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-rw-r--r--libgo/go/template/parse/parse.go436
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diff --git a/libgo/go/template/parse/parse.go b/libgo/go/template/parse/parse.go
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--- a/libgo/go/template/parse/parse.go
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-// Copyright 2011 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 parse builds parse trees for templates. The grammar is defined
-// in the documents for the template package.
-package parse
-
-import (
- "fmt"
- "runtime"
- "strconv"
- "unicode"
-)
-
-// Tree is the representation of a parsed template.
-type Tree struct {
- Name string // Name is the name of the template.
- Root *ListNode // Root is the top-level root of the parse tree.
- // Parsing only; cleared after parse.
- funcs []map[string]interface{}
- lex *lexer
- token [2]item // two-token lookahead for parser.
- peekCount int
- vars []string // variables defined at the moment.
-}
-
-// next returns the next token.
-func (t *Tree) next() item {
- if t.peekCount > 0 {
- t.peekCount--
- } else {
- t.token[0] = t.lex.nextItem()
- }
- return t.token[t.peekCount]
-}
-
-// backup backs the input stream up one token.
-func (t *Tree) backup() {
- t.peekCount++
-}
-
-// backup2 backs the input stream up two tokens
-func (t *Tree) backup2(t1 item) {
- t.token[1] = t1
- t.peekCount = 2
-}
-
-// peek returns but does not consume the next token.
-func (t *Tree) peek() item {
- if t.peekCount > 0 {
- return t.token[t.peekCount-1]
- }
- t.peekCount = 1
- t.token[0] = t.lex.nextItem()
- return t.token[0]
-}
-
-// Parsing.
-
-// New allocates a new template with the given name.
-func New(name string, funcs ...map[string]interface{}) *Tree {
- return &Tree{
- Name: name,
- funcs: funcs,
- }
-}
-
-// errorf formats the error and terminates processing.
-func (t *Tree) errorf(format string, args ...interface{}) {
- t.Root = nil
- format = fmt.Sprintf("template: %s:%d: %s", t.Name, t.lex.lineNumber(), format)
- panic(fmt.Errorf(format, args...))
-}
-
-// error terminates processing.
-func (t *Tree) error(err error) {
- t.errorf("%s", err)
-}
-
-// expect consumes the next token and guarantees it has the required type.
-func (t *Tree) expect(expected itemType, context string) item {
- token := t.next()
- if token.typ != expected {
- t.errorf("expected %s in %s; got %s", expected, context, token)
- }
- return token
-}
-
-// unexpected complains about the token and terminates processing.
-func (t *Tree) unexpected(token item, context string) {
- t.errorf("unexpected %s in %s", token, context)
-}
-
-// recover is the handler that turns panics into returns from the top level of Parse.
-func (t *Tree) recover(errp *error) {
- e := recover()
- if e != nil {
- if _, ok := e.(runtime.Error); ok {
- panic(e)
- }
- if t != nil {
- t.stopParse()
- }
- *errp = e.(error)
- }
- return
-}
-
-// startParse starts the template parsing from the lexer.
-func (t *Tree) startParse(funcs []map[string]interface{}, lex *lexer) {
- t.Root = nil
- t.lex = lex
- t.vars = []string{"$"}
- t.funcs = funcs
-}
-
-// stopParse terminates parsing.
-func (t *Tree) stopParse() {
- t.lex = nil
- t.vars = nil
- t.funcs = nil
-}
-
-// atEOF returns true if, possibly after spaces, we're at EOF.
-func (t *Tree) atEOF() bool {
- for {
- token := t.peek()
- switch token.typ {
- case itemEOF:
- return true
- case itemText:
- for _, r := range token.val {
- if !unicode.IsSpace(r) {
- return false
- }
- }
- t.next() // skip spaces.
- continue
- }
- break
- }
- return false
-}
-
-// Parse parses the template definition string to construct an internal
-// representation of the template for execution. If either action delimiter
-// string is empty, the default ("{{" or "}}") is used.
-func (t *Tree) Parse(s, leftDelim, rightDelim string, funcs ...map[string]interface{}) (tree *Tree, err error) {
- defer t.recover(&err)
- t.startParse(funcs, lex(t.Name, s, leftDelim, rightDelim))
- t.parse(true)
- t.stopParse()
- return t, nil
-}
-
-// parse is the helper for Parse.
-// It triggers an error if we expect EOF but don't reach it.
-func (t *Tree) parse(toEOF bool) (next Node) {
- t.Root, next = t.itemList(true)
- if toEOF && next != nil {
- t.errorf("unexpected %s", next)
- }
- return next
-}
-
-// itemList:
-// textOrAction*
-// Terminates at EOF and at {{end}} or {{else}}, which is returned separately.
-// The toEOF flag tells whether we expect to reach EOF.
-func (t *Tree) itemList(toEOF bool) (list *ListNode, next Node) {
- list = newList()
- for t.peek().typ != itemEOF {
- n := t.textOrAction()
- switch n.Type() {
- case nodeEnd, nodeElse:
- return list, n
- }
- list.append(n)
- }
- if !toEOF {
- t.unexpected(t.next(), "input")
- }
- return list, nil
-}
-
-// textOrAction:
-// text | action
-func (t *Tree) textOrAction() Node {
- switch token := t.next(); token.typ {
- case itemText:
- return newText(token.val)
- case itemLeftDelim:
- return t.action()
- default:
- t.unexpected(token, "input")
- }
- return nil
-}
-
-// Action:
-// control
-// command ("|" command)*
-// Left delim is past. Now get actions.
-// First word could be a keyword such as range.
-func (t *Tree) action() (n Node) {
- switch token := t.next(); token.typ {
- case itemElse:
- return t.elseControl()
- case itemEnd:
- return t.endControl()
- case itemIf:
- return t.ifControl()
- case itemRange:
- return t.rangeControl()
- case itemTemplate:
- return t.templateControl()
- case itemWith:
- return t.withControl()
- }
- t.backup()
- // Do not pop variables; they persist until "end".
- return newAction(t.lex.lineNumber(), t.pipeline("command"))
-}
-
-// Pipeline:
-// field or command
-// pipeline "|" pipeline
-func (t *Tree) pipeline(context string) (pipe *PipeNode) {
- var decl []*VariableNode
- // Are there declarations?
- for {
- if v := t.peek(); v.typ == itemVariable {
- t.next()
- if next := t.peek(); next.typ == itemColonEquals || next.typ == itemChar {
- t.next()
- variable := newVariable(v.val)
- if len(variable.Ident) != 1 {
- t.errorf("illegal variable in declaration: %s", v.val)
- }
- decl = append(decl, variable)
- t.vars = append(t.vars, v.val)
- if next.typ == itemChar && next.val == "," {
- if context == "range" && len(decl) < 2 {
- continue
- }
- t.errorf("too many declarations in %s", context)
- }
- } else {
- t.backup2(v)
- }
- }
- break
- }
- pipe = newPipeline(t.lex.lineNumber(), decl)
- for {
- switch token := t.next(); token.typ {
- case itemRightDelim:
- if len(pipe.Cmds) == 0 {
- t.errorf("missing value for %s", context)
- }
- return
- case itemBool, itemCharConstant, itemComplex, itemDot, itemField, itemIdentifier,
- itemVariable, itemNumber, itemRawString, itemString:
- t.backup()
- pipe.append(t.command())
- default:
- t.unexpected(token, context)
- }
- }
- return
-}
-
-func (t *Tree) parseControl(context string) (lineNum int, pipe *PipeNode, list, elseList *ListNode) {
- lineNum = t.lex.lineNumber()
- defer t.popVars(len(t.vars))
- pipe = t.pipeline(context)
- var next Node
- list, next = t.itemList(false)
- switch next.Type() {
- case nodeEnd: //done
- case nodeElse:
- elseList, next = t.itemList(false)
- if next.Type() != nodeEnd {
- t.errorf("expected end; found %s", next)
- }
- elseList = elseList
- }
- return lineNum, pipe, list, elseList
-}
-
-// If:
-// {{if pipeline}} itemList {{end}}
-// {{if pipeline}} itemList {{else}} itemList {{end}}
-// If keyword is past.
-func (t *Tree) ifControl() Node {
- return newIf(t.parseControl("if"))
-}
-
-// Range:
-// {{range pipeline}} itemList {{end}}
-// {{range pipeline}} itemList {{else}} itemList {{end}}
-// Range keyword is past.
-func (t *Tree) rangeControl() Node {
- return newRange(t.parseControl("range"))
-}
-
-// With:
-// {{with pipeline}} itemList {{end}}
-// {{with pipeline}} itemList {{else}} itemList {{end}}
-// If keyword is past.
-func (t *Tree) withControl() Node {
- return newWith(t.parseControl("with"))
-}
-
-// End:
-// {{end}}
-// End keyword is past.
-func (t *Tree) endControl() Node {
- t.expect(itemRightDelim, "end")
- return newEnd()
-}
-
-// Else:
-// {{else}}
-// Else keyword is past.
-func (t *Tree) elseControl() Node {
- t.expect(itemRightDelim, "else")
- return newElse(t.lex.lineNumber())
-}
-
-// Template:
-// {{template stringValue pipeline}}
-// Template keyword is past. The name must be something that can evaluate
-// to a string.
-func (t *Tree) templateControl() Node {
- var name string
- switch token := t.next(); token.typ {
- case itemString, itemRawString:
- s, err := strconv.Unquote(token.val)
- if err != nil {
- t.error(err)
- }
- name = s
- default:
- t.unexpected(token, "template invocation")
- }
- var pipe *PipeNode
- if t.next().typ != itemRightDelim {
- t.backup()
- // Do not pop variables; they persist until "end".
- pipe = t.pipeline("template")
- }
- return newTemplate(t.lex.lineNumber(), name, pipe)
-}
-
-// command:
-// space-separated arguments up to a pipeline character or right delimiter.
-// we consume the pipe character but leave the right delim to terminate the action.
-func (t *Tree) command() *CommandNode {
- cmd := newCommand()
-Loop:
- for {
- switch token := t.next(); token.typ {
- case itemRightDelim:
- t.backup()
- break Loop
- case itemPipe:
- break Loop
- case itemError:
- t.errorf("%s", token.val)
- case itemIdentifier:
- if !t.hasFunction(token.val) {
- t.errorf("function %q not defined", token.val)
- }
- cmd.append(NewIdentifier(token.val))
- case itemDot:
- cmd.append(newDot())
- case itemVariable:
- cmd.append(t.useVar(token.val))
- case itemField:
- cmd.append(newField(token.val))
- case itemBool:
- cmd.append(newBool(token.val == "true"))
- case itemCharConstant, itemComplex, itemNumber:
- number, err := newNumber(token.val, token.typ)
- if err != nil {
- t.error(err)
- }
- cmd.append(number)
- case itemString, itemRawString:
- s, err := strconv.Unquote(token.val)
- if err != nil {
- t.error(err)
- }
- cmd.append(newString(token.val, s))
- default:
- t.unexpected(token, "command")
- }
- }
- if len(cmd.Args) == 0 {
- t.errorf("empty command")
- }
- return cmd
-}
-
-// hasFunction reports if a function name exists in the Tree's maps.
-func (t *Tree) hasFunction(name string) bool {
- for _, funcMap := range t.funcs {
- if funcMap == nil {
- continue
- }
- if funcMap[name] != nil {
- return true
- }
- }
- return false
-}
-
-// popVars trims the variable list to the specified length
-func (t *Tree) popVars(n int) {
- t.vars = t.vars[:n]
-}
-
-// useVar returns a node for a variable reference. It errors if the
-// variable is not defined.
-func (t *Tree) useVar(name string) Node {
- v := newVariable(name)
- for _, varName := range t.vars {
- if varName == v.Ident[0] {
- return v
- }
- }
- t.errorf("undefined variable %q", v.Ident[0])
- return nil
-}