Example #1
0
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)
		}
	}
}
Example #2
0
// 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
}
Example #3
0
// 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
}
Example #4
0
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])
		}
	}
}
Example #5
0
// 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
}
Example #6
0
// 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
}
Example #7
0
// 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
}
Example #8
0
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
}
Example #9
0
func lexFragmentSpread(l *lex.Lexer) lex.StateFn {
	for {
		r := l.Next()
		if isNameSuffix(r) {
			continue
		}
		l.Backup()
		l.Emit(itemFragmentSpread)
		break
	}
	return lexInside
}
Example #10
0
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
}
Example #11
0
// 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
}
Example #12
0
// 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
}
Example #13
0
// 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
}
Example #14
0
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
}
Example #15
0
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
}
Example #16
0
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])
		}
	}
}
Example #17
0
// 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])
		}
	}
}
Example #18
0
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
}
Example #19
0
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)
}
Example #20
0
// 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
}
Example #21
0
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")
		}
	}

}
Example #22
0
// 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)
		}
	}
}
Example #23
0
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

}
Example #24
0
// 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
}
Example #25
0
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
}