Migrate to new swagger docs generation (#18)
This commit is contained in:
konrad
556
vendor/github.com/alecthomas/template/parse/lex.go
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vendored
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556
vendor/github.com/alecthomas/template/parse/lex.go
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vendored
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// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package parse
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import (
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"fmt"
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"strings"
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"unicode"
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"unicode/utf8"
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)
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// item represents a token or text string returned from the scanner.
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type item struct {
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typ itemType // The type of this item.
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pos Pos // The starting position, in bytes, of this item in the input string.
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val string // The value of this item.
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}
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func (i item) String() string {
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switch {
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case i.typ == itemEOF:
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return "EOF"
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case i.typ == itemError:
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return i.val
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case i.typ > itemKeyword:
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return fmt.Sprintf("<%s>", i.val)
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case len(i.val) > 10:
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return fmt.Sprintf("%.10q...", i.val)
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}
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return fmt.Sprintf("%q", i.val)
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}
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// itemType identifies the type of lex items.
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type itemType int
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const (
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itemError itemType = iota // error occurred; value is text of error
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itemBool // boolean constant
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itemChar // printable ASCII character; grab bag for comma etc.
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itemCharConstant // character constant
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itemComplex // complex constant (1+2i); imaginary is just a number
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itemColonEquals // colon-equals (':=') introducing a declaration
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itemEOF
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itemField // alphanumeric identifier starting with '.'
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itemIdentifier // alphanumeric identifier not starting with '.'
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itemLeftDelim // left action delimiter
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itemLeftParen // '(' inside action
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itemNumber // simple number, including imaginary
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itemPipe // pipe symbol
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itemRawString // raw quoted string (includes quotes)
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itemRightDelim // right action delimiter
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itemElideNewline // elide newline after right delim
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itemRightParen // ')' inside action
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itemSpace // run of spaces separating arguments
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itemString // quoted string (includes quotes)
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itemText // plain text
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itemVariable // variable starting with '$', such as '$' or '$1' or '$hello'
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// Keywords appear after all the rest.
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itemKeyword // used only to delimit the keywords
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itemDot // the cursor, spelled '.'
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itemDefine // define keyword
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itemElse // else keyword
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itemEnd // end keyword
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itemIf // if keyword
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itemNil // the untyped nil constant, easiest to treat as a keyword
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itemRange // range keyword
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itemTemplate // template keyword
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itemWith // with keyword
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)
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var key = map[string]itemType{
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".": itemDot,
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"define": itemDefine,
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"else": itemElse,
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"end": itemEnd,
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"if": itemIf,
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"range": itemRange,
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"nil": itemNil,
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"template": itemTemplate,
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"with": itemWith,
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}
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const eof = -1
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// stateFn represents the state of the scanner as a function that returns the next state.
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type stateFn func(*lexer) stateFn
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// lexer holds the state of the scanner.
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type lexer struct {
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name string // the name of the input; used only for error reports
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input string // the string being scanned
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leftDelim string // start of action
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rightDelim string // end of action
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state stateFn // the next lexing function to enter
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pos Pos // current position in the input
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start Pos // start position of this item
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width Pos // width of last rune read from input
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lastPos Pos // position of most recent item returned by nextItem
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items chan item // channel of scanned items
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parenDepth int // nesting depth of ( ) exprs
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}
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// next returns the next rune in the input.
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func (l *lexer) next() rune {
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if int(l.pos) >= len(l.input) {
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l.width = 0
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return eof
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}
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r, w := utf8.DecodeRuneInString(l.input[l.pos:])
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l.width = Pos(w)
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l.pos += l.width
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return r
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}
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// peek returns but does not consume the next rune in the input.
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func (l *lexer) peek() rune {
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r := l.next()
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l.backup()
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return r
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}
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// backup steps back one rune. Can only be called once per call of next.
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func (l *lexer) backup() {
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l.pos -= l.width
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}
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// emit passes an item back to the client.
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func (l *lexer) emit(t itemType) {
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l.items <- item{t, l.start, l.input[l.start:l.pos]}
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l.start = l.pos
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}
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// ignore skips over the pending input before this point.
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func (l *lexer) ignore() {
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l.start = l.pos
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}
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// accept consumes the next rune if it's from the valid set.
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func (l *lexer) accept(valid string) bool {
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if strings.IndexRune(valid, l.next()) >= 0 {
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return true
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}
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l.backup()
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return false
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}
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// acceptRun consumes a run of runes from the valid set.
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func (l *lexer) acceptRun(valid string) {
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for strings.IndexRune(valid, l.next()) >= 0 {
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}
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l.backup()
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}
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// lineNumber reports which line we're on, based on the position of
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// the previous item returned by nextItem. Doing it this way
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// means we don't have to worry about peek double counting.
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func (l *lexer) lineNumber() int {
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return 1 + strings.Count(l.input[:l.lastPos], "\n")
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}
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// errorf returns an error token and terminates the scan by passing
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// back a nil pointer that will be the next state, terminating l.nextItem.
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func (l *lexer) errorf(format string, args ...interface{}) stateFn {
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l.items <- item{itemError, l.start, fmt.Sprintf(format, args...)}
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return nil
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}
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// nextItem returns the next item from the input.
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func (l *lexer) nextItem() item {
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item := <-l.items
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l.lastPos = item.pos
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return item
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}
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// lex creates a new scanner for the input string.
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func lex(name, input, left, right string) *lexer {
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if left == "" {
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left = leftDelim
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}
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if right == "" {
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right = rightDelim
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}
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l := &lexer{
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name: name,
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input: input,
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leftDelim: left,
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rightDelim: right,
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items: make(chan item),
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}
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go l.run()
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return l
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}
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// run runs the state machine for the lexer.
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func (l *lexer) run() {
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for l.state = lexText; l.state != nil; {
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l.state = l.state(l)
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}
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}
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// state functions
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const (
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leftDelim = "{{"
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rightDelim = "}}"
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leftComment = "/*"
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rightComment = "*/"
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)
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// lexText scans until an opening action delimiter, "{{".
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func lexText(l *lexer) stateFn {
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for {
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if strings.HasPrefix(l.input[l.pos:], l.leftDelim) {
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if l.pos > l.start {
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l.emit(itemText)
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}
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return lexLeftDelim
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}
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if l.next() == eof {
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break
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}
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}
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// Correctly reached EOF.
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if l.pos > l.start {
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l.emit(itemText)
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}
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l.emit(itemEOF)
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return nil
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}
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// lexLeftDelim scans the left delimiter, which is known to be present.
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func lexLeftDelim(l *lexer) stateFn {
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l.pos += Pos(len(l.leftDelim))
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if strings.HasPrefix(l.input[l.pos:], leftComment) {
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return lexComment
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}
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l.emit(itemLeftDelim)
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l.parenDepth = 0
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return lexInsideAction
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}
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// lexComment scans a comment. The left comment marker is known to be present.
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func lexComment(l *lexer) stateFn {
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l.pos += Pos(len(leftComment))
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i := strings.Index(l.input[l.pos:], rightComment)
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if i < 0 {
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return l.errorf("unclosed comment")
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}
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l.pos += Pos(i + len(rightComment))
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if !strings.HasPrefix(l.input[l.pos:], l.rightDelim) {
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return l.errorf("comment ends before closing delimiter")
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}
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l.pos += Pos(len(l.rightDelim))
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l.ignore()
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return lexText
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}
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// lexRightDelim scans the right delimiter, which is known to be present.
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func lexRightDelim(l *lexer) stateFn {
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l.pos += Pos(len(l.rightDelim))
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l.emit(itemRightDelim)
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if l.peek() == '\\' {
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l.pos++
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l.emit(itemElideNewline)
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}
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return lexText
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}
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// lexInsideAction scans the elements inside action delimiters.
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func lexInsideAction(l *lexer) stateFn {
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// Either number, quoted string, or identifier.
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// Spaces separate arguments; runs of spaces turn into itemSpace.
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// Pipe symbols separate and are emitted.
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if strings.HasPrefix(l.input[l.pos:], l.rightDelim+"\\") || strings.HasPrefix(l.input[l.pos:], l.rightDelim) {
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if l.parenDepth == 0 {
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return lexRightDelim
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}
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return l.errorf("unclosed left paren")
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}
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switch r := l.next(); {
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case r == eof || isEndOfLine(r):
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return l.errorf("unclosed action")
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case isSpace(r):
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return lexSpace
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case r == ':':
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if l.next() != '=' {
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return l.errorf("expected :=")
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}
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l.emit(itemColonEquals)
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case r == '|':
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l.emit(itemPipe)
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case r == '"':
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return lexQuote
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case r == '`':
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return lexRawQuote
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case r == '$':
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return lexVariable
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case r == '\'':
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return lexChar
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case r == '.':
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// special look-ahead for ".field" so we don't break l.backup().
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if l.pos < Pos(len(l.input)) {
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r := l.input[l.pos]
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if r < '0' || '9' < r {
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return lexField
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}
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}
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fallthrough // '.' can start a number.
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case r == '+' || r == '-' || ('0' <= r && r <= '9'):
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l.backup()
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return lexNumber
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case isAlphaNumeric(r):
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l.backup()
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return lexIdentifier
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case r == '(':
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l.emit(itemLeftParen)
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l.parenDepth++
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return lexInsideAction
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case r == ')':
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l.emit(itemRightParen)
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l.parenDepth--
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if l.parenDepth < 0 {
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return l.errorf("unexpected right paren %#U", r)
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}
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return lexInsideAction
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case r <= unicode.MaxASCII && unicode.IsPrint(r):
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l.emit(itemChar)
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return lexInsideAction
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default:
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return l.errorf("unrecognized character in action: %#U", r)
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}
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return lexInsideAction
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}
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// lexSpace scans a run of space characters.
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// One space has already been seen.
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func lexSpace(l *lexer) stateFn {
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for isSpace(l.peek()) {
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l.next()
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}
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l.emit(itemSpace)
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return lexInsideAction
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}
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// lexIdentifier scans an alphanumeric.
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func lexIdentifier(l *lexer) stateFn {
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Loop:
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for {
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switch r := l.next(); {
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case isAlphaNumeric(r):
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// absorb.
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default:
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l.backup()
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word := l.input[l.start:l.pos]
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if !l.atTerminator() {
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return l.errorf("bad character %#U", r)
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}
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switch {
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case key[word] > itemKeyword:
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l.emit(key[word])
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case word[0] == '.':
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l.emit(itemField)
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case word == "true", word == "false":
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l.emit(itemBool)
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default:
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l.emit(itemIdentifier)
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}
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break Loop
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}
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}
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return lexInsideAction
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}
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// lexField scans a field: .Alphanumeric.
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// The . has been scanned.
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func lexField(l *lexer) stateFn {
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return lexFieldOrVariable(l, itemField)
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||||
}
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||||
|
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// lexVariable scans a Variable: $Alphanumeric.
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// The $ has been scanned.
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||||
func lexVariable(l *lexer) stateFn {
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||||
if l.atTerminator() { // Nothing interesting follows -> "$".
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||||
l.emit(itemVariable)
|
||||
return lexInsideAction
|
||||
}
|
||||
return lexFieldOrVariable(l, itemVariable)
|
||||
}
|
||||
|
||||
// lexVariable scans a field or variable: [.$]Alphanumeric.
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||||
// The . or $ has been scanned.
|
||||
func lexFieldOrVariable(l *lexer, typ itemType) stateFn {
|
||||
if l.atTerminator() { // Nothing interesting follows -> "." or "$".
|
||||
if typ == itemVariable {
|
||||
l.emit(itemVariable)
|
||||
} else {
|
||||
l.emit(itemDot)
|
||||
}
|
||||
return lexInsideAction
|
||||
}
|
||||
var r rune
|
||||
for {
|
||||
r = l.next()
|
||||
if !isAlphaNumeric(r) {
|
||||
l.backup()
|
||||
break
|
||||
}
|
||||
}
|
||||
if !l.atTerminator() {
|
||||
return l.errorf("bad character %#U", r)
|
||||
}
|
||||
l.emit(typ)
|
||||
return lexInsideAction
|
||||
}
|
||||
|
||||
// atTerminator reports whether the input is at valid termination character to
|
||||
// appear after an identifier. Breaks .X.Y into two pieces. Also catches cases
|
||||
// like "$x+2" not being acceptable without a space, in case we decide one
|
||||
// day to implement arithmetic.
|
||||
func (l *lexer) atTerminator() bool {
|
||||
r := l.peek()
|
||||
if isSpace(r) || isEndOfLine(r) {
|
||||
return true
|
||||
}
|
||||
switch r {
|
||||
case eof, '.', ',', '|', ':', ')', '(':
|
||||
return true
|
||||
}
|
||||
// Does r start the delimiter? This can be ambiguous (with delim=="//", $x/2 will
|
||||
// succeed but should fail) but only in extremely rare cases caused by willfully
|
||||
// bad choice of delimiter.
|
||||
if rd, _ := utf8.DecodeRuneInString(l.rightDelim); rd == r {
|
||||
return true
|
||||
}
|
||||
return false
|
||||
}
|
||||
|
||||
// lexChar scans a character constant. The initial quote is already
|
||||
// scanned. Syntax checking is done by the parser.
|
||||
func lexChar(l *lexer) stateFn {
|
||||
Loop:
|
||||
for {
|
||||
switch l.next() {
|
||||
case '\\':
|
||||
if r := l.next(); r != eof && r != '\n' {
|
||||
break
|
||||
}
|
||||
fallthrough
|
||||
case eof, '\n':
|
||||
return l.errorf("unterminated character constant")
|
||||
case '\'':
|
||||
break Loop
|
||||
}
|
||||
}
|
||||
l.emit(itemCharConstant)
|
||||
return lexInsideAction
|
||||
}
|
||||
|
||||
// lexNumber scans a number: decimal, octal, hex, float, or imaginary. This
|
||||
// isn't a perfect number scanner - for instance it accepts "." and "0x0.2"
|
||||
// and "089" - but when it's wrong the input is invalid and the parser (via
|
||||
// strconv) will notice.
|
||||
func lexNumber(l *lexer) stateFn {
|
||||
if !l.scanNumber() {
|
||||
return l.errorf("bad number syntax: %q", l.input[l.start:l.pos])
|
||||
}
|
||||
if sign := l.peek(); sign == '+' || sign == '-' {
|
||||
// Complex: 1+2i. No spaces, must end in 'i'.
|
||||
if !l.scanNumber() || l.input[l.pos-1] != 'i' {
|
||||
return l.errorf("bad number syntax: %q", l.input[l.start:l.pos])
|
||||
}
|
||||
l.emit(itemComplex)
|
||||
} else {
|
||||
l.emit(itemNumber)
|
||||
}
|
||||
return lexInsideAction
|
||||
}
|
||||
|
||||
func (l *lexer) scanNumber() bool {
|
||||
// Optional leading sign.
|
||||
l.accept("+-")
|
||||
// Is it hex?
|
||||
digits := "0123456789"
|
||||
if l.accept("0") && l.accept("xX") {
|
||||
digits = "0123456789abcdefABCDEF"
|
||||
}
|
||||
l.acceptRun(digits)
|
||||
if l.accept(".") {
|
||||
l.acceptRun(digits)
|
||||
}
|
||||
if l.accept("eE") {
|
||||
l.accept("+-")
|
||||
l.acceptRun("0123456789")
|
||||
}
|
||||
// Is it imaginary?
|
||||
l.accept("i")
|
||||
// Next thing mustn't be alphanumeric.
|
||||
if isAlphaNumeric(l.peek()) {
|
||||
l.next()
|
||||
return false
|
||||
}
|
||||
return true
|
||||
}
|
||||
|
||||
// lexQuote scans a quoted string.
|
||||
func lexQuote(l *lexer) stateFn {
|
||||
Loop:
|
||||
for {
|
||||
switch l.next() {
|
||||
case '\\':
|
||||
if r := l.next(); r != eof && r != '\n' {
|
||||
break
|
||||
}
|
||||
fallthrough
|
||||
case eof, '\n':
|
||||
return l.errorf("unterminated quoted string")
|
||||
case '"':
|
||||
break Loop
|
||||
}
|
||||
}
|
||||
l.emit(itemString)
|
||||
return lexInsideAction
|
||||
}
|
||||
|
||||
// lexRawQuote scans a raw quoted string.
|
||||
func lexRawQuote(l *lexer) stateFn {
|
||||
Loop:
|
||||
for {
|
||||
switch l.next() {
|
||||
case eof, '\n':
|
||||
return l.errorf("unterminated raw quoted string")
|
||||
case '`':
|
||||
break Loop
|
||||
}
|
||||
}
|
||||
l.emit(itemRawString)
|
||||
return lexInsideAction
|
||||
}
|
||||
|
||||
// isSpace reports whether r is a space character.
|
||||
func isSpace(r rune) bool {
|
||||
return r == ' ' || r == '\t'
|
||||
}
|
||||
|
||||
// isEndOfLine reports whether r is an end-of-line character.
|
||||
func isEndOfLine(r rune) bool {
|
||||
return r == '\r' || r == '\n'
|
||||
}
|
||||
|
||||
// isAlphaNumeric reports whether r is an alphabetic, digit, or underscore.
|
||||
func isAlphaNumeric(r rune) bool {
|
||||
return r == '_' || unicode.IsLetter(r) || unicode.IsDigit(r)
|
||||
}
|
||||
Reference in New Issue
Block a user