mirror of
https://github.com/gohugoio/hugo.git
synced 2025-08-15 20:44:01 +02:00
Bjørn Erik Pedersen
322
parser/pageparser/pagelexer_shortcode.go
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322
parser/pageparser/pagelexer_shortcode.go
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// Copyright 2018 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package pageparser provides a parser for Hugo content files (Markdown, HTML etc.) in Hugo.
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// This implementation is highly inspired by the great talk given by Rob Pike called "Lexical Scanning in Go"
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// It's on YouTube, Google it!.
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// See slides here: http://cuddle.googlecode.com/hg/talk/lex.html
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package pageparser
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type lexerShortcodeState struct {
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currLeftDelimItem ItemType
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currRightDelimItem ItemType
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isInline bool
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currShortcodeName string // is only set when a shortcode is in opened state
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closingState int // > 0 = on its way to be closed
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elementStepNum int // step number in element
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paramElements int // number of elements (name + value = 2) found first
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openShortcodes map[string]bool // set of shortcodes in open state
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}
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// Shortcode syntax
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var (
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leftDelimSc = []byte("{{")
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leftDelimScNoMarkup = []byte("{{<")
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rightDelimScNoMarkup = []byte(">}}")
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leftDelimScWithMarkup = []byte("{{%")
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rightDelimScWithMarkup = []byte("%}}")
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leftComment = []byte("/*") // comments in this context us used to to mark shortcodes as "not really a shortcode"
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rightComment = []byte("*/")
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)
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func (l *pageLexer) isShortCodeStart() bool {
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return l.hasPrefix(leftDelimScWithMarkup) || l.hasPrefix(leftDelimScNoMarkup)
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}
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func lexShortcodeLeftDelim(l *pageLexer) stateFunc {
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l.pos += len(l.currentLeftShortcodeDelim())
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if l.hasPrefix(leftComment) {
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return lexShortcodeComment
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}
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l.emit(l.currentLeftShortcodeDelimItem())
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l.elementStepNum = 0
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l.paramElements = 0
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return lexInsideShortcode
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}
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func lexShortcodeComment(l *pageLexer) stateFunc {
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posRightComment := l.index(append(rightComment, l.currentRightShortcodeDelim()...))
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if posRightComment <= 1 {
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return l.errorf("comment must be closed")
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}
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// we emit all as text, except the comment markers
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l.emit(tText)
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l.pos += len(leftComment)
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l.ignore()
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l.pos += posRightComment - len(leftComment)
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l.emit(tText)
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l.pos += len(rightComment)
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l.ignore()
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l.pos += len(l.currentRightShortcodeDelim())
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l.emit(tText)
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return lexMainSection
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}
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func lexShortcodeRightDelim(l *pageLexer) stateFunc {
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l.closingState = 0
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l.pos += len(l.currentRightShortcodeDelim())
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l.emit(l.currentRightShortcodeDelimItem())
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return lexMainSection
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}
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// either:
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// 1. param
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// 2. "param" or "param\"
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// 3. param="123" or param="123\"
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// 4. param="Some \"escaped\" text"
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func lexShortcodeParam(l *pageLexer, escapedQuoteStart bool) stateFunc {
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first := true
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nextEq := false
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var r rune
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for {
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r = l.next()
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if first {
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if r == '"' {
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// a positional param with quotes
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if l.paramElements == 2 {
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return l.errorf("got quoted positional parameter. Cannot mix named and positional parameters")
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}
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l.paramElements = 1
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l.backup()
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return lexShortcodeQuotedParamVal(l, !escapedQuoteStart, tScParam)
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}
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first = false
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} else if r == '=' {
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// a named param
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l.backup()
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nextEq = true
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break
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}
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if !isAlphaNumericOrHyphen(r) {
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l.backup()
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break
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}
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}
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if l.paramElements == 0 {
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l.paramElements++
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if nextEq {
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l.paramElements++
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}
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} else {
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if nextEq && l.paramElements == 1 {
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return l.errorf("got named parameter '%s'. Cannot mix named and positional parameters", l.current())
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} else if !nextEq && l.paramElements == 2 {
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return l.errorf("got positional parameter '%s'. Cannot mix named and positional parameters", l.current())
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}
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}
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l.emit(tScParam)
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return lexInsideShortcode
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}
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func lexShortcodeQuotedParamVal(l *pageLexer, escapedQuotedValuesAllowed bool, typ ItemType) stateFunc {
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openQuoteFound := false
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escapedInnerQuoteFound := false
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escapedQuoteState := 0
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Loop:
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for {
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switch r := l.next(); {
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case r == '\\':
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if l.peek() == '"' {
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if openQuoteFound && !escapedQuotedValuesAllowed {
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l.backup()
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break Loop
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} else if openQuoteFound {
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// the coming quoute is inside
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escapedInnerQuoteFound = true
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escapedQuoteState = 1
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}
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}
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case r == eof, r == '\n':
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return l.errorf("unterminated quoted string in shortcode parameter-argument: '%s'", l.current())
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case r == '"':
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if escapedQuoteState == 0 {
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if openQuoteFound {
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l.backup()
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break Loop
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} else {
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openQuoteFound = true
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l.ignore()
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}
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} else {
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escapedQuoteState = 0
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}
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}
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}
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if escapedInnerQuoteFound {
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l.ignoreEscapesAndEmit(typ)
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} else {
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l.emit(typ)
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}
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r := l.next()
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if r == '\\' {
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if l.peek() == '"' {
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// ignore the escaped closing quote
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l.ignore()
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l.next()
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l.ignore()
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}
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} else if r == '"' {
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// ignore closing quote
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l.ignore()
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} else {
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// handled by next state
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l.backup()
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}
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return lexInsideShortcode
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}
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// Inline shortcodes has the form {{< myshortcode.inline >}}
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var inlineIdentifier = []byte("inline ")
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// scans an alphanumeric inside shortcode
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func lexIdentifierInShortcode(l *pageLexer) stateFunc {
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lookForEnd := false
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Loop:
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for {
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switch r := l.next(); {
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case isAlphaNumericOrHyphen(r):
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// Allow forward slash inside names to make it possible to create namespaces.
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case r == '/':
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case r == '.':
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l.isInline = l.hasPrefix(inlineIdentifier)
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if !l.isInline {
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return l.errorf("period in shortcode name only allowed for inline identifiers")
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}
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default:
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l.backup()
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word := string(l.input[l.start:l.pos])
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if l.closingState > 0 && !l.openShortcodes[word] {
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return l.errorf("closing tag for shortcode '%s' does not match start tag", word)
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} else if l.closingState > 0 {
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l.openShortcodes[word] = false
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lookForEnd = true
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}
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l.closingState = 0
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l.currShortcodeName = word
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l.openShortcodes[word] = true
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l.elementStepNum++
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if l.isInline {
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l.emit(tScNameInline)
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} else {
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l.emit(tScName)
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}
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break Loop
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}
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}
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if lookForEnd {
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return lexEndOfShortcode
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}
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return lexInsideShortcode
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}
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func lexEndOfShortcode(l *pageLexer) stateFunc {
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l.isInline = false
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if l.hasPrefix(l.currentRightShortcodeDelim()) {
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return lexShortcodeRightDelim
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}
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switch r := l.next(); {
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case isSpace(r):
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l.ignore()
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default:
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return l.errorf("unclosed shortcode")
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}
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return lexEndOfShortcode
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}
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// scans the elements inside shortcode tags
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func lexInsideShortcode(l *pageLexer) stateFunc {
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if l.hasPrefix(l.currentRightShortcodeDelim()) {
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return lexShortcodeRightDelim
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}
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switch r := l.next(); {
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case r == eof:
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// eol is allowed inside shortcodes; this may go to end of document before it fails
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return l.errorf("unclosed shortcode action")
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case isSpace(r), isEndOfLine(r):
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l.ignore()
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case r == '=':
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l.ignore()
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return lexShortcodeQuotedParamVal(l, l.peek() != '\\', tScParamVal)
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case r == '/':
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if l.currShortcodeName == "" {
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return l.errorf("got closing shortcode, but none is open")
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}
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l.closingState++
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l.emit(tScClose)
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case r == '\\':
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l.ignore()
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if l.peek() == '"' {
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return lexShortcodeParam(l, true)
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}
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case l.elementStepNum > 0 && (isAlphaNumericOrHyphen(r) || r == '"'): // positional params can have quotes
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l.backup()
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return lexShortcodeParam(l, false)
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case isAlphaNumeric(r):
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l.backup()
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return lexIdentifierInShortcode
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default:
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return l.errorf("unrecognized character in shortcode action: %#U. Note: Parameters with non-alphanumeric args must be quoted", r)
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}
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return lexInsideShortcode
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}
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func (l *pageLexer) currentLeftShortcodeDelimItem() ItemType {
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return l.currLeftDelimItem
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}
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func (l *pageLexer) currentRightShortcodeDelimItem() ItemType {
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return l.currRightDelimItem
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}
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func (l *pageLexer) currentLeftShortcodeDelim() []byte {
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if l.currLeftDelimItem == tLeftDelimScWithMarkup {
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return leftDelimScWithMarkup
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}
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return leftDelimScNoMarkup
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}
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func (l *pageLexer) currentRightShortcodeDelim() []byte {
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if l.currRightDelimItem == tRightDelimScWithMarkup {
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return rightDelimScWithMarkup
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}
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return rightDelimScNoMarkup
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}
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