panics are unexpected and so are re-enabled.
+func checkError(error *os.Error) {
+	if v := recover(); v != nil {
+		if e, ok := v.(*Error); ok {
+			*error = e
+		} else {
+			// runtime errors should crash
+			panic(v)
+		}
+	}
+}
+
+// Most of the literals are aces.
+var lbrace = []byte{'{'}
+var rbrace = []byte{'}'}
+var space = []byte{' '}
+var tab = []byte{'\t'}
+
+// The various types of "tokens", which are plain text or (usually) brace-delimited descriptors
+const (
+	tokAlternates = iota
+	tokComment
+	tokEnd
+	tokLiteral
+	tokOr
+	tokRepeated
+	tokSection
+	tokText
+	tokVariable
+)
+
+// FormatterMap is the type describing the mapping from formatter
+// names to the functions that implement them.
+type FormatterMap map[string]func(io.Writer, string, ...interface{})
+
+// Built-in formatters.
+var builtins = FormatterMap{
+	"html": HTMLFormatter,
+	"str":  StringFormatter,
+	"":     StringFormatter,
+}
+
+// The parsed state of a template is a vector of xxxElement structs.
+// Sections have line numbers so errors can be reported better during execution.
+
+// Plain text.
+type textElement struct {
+	text []byte
+}
+
+// A literal such as .meta-left or .meta-right
+type literalElement struct {
+	text []byte
+}
+
+// A variable invocation to be evaluated
+type variableElement struct {
+	linenum int
+	args    []interface{} // The fields and literals in the invocation.
+	fmts    []string      // Names of formatters to apply. len(fmts) > 0
+}
+
+// A variableElement arg to be evaluated as a field name
+type fieldName string
+
+// A .section block, possibly with a .or
+type sectionElement struct {
+	linenum int    // of .section itself
+	field   string // cursor field for this block
+	start   int    // first element
+	or      int    // first element of .or block
+	end     int    // one beyond last element
+}
+
+// A .repeated block, possibly with a .or and a .alternates
+type repeatedElement struct {
+	sectionElement     // It has the same structure...
+	altstart       int // ... except for alternates
+	altend         int
+}
+
+// Template is the type that represents a template definition.
+// It is unchanged after parsing.
+type Template struct {
+	fmap FormatterMap // formatters for variables
+	// Used during parsing:
+	ldelim, rdelim []byte // delimiters; default {}
+	buf            []byte // input text to process
+	p              int    // position in buf
+	linenum        int    // position in input
+	// Parsed results:
+	elems []interface{}
+}
+
+// New creates a new template with the specified formatter map (which
+// may be nil) to define auxiliary functions for formatting variables.
+func New(fmap FormatterMap) *Template {
+	t := new(Template)
+	t.fmap = fmap
+	t.ldelim = lbrace
+	t.rdelim = rbrace
+	t.elems = make([]interface{}, 0, 16)
+	return t
+}
+
+// Report error and stop executing.  The line number must be provided explicitly.
+func (t *Template) execError(st *state, line int, err string, args ...interface{}) {
+	panic(&Error{line, fmt.Sprintf(err, args...)})
+}
+
+// Report error, panic to terminate parsing.
+// The line number comes from the template state.
+func (t *Template) parseError(err string, args ...interface{}) {
+	panic(&Error{t.linenum, fmt.Sprintf(err, args...)})
+}
+
+// Is this an exported - upper case - name?
+func isExported(name string) bool {
+	rune, _ := utf8.DecodeRuneInString(name)
+	return unicode.IsUpper(rune)
+}
+
+// -- Lexical analysis
+
+// Is c a space character?
+func isSpace(c uint8) bool { return c == ' ' || c == '\t' || c == '\r' || c == '\n' }
+
+// Safely, does s[n:n+len(t)] == t?
+func equal(s []byte, n int, t []byte) bool {
+	b := s[n:]
+	if len(t) > len(b) { // not enough space left for a match.
+		return false
+	}
+	for i, c := range t {
+		if c != b[i] {
+			return false
+		}
+	}
+	return true
+}
+
+// isQuote returns true if c is a string- or character-delimiting quote character.
+func isQuote(c byte) bool {
+	return c == '"' || c == '`' || c == '\''
+}
+
+// endQuote returns the end quote index for the quoted string that
+// starts at n, or -1 if no matching end quote is found before the end
+// of the line.
+func endQuote(s []byte, n int) int {
+	quote := s[n]
+	for n++; n < len(s); n++ {
+		switch s[n] {
+		case '\\':
+			if quote == '"' || quote == '\'' {
+				n++
+			}
+		case '\n':
+			return -1
+		case quote:
+			return n
+		}
+	}
+	return -1
+}
+
+// nextItem returns the next item from the input buffer.  If the returned
+// item is empty, we are at EOF.  The item will be either a
+// delimited string or a non-empty string between delimited
+// strings. Tokens stop at (but include, if plain text) a newline.
+// Action tokens on a line by themselves drop any space on
+// either side, up to and including the newline.
+func (t *Template) nextItem() []byte {
+	startOfLine := t.p == 0 || t.buf[t.p-1] == '\n'
+	start := t.p
+	var i int
+	newline := func() {
+		t.linenum++
+		i++
+	}
+	// Leading space up to but not including newline
+	for i = start; i < len(t.buf); i++ {
+		if t.buf[i] == '\n' || !isSpace(t.buf[i]) {
+			break
+		}
+	}
+	leadingSpace := i > start
+	// What's left is nothing, newline, delimited string, or plain text
+	switch {
+	case i == len(t.buf):
+		// EOF; nothing to do
+	case t.buf[i] == '\n':
+		newline()
+	case equal(t.buf, i, t.ldelim):
+		left := i         // Start of left delimiter.
+		right := -1       // Will be (immediately after) right delimiter.
+		haveText := false // Delimiters contain text.
+		i += len(t.ldelim)
+		// Find the end of the action.
+		for ; i < len(t.buf); i++ {
+			if t.buf[i] == '\n' {
+				break
+			}
+			if isQuote(t.buf[i]) {
+				i = endQuote(t.buf, i)
+				if i == -1 {
+					t.parseError("unmatched quote")
+					return nil
+				}
+				continue
+			}
+			if equal(t.buf, i, t.rdelim) {
+				i += len(t.rdelim)
+				right = i
+				break
+			}
+			haveText = true
+		}
+		if right < 0 {
+			t.parseError("unmatched opening delimiter")
+			return nil
+		}
+		// Is this a special action (starts with '.' or '#') and the only thing on the line?
+		if startOfLine && haveText {
+			firstChar := t.buf[left+len(t.ldelim)]
+			if firstChar == '.' || firstChar == '#' {
+				// It's special and the first thing on the line. Is it the last?
+				for j := right; j < len(t.buf) && isSpace(t.buf[j]); j++ {
+					if t.buf[j] == '\n' {
+						// Yes it is. Drop the surrounding space and return the {.foo}
+						t.linenum++
+						t.p = j + 1
+						return t.buf[left:right]
+					}
+				}
+			}
+		}
+		// No it's not. If there's leading space, return that.
+		if leadingSpace {
+			// not trimming space: return leading space if there is some.
+			t.p = left
+			return t.buf[start:left]
+		}
+		// Return the word, leave the trailing space.
+		start = left
+		break
+	default:
+		for ; i < len(t.buf); i++ {
+			if t.buf[i] == '\n' {
+				newline()
+				break
+			}
+			if equal(t.buf, i, t.ldelim) {
+				break
+			}
+		}
+	}
+	item := t.buf[start:i]
+	t.p = i
+	return item
+}
+
+// Turn a byte array into a space-split array of strings,
+// taking into account quoted strings.
+func words(buf []byte) []string {
+	s := make([]string, 0, 5)
+	for i := 0; i < len(buf); {
+		// One word per loop
+		for i < len(buf) && isSpace(buf[i]) {
+			i++
+		}
+		if i == len(buf) {
+			break
+		}
+		// Got a word
+		start := i
+		if isQuote(buf[i]) {
+			i = endQuote(buf, i)
+			if i < 0 {
+				i = len(buf)
+			} else {
+				i++
+			}
+		}
+		// Even with quotes, break on space only.  This handles input
+		// such as {""|} and catches quoting mistakes.
+		for i < len(buf) && !isSpace(buf[i]) {
+			i++
+		}
+		s = append(s, string(buf[start:i]))
+	}
+	return s
+}
+
+// Analyze an item and return its token type and, if it's an action item, an array of
+// its constituent words.
+func (t *Template) analyze(item []byte) (tok int, w []string) {
+	// item is known to be non-empty
+	if !equal(item, 0, t.ldelim) { // doesn't start with left delimiter
+		tok = tokText
+		return
+	}
+	if !equal(item, len(item)-len(t.rdelim), t.rdelim) { // doesn't end with right delimiter
+		t.parseError("internal error: unmatched opening delimiter") // lexing should prevent this
+		return
+	}
+	if len(item) <= len(t.ldelim)+len(t.rdelim) { // no contents
+		t.parseError("empty directive")
+		return
+	}
+	// Comment
+	if item[len(t.ldelim)] == '#' {
+		tok = tokComment
+		return
+	}
+	// Split into words
+	w = words(item[len(t.ldelim) : len(item)-len(t.rdelim)]) // drop final delimiter
+	if len(w) == 0 {
+		t.parseError("empty directive")
+		return
+	}
+	first := w[0]
+	if first[0] != '.' {
+		tok = tokVariable
+		return
+	}
+	if len(first) > 1 && first[1] >= '0' && first[1] <= '9' {
+		// Must be a float.
+		tok = tokVariable
+		return
+	}
+	switch first {
+	case ".meta-left", ".meta-right", ".space", ".tab":
+		tok = tokLiteral
+		return
+	case ".or":
+		tok = tokOr
+		return
+	case ".end":
+		tok = tokEnd
+		return
+	case ".section":
+		if len(w) != 2 {
+			t.parseError("incorrect fields for .section: %s", item)
+			return
+		}
+		tok = tokSection
+		return
+	case ".repeated":
+		if len(w) != 3 || w[1] != "section" {
+			t.parseError("incorrect fields for .repeated: %s", item)
+			return
+		}
+		tok = tokRepeated
+		return
+	case ".alternates":
+		if len(w) != 2 || w[1] != "with" {
+			t.parseError("incorrect fields for .alternates: %s", item)
+			return
+		}
+		tok = tokAlternates
+		return
+	}
+	t.parseError("bad directive: %s", item)
+	return
+}
+
+// formatter returns the Formatter with the given name in the Template, or nil if none exists.
+func (t *Template) formatter(name string) func(io.Writer, string, ...interface{}) {
+	if t.fmap != nil {
+		if fn := t.fmap[name]; fn != nil {
+			return fn
+		}
+	}
+	return builtins[name]
+}
+
+// -- Parsing
+
+// newVariable allocates a new variable-evaluation element.
+func (t *Template) newVariable(words []string) *variableElement {
+	formatters := extractFormatters(words)
+	args := make([]interface{}, len(words))
+
+	// Build argument list, processing any literals
+	for i, word := range words {
+		var lerr os.Error
+		switch word[0] {
+		case '"', '`', '\'':
+			v, err := strconv.Unquote(word)
+			if err == nil && word[0] == '\'' {
+				args[i] = []int(v)[0]
+			} else {
+				args[i], lerr = v, err
+			}
+
+		case '.', '+', '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+			v, err := strconv.Btoi64(word, 0)
+			if err == nil {
+				args[i] = v
+			} else {
+				v, err := strconv.Atof64(word)
+				args[i], lerr = v, err
+			}
+
+		default:
+			args[i] = fieldName(word)
+		}
+		if lerr != nil {
+			t.parseError("invalid literal: %q: %s", word, lerr)
+		}
+	}
+
+	// We could remember the function address here and avoid the lookup later,
+	// but it's more dynamic to let the user change the map contents underfoot.
+	// We do require the name to be present, though.
+
+	// Is it in user-supplied map?
+	for _, f := range formatters {
+		if t.formatter(f) == nil {
+			t.parseError("unknown formatter: %q", f)
+		}
+	}
+
+	return &variableElement{t.linenum, args, formatters}
+}
+
+// extractFormatters extracts a list of formatters from words.
+// After the final space-separated argument in a variable, formatters may be
+// specified separated by pipe symbols. For example: {a b c|d|e}
+// The words parameter still has the formatters joined by '|' in the last word.
+// extractFormatters splits formatters, replaces the last word with the content
+// found before the first '|' within it, and returns the formatters obtained.
+// If no formatters are found in words, the default formatter is returned.
+func extractFormatters(words []string) (formatters []string) {
+	// "" is the default formatter.
+	formatters = []string{""}
+	if len(words) == 0 {
+		return
+	}
+	var bar int
+	lastWord := words[len(words)-1]
+	if isQuote(lastWord[0]) {
+		end := endQuote([]byte(lastWord), 0)
+		if end < 0 || end+1 == len(lastWord) || lastWord[end+1] != '|' {
+			return
+		}
+		bar = end + 1
+	} else {
+		bar = strings.IndexRune(lastWord, '|')
+		if bar < 0 {
+			return
+		}
+	}
+	words[len(words)-1] = lastWord[0:bar]
+	formatters = strings.Split(lastWord[bar+1:], "|")
+	return
+}
+
+// Grab the next item.  If it's simple, just append it to the template.
+// Otherwise return its details.
+func (t *Template) parseSimple(item []byte) (done bool, tok int, w []string) {
+	tok, w = t.analyze(item)
+	done = true // assume for simplicity
+	switch tok {
+	case tokComment:
+		return
+	case tokText:
+		t.elems = append(t.elems, &textElement{item})
+		return
+	case tokLiteral:
+		switch w[0] {
+		case ".meta-left":
+			t.elems = append(t.elems, &literalElement{t.ldelim})
+		case ".meta-right":
+			t.elems = append(t.elems, &literalElement{t.rdelim})
+		case ".space":
+			t.elems = append(t.elems, &literalElement{space})
+		case ".tab":
+			t.elems = append(t.elems, &literalElement{tab})
+		default:
+			t.parseError("internal error: unknown literal: %s", w[0])
+		}
+		return
+	case tokVariable:
+		t.elems = append(t.elems, t.newVariable(w))
+		return
+	}
+	return false, tok, w
+}
+
+// parseRepeated and parseSection are mutually recursive
+
+func (t *Template) parseRepeated(words []string) *repeatedElement {
+	r := new(repeatedElement)
+	t.elems = append(t.elems, r)
+	r.linenum = t.linenum
+	r.field = words[2]
+	// Scan section, collecting true and false (.or) blocks.
+	r.start = len(t.elems)
+	r.or = -1
+	r.altstart = -1
+	r.altend = -1
+Loop:
+	for {
+		item := t.nextItem()
+		if len(item) == 0 {
+			t.parseError("missing .end for .repeated section")
+			break
+		}
+		done, tok, w := t.parseSimple(item)
+		if done {
+			continue
+		}
+		switch tok {
+		case tokEnd:
+			break Loop
+		case tokOr:
+			if r.or >= 0 {
+				t.parseError("extra .or in .repeated section")
+				break Loop
+			}
+			r.altend = len(t.elems)
+			r.or = len(t.elems)
+		case tokSection:
+			t.parseSection(w)
+		case tokRepeated:
+			t.parseRepeated(w)
+		case tokAlternates:
+			if r.altstart >= 0 {
+				t.parseError("extra .alternates in .repeated section")
+				break Loop
+			}
+			if r.or >= 0 {
+				t.parseError(".alternates inside .or block in .repeated section")
+				break Loop
+			}
+			r.altstart = len(t.elems)
+		default:
+			t.parseError("internal error: unknown repeated section item: %s", item)
+			break Loop
+		}
+	}
+	if r.altend < 0 {
+		r.altend = len(t.elems)
+	}
+	r.end = len(t.elems)
+	return r
+}
+
+func (t *Template) parseSection(words []string) *sectionElement {
+	s := new(sectionElement)
+	t.elems = append(t.elems, s)
+	s.linenum = t.linenum
+	s.field = words[1]
+	// Scan section, collecting true and false (.or) blocks.
+	s.start = len(t.elems)
+	s.or = -1
+Loop:
+	for {
+		item := t.nextItem()
+		if len(item) == 0 {
+			t.parseError("missing .end for .section")
+			break
+		}
+		done, tok, w := t.parseSimple(item)
+		if done {
+			continue
+		}
+		switch tok {
+		case tokEnd:
+			break Loop
+		case tokOr:
+			if s.or >= 0 {
+				t.parseError("extra .or in .section")
+				break Loop
+			}
+			s.or = len(t.elems)
+		case tokSection:
+			t.parseSection(w)
+		case tokRepeated:
+			t.parseRepeated(w)
+		case tokAlternates:
+			t.parseError(".alternates not in .repeated")
+		default:
+			t.parseError("internal error: unknown section item: %s", item)
+		}
+	}
+	s.end = len(t.elems)
+	return s
+}
+
+func (t *Template) parse() {
+	for {
+		item := t.nextItem()
+		if len(item) == 0 {
+			break
+		}
+		done, tok, w := t.parseSimple(item)
+		if done {
+			continue
+		}
+		switch tok {
+		case tokOr, tokEnd, tokAlternates:
+			t.parseError("unexpected %s", w[0])
+		case tokSection:
+			t.parseSection(w)
+		case tokRepeated:
+			t.parseRepeated(w)
+		default:
+			t.parseError("internal error: bad directive in parse: %s", item)
+		}
+	}
+}
+
+// -- Execution
+
+// -- Public interface
+
+// Parse initializes a Template by parsing its definition.  The string
+// s contains the template text.  If any errors occur, Parse returns
+// the error.
+func (t *Template) Parse(s string) (err os.Error) {
+	if t.elems == nil {
+		return &Error{1, "template not allocated with New"}
+	}
+	if !validDelim(t.ldelim) || !validDelim(t.rdelim) {
+		return &Error{1, fmt.Sprintf("bad delimiter strings %q %q", t.ldelim, t.rdelim)}
+	}
+	defer checkError(&err)
+	t.buf = []byte(s)
+	t.p = 0
+	t.linenum = 1
+	t.parse()
+	return nil
+}
+
+// ParseFile is like Parse but reads the template definition from the
+// named file.
+func (t *Template) ParseFile(filename string) (err os.Error) {
+	b, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return err
+	}
+	return t.Parse(string(b))
+}
+
+// Execute applies a parsed template to the specified data object,
+// generating output to wr.
+func (t *Template) Execute(wr io.Writer, data interface{}) (err os.Error) {
+	// Extract the driver data.
+	val := reflect.ValueOf(data)
+	defer checkError(&err)
+	t.p = 0
+	t.execute(0, len(t.elems), &state{parent: nil, data: val, wr: wr})
+	return nil
+}
+
+// SetDelims sets the left and right delimiters for operations in the
+// template.  They are validated during parsing.  They could be
+// validated here but it's better to keep the routine simple.  The
+// delimiters are very rarely invalid and Parse has the necessary
+// error-handling interface already.
+func (t *Template) SetDelims(left, right string) {
+	t.ldelim = []byte(left)
+	t.rdelim = []byte(right)
+}
+
+// Parse creates a Template with default parameters (such as {} for
+// metacharacters).  The string s contains the template text while
+// the formatter map fmap, which may be nil, defines auxiliary functions
+// for formatting variables.  The template is returned. If any errors
+// occur, err will be non-nil.
+func Parse(s string, fmap FormatterMap) (t *Template, err os.Error) {
+	t = New(fmap)
+	err = t.Parse(s)
+	if err != nil {
+		t = nil
+	}
+	return
+}
+
+// ParseFile is a wrapper function that creates a Template with default
+// parameters (such as {} for metacharacters).  The filename identifies
+// a file containing the template text, while the formatter map fmap, which
+// may be nil, defines auxiliary functions for formatting variables.
+// The template is returned. If any errors occur, err will be non-nil.
+func ParseFile(filename string, fmap FormatterMap) (t *Template, err os.Error) {
+	b, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	return Parse(string(b), fmap)
+}
+
+// MustParse is like Parse but panics if the template cannot be parsed.
+func MustParse(s string, fmap FormatterMap) *Template {
+	t, err := Parse(s, fmap)
+	if err != nil {
+		panic("template.MustParse error: " + err.String())
+	}
+	return t
+}
+
+// MustParseFile is like ParseFile but panics if the file cannot be read
+// or the template cannot be parsed.
+func MustParseFile(filename string, fmap FormatterMap) *Template {
+	b, err := ioutil.ReadFile(filename)
+	if err != nil {
+		panic("template.MustParseFile error: " + err.String())
+	}
+	return MustParse(string(b), fmap)
+}

src/pkg/old/template/template_test.go

+// 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 template
+
+import (
+	"bytes"
+	"container/vector"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"json"
+	"os"
+	"strings"
+	"testing"
+)
+
+type Test struct {
+	in, out, err string
+}
+
+type T struct {
+	Item  string
+	Value string
+}
+
+type U struct {
+	Mp map[string]int
+}
+
+type S struct {
+	Header        string
+	HeaderPtr     *string
+	Integer       int
+	IntegerPtr    *int
+	NilPtr        *int
+	InnerT        T
+	InnerPointerT *T
+	Data          []T
+	Pdata         []*T
+	Empty         []*T
+	Emptystring   string
+	Null          []*T
+	Vec           *vector.Vector
+	True          bool
+	False         bool
+	Mp            map[string]string
+	JSON          interface{}
+	Innermap      U
+	Stringmap     map[string]string
+	Ptrmap        map[string]*string
+	Iface         interface{}
+	Ifaceptr      interface{}
+}
+
+func (s *S) PointerMethod() string { return "ptrmethod!" }
+
+func (s S) ValueMethod() string { return "valmethod!" }
+
+var t1 = T{"ItemNumber1", "ValueNumber1"}
+var t2 = T{"ItemNumber2", "ValueNumber2"}
+
+func uppercase(v interface{}) string {
+	s := v.(string)
+	t := ""
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		if 'a' <= c && c <= 'z' {
+			c = c + 'A' - 'a'
+		}
+		t += string(c)
+	}
+	return t
+}
+
+func plus1(v interface{}) string {
+	i := v.(int)
+	return fmt.Sprint(i + 1)
+}
+
+func writer(f func(interface{}) string) func(io.Writer, string, ...interface{}) {
+	return func(w io.Writer, format string, v ...interface{}) {
+		if len(v) != 1 {
+			panic("test writer expected one arg")
+		}
+		io.WriteString(w, f(v[0]))
+	}
+}
+
+func multiword(w io.Writer, format string, value ...interface{}) {
+	for _, v := range value {
+		fmt.Fprintf(w, "<%v>", v)
+	}
+}
+
+func printf(w io.Writer, format string, v ...interface{}) {
+	io.WriteString(w, fmt.Sprintf(v[0].(string), v[1:]...))
+}
+
+var formatters = FormatterMap{
+	"uppercase": writer(uppercase),
+	"+1":        writer(plus1),
+	"multiword": multiword,
+	"printf":    printf,
+}
+
+var tests = []*Test{
+	// Simple
+	&Test{"", "", ""},
+	&Test{"abc", "abc", ""},
+	&Test{"abc\ndef\n", "abc\ndef\n", ""},
+	&Test{" {.meta-left}   \n", "{", ""},
+	&Test{" {.meta-right}   \n", "}", ""},
+	&Test{" {.space}   \n", " ", ""},
+	&Test{" {.tab}   \n", "\t", ""},
+	&Test{"     {#comment}   \n", "", ""},
+	&Test{"\tSome Text\t\n", "\tSome Text\t\n", ""},
+	&Test{" {.meta-right} {.meta-right} {.meta-right} \n", " } } } \n", ""},
+
+	// Variables at top level
+	&Test{
+		in: "{Header}={Integer}\n",
+
+		out: "Header=77\n",
+	},
+
+	&Test{
+		in: "Pointers: {*HeaderPtr}={*IntegerPtr}\n",
+
+		out: "Pointers: Header=77\n",
+	},
+
+	&Test{
+		in: "Stars but not pointers: {*Header}={*Integer}\n",
+
+		out: "Stars but not pointers: Header=77\n",
+	},
+
+	&Test{
+		in: "nil pointer: {*NilPtr}={*Integer}\n",
+
+		out: "nil pointer: <nil>=77\n",
+	},
+
+	&Test{
+		in: `{"Strings" ":"} {""} {"|"} {"\t\u0123 \x23\\"} {"\"}{\\"}`,
+
+		out: "Strings:  | \t\u0123 \x23\\ \"}{\\",
+	},
+
+	&Test{
+		in: "{`Raw strings` `:`} {``} {`|`} {`\\t\\u0123 \\x23\\`} {`}{\\`}",
+
+		out: "Raw strings:  | \\t\\u0123 \\x23\\ }{\\",
+	},
+
+	&Test{
+		in: "Characters: {'a'} {'\\u0123'} {' '} {'{'} {'|'} {'}'}",
+
+		out: "Characters: 97 291 32 123 124 125",
+	},
+
+	&Test{
+		in: "Integers: {1} {-2} {+42} {0777} {0x0a}",
+
+		out: "Integers: 1 -2 42 511 10",
+	},
+
+	&Test{
+		in: "Floats: {.5} {-.5} {1.1} {-2.2} {+42.1} {1e10} {1.2e-3} {1.2e3} {-1.2e3}",
+
+		out: "Floats: 0.5 -0.5 1.1 -2.2 42.1 1e+10 0.0012 1200 -1200",
+	},
+
+	// Method at top level
+	&Test{
+		in: "ptrmethod={PointerMethod}\n",
+
+		out: "ptrmethod=ptrmethod!\n",
+	},
+
+	&Test{
+		in: "valmethod={ValueMethod}\n",
+
+		out: "valmethod=valmethod!\n",
+	},
+
+	// Section
+	&Test{
+		in: "{.section Data }\n" +
+			"some text for the section\n" +
+			"{.end}\n",
+
+		out: "some text for the section\n",
+	},
+	&Test{
+		in: "{.section Data }\n" +
+			"{Header}={Integer}\n" +
+			"{.end}\n",
+
+		out: "Header=77\n",
+	},
+	&Test{
+		in: "{.section Pdata }\n" +
+			"{Header}={Integer}\n" +
+			"{.end}\n",
+
+		out: "Header=77\n",
+	},
+	&Test{
+		in: "{.section Pdata }\n" +
+			"data present\n" +
+			"{.or}\n" +
+			"data not present\n" +
+			"{.end}\n",
+
+		out: "data present\n",
+	},
+	&Test{
+		in: "{.section Empty }\n" +
+			"data present\n" +
+			"{.or}\n" +
+			"data not present\n" +
+			"{.end}\n",
+
+		out: "data not present\n",
+	},
+	&Test{
+		in: "{.section Null }\n" +
+			"data present\n" +
+			"{.or}\n" +
+			"data not present\n" +
+			"{.end}\n",
+
+		out: "data not present\n",
+	},
+	&Test{
+		in: "{.section Pdata }\n" +
+			"{Header}={Integer}\n" +
+			"{.section @ }\n" +
+			"{Header}={Integer}\n" +
+			"{.end}\n" +
+			"{.end}\n",
+
+		out: "Header=77\n" +
+			"Header=77\n",
+	},
+
+	&Test{
+		in: "{.section Data}{.end} {Header}\n",
+
+		out: " Header\n",
+	},
+
+	&Test{
+		in: "{.section Integer}{@}{.end}",
+
+		out: "77",
+	},
+
+	// Repeated
+	&Test{
+		in: "{.section Pdata }\n" +
+			"{.repeated section @ }\n" +
+			"{Item}={Value}\n" +
+			"{.end}\n" +
+			"{.end}\n",
+
+		out: "ItemNumber1=ValueNumber1\n" +
+			"ItemNumber2=ValueNumber2\n",
+	},
+	&Test{
+		in: "{.section Pdata }\n" +
+			"{.repeated section @ }\n" +
+			"{Item}={Value}\n" +
+			"{.or}\n" +
+			"this should not appear\n" +
+			"{.end}\n" +
+			"{.end}\n",
+
+		out: "ItemNumber1=ValueNumber1\n" +
+			"ItemNumber2=ValueNumber2\n",
+	},
+	&Test{
+		in: "{.section @ }\n" +
+			"{.repeated section Empty }\n" +
+			"{Item}={Value}\n" +
+			"{.or}\n" +
+			"this should appear: empty field\n" +
+			"{.end}\n" +
+			"{.end}\n",
+
+		out: "this should appear: empty field\n",
+	},
+	&Test{
+		in: "{.repeated section Pdata }\n" +
+			"{Item}\n" +
+			"{.alternates with}\n" +
+			"is\nover\nmultiple\nlines\n" +
+			"{.end}\n",
+
+		out: "ItemNumber1\n" +
+			"is\nover\nmultiple\nlines\n" +
+			"ItemNumber2\n",
+	},
+	&Test{
+		in: "{.repeated section Pdata }\n" +
+			"{Item}\n" +
+			"{.alternates with}\n" +
+			"is\nover\nmultiple\nlines\n" +
+			" {.end}\n",
+
+		out: "ItemNumber1\n" +
+			"is\nover\nmultiple\nlines\n" +
+			"ItemNumber2\n",
+	},
+	&Test{
+		in: "{.section Pdata }\n" +
+			"{.repeated section @ }\n" +
+			"{Item}={Value}\n" +
+			"{.alternates with}DIVIDER\n" +
+			"{.or}\n" +
+			"this should not appear\n" +
+			"{.end}\n" +
+			"{.end}\n",
+
+		out: "ItemNumber1=ValueNumber1\n" +
+			"DIVIDER\n" +
+			"ItemNumber2=ValueNumber2\n",
+	},
+	&Test{
+		in: "{.repeated section Vec }\n" +
+			"{@}\n" +
+			"{.end}\n",
+
+		out: "elt1\n" +
+			"elt2\n",
+	},
+	// Same but with a space before {.end}: was a bug.
+	&Test{
+		in: "{.repeated section Vec }\n" +
+			"{@} {.end}\n",
+
+		out: "elt1 elt2 \n",
+	},
+	&Test{
+		in: "{.repeated section Integer}{.end}",
+
+		err: "line 1: .repeated: cannot repeat Integer (type int)",
+	},
+
+	// Nested names
+	&Test{
+		in: "{.section @ }\n" +
+			"{InnerT.Item}={InnerT.Value}\n" +
+			"{.end}",
+
+		out: "ItemNumber1=ValueNumber1\n",
+	},
+	&Test{
+		in: "{.section @ }\n" +
+			"{InnerT.Item}={.section InnerT}{.section Value}{@}{.end}{.end}\n" +
+			"{.end}",
+
+		out: "ItemNumber1=ValueNumber1\n",
+	},
+
+	&Test{
+		in: "{.section Emptystring}emptystring{.end}\n" +
+			"{.section Header}header{.end}\n",
+
+		out: "\nheader\n",
+	},
+
+	&Test{
+		in: "{.section True}1{.or}2{.end}\n" +
+			"{.section False}3{.or}4{.end}\n",
+
+		out: "1\n4\n",
+	},
+
+	// Maps
+
+	&Test{
+		in: "{Mp.mapkey}\n",
+
+		out: "Ahoy!\n",
+	},
+	&Test{
+		in: "{Innermap.Mp.innerkey}\n",
+
+		out: "55\n",
+	},
+	&Test{
+		in: "{.section Innermap}{.section Mp}{innerkey}{.end}{.end}\n",
+
+		out: "55\n",
+	},
+	&Test{
+		in: "{.section JSON}{.repeated section maps}{a}{b}{.end}{.end}\n",
+
+		out: "1234\n",
+	},
+	&Test{
+		in: "{Stringmap.stringkey1}\n",
+
+		out: "stringresult\n",
+	},
+	&Test{
+		in: "{.repeated section Stringmap}\n" +
+			"{@}\n" +
+			"{.end}",
+
+		out: "stringresult\n" +
+			"stringresult\n",
+	},
+	&Test{
+		in: "{.repeated section Stringmap}\n" +
+			"\t{@}\n" +
+			"{.end}",
+
+		out: "\tstringresult\n" +
+			"\tstringresult\n",
+	},
+	&Test{
+		in: "{*Ptrmap.stringkey1}\n",
+
+		out: "pointedToString\n",
+	},
+	&Test{
+		in: "{.repeated section Ptrmap}\n" +
+			"{*@}\n" +
+			"{.end}",
+
+		out: "pointedToString\n" +
+			"pointedToString\n",
+	},
+
+	// Interface values
+
+	&Test{
+		in: "{Iface}",
+
+		out: "[1 2 3]",
+	},
+	&Test{
+		in: "{.repeated section Iface}{@}{.alternates with} {.end}",
+
+		out: "1 2 3",
+	},
+	&Test{
+		in: "{.section Iface}{@}{.end}",
+
+		out: "[1 2 3]",
+	},
+	&Test{
+		in: "{.section Ifaceptr}{Item} {Value}{.end}",
+
+		out: "Item Value",
+	},
+}
+
+func TestAll(t *testing.T) {
+	// Parse
+	testAll(t, func(test *Test) (*Template, os.Error) { return Parse(test.in, formatters) })
+	// ParseFile
+	testAll(t, func(test *Test) (*Template, os.Error) {
+		err := ioutil.WriteFile("_test/test.tmpl", []byte(test.in), 0600)
+		if err != nil {
+			t.Error("unexpected write error:", err)
+			return nil, err
+		}
+		return ParseFile("_test/test.tmpl", formatters)
+	})
+	// tmpl.ParseFile
+	testAll(t, func(test *Test) (*Template, os.Error) {
+		err := ioutil.WriteFile("_test/test.tmpl", []byte(test.in), 0600)
+		if err != nil {
+			t.Error("unexpected write error:", err)
+			return nil, err
+		}
+		tmpl := New(formatters)
+		return tmpl, tmpl.ParseFile("_test/test.tmpl")
+	})
+}
+
+func testAll(t *testing.T, parseFunc func(*Test) (*Template, os.Error)) {
+	s := new(S)
+	// initialized by hand for clarity.
+	s.Header = "Header"
+	s.HeaderPtr = &s.Header
+	s.Integer = 77
+	s.IntegerPtr = &s.Integer
+	s.InnerT = t1
+	s.Data = []T{t1, t2}
+	s.Pdata = []*T{&t1, &t2}
+	s.Empty = []*T{}
+	s.Null = nil
+	s.Vec = new(vector.Vector)
+	s.Vec.Push("elt1")
+	s.Vec.Push("elt2")
+	s.True = true
+	s.False = false
+	s.Mp = make(map[string]string)
+	s.Mp["mapkey"] = "Ahoy!"
+	json.Unmarshal([]byte(`{"maps":[{"a":1,"b":2},{"a":3,"b":4}]}`), &s.JSON)
+	s.Innermap.Mp = make(map[string]int)
+	s.Innermap.Mp["innerkey"] = 55
+	s.Stringmap = make(map[string]string)
+	s.Stringmap["stringkey1"] = "stringresult" // the same value so repeated section is order-independent
+	s.Stringmap["stringkey2"] = "stringresult"
+	s.Ptrmap = make(map[string]*string)
+	x := "pointedToString"
+	s.Ptrmap["stringkey1"] = &x // the same value so repeated section is order-independent
+	s.Ptrmap["stringkey2"] = &x
+	s.Iface = []int{1, 2, 3}
+	s.Ifaceptr = &T{"Item", "Value"}
+
+	var buf bytes.Buffer
+	for _, test := range tests {
+		buf.Reset()
+		tmpl, err := parseFunc(test)
+		if err != nil {
+			t.Error("unexpected parse error: ", err)
+			continue
+		}
+		err = tmpl.Execute(&buf, s)
+		if test.err == "" {
+			if err != nil {
+				t.Error("unexpected execute error:", err)
+			}
+		} else {
+			if err == nil {
+				t.Errorf("expected execute error %q, got nil", test.err)
+			} else if err.String() != test.err {
+				t.Errorf("expected execute error %q, got %q", test.err, err.String())
+			}
+		}
+		if buf.String() != test.out {
+			t.Errorf("for %q: expected %q got %q", test.in, test.out, buf.String())
+		}
+	}
+}
+
+func TestMapDriverType(t *testing.T) {
+	mp := map[string]string{"footer": "Ahoy!"}
+	tmpl, err := Parse("template: {footer}", nil)
+	if err != nil {
+		t.Error("unexpected parse error:", err)
+	}
+	var b bytes.Buffer
+	err = tmpl.Execute(&b, mp)
+	if err != nil {
+		t.Error("unexpected execute error:", err)
+	}
+	s := b.String()
+	expect := "template: Ahoy!"
+	if s != expect {
+		t.Errorf("failed passing string as data: expected %q got %q", expect, s)
+	}
+}
+
+func TestMapNoEntry(t *testing.T) {
+	mp := make(map[string]int)
+	tmpl, err := Parse("template: {notthere}!", nil)
+	if err != nil {
+		t.Error("unexpected parse error:", err)
+	}
+	var b bytes.Buffer
+	err = tmpl.Execute(&b, mp)
+	if err != nil {
+		t.Error("unexpected execute error:", err)
+	}
+	s := b.String()
+	expect := "template: 0!"
+	if s != expect {
+		t.Errorf("failed passing string as data: expected %q got %q", expect, s)
+	}
+}
+
+func TestStringDriverType(t *testing.T) {
+	tmpl, err := Parse("template: {@}", nil)
+	if err != nil {
+		t.Error("unexpected parse error:", err)
+	}
+	var b bytes.Buffer
+	err = tmpl.Execute(&b, "hello")
+	if err != nil {
+		t.Error("unexpected execute error:", err)
+	}
+	s := b.String()
+	expect := "template: hello"
+	if s != expect {
+		t.Errorf("failed passing string as data: expected %q got %q", expect, s)
+	}
+}
+
+func TestTwice(t *testing.T) {
+	tmpl, err := Parse("template: {@}", nil)
+	if err != nil {
+		t.Error("unexpected parse error:", err)
+	}
+	var b bytes.Buffer
+	err = tmpl.Execute(&b, "hello")
+	if err != nil {
+		t.Error("unexpected parse error:", err)
+	}
+	s := b.String()
+	expect := "template: hello"
+	if s != expect {
+		t.Errorf("failed passing string as data: expected %q got %q", expect, s)
+	}
+	err = tmpl.Execute(&b, "hello")
+	if err != nil {
+		t.Error("unexpected parse error:", err)
+	}
+	s = b.String()
+	expect += expect
+	if s != expect {
+		t.Errorf("failed passing string as data: expected %q got %q", expect, s)
+	}
+}
+
+func TestCustomDelims(t *testing.T) {
+	// try various lengths.  zero should catch error.
+	for i := 0; i < 7; i++ {
+		for j := 0; j < 7; j++ {
+			tmpl := New(nil)
+			// first two chars deliberately the same to test equal left and right delims
+			ldelim := "$!#$%^&"[0:i]
+			rdelim := "$*&^%$!"[0:j]
+			tmpl.SetDelims(ldelim, rdelim)
+			// if braces, this would be template: {@}{.meta-left}{.meta-right}
+			text := "template: " +
+				ldelim + "@" + rdelim +
+				ldelim + ".meta-left" + rdelim +
+				ldelim + ".meta-right" + rdelim
+			err := tmpl.Parse(text)
+			if err != nil {
+				if i == 0 || j == 0 { // expected
+					continue
+				}
+				t.Error("unexpected parse error:", err)
+			} else if i == 0 || j == 0 {
+				t.Errorf("expected parse error for empty delimiter: %d %d %q %q", i, j, ldelim, rdelim)
+				continue
+			}
+			var b bytes.Buffer
+			err = tmpl.Execute(&b, "hello")
+			s := b.String()
+			if s != "template: hello"+ldelim+rdelim {
+				t.Errorf("failed delim check(%q %q) %q got %q", ldelim, rdelim, text, s)
+			}
+		}
+	}
+}
+
+// Test that a variable evaluates to the field itself and does not further indirection
+func TestVarIndirection(t *testing.T) {
+	s := new(S)
+	// initialized by hand for clarity.
+	s.InnerPointerT = &t1
+
+	var buf bytes.Buffer
+	input := "{.section @}{InnerPointerT}{.end}"
+	tmpl, err := Parse(input, nil)
+	if err != nil {
+		t.Fatal("unexpected parse error:", err)
+	}
+	err = tmpl.Execute(&buf, s)
+	if err != nil {
+		t.Fatal("unexpected execute error:", err)
+	}
+	expect := fmt.Sprintf("%v", &t1) // output should be hex address of t1
+	if buf.String() != expect {
+		t.Errorf("for %q: expected %q got %q", input, expect, buf.String())
+	}
+}
+
+func TestHTMLFormatterWithByte(t *testing.T) {
+	s := "Test string."
+	b := []byte(s)
+	var buf bytes.Buffer
+	HTMLFormatter(&buf, "", b)
+	bs := buf.String()
+	if bs != s {
+		t.Errorf("munged []byte, expected: %s got: %s", s, bs)
+	}
+}
+
+type UF struct {
+	I int
+	s string
+}
+
+func TestReferenceToUnexported(t *testing.T) {
+	u := &UF{3, "hello"}
+	var buf bytes.Buffer
+	input := "{.section @}{I}{s}{.end}"
+	tmpl, err := Parse(input, nil)
+	if err != nil {
+		t.Fatal("unexpected parse error:", err)
+	}
+	err = tmpl.Execute(&buf, u)
+	if err == nil {
+		t.Fatal("expected execute error, got none")
+	}
+	if strings.Index(err.String(), "not exported") < 0 {
+		t.Fatal("expected unexported error; got", err)
+	}
+}
+
+var formatterTests = []Test{
+	{
+		in: "{Header|uppercase}={Integer|+1}\n" +
+			"{Header|html}={Integer|str}\n",
+
+		out: "HEADER=78\n" +
+			"Header=77\n",
+	},
+
+	{
+		in: "{Header|uppercase}={Integer Header|multiword}\n" +
+			"{Header|html}={Header Integer|multiword}\n" +
+			"{Header|html}={Header Integer}\n",
+
+		out: "HEADER=<77><Header>\n" +
+			"Header=<Header><77>\n" +
+			"Header=Header77\n",
+	},
+	{
+		in: "{Raw}\n" +
+			"{Raw|html}\n",
+
+		out: "a <&> b\n" +
+			"a &lt;&amp;&gt; b\n",
+	},
+	{
+		in:  "{Bytes}",
+		out: "hello",
+	},
+	{
+		in:  "{Raw|uppercase|html|html}",
+		out: "A &amp;lt;&amp;amp;&amp;gt; B",
+	},
+	{
+		in:  "{Header Integer|multiword|html}",
+		out: "&lt;Header&gt;&lt;77&gt;",
+	},
+	{
+		in:  "{Integer|no_formatter|html}",
+		err: `unknown formatter: "no_formatter"`,
+	},
+	{
+		in:  "{Integer|||||}", // empty string is a valid formatter
+		out: "77",
+	},
+	{
+		in:  `{"%.02f 0x%02X" 1.1 10|printf}`,
+		out: "1.10 0x0A",
+	},
+	{
+		in:  `{""|}{""||}{""|printf}`, // Issue #1896.
+		out: "",
+	},
+}
+
+func TestFormatters(t *testing.T) {
+	data := map[string]interface{}{
+		"Header":  "Header",
+		"Integer": 77,
+		"Raw":     "a <&> b",
+		"Bytes":   []byte("hello"),
+	}
+	for _, c := range formatterTests {
+		tmpl, err := Parse(c.in, formatters)
+		if err != nil {
+			if c.err == "" {
+				t.Error("unexpected parse error:", err)
+				continue
+			}
+			if strings.Index(err.String(), c.err) < 0 {
+				t.Errorf("unexpected error: expected %q, got %q", c.err, err.String())
+				continue
+			}
+		} else {
+			if c.err != "" {
+				t.Errorf("For %q, expected error, got none.", c.in)
+				continue
+			}
+			buf := bytes.NewBuffer(nil)
+			err = tmpl.Execute(buf, data)
+			if err != nil {
+				t.Error("unexpected Execute error: ", err)
+				continue
+			}
+			actual := buf.String()
+			if actual != c.out {
+				t.Errorf("for %q: expected %q but got %q.", c.in, c.out, actual)
+			}
+		}
+	}
+}