1""" 

2@file 

3@brief Use grammar 

4This module requires `antlr4-python3-runtime <https://pypi.python.org/pypi/antlr4-python3-runtime/>`_. 

5""" 

6import os 

7from antlr4 import ParseTreeWalker, CommonTokenStream, InputStream 

8from .tree_string_listener import TreeStringListener 

9from .tree_graph_listener import TreeGraphListener 

10 

11 

12def get_parser_lexer(language): 

13 """ 

14 Returns two classes, a parser and a lexer from :epkg:`antlr4`. 

15 

16 @param language to analyse 

17 @return Parser, Lexer 

18 """ 

19 try: 

20 if language == "C#" or language == "CSharp": 

21 language = "CSharp4" 

22 

23 if language == "R": 

24 from .RLexer import RLexer 

25 from .RParser import RParser 

26 return RParser, RLexer 

27 elif language == "CSharp4": 

28 from .CSharpLexer import CSharpLexer 

29 from .CSharpParser import CSharpParser 

30 return CSharpParser, CSharpLexer 

31 elif language == "SQLite": 

32 from .SQLiteLexer import SQLiteLexer 

33 from .SQLiteParser import SQLiteParser 

34 return SQLiteParser, SQLiteLexer 

35 elif language == "DOT": 

36 from .DOTLexer import DOTLexer 

37 from .DOTParser import DOTParser 

38 return DOTParser, DOTLexer 

39 elif language == "Pig": 

40 raise ImportError("Pig is not available yet") 

41 # from .PigLexer import PigLexer 

42 # from .PigParser import PigParser 

43 # return PigParser, PigLexer 

44 elif language == "Python3": 

45 from .Python3Lexer import Python3Lexer 

46 from .Python3Parser import Python3Parser 

47 return Python3Parser, Python3Lexer 

48 elif language == "SimpleWorkflow": 

49 from .SimpleWorkflowLexer import SimpleWorkflowLexer 

50 from .SimpleWorkflowParser import SimpleWorkflowParser 

51 return SimpleWorkflowParser, SimpleWorkflowLexer 

52 else: 

53 folder = os.path.dirname(__file__) 

54 if folder == "": 

55 folder = "." 

56 files = os.listdir(folder) 

57 raise ImportError( 

58 "unable to import parsers for language: " + 

59 language + 

60 "\navailable files:\n{0}".format( 

61 "\n".join(files))) 

62 except ImportError as e: 

63 folder = os.path.dirname(__file__) 

64 if folder == "": 

65 folder = "." 

66 files = os.listdir(folder) 

67 raise ImportError( 

68 "unable to import parsers for language: " + 

69 language + 

70 "\navailable files:\n{0}".format( 

71 "\n".join(files))) from e 

72 

73 

74def parse_code(code, class_parser, class_lexer): 

75 """ 

76 Parses a code and returns a tree. 

77 

78 @param code code to parse 

79 @param class_parser parser 

80 @param class_lexer lexer 

81 @return parsed code 

82 

83 .. exref:: 

84 :title: Check the syntax of a script PIG 

85 

86 :: 

87 

88 code = ''' 

89 A = LOAD 'filename.txt' USING PigStorage('\t'); 

90 STORE A INTO 'samefile.txt' ; 

91 ''' 

92 

93 clparser, cllexer = get_parser_lexer("Pig") 

94 parser = parse_code(code, clparser, cllexer) 

95 tree = parser.compilation_unit() 

96 st = get_tree_string(tree, parser, None) 

97 print(st) 

98 """ 

99 if isinstance(code, str): 

100 # we assume it is a string 

101 code = InputStream(code) 

102 

103 lexer = class_lexer(code) 

104 stream = CommonTokenStream(lexer) 

105 parser = class_parser(stream) 

106 return parser 

107 

108 

109def get_tree_string(tree, parser, format=TreeStringListener): 

110 """ 

111 Returns a string which shows the parsed tree. 

112 

113 @param tree from @see fn parse_code 

114 @param parser the parser used to build the tree, output of @see fn parse_code 

115 @param format None or a class `ParseTreeListener <https://github.com/antlr/antlr4-python3/blob/master/src/antlr4/tree/Tree.py>`_ 

116 @return string 

117 """ 

118 if format is None: 

119 return tree.toStringTree() 

120 else: 

121 walker = ParseTreeWalker() 

122 listen = format(parser) 

123 walker.walk(listen, tree) 

124 return str(listen) 

125 

126 

127def get_tree_graph(tree, parser, format=TreeGraphListener): 

128 """ 

129 Returns a graph with :epkg:`networkx`. 

130 

131 @param tree from @see fn parse_code 

132 @param parser the parser used to build the tree, output of @see fn parse_code 

133 @param format None or a class `ParseTreeListener <https://github.com/antlr/antlr4-python3/blob/master/src/antlr4/tree/Tree.py>`_ 

134 @return string 

135 """ 

136 if format is None: 

137 raise TypeError( # pragma: no cover 

138 "format cannot be None") 

139 walker = ParseTreeWalker() 

140 listen = format(parser) 

141 walker.walk(listen, tree) 

142 return listen