Move the shortcode parser to the new pageparser package

See #5324

2 files changed, 851 insertions, 0 deletions

diff --git a/parser/pageparser/shortcodeparser.go b/parser/pageparser/shortcodeparser.go
new file mode 100644
index 000000000..a12597a7c
--- /dev/null
+++ b/parser/pageparser/shortcodeparser.go
@@ -0,0 +1,644 @@
+// Copyright 2018 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pageparser
+
+import (
+	"fmt"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+// The lexical scanning below is highly inspired by the great talk given by
+// Rob Pike called "Lexical Scanning in Go" (it's on YouTube, Google it!).
+// See slides here: http://cuddle.googlecode.com/hg/talk/lex.html
+
+// parsing
+
+type Tokens struct {
+	lexer     *pagelexer
+	token     [3]Item // 3-item look-ahead is what we currently need
+	peekCount int
+}
+
+func (t *Tokens) Next() Item {
+	if t.peekCount > 0 {
+		t.peekCount--
+	} else {
+		t.token[0] = t.lexer.nextItem()
+	}
+	return t.token[t.peekCount]
+}
+
+// backs up one token.
+func (t *Tokens) Backup() {
+	t.peekCount++
+}
+
+// backs up two tokens.
+func (t *Tokens) Backup2(t1 Item) {
+	t.token[1] = t1
+	t.peekCount = 2
+}
+
+// backs up three tokens.
+func (t *Tokens) Backup3(t2, t1 Item) {
+	t.token[1] = t1
+	t.token[2] = t2
+	t.peekCount = 3
+}
+
+// check for non-error and non-EOF types coming next
+func (t *Tokens) IsValueNext() bool {
+	i := t.Peek()
+	return i.typ != tError && i.typ != tEOF
+}
+
+// look at, but do not consume, the next item
+// repeated, sequential calls will return the same item
+func (t *Tokens) Peek() Item {
+	if t.peekCount > 0 {
+		return t.token[t.peekCount-1]
+	}
+	t.peekCount = 1
+	t.token[0] = t.lexer.nextItem()
+	return t.token[0]
+}
+
+// Consume is a convencience method to consume the next n tokens,
+// but back off Errors and EOF.
+func (t *Tokens) Consume(cnt int) {
+	for i := 0; i < cnt; i++ {
+		token := t.Next()
+		if token.typ == tError || token.typ == tEOF {
+			t.Backup()
+			break
+		}
+	}
+}
+
+// LineNumber returns the current line number. Used for logging.
+func (t *Tokens) LineNumber() int {
+	return t.lexer.lineNum()
+}
+
+// lexical scanning
+
+// position (in bytes)
+type pos int
+
+type Item struct {
+	typ itemType
+	pos pos
+	Val string
+}
+
+func (i Item) IsText() bool {
+	return i.typ == tText
+}
+
+func (i Item) IsShortcodeName() bool {
+	return i.typ == tScName
+}
+
+func (i Item) IsLeftShortcodeDelim() bool {
+	return i.typ == tLeftDelimScWithMarkup || i.typ == tLeftDelimScNoMarkup
+}
+
+func (i Item) IsRightShortcodeDelim() bool {
+	return i.typ == tRightDelimScWithMarkup || i.typ == tRightDelimScNoMarkup
+}
+
+func (i Item) IsShortcodeClose() bool {
+	return i.typ == tScClose
+}
+
+func (i Item) IsShortcodeParam() bool {
+	return i.typ == tScParam
+}
+
+func (i Item) IsShortcodeParamVal() bool {
+	return i.typ == tScParamVal
+}
+
+func (i Item) IsShortcodeMarkupDelimiter() bool {
+	return i.typ == tLeftDelimScWithMarkup || i.typ == tRightDelimScWithMarkup
+}
+
+func (i Item) IsDone() bool {
+	return i.typ == tError || i.typ == tEOF
+}
+
+func (i Item) IsEOF() bool {
+	return i.typ == tEOF
+}
+
+func (i Item) IsError() bool {
+	return i.typ == tError
+}
+
+func (i Item) String() string {
+	switch {
+	case i.typ == tEOF:
+		return "EOF"
+	case i.typ == tError:
+		return i.Val
+	case i.typ > tKeywordMarker:
+		return fmt.Sprintf("<%s>", i.Val)
+	case len(i.Val) > 20:
+		return fmt.Sprintf("%.20q...", i.Val)
+	}
+	return fmt.Sprintf("[%s]", i.Val)
+}
+
+type itemType int
+
+const (
+	tError itemType = iota
+	tEOF
+
+	// shortcode items
+	tLeftDelimScNoMarkup
+	tRightDelimScNoMarkup
+	tLeftDelimScWithMarkup
+	tRightDelimScWithMarkup
+	tScClose
+	tScName
+	tScParam
+	tScParamVal
+
+	//itemIdentifier
+	tText // plain text, used for everything outside the shortcodes
+
+	// preserved for later - keywords come after this
+	tKeywordMarker
+)
+
+const eof = -1
+
+// returns the next state in scanner.
+type stateFunc func(*pagelexer) stateFunc
+
+type pagelexer struct {
+	name    string
+	input   string
+	state   stateFunc
+	pos     pos // input position
+	start   pos // item start position
+	width   pos // width of last element
+	lastPos pos // position of the last item returned by nextItem
+
+	// shortcode state
+	currLeftDelimItem  itemType
+	currRightDelimItem itemType
+	currShortcodeName  string          // is only set when a shortcode is in opened state
+	closingState       int             // > 0 = on its way to be closed
+	elementStepNum     int             // step number in element
+	paramElements      int             // number of elements (name + value = 2) found first
+	openShortcodes     map[string]bool // set of shortcodes in open state
+
+	// items delivered to client
+	items []Item
+}
+
+func Parse(s string) *Tokens {
+	return ParseFrom(s, 0)
+}
+
+func ParseFrom(s string, from int) *Tokens {
+	return &Tokens{lexer: newShortcodeLexer("default", s, pos(from))}
+}
+
+// note: the input position here is normally 0 (start), but
+// can be set if position of first shortcode is known
+func newShortcodeLexer(name, input string, inputPosition pos) *pagelexer {
+	lexer := &pagelexer{
+		name:               name,
+		input:              input,
+		currLeftDelimItem:  tLeftDelimScNoMarkup,
+		currRightDelimItem: tRightDelimScNoMarkup,
+		pos:                inputPosition,
+		openShortcodes:     make(map[string]bool),
+		items:              make([]Item, 0, 5),
+	}
+	lexer.runShortcodeLexer()
+	return lexer
+}
+
+// main loop
+// this looks kind of funky, but it works
+func (l *pagelexer) runShortcodeLexer() {
+	for l.state = lexTextOutsideShortcodes; l.state != nil; {
+		l.state = l.state(l)
+	}
+}
+
+// state functions
+
+const (
+	leftDelimScNoMarkup    = "{{<"
+	rightDelimScNoMarkup   = ">}}"
+	leftDelimScWithMarkup  = "{{%"
+	rightDelimScWithMarkup = "%}}"
+	leftComment            = "/*" // comments in this context us used to to mark shortcodes as "not really a shortcode"
+	rightComment           = "*/"
+)
+
+func (l *pagelexer) next() rune {
+	if int(l.pos) >= len(l.input) {
+		l.width = 0
+		return eof
+	}
+
+	// looks expensive, but should produce the same iteration sequence as the string range loop
+	// see: http://blog.golang.org/strings
+	runeValue, runeWidth := utf8.DecodeRuneInString(l.input[l.pos:])
+	l.width = pos(runeWidth)
+	l.pos += l.width
+	return runeValue
+}
+
+// peek, but no consume
+func (l *pagelexer) peek() rune {
+	r := l.next()
+	l.backup()
+	return r
+}
+
+// steps back one
+func (l *pagelexer) backup() {
+	l.pos -= l.width
+}
+
+// sends an item back to the client.
+func (l *pagelexer) emit(t itemType) {
+	l.items = append(l.items, Item{t, l.start, l.input[l.start:l.pos]})
+	l.start = l.pos
+}
+
+// special case, do not send '\\' back to client
+func (l *pagelexer) ignoreEscapesAndEmit(t itemType) {
+	val := strings.Map(func(r rune) rune {
+		if r == '\\' {
+			return -1
+		}
+		return r
+	}, l.input[l.start:l.pos])
+	l.items = append(l.items, Item{t, l.start, val})
+	l.start = l.pos
+}
+
+// gets the current value (for debugging and error handling)
+func (l *pagelexer) current() string {
+	return l.input[l.start:l.pos]
+}
+
+// ignore current element
+func (l *pagelexer) ignore() {
+	l.start = l.pos
+}
+
+// nice to have in error logs
+func (l *pagelexer) lineNum() int {
+	return strings.Count(l.input[:l.lastPos], "\n") + 1
+}
+
+// nil terminates the parser
+func (l *pagelexer) errorf(format string, args ...interface{}) stateFunc {
+	l.items = append(l.items, Item{tError, l.start, fmt.Sprintf(format, args...)})
+	return nil
+}
+
+// consumes and returns the next item
+func (l *pagelexer) nextItem() Item {
+	item := l.items[0]
+	l.items = l.items[1:]
+	l.lastPos = item.pos
+	return item
+}
+
+// scans until an opening shortcode opening bracket.
+// if no shortcodes, it will keep on scanning until EOF
+func lexTextOutsideShortcodes(l *pagelexer) stateFunc {
+	for {
+		if strings.HasPrefix(l.input[l.pos:], leftDelimScWithMarkup) || strings.HasPrefix(l.input[l.pos:], leftDelimScNoMarkup) {
+			if l.pos > l.start {
+				l.emit(tText)
+			}
+			if strings.HasPrefix(l.input[l.pos:], leftDelimScWithMarkup) {
+				l.currLeftDelimItem = tLeftDelimScWithMarkup
+				l.currRightDelimItem = tRightDelimScWithMarkup
+			} else {
+				l.currLeftDelimItem = tLeftDelimScNoMarkup
+				l.currRightDelimItem = tRightDelimScNoMarkup
+			}
+			return lexShortcodeLeftDelim
+
+		}
+		if l.next() == eof {
+			break
+		}
+	}
+	// Done!
+	if l.pos > l.start {
+		l.emit(tText)
+	}
+	l.emit(tEOF)
+	return nil
+}
+
+func lexShortcodeLeftDelim(l *pagelexer) stateFunc {
+	l.pos += pos(len(l.currentLeftShortcodeDelim()))
+	if strings.HasPrefix(l.input[l.pos:], leftComment) {
+		return lexShortcodeComment
+	}
+	l.emit(l.currentLeftShortcodeDelimItem())
+	l.elementStepNum = 0
+	l.paramElements = 0
+	return lexInsideShortcode
+}
+
+func lexShortcodeComment(l *pagelexer) stateFunc {
+	posRightComment := strings.Index(l.input[l.pos:], rightComment+l.currentRightShortcodeDelim())
+	if posRightComment <= 1 {
+		return l.errorf("comment must be closed")
+	}
+	// we emit all as text, except the comment markers
+	l.emit(tText)
+	l.pos += pos(len(leftComment))
+	l.ignore()
+	l.pos += pos(posRightComment - len(leftComment))
+	l.emit(tText)
+	l.pos += pos(len(rightComment))
+	l.ignore()
+	l.pos += pos(len(l.currentRightShortcodeDelim()))
+	l.emit(tText)
+	return lexTextOutsideShortcodes
+}
+
+func lexShortcodeRightDelim(l *pagelexer) stateFunc {
+	l.closingState = 0
+	l.pos += pos(len(l.currentRightShortcodeDelim()))
+	l.emit(l.currentRightShortcodeDelimItem())
+	return lexTextOutsideShortcodes
+}
+
+// either:
+// 1. param
+// 2. "param" or "param\"
+// 3. param="123" or param="123\"
+// 4. param="Some \"escaped\" text"
+func lexShortcodeParam(l *pagelexer, escapedQuoteStart bool) stateFunc {
+
+	first := true
+	nextEq := false
+
+	var r rune
+
+	for {
+		r = l.next()
+		if first {
+			if r == '"' {
+				// a positional param with quotes
+				if l.paramElements == 2 {
+					return l.errorf("got quoted positional parameter. Cannot mix named and positional parameters")
+				}
+				l.paramElements = 1
+				l.backup()
+				return lexShortcodeQuotedParamVal(l, !escapedQuoteStart, tScParam)
+			}
+			first = false
+		} else if r == '=' {
+			// a named param
+			l.backup()
+			nextEq = true
+			break
+		}
+
+		if !isAlphaNumericOrHyphen(r) {
+			l.backup()
+			break
+		}
+	}
+
+	if l.paramElements == 0 {
+		l.paramElements++
+
+		if nextEq {
+			l.paramElements++
+		}
+	} else {
+		if nextEq && l.paramElements == 1 {
+			return l.errorf("got named parameter '%s'. Cannot mix named and positional parameters", l.current())
+		} else if !nextEq && l.paramElements == 2 {
+			return l.errorf("got positional parameter '%s'. Cannot mix named and positional parameters", l.current())
+		}
+	}
+
+	l.emit(tScParam)
+	return lexInsideShortcode
+
+}
+
+func lexShortcodeQuotedParamVal(l *pagelexer, escapedQuotedValuesAllowed bool, typ itemType) stateFunc {
+	openQuoteFound := false
+	escapedInnerQuoteFound := false
+	escapedQuoteState := 0
+
+Loop:
+	for {
+		switch r := l.next(); {
+		case r == '\\':
+			if l.peek() == '"' {
+				if openQuoteFound && !escapedQuotedValuesAllowed {
+					l.backup()
+					break Loop
+				} else if openQuoteFound {
+					// the coming quoute is inside
+					escapedInnerQuoteFound = true
+					escapedQuoteState = 1
+				}
+			}
+		case r == eof, r == '\n':
+			return l.errorf("unterminated quoted string in shortcode parameter-argument: '%s'", l.current())
+		case r == '"':
+			if escapedQuoteState == 0 {
+				if openQuoteFound {
+					l.backup()
+					break Loop
+
+				} else {
+					openQuoteFound = true
+					l.ignore()
+				}
+			} else {
+				escapedQuoteState = 0
+			}
+
+		}
+	}
+
+	if escapedInnerQuoteFound {
+		l.ignoreEscapesAndEmit(typ)
+	} else {
+		l.emit(typ)
+	}
+
+	r := l.next()
+
+	if r == '\\' {
+		if l.peek() == '"' {
+			// ignore the escaped closing quote
+			l.ignore()
+			l.next()
+			l.ignore()
+		}
+	} else if r == '"' {
+		// ignore closing quote
+		l.ignore()
+	} else {
+		// handled by next state
+		l.backup()
+	}
+
+	return lexInsideShortcode
+}
+
+// scans an alphanumeric inside shortcode
+func lexIdentifierInShortcode(l *pagelexer) stateFunc {
+	lookForEnd := false
+Loop:
+	for {
+		switch r := l.next(); {
+		case isAlphaNumericOrHyphen(r):
+		// Allow forward slash inside names to make it possible to create namespaces.
+		case r == '/':
+		default:
+			l.backup()
+			word := l.input[l.start:l.pos]
+			if l.closingState > 0 && !l.openShortcodes[word] {
+				return l.errorf("closing tag for shortcode '%s' does not match start tag", word)
+			} else if l.closingState > 0 {
+				l.openShortcodes[word] = false
+				lookForEnd = true
+			}
+
+			l.closingState = 0
+			l.currShortcodeName = word
+			l.openShortcodes[word] = true
+			l.elementStepNum++
+			l.emit(tScName)
+			break Loop
+		}
+	}
+
+	if lookForEnd {
+		return lexEndOfShortcode
+	}
+	return lexInsideShortcode
+}
+
+func lexEndOfShortcode(l *pagelexer) stateFunc {
+	if strings.HasPrefix(l.input[l.pos:], l.currentRightShortcodeDelim()) {
+		return lexShortcodeRightDelim
+	}
+	switch r := l.next(); {
+	case isSpace(r):
+		l.ignore()
+	default:
+		return l.errorf("unclosed shortcode")
+	}
+	return lexEndOfShortcode
+}
+
+// scans the elements inside shortcode tags
+func lexInsideShortcode(l *pagelexer) stateFunc {
+	if strings.HasPrefix(l.input[l.pos:], l.currentRightShortcodeDelim()) {
+		return lexShortcodeRightDelim
+	}
+	switch r := l.next(); {
+	case r == eof:
+		// eol is allowed inside shortcodes; this may go to end of document before it fails
+		return l.errorf("unclosed shortcode action")
+	case isSpace(r), isEndOfLine(r):
+		l.ignore()
+	case r == '=':
+		l.ignore()
+		return lexShortcodeQuotedParamVal(l, l.peek() != '\\', tScParamVal)
+	case r == '/':
+		if l.currShortcodeName == "" {
+			return l.errorf("got closing shortcode, but none is open")
+		}
+		l.closingState++
+		l.emit(tScClose)
+	case r == '\\':
+		l.ignore()
+		if l.peek() == '"' {
+			return lexShortcodeParam(l, true)
+		}
+	case l.elementStepNum > 0 && (isAlphaNumericOrHyphen(r) || r == '"'): // positional params can have quotes
+		l.backup()
+		return lexShortcodeParam(l, false)
+	case isAlphaNumeric(r):
+		l.backup()
+		return lexIdentifierInShortcode
+	default:
+		return l.errorf("unrecognized character in shortcode action: %#U. Note: Parameters with non-alphanumeric args must be quoted", r)
+	}
+	return lexInsideShortcode
+}
+
+// state helpers
+
+func (l *pagelexer) currentLeftShortcodeDelimItem() itemType {
+	return l.currLeftDelimItem
+}
+
+func (l *pagelexer) currentRightShortcodeDelimItem() itemType {
+	return l.currRightDelimItem
+}
+
+func (l *pagelexer) currentLeftShortcodeDelim() string {
+	if l.currLeftDelimItem == tLeftDelimScWithMarkup {
+		return leftDelimScWithMarkup
+	}
+	return leftDelimScNoMarkup
+
+}
+
+func (l *pagelexer) currentRightShortcodeDelim() string {
+	if l.currRightDelimItem == tRightDelimScWithMarkup {
+		return rightDelimScWithMarkup
+	}
+	return rightDelimScNoMarkup
+}
+
+// helper functions
+
+func isSpace(r rune) bool {
+	return r == ' ' || r == '\t'
+}
+
+func isAlphaNumericOrHyphen(r rune) bool {
+	// let unquoted YouTube ids as positional params slip through (they contain hyphens)
+	return isAlphaNumeric(r) || r == '-'
+}
+
+func isEndOfLine(r rune) bool {
+	return r == '\r' || r == '\n'
+}
+
+func isAlphaNumeric(r rune) bool {
+	return r == '_' || unicode.IsLetter(r) || unicode.IsDigit(r)
+}
diff --git a/parser/pageparser/shortcodeparser_test.go b/parser/pageparser/shortcodeparser_test.go
new file mode 100644
index 000000000..bba4bf888
--- /dev/null
+++ b/parser/pageparser/shortcodeparser_test.go
@@ -0,0 +1,207 @@
+// Copyright 2018 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pageparser
+
+import (
+	"testing"
+)
+
+type shortCodeLexerTest struct {
+	name  string
+	input string
+	items []Item
+}
+
+var (
+	tstEOF       = Item{tEOF, 0, ""}
+	tstLeftNoMD  = Item{tLeftDelimScNoMarkup, 0, "{{<"}
+	tstRightNoMD = Item{tRightDelimScNoMarkup, 0, ">}}"}
+	tstLeftMD    = Item{tLeftDelimScWithMarkup, 0, "{{%"}
+	tstRightMD   = Item{tRightDelimScWithMarkup, 0, "%}}"}
+	tstSCClose   = Item{tScClose, 0, "/"}
+	tstSC1       = Item{tScName, 0, "sc1"}
+	tstSC2       = Item{tScName, 0, "sc2"}
+	tstSC3       = Item{tScName, 0, "sc3"}
+	tstSCSlash   = Item{tScName, 0, "sc/sub"}
+	tstParam1    = Item{tScParam, 0, "param1"}
+	tstParam2    = Item{tScParam, 0, "param2"}
+	tstVal       = Item{tScParamVal, 0, "Hello World"}
+)
+
+var shortCodeLexerTests = []shortCodeLexerTest{
+	{"empty", "", []Item{tstEOF}},
+	{"spaces", " \t\n", []Item{{tText, 0, " \t\n"}, tstEOF}},
+	{"text", `to be or not`, []Item{{tText, 0, "to be or not"}, tstEOF}},
+	{"no markup", `{{< sc1 >}}`, []Item{tstLeftNoMD, tstSC1, tstRightNoMD, tstEOF}},
+	{"with EOL", "{{< sc1 \n >}}", []Item{tstLeftNoMD, tstSC1, tstRightNoMD, tstEOF}},
+
+	{"forward slash inside name", `{{< sc/sub >}}`, []Item{tstLeftNoMD, tstSCSlash, tstRightNoMD, tstEOF}},
+
+	{"simple with markup", `{{% sc1 %}}`, []Item{tstLeftMD, tstSC1, tstRightMD, tstEOF}},
+	{"with spaces", `{{<     sc1     >}}`, []Item{tstLeftNoMD, tstSC1, tstRightNoMD, tstEOF}},
+	{"mismatched rightDelim", `{{< sc1 %}}`, []Item{tstLeftNoMD, tstSC1,
+		{tError, 0, "unrecognized character in shortcode action: U+0025 '%'. Note: Parameters with non-alphanumeric args must be quoted"}}},
+	{"inner, markup", `{{% sc1 %}} inner {{% /sc1 %}}`, []Item{
+		tstLeftMD,
+		tstSC1,
+		tstRightMD,
+		{tText, 0, " inner "},
+		tstLeftMD,
+		tstSCClose,
+		tstSC1,
+		tstRightMD,
+		tstEOF,
+	}},
+	{"close, but no open", `{{< /sc1 >}}`, []Item{
+		tstLeftNoMD, {tError, 0, "got closing shortcode, but none is open"}}},
+	{"close wrong", `{{< sc1 >}}{{< /another >}}`, []Item{
+		tstLeftNoMD, tstSC1, tstRightNoMD, tstLeftNoMD, tstSCClose,
+		{tError, 0, "closing tag for shortcode 'another' does not match start tag"}}},
+	{"close, but no open, more", `{{< sc1 >}}{{< /sc1 >}}{{< /another >}}`, []Item{
+		tstLeftNoMD, tstSC1, tstRightNoMD, tstLeftNoMD, tstSCClose, tstSC1, tstRightNoMD, tstLeftNoMD, tstSCClose,
+		{tError, 0, "closing tag for shortcode 'another' does not match start tag"}}},
+	{"close with extra keyword", `{{< sc1 >}}{{< /sc1 keyword>}}`, []Item{
+		tstLeftNoMD, tstSC1, tstRightNoMD, tstLeftNoMD, tstSCClose, tstSC1,
+		{tError, 0, "unclosed shortcode"}}},
+	{"Youtube id", `{{< sc1 -ziL-Q_456igdO-4 >}}`, []Item{
+		tstLeftNoMD, tstSC1, {tScParam, 0, "-ziL-Q_456igdO-4"}, tstRightNoMD, tstEOF}},
+	{"non-alphanumerics param quoted", `{{< sc1 "-ziL-.%QigdO-4" >}}`, []Item{
+		tstLeftNoMD, tstSC1, {tScParam, 0, "-ziL-.%QigdO-4"}, tstRightNoMD, tstEOF}},
+
+	{"two params", `{{< sc1 param1   param2 >}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1, tstParam2, tstRightNoMD, tstEOF}},
+	// issue #934
+	{"self-closing", `{{< sc1 />}}`, []Item{
+		tstLeftNoMD, tstSC1, tstSCClose, tstRightNoMD, tstEOF}},
+	// Issue 2498
+	{"multiple self-closing", `{{< sc1 />}}{{< sc1 />}}`, []Item{
+		tstLeftNoMD, tstSC1, tstSCClose, tstRightNoMD,
+		tstLeftNoMD, tstSC1, tstSCClose, tstRightNoMD, tstEOF}},
+	{"self-closing with param", `{{< sc1 param1 />}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1, tstSCClose, tstRightNoMD, tstEOF}},
+	{"multiple self-closing with param", `{{< sc1 param1 />}}{{< sc1 param1 />}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1, tstSCClose, tstRightNoMD,
+		tstLeftNoMD, tstSC1, tstParam1, tstSCClose, tstRightNoMD, tstEOF}},
+	{"multiple different self-closing with param", `{{< sc1 param1 />}}{{< sc2 param1 />}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1, tstSCClose, tstRightNoMD,
+		tstLeftNoMD, tstSC2, tstParam1, tstSCClose, tstRightNoMD, tstEOF}},
+	{"nested simple", `{{< sc1 >}}{{< sc2 >}}{{< /sc1 >}}`, []Item{
+		tstLeftNoMD, tstSC1, tstRightNoMD,
+		tstLeftNoMD, tstSC2, tstRightNoMD,
+		tstLeftNoMD, tstSCClose, tstSC1, tstRightNoMD, tstEOF}},
+	{"nested complex", `{{< sc1 >}}ab{{% sc2 param1 %}}cd{{< sc3 >}}ef{{< /sc3 >}}gh{{% /sc2 %}}ij{{< /sc1 >}}kl`, []Item{
+		tstLeftNoMD, tstSC1, tstRightNoMD,
+		{tText, 0, "ab"},
+		tstLeftMD, tstSC2, tstParam1, tstRightMD,
+		{tText, 0, "cd"},
+		tstLeftNoMD, tstSC3, tstRightNoMD,
+		{tText, 0, "ef"},
+		tstLeftNoMD, tstSCClose, tstSC3, tstRightNoMD,
+		{tText, 0, "gh"},
+		tstLeftMD, tstSCClose, tstSC2, tstRightMD,
+		{tText, 0, "ij"},
+		tstLeftNoMD, tstSCClose, tstSC1, tstRightNoMD,
+		{tText, 0, "kl"}, tstEOF,
+	}},
+
+	{"two quoted params", `{{< sc1 "param nr. 1" "param nr. 2" >}}`, []Item{
+		tstLeftNoMD, tstSC1, {tScParam, 0, "param nr. 1"}, {tScParam, 0, "param nr. 2"}, tstRightNoMD, tstEOF}},
+	{"two named params", `{{< sc1 param1="Hello World" param2="p2Val">}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1, tstVal, tstParam2, {tScParamVal, 0, "p2Val"}, tstRightNoMD, tstEOF}},
+	{"escaped quotes", `{{< sc1 param1=\"Hello World\"  >}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1, tstVal, tstRightNoMD, tstEOF}},
+	{"escaped quotes, positional param", `{{< sc1 \"param1\"  >}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1, tstRightNoMD, tstEOF}},
+	{"escaped quotes inside escaped quotes", `{{< sc1 param1=\"Hello \"escaped\" World\"  >}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1,
+		{tScParamVal, 0, `Hello `}, {tError, 0, `got positional parameter 'escaped'. Cannot mix named and positional parameters`}}},
+	{"escaped quotes inside nonescaped quotes",
+		`{{< sc1 param1="Hello \"escaped\" World"  >}}`, []Item{
+			tstLeftNoMD, tstSC1, tstParam1, {tScParamVal, 0, `Hello "escaped" World`}, tstRightNoMD, tstEOF}},
+	{"escaped quotes inside nonescaped quotes in positional param",
+		`{{< sc1 "Hello \"escaped\" World"  >}}`, []Item{
+			tstLeftNoMD, tstSC1, {tScParam, 0, `Hello "escaped" World`}, tstRightNoMD, tstEOF}},
+	{"unterminated quote", `{{< sc1 param2="Hello World>}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam2, {tError, 0, "unterminated quoted string in shortcode parameter-argument: 'Hello World>}}'"}}},
+	{"one named param, one not", `{{< sc1 param1="Hello World" p2 >}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1, tstVal,
+		{tError, 0, "got positional parameter 'p2'. Cannot mix named and positional parameters"}}},
+	{"one named param, one quoted positional param", `{{< sc1 param1="Hello World" "And Universe" >}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1, tstVal,
+		{tError, 0, "got quoted positional parameter. Cannot mix named and positional parameters"}}},
+	{"one quoted positional param, one named param", `{{< sc1 "param1" param2="And Universe" >}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1,
+		{tError, 0, "got named parameter 'param2'. Cannot mix named and positional parameters"}}},
+	{"ono positional param, one not", `{{< sc1 param1 param2="Hello World">}}`, []Item{
+		tstLeftNoMD, tstSC1, tstParam1,
+		{tError, 0, "got named parameter 'param2'. Cannot mix named and positional parameters"}}},
+	{"commented out", `{{</* sc1 */>}}`, []Item{
+		{tText, 0, "{{<"}, {tText, 0, " sc1 "}, {tText, 0, ">}}"}, tstEOF}},
+	{"commented out, with asterisk inside", `{{</* sc1 "**/*.pdf" */>}}`, []Item{
+		{tText, 0, "{{<"}, {tText, 0, " sc1 \"**/*.pdf\" "}, {tText, 0, ">}}"}, tstEOF}},
+	{"commented out, missing close", `{{</* sc1 >}}`, []Item{
+		{tError, 0, "comment must be closed"}}},
+	{"commented out, misplaced close", `{{</* sc1 >}}*/`, []Item{
+		{tError, 0, "comment must be closed"}}},
+}
+
+func TestShortcodeLexer(t *testing.T) {
+	t.Parallel()
+	for i, test := range shortCodeLexerTests {
+		items := collect(&test)
+		if !equal(items, test.items) {
+			t.Errorf("[%d] %s: got\n\t%v\nexpected\n\t%v", i, test.name, items, test.items)
+		}
+	}
+}
+
+func BenchmarkShortcodeLexer(b *testing.B) {
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		for _, test := range shortCodeLexerTests {
+			items := collect(&test)
+			if !equal(items, test.items) {
+				b.Errorf("%s: got\n\t%v\nexpected\n\t%v", test.name, items, test.items)
+			}
+		}
+	}
+}
+
+func collect(t *shortCodeLexerTest) (items []Item) {
+	l := newShortcodeLexer(t.name, t.input, 0)
+	for {
+		item := l.nextItem()
+		items = append(items, item)
+		if item.typ == tEOF || item.typ == tError {
+			break
+		}
+	}
+	return
+}
+
+// no positional checking, for now ...
+func equal(i1, i2 []Item) bool {
+	if len(i1) != len(i2) {
+		return false
+	}
+	for k := range i1 {
+		if i1[k].typ != i2[k].typ {
+			return false
+		}
+		if i1[k].Val != i2[k].Val {
+			return false
+		}
+	}
+	return true
+}