Implement parsing of multi-line schema item descriptions

language/lexer.go

@@ -53,6 +53,7 @@ const (
 	BOOL   // true, false
 	NULL   // null
 
+	MULTILINE_STRING // """abc\ndef"""
 )
 
 func (tokenType TokenType) String() string {
@@ -111,6 +112,8 @@ func (tokenType TokenType) String() string {
 		return "Boolean"
 	case NULL:
 		return "null"
+	case MULTILINE_STRING:
+		return "MultilineString"
 	default:
 		return "Unknown"
 	}
@@ -197,6 +200,9 @@ func (lexer *Lexer) Emit(tokenType TokenType) {
 			panic(err)
 		}
 	}
+	if tokenType == MULTILINE_STRING {
+		value = value[3 : len(value)-3]
+	}
 	lexer.Tokens <- Token{tokenType, value, startPos, endPos}
 	lexer.Start = lexer.Pos
 	lexer.Width = 0
@@ -351,6 +357,9 @@ func LexText(lexer *Lexer) StateFn {
 			lexer.Backup()
 			return LexComment
 		case rn == '"':
+			if lexer.AcceptString("\"\"") {
+				return LexMultilineQuote
+			}
 			lexer.Backup()
 			return LexQuote
 		case rn == '.':
@@ -421,7 +430,10 @@ func LexComment(lexer *Lexer) StateFn {
 	}
 	for {
 		switch rn := lexer.Next(); rn {
-		case -1, '\u000A', '\u000D':
+		case -1:
+			lexer.Backup()
+			return LexText
+		case '\u000A', '\u000D':
 			if rn == '\u000D' && lexer.Peek() == '\u000A' {
 				lexer.Next()
 			}
@@ -438,6 +450,27 @@ func LexComment(lexer *Lexer) StateFn {
 	return LexText
 }
 
+func LexMultilineQuote(lexer *Lexer) StateFn {
+	for {
+		switch rn := lexer.Next(); rn {
+		case -1, '\u000A', '\u000D':
+			if rn == '\u000D' && lexer.Peek() == '\u000A' {
+				lexer.Next()
+			}
+			lexer.Line += 1
+			lexer.Column = 1
+			continue
+		case '"':
+			if lexer.AcceptString("\"\"") {
+				lexer.Emit(MULTILINE_STRING)
+				return LexText
+			}
+			return lexer.Errorf(`GraphQL Syntax Error (%d:%d) Invalid multiline description`, lexer.Line, lexer.Column-1)
+		}
+	}
+	return LexText
+}
+
 func LexQuote(lexer *Lexer) StateFn {
 	quote := lexer.Next()
 	index := 1

language/parser.go

@@ -112,19 +112,29 @@ func (parser *Parser) description() (string, error) {
 	text := ""
 	isBody := false
 	token := parser.lookahead
-	for token.Type == DESCRIPTION {
-		text += strings.Trim(token.Val[2:], " ")
-		if isBody {
-			text += " "
-		} else {
-			isBody = true
+	switch token.Type {
+	case STRING:
+		for token.Type == STRING {
+			text += strings.Trim(token.Val, " ")
+			if isBody {
+				text += " "
+			} else {
+				isBody = true
+			}
+			err := parser.match(STRING)
+			if err != nil {
+				return text, err
+			}
+			token = parser.lookahead
 		}
-		err := parser.match(DESCRIPTION)
+	case MULTILINE_STRING:
+		err := parser.match(MULTILINE_STRING)
 		if err != nil {
 			return text, err
 		}
-		token = parser.lookahead
+		text = strings.Trim(token.Val, "\n")
 	}
+
 	return text, nil
 }
 

language/parser_test.go

@@ -1367,6 +1367,41 @@ input Hello {
 			})
 			So(err, ShouldNotEqual, nil)
 		})
+
+		Convey("multiline descriptions", func() {
+			result, err = parser.Parse(&ParseParams{
+				Source: `
+# Comment
+"""
+Multiline Description on Scalar
+Line 2
+"""
+scalar Scalar
+
+"""
+Multiline Description on Object
+Line 2
+"""
+type Object {
+	"""
+	Multiline Description on Field
+	Line 2
+	"""
+	field: String!
+}
+`,
+			})
+			So(err, ShouldEqual, nil)
+
+			scalar := result.Definitions[0].(*ScalarTypeDefinition)
+			object := result.Definitions[1].(*ObjectTypeDefinition)
+			field := object.Fields[0]
+
+			So(scalar.Description, ShouldEqual, "Multiline Description on Scalar\nLine 2")
+			So(object.Description, ShouldEqual, "Multiline Description on Object\nLine 2")
+			So(field.Description, ShouldEqual, "\tMultiline Description on Field\n\tLine 2\n\t")
+		})
+
 	})
 
 }