Coverage for python/lsst/daf/butler/registry/queries/expressions/parser/parserLex.py: 51%

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1# This file is part of daf_butler. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (https://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# This program is free software: you can redistribute it and/or modify 

10# it under the terms of the GNU General Public License as published by 

11# the Free Software Foundation, either version 3 of the License, or 

12# (at your option) any later version. 

13# 

14# This program is distributed in the hope that it will be useful, 

15# but WITHOUT ANY WARRANTY; without even the implied warranty of 

16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

17# GNU General Public License for more details. 

18# 

19# You should have received a copy of the GNU General Public License 

20# along with this program. If not, see <https://www.gnu.org/licenses/>. 

21 

22# type: ignore 

23 

24"""Module which defines PLY lexer for user expressions parsed by pre-flight. 

25""" 

26 

27__all__ = ["ParserLex", "ParserLexError"] 

28 

29# ------------------------------- 

30# Imports of standard modules -- 

31# ------------------------------- 

32import re 

33 

34# ----------------------------- 

35# Imports for other modules -- 

36# ----------------------------- 

37from .ply import lex 

38 

39# ---------------------------------- 

40# Local non-exported definitions -- 

41# ---------------------------------- 

42 

43_RE_RANGE = r"(?P<start>-?\d+)\s*\.\.\s*(?P<stop>-?\d+)(\s*:\s*(?P<stride>[1-9]\d*))?" 

44"""Regular expression to match range literal in the form NUM..NUM[:NUM], 

45this must match t_RANGE_LITERAL docstring. 

46""" 

47 

48# ------------------------ 

49# Exported definitions -- 

50# ------------------------ 

51 

52 

53class ParserLexError(Exception): 

54 """Exception raised for lex-phase errors. 

55 

56 Attributes 

57 ---------- 

58 expression : str 

59 Full initial expression being parsed 

60 remain : str 

61 Remaining non-parsed part of the expression 

62 pos : int 

63 Current parsing position, offset from beginning of expression in 

64 characters 

65 lineno : int 

66 Current line number in the expression 

67 """ 

68 

69 def __init__(self, expression, remain, pos, lineno): 

70 Exception.__init__(self, "Unexpected character at position {}".format(pos)) 

71 self.expression = expression 

72 self.remain = remain 

73 self.pos = pos 

74 self.lineno = lineno 

75 

76 

77class ParserLex: 

78 """Class which defines PLY lexer.""" 

79 

80 @classmethod 

81 def make_lexer(cls, reflags=0, **kwargs): 

82 """Factory for lexers. 

83 

84 Returns 

85 ------- 

86 `ply.lex.Lexer` instance. 

87 """ 

88 

89 # make sure that flags that we need are there 

90 kw = dict(reflags=reflags | re.IGNORECASE | re.VERBOSE) 

91 kw.update(kwargs) 

92 

93 return lex.lex(object=cls(), **kw) 

94 

95 # literals = "" 

96 

97 # reserved words in a grammar. 

98 # SQL has reserved words which we could potentially make reserved in our 

99 # grammar too, for now try to pretend we don't care about SQL 

100 reserved = dict( 

101 # IS="IS", 

102 IN="IN", 

103 # NULL="NULL", 

104 OR="OR", 

105 AND="AND", 

106 NOT="NOT", 

107 OVERLAPS="OVERLAPS", 

108 # BETWEEN="BETWEEN", 

109 # LIKE="LIKE", 

110 # ESCAPE="ESCAPE", 

111 # REGEXP="REGEXP" 

112 ) 

113 

114 # List of token names. 

115 tokens = ( 

116 "NUMERIC_LITERAL", 

117 "TIME_LITERAL", 

118 "STRING_LITERAL", 

119 "RANGE_LITERAL", 

120 # 'DURATION_LITERAL', 

121 "QUALIFIED_IDENTIFIER", 

122 "SIMPLE_IDENTIFIER", 

123 "LPAREN", 

124 "RPAREN", 

125 "EQ", 

126 "NE", 

127 "LT", 

128 "LE", 

129 "GT", 

130 "GE", 

131 "ADD", 

132 "SUB", 

133 "MUL", 

134 "DIV", 

135 "MOD", 

136 "COMMA", 

137 ) + tuple(reserved.values()) 

138 

139 # Regular expression rules for simple tokens 

140 t_LPAREN = r"\(" 

141 t_RPAREN = r"\)" 

142 t_EQ = "=" 

143 t_NE = "!=" 

144 t_LT = "<" 

145 t_LE = "<=" 

146 t_GT = ">" 

147 t_GE = ">=" 

148 t_ADD = r"\+" 

149 t_SUB = "-" 

150 t_MUL = r"\*" 

151 t_DIV = "/" 

152 t_MOD = "%" 

153 t_COMMA = "," 

154 

155 # A string containing ignored characters (spaces and tabs) 

156 t_ignore = " \t" 

157 

158 # Define a rule so we can track line numbers 

159 def t_newline(self, t): 

160 r"\n+" 

161 t.lexer.lineno += len(t.value) 

162 

163 # quoted string prefixed with 'T' 

164 def t_TIME_LITERAL(self, t): 

165 r"T'.*?'" 

166 # strip quotes 

167 t.value = t.value[2:-1] 

168 return t 

169 

170 # quoted string 

171 def t_STRING_LITERAL(self, t): 

172 r"'.*?'" 

173 # strip quotes 

174 t.value = t.value[1:-1] 

175 return t 

176 

177 # range literal in format N..M[:S], spaces allowed, see _RE_RANGE 

178 @lex.TOKEN(_RE_RANGE) 

179 def t_RANGE_LITERAL(self, t): 

180 match = re.match(_RE_RANGE, t.value) 

181 start = int(match.group("start")) 

182 stop = int(match.group("stop")) 

183 stride = match.group("stride") 

184 if stride is not None: 

185 stride = int(stride) 

186 t.value = (start, stop, stride) 

187 return t 

188 

189 # numbers are used as strings by parser, do not convert 

190 def t_NUMERIC_LITERAL(self, t): 

191 r"""\d+(\.\d*)?(e[-+]?\d+)? # 1, 1., 1.1, 1e10, 1.1e-10, etc. 

192 | 

193 \.\d+(e[-+]?\d+)? # .1, .1e10, .1e+10 

194 """ 

195 return t 

196 

197 # qualified identifiers have one or two dots 

198 def t_QUALIFIED_IDENTIFIER(self, t): 

199 r"[a-zA-Z_][a-zA-Z0-9_]*(\.[a-zA-Z_][a-zA-Z0-9_]*){1,2}" 

200 t.type = "QUALIFIED_IDENTIFIER" 

201 return t 

202 

203 # we only support ASCII in identifier names 

204 def t_SIMPLE_IDENTIFIER(self, t): 

205 r"[a-zA-Z_][a-zA-Z0-9_]*" 

206 # Check for reserved words and make sure they are upper case 

207 reserved = self.reserved.get(t.value.upper()) 

208 if reserved is not None: 

209 t.type = reserved 

210 t.value = reserved 

211 else: 

212 t.type = "SIMPLE_IDENTIFIER" 

213 return t 

214 

215 def t_error(self, t): 

216 "Error handling rule" 

217 lexer = t.lexer 

218 raise ParserLexError(lexer.lexdata, t.value, lexer.lexpos, lexer.lineno)