func lexInside(l *lex.Lexer) lex.StateFn {
for {
switch r := l.Next(); {
case r == rightCurl:
l.Depth -= 1
l.Emit(itemRightCurl)
if l.Depth == 0 {
return lexText
}
case r == leftCurl:
l.Depth += 1
l.Emit(itemLeftCurl)
case r == lex.EOF:
return l.Errorf("unclosed action")
case isSpace(r) || isEndOfLine(r) || r == ',':
l.Ignore()
case isNameBegin(r):
return lexName
case r == '#':
l.Backup()
return lexComment
case r == '(':
l.Emit(itemLeftRound)
return lexArgInside
default:
return l.Errorf("Unrecognized character in lexInside: %#U", r)
}
}
}
// lexDirective is called right after we see a @.
func lexDirective(l *lex.Lexer) lex.StateFn {
r := l.Next()
if !isNameBegin(r) {
return l.Errorf("Unrecognized character in lexDirective: %#U", r)
}
l.Backup()
// This gives our buffer an initial capacity. Its length is zero though. The
// buffer can grow beyond this initial capacity.
buf := bytes.NewBuffer(make([]byte, 0, 15))
for {
// The caller already checked isNameBegin, and absorbed one rune.
r = l.Next()
buf.WriteRune(r)
if isNameSuffix(r) {
continue
}
l.Backup()
l.Emit(itemDirectiveName)
directive := buf.Bytes()[:buf.Len()-1]
// The lexer may behave differently for different directives. Hence, we need
// to check the directive here and go into the right state.
if string(directive) == "filter" {
return lexFilterInside
}
return l.Errorf("Unhandled directive %s", directive)
}
return lexInside
}
// This function inspects the next rune and calls the appropriate stateFn.
func lexText(l *lex.Lexer) lex.StateFn {
Loop:
for {
switch r := l.Next(); {
case r == '<' || r == '_':
if l.Depth == atSubject {
l.Backup()
l.Emit(itemText) // emit whatever we have so far.
return lexSubject
}
if l.Depth == atPredicate {
l.Backup()
l.Emit(itemText)
return lexPredicate
}
if l.Depth == atObject {
l.Backup()
l.Emit(itemText)
return lexObject
}
if l.Depth == atLabel {
l.Backup()
l.Emit(itemText)
return lexLabel
}
return l.Errorf("Invalid input: %c at lexText", r)
case r == '"':
if l.Depth != atObject {
return l.Errorf("Invalid quote for non-object.")
}
l.Backup()
l.Emit(itemText)
return lexObject
case r == lex.EOF:
break Loop
case r == '.':
if l.Depth > atObject {
l.Emit(itemValidEnd)
}
break Loop
case isSpace(r):
continue
default:
l.Errorf("Invalid input: %c at lexText", r)
}
}
if l.Pos > l.Start {
l.Emit(itemText)
}
l.Emit(lex.ItemEOF)
return nil
}
func lexObject(l *lex.Lexer) lex.StateFn {
for {
switch r := l.Next(); {
case r == rightCurl:
return lexText
case isSpace(r) || isEndOfLine(r):
l.Ignore()
case isNameBegin(r):
{
for {
r := l.Next()
if isNameSuffix(r) {
continue // absorb
}
l.Backup()
l.Emit(itemObject)
break
}
return lexObjectBlock
}
default:
return l.Errorf("Invalid schema. Unexpected %s", l.Input[l.Start:l.Pos])
}
}
}
// Assumes '"' has already been encountered.
func lexLiteral(l *lex.Lexer) lex.StateFn {
for {
r := l.Next()
if r == '\u005c' { // backslash
r = l.Next()
continue // This would skip over the escaped rune.
}
if r == lex.EOF || isEndLiteral(r) {
break
}
}
l.Backup()
l.Emit(itemLiteral)
l.Next() // Move to end literal.
l.Ignore() // Ignore end literal.
l.Depth++
r := l.Peek()
if r == '@' {
return lexLanguage(l)
}
if r == '^' {
return lexObjectType(l)
}
return lexText
}
// lexTextMutation lexes and absorbs the text inside a mutation operation block.
func lexTextMutation(l *lex.Lexer) lex.StateFn {
for {
r := l.Next()
if r == lex.EOF {
return l.Errorf("Unclosed mutation text")
}
if r == quote {
return lexMutationValue
}
if r == leftCurl {
l.Depth++
}
if r == rightCurl {
if l.Depth > 2 {
l.Depth--
continue
}
}
if r != rightCurl {
// Absorb everything until we find '}'.
continue
}
l.Backup()
l.Emit(itemMutationContent)
break
}
return lexInsideMutation
}
// lexOperationType lexes a query or mutation operation type.
func lexOperationType(l *lex.Lexer) lex.StateFn {
for {
r := l.Next()
if isNameSuffix(r) {
continue // absorb
}
l.Backup()
// l.Pos would be index of the end of operation type + 1.
word := l.Input[l.Start:l.Pos]
if word == "mutation" {
l.Emit(itemOpType)
l.Mode = mutationMode
} else if word == "fragment" {
l.Emit(itemOpType)
l.Mode = fragmentMode
} else if word == "query" {
l.Emit(itemOpType)
l.Mode = queryMode
} else {
if l.Mode == 0 {
l.Errorf("Invalid operation type")
}
}
break
}
return lexText
}
func lexText(l *lex.Lexer) lex.StateFn {
Loop:
for {
switch r := l.Next(); {
case r == leftCurl:
l.Backup()
l.Emit(itemText) // emit whatever we have so far.
l.Next() // advance one to get back to where we saw leftCurl.
l.Depth += 1 // one level down.
l.Emit(itemLeftCurl)
return lexInside // we're in.
case r == rightCurl:
return l.Errorf("Too many right characters")
case r == lex.EOF:
break Loop
case isNameBegin(r):
l.Backup()
l.Emit(itemText)
return lexOperationType
}
}
if l.Pos > l.Start {
l.Emit(itemText)
}
l.Emit(lex.ItemEOF)
return nil
}
func lexFragmentSpread(l *lex.Lexer) lex.StateFn {
for {
r := l.Next()
if isNameSuffix(r) {
continue
}
l.Backup()
l.Emit(itemFragmentSpread)
break
}
return lexInside
}
func lexText(l *lex.Lexer) lex.StateFn {
Loop:
for {
switch r := l.Next(); {
case r == '<' || r == '_':
if l.Depth == AT_SUBJECT {
l.Backup()
l.Emit(itemText) // emit whatever we have so far.
return lexSubject
} else if l.Depth == AT_PREDICATE {
l.Backup()
l.Emit(itemText)
return lexPredicate
} else if l.Depth == AT_OBJECT {
l.Backup()
l.Emit(itemText)
return lexObject
} else if l.Depth == AT_LABEL {
l.Backup()
l.Emit(itemText)
return lexLabel
} else {
return l.Errorf("Invalid input: %v at lexText", r)
}
case r == '"':
if l.Depth != AT_OBJECT {
return l.Errorf("Invalid quote for non-object.")
}
l.Backup()
l.Emit(itemText)
return lexObject
case r == lex.EOF:
break Loop
case r == '.':
if l.Depth > AT_OBJECT {
l.Emit(itemValidEnd)
}
break Loop
}
}
if l.Pos > l.Start {
l.Emit(itemText)
}
l.Emit(lex.ItemEOF)
return nil
}
// lexArgName lexes and emits the name part of an argument.
func lexArgName(l *lex.Lexer) lex.StateFn {
for {
r := l.Next()
if isNameSuffix(r) {
continue
}
l.Backup()
l.Emit(itemArgName)
break
}
return lexArgInside
}
// lexNameMutation lexes the itemMutationOp, which could be set or delete.
func lexNameMutation(l *lex.Lexer) lex.StateFn {
for {
// The caller already checked isNameBegin, and absorbed one rune.
r := l.Next()
if isNameBegin(r) {
continue
}
l.Backup()
l.Emit(itemMutationOp)
break
}
return lexInsideMutation
}
// lexFilterFuncName expects input to look like equal("...", "...").
func lexFilterFuncName(l *lex.Lexer) lex.StateFn {
for {
// The caller already checked isNameBegin, and absorbed one rune.
r := l.Next()
if isNameSuffix(r) {
continue
}
l.Backup()
l.Emit(itemFilterFunc)
break
}
return lexFilterFuncInside
}
func lexAlias(l *lex.Lexer) lex.StateFn {
l.AcceptRun(isSpace)
l.Ignore() // Any spaces encountered.
for {
r := l.Next()
if isNameSuffix(r) {
continue
}
l.Backup()
l.Emit(itemAlias)
break
}
return lexInside
}
func lexOperationType(l *lex.Lexer) lex.StateFn {
for {
r := l.Next()
if isNameSuffix(r) {
continue // absorb
}
l.Backup()
word := l.Input[l.Start:l.Pos]
if word == "query" || word == "mutation" {
l.Emit(itemOpType)
}
break
}
return lexText
}
func lexScalarBlock(l *lex.Lexer) lex.StateFn {
for {
switch r := l.Next(); {
case r == ')':
l.Emit(itemRightRound)
return lexText
case isNameBegin(r):
l.Backup()
return lexScalarPair1
case isSpace(r) || isEndOfLine(r):
l.Ignore()
default:
return l.Errorf("Invalid schema. Unexpected %s", l.Input[l.Start:l.Pos])
}
}
}
// lexArgVal lexes and emits the value part of an argument.
func lexArgVal(l *lex.Lexer) lex.StateFn {
l.AcceptRun(isSpace)
l.Ignore() // Any spaces encountered.
for {
r := l.Next()
if isSpace(r) || isEndOfLine(r) || r == rightRound || r == comma {
l.Backup()
l.Emit(itemArgVal)
return lexArgInside
}
if r == lex.EOF {
return l.Errorf("Reached lex.EOF while reading var value: %v",
l.Input[l.Start:l.Pos])
}
}
}
func lexArgVal(l *lex.Lexer) lex.StateFn {
l.AcceptRun(isSpace)
l.Ignore() // Any spaces encountered.
for {
r := l.Next()
if isSpace(r) || isEndOfLine(r) || r == ')' || r == ',' {
l.Backup()
l.Emit(itemArgVal)
return lexArgInside
}
if r == lex.EOF {
return l.Errorf("Reached lex.EOF while reading var value: %v",
l.Input[l.Start:l.Pos])
}
}
glog.Fatal("This shouldn't be reached.")
return nil
}
func lexLabel(l *lex.Lexer) lex.StateFn {
r := l.Next()
// Graph label can either be an IRI or a blank node according to spec.
if r == '<' {
l.Depth++
return lexUntilClosing(l, itemLabel, lexText)
}
if r == '_' {
l.Depth++
r = l.Next()
if r != ':' {
return l.Errorf("Invalid char: %c at lexLabel", r)
}
l.Backup()
return lexBlankNode(l, itemLabel, lexText)
}
return l.Errorf("Invalid char: %v at lexLabel", r)
}
// lexText lexes the input string and calls other lex functions.
func lexText(l *lex.Lexer) lex.StateFn {
Loop:
for {
switch r := l.Next(); {
case r == lex.EOF:
break Loop
case isNameBegin(r):
l.Backup()
return lexStart
case isSpace(r) || isEndOfLine(r):
l.Ignore()
default:
return l.Errorf("Invalid schema. Unexpected %s", l.Input[l.Start:l.Pos])
}
}
if l.Pos > l.Start {
l.Emit(itemText)
}
l.Emit(lex.ItemEOF)
return nil
}
func lexStart(l *lex.Lexer) lex.StateFn {
for {
r := l.Next()
if isNameSuffix(r) {
continue // absorb
}
l.Backup()
// l.Pos would be index of the end of operation type + 1.
word := l.Input[l.Start:l.Pos]
if word == "scalar" {
l.Emit(itemScalar)
return lexScalar
} else if word == "type" {
l.Emit(itemType)
return lexObject
} else {
return l.Errorf("Invalid schema")
}
}
}
// lexInside lexes the content inside a query block.
func lexInside(l *lex.Lexer) lex.StateFn {
for {
switch r := l.Next(); {
case r == period:
if l.Next() == period && l.Next() == period {
return lexFragmentSpread
}
// We do not expect a period at all. If you do, you may want to
// backup the two extra periods we try to read.
return l.Errorf("Unrecognized character in lexInside: %#U", r)
case r == rightCurl:
l.Depth--
l.Emit(itemRightCurl)
if l.Depth == 0 {
return lexText
}
case r == leftCurl:
l.Depth++
l.Emit(itemLeftCurl)
case r == lex.EOF:
return l.Errorf("Unclosed action")
case isSpace(r) || isEndOfLine(r) || r == comma:
l.Ignore()
case isNameBegin(r):
return lexName
case r == '#':
l.Backup()
return lexComment
case r == leftRound:
l.Emit(itemLeftRound)
l.AcceptRun(isSpace)
l.Ignore()
k := l.Next()
if k == '_' || l.Depth != 1 || l.Mode == fragmentMode {
l.Backup()
l.Emit(itemArgument)
return lexArgInside
}
// This is a generator function.
l.Backup()
l.Emit(itemGenerator)
l.FilterDepth++
return lexFilterInside
case r == ':':
return lexAlias
case r == '@':
return lexDirective
default:
return l.Errorf("Unrecognized character in lexInside: %#U", r)
}
}
}
func lexObjectPair(l *lex.Lexer) lex.StateFn {
for {
r := l.Next()
if isNameSuffix(r) {
continue // absorb
}
l.Backup()
l.Emit(itemObjectName)
break
}
L:
for {
switch r := l.Next(); {
case isSpace(r) || isEndOfLine(r):
l.Ignore()
case r == ':':
l.Emit(itemCollon)
break
case isNameBegin(r):
l.Backup()
break L
default:
return l.Errorf("Invalid schema. Unexpected %s", l.Input[l.Start:l.Pos])
}
}
for {
r := l.Next()
if isNameSuffix(r) {
continue // absorb
}
l.Backup()
l.Emit(itemObjectType)
break
}
return lexObjectBlock
}
// lexText lexes the input string and calls other lex functions.
func lexText(l *lex.Lexer) lex.StateFn {
Loop:
for {
switch r := l.Next(); {
case r == leftCurl:
l.Backup()
l.Emit(itemText) // emit whatever we have so far.
l.Next() // advance one to get back to where we saw leftCurl.
l.Depth++ // one level down.
l.Emit(itemLeftCurl)
if l.Mode == mutationMode {
return lexInsideMutation
}
// Both queryMode and fragmentMode are handled by lexInside.
return lexInside
case r == rightCurl:
return l.Errorf("Too many right characters")
case r == lex.EOF:
break Loop
case r == leftRound:
l.Backup()
l.Emit(itemText)
l.Next()
l.Emit(itemLeftRound)
return lexVarInside
case isNameBegin(r):
l.Backup()
l.Emit(itemText)
return lexOperationType
}
}
if l.Pos > l.Start {
l.Emit(itemText)
}
l.Emit(lex.ItemEOF)
return nil
}
func lexScalarPair1(l *lex.Lexer) lex.StateFn {
for {
r := l.Next()
if isNameSuffix(r) {
continue // absorb
}
l.Backup()
// l.Pos would be index of the end of operation type + 1.
l.Emit(itemScalarName)
break
}
L:
for {
switch r := l.Next(); {
case isSpace(r) || isEndOfLine(r):
l.Ignore()
case r == ':':
l.Emit(itemCollon)
break
case isNameBegin(r):
l.Backup()
break L
default:
return l.Errorf("Invalid schema. Unexpected %s", l.Input[l.Start:l.Pos])
}
}
for {
r := l.Next()
if isNameSuffix(r) {
continue // absorb
}
l.Backup()
l.Emit(itemScalarType)
break
}
// Check for the mention of @index.
var isIndexed bool
L1:
for {
switch r := l.Next(); {
case isSpace(r):
l.Ignore()
case isEndOfLine(r):
break L1
case r == '@':
l.Emit(itemAt)
isIndexed = true
for {
r := l.Next()
if isNameSuffix(r) {
continue // absorb
}
l.Backup()
// l.Pos would be index of the end of operation type + 1.
word := l.Input[l.Start:l.Pos]
if word == "index" {
l.Emit(itemIndex)
break L1
} else {
return l.Errorf("Invalid mention of index")
}
}
break L1
default:
return l.Errorf("Invalid schema. Unexpected %s", l.Input[l.Start:l.Pos])
}
}
if !isIndexed {
l.Emit(itemDummy)
}
return lexScalarBlock
}
