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1 | 1 | # parser.py - simple top-down operator precedence parser for mercurial |
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2 | 2 | # |
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3 | 3 | # Copyright 2010 Matt Mackall <mpm@selenic.com> |
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4 | 4 | # |
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5 | 5 | # This software may be used and distributed according to the terms of the |
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6 | 6 | # GNU General Public License version 2 or any later version. |
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7 | 7 | |
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8 | 8 | # see http://effbot.org/zone/simple-top-down-parsing.htm and |
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9 | 9 | # http://eli.thegreenplace.net/2010/01/02/top-down-operator-precedence-parsing/ |
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10 | 10 | # for background |
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11 | 11 | |
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12 | 12 | # takes a tokenizer and elements |
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13 | 13 | # tokenizer is an iterator that returns (type, value, pos) tuples |
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14 | 14 | # elements is a mapping of types to binding strength, primary, prefix, infix |
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15 | 15 | # and suffix actions |
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16 | 16 | # an action is a tree node name, a tree label, and an optional match |
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17 | 17 | # __call__(program) parses program into a labeled tree |
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18 | 18 | |
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19 | 19 | from __future__ import absolute_import |
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20 | 20 | |
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21 | 21 | from .i18n import _ |
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22 | 22 | from . import error |
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23 | 23 | |
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24 | 24 | class parser(object): |
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25 | 25 | def __init__(self, elements, methods=None): |
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26 | 26 | self._elements = elements |
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27 | 27 | self._methods = methods |
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28 | 28 | self.current = None |
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29 | 29 | def _advance(self): |
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30 | 30 | 'advance the tokenizer' |
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31 | 31 | t = self.current |
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32 | 32 | self.current = next(self._iter, None) |
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33 | 33 | return t |
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34 | 34 | def _hasnewterm(self): |
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35 | 35 | 'True if next token may start new term' |
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36 | 36 | return any(self._elements[self.current[0]][1:3]) |
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37 | 37 | def _match(self, m): |
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38 | 38 | 'make sure the tokenizer matches an end condition' |
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39 | 39 | if self.current[0] != m: |
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40 | 40 | raise error.ParseError(_("unexpected token: %s") % self.current[0], |
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41 | 41 | self.current[2]) |
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42 | 42 | self._advance() |
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43 | 43 | def _parseoperand(self, bind, m=None): |
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44 | 44 | 'gather right-hand-side operand until an end condition or binding met' |
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45 | 45 | if m and self.current[0] == m: |
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46 | 46 | expr = None |
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47 | 47 | else: |
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48 | 48 | expr = self._parse(bind) |
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49 | 49 | if m: |
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50 | 50 | self._match(m) |
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51 | 51 | return expr |
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52 | 52 | def _parse(self, bind=0): |
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53 | 53 | token, value, pos = self._advance() |
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54 | 54 | # handle prefix rules on current token, take as primary if unambiguous |
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55 | 55 | primary, prefix = self._elements[token][1:3] |
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56 | 56 | if primary and not (prefix and self._hasnewterm()): |
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57 | 57 | expr = (primary, value) |
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58 | 58 | elif prefix: |
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59 | 59 | expr = (prefix[0], self._parseoperand(*prefix[1:])) |
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60 | 60 | else: |
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61 | 61 | raise error.ParseError(_("not a prefix: %s") % token, pos) |
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62 | 62 | # gather tokens until we meet a lower binding strength |
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63 | 63 | while bind < self._elements[self.current[0]][0]: |
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64 | 64 | token, value, pos = self._advance() |
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65 | 65 | # handle infix rules, take as suffix if unambiguous |
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66 | 66 | infix, suffix = self._elements[token][3:] |
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67 | 67 | if suffix and not (infix and self._hasnewterm()): |
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68 | 68 | expr = (suffix[0], expr) |
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69 | 69 | elif infix: |
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70 | 70 | expr = (infix[0], expr, self._parseoperand(*infix[1:])) |
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71 | 71 | else: |
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72 | 72 | raise error.ParseError(_("not an infix: %s") % token, pos) |
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73 | 73 | return expr |
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74 | 74 | def parse(self, tokeniter): |
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75 | 75 | 'generate a parse tree from tokens' |
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76 | 76 | self._iter = tokeniter |
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77 | 77 | self._advance() |
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78 | 78 | res = self._parse() |
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79 | 79 | token, value, pos = self.current |
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80 | 80 | return res, pos |
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81 | 81 | def eval(self, tree): |
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82 | 82 | 'recursively evaluate a parse tree using node methods' |
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83 | 83 | if not isinstance(tree, tuple): |
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84 | 84 | return tree |
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85 | 85 | return self._methods[tree[0]](*[self.eval(t) for t in tree[1:]]) |
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86 | 86 | def __call__(self, tokeniter): |
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87 | 87 | 'parse tokens into a parse tree and evaluate if methods given' |
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88 | 88 | t = self.parse(tokeniter) |
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89 | 89 | if self._methods: |
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90 | 90 | return self.eval(t) |
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91 | 91 | return t |
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92 | 92 | |
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93 | 93 | def buildargsdict(trees, funcname, keys, keyvaluenode, keynode): |
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94 | 94 | """Build dict from list containing positional and keyword arguments |
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95 | 95 | |
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96 | 96 | Invalid keywords or too many positional arguments are rejected, but |
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97 | 97 | missing arguments are just omitted. |
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98 | 98 | """ |
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99 | 99 | if len(trees) > len(keys): |
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100 | 100 | raise error.ParseError(_("%(func)s takes at most %(nargs)d arguments") |
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101 | 101 | % {'func': funcname, 'nargs': len(keys)}) |
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102 | 102 | args = {} |
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103 | 103 | # consume positional arguments |
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104 | 104 | for k, x in zip(keys, trees): |
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105 | 105 | if x[0] == keyvaluenode: |
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106 | 106 | break |
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107 | 107 | args[k] = x |
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108 | 108 | # remainder should be keyword arguments |
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109 | 109 | for x in trees[len(args):]: |
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110 | 110 | if x[0] != keyvaluenode or x[1][0] != keynode: |
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111 | 111 | raise error.ParseError(_("%(func)s got an invalid argument") |
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112 | 112 | % {'func': funcname}) |
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113 | 113 | k = x[1][1] |
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114 | 114 | if k not in keys: |
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115 | 115 | raise error.ParseError(_("%(func)s got an unexpected keyword " |
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116 | 116 | "argument '%(key)s'") |
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117 | 117 | % {'func': funcname, 'key': k}) |
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118 | 118 | if k in args: |
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119 | 119 | raise error.ParseError(_("%(func)s got multiple values for keyword " |
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120 | 120 | "argument '%(key)s'") |
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121 | 121 | % {'func': funcname, 'key': k}) |
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122 | 122 | args[k] = x[2] |
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123 | 123 | return args |
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124 | 124 | |
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125 | 125 | def unescapestr(s): |
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126 | 126 | try: |
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127 | 127 | return s.decode("string_escape") |
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128 | 128 | except ValueError as e: |
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129 | 129 | # mangle Python's exception into our format |
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130 | 130 | raise error.ParseError(str(e).lower()) |
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131 | 131 | |
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132 | 132 | def _prettyformat(tree, leafnodes, level, lines): |
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133 | 133 | if not isinstance(tree, tuple) or tree[0] in leafnodes: |
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134 | 134 | lines.append((level, str(tree))) |
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135 | 135 | else: |
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136 | 136 | lines.append((level, '(%s' % tree[0])) |
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137 | 137 | for s in tree[1:]: |
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138 | 138 | _prettyformat(s, leafnodes, level + 1, lines) |
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139 | 139 | lines[-1:] = [(lines[-1][0], lines[-1][1] + ')')] |
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140 | 140 | |
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141 | 141 | def prettyformat(tree, leafnodes): |
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142 | 142 | lines = [] |
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143 | 143 | _prettyformat(tree, leafnodes, 0, lines) |
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144 | 144 | output = '\n'.join((' ' * l + s) for l, s in lines) |
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145 | 145 | return output |
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146 | 146 | |
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147 | 147 | def simplifyinfixops(tree, targetnodes): |
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148 | 148 | """Flatten chained infix operations to reduce usage of Python stack |
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149 | 149 | |
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150 | 150 | >>> def f(tree): |
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151 | 151 | ... print prettyformat(simplifyinfixops(tree, ('or',)), ('symbol',)) |
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152 | 152 | >>> f(('or', |
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153 | 153 | ... ('or', |
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154 | 154 | ... ('symbol', '1'), |
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155 | 155 | ... ('symbol', '2')), |
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156 | 156 | ... ('symbol', '3'))) |
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157 | 157 | (or |
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158 | 158 | ('symbol', '1') |
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159 | 159 | ('symbol', '2') |
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160 | 160 | ('symbol', '3')) |
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161 | 161 | >>> f(('func', |
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162 | 162 | ... ('symbol', 'p1'), |
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163 | 163 | ... ('or', |
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164 | 164 | ... ('or', |
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165 | 165 | ... ('func', |
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166 | 166 | ... ('symbol', 'sort'), |
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167 | 167 | ... ('list', |
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168 | 168 | ... ('or', |
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169 | 169 | ... ('or', |
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170 | 170 | ... ('symbol', '1'), |
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171 | 171 | ... ('symbol', '2')), |
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172 | 172 | ... ('symbol', '3')), |
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173 | 173 | ... ('negate', |
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174 | 174 | ... ('symbol', 'rev')))), |
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175 | 175 | ... ('and', |
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176 | 176 | ... ('symbol', '4'), |
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177 | 177 | ... ('group', |
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178 | 178 | ... ('or', |
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179 | 179 | ... ('or', |
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180 | 180 | ... ('symbol', '5'), |
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181 | 181 | ... ('symbol', '6')), |
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182 | 182 | ... ('symbol', '7'))))), |
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183 | 183 | ... ('symbol', '8')))) |
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184 | 184 | (func |
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185 | 185 | ('symbol', 'p1') |
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186 | 186 | (or |
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187 | 187 | (func |
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188 | 188 | ('symbol', 'sort') |
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189 | 189 | (list |
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190 | 190 | (or |
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191 | 191 | ('symbol', '1') |
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192 | 192 | ('symbol', '2') |
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193 | 193 | ('symbol', '3')) |
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194 | 194 | (negate |
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195 | 195 | ('symbol', 'rev')))) |
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196 | 196 | (and |
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197 | 197 | ('symbol', '4') |
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198 | 198 | (group |
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199 | 199 | (or |
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200 | 200 | ('symbol', '5') |
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201 | 201 | ('symbol', '6') |
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202 | 202 | ('symbol', '7')))) |
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203 | 203 | ('symbol', '8'))) |
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204 | 204 | """ |
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205 | 205 | if not isinstance(tree, tuple): |
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206 | 206 | return tree |
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207 | 207 | op = tree[0] |
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208 | 208 | if op not in targetnodes: |
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209 | 209 | return (op,) + tuple(simplifyinfixops(x, targetnodes) for x in tree[1:]) |
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210 | 210 | |
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211 | 211 | # walk down left nodes taking each right node. no recursion to left nodes |
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212 | 212 | # because infix operators are left-associative, i.e. left tree is deep. |
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213 | 213 | # e.g. '1 + 2 + 3' -> (+ (+ 1 2) 3) -> (+ 1 2 3) |
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214 | 214 | simplified = [] |
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215 | 215 | x = tree |
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216 | 216 | while x[0] == op: |
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217 | 217 | l, r = x[1:] |
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218 | 218 | simplified.append(simplifyinfixops(r, targetnodes)) |
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219 | 219 | x = l |
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220 | 220 | simplified.append(simplifyinfixops(x, targetnodes)) |
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221 | 221 | simplified.append(op) |
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222 | 222 | return tuple(reversed(simplified)) |
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223 | 223 | |
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224 | 224 | def parseerrordetail(inst): |
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225 | 225 | """Compose error message from specified ParseError object |
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226 | 226 | """ |
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227 | 227 | if len(inst.args) > 1: |
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228 | 228 | return _('at %s: %s') % (inst.args[1], inst.args[0]) |
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229 | 229 | else: |
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230 | 230 | return inst.args[0] |
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231 | 231 | |
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232 | 232 | class alias(object): |
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233 | 233 | """Parsed result of alias""" |
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234 | 234 | |
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235 | 235 | def __init__(self, name, tree, args, err, replacement): |
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236 | 236 | self.name = name |
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237 | 237 | self.tree = tree |
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238 | 238 | self.args = args |
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239 | 239 | self.error = err |
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240 | 240 | self.replacement = replacement |
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241 | 241 | # whether own `error` information is already shown or not. |
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242 | 242 | # this avoids showing same warning multiple times at each `findaliases`. |
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243 | 243 | self.warned = False |
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244 | 244 | |
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245 | 245 | class basealiasrules(object): |
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246 | 246 | """Parsing and expansion rule set of aliases |
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247 | 247 | |
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248 | 248 | This is a helper for fileset/revset/template aliases. A concrete rule set |
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249 | 249 | should be made by sub-classing this and implementing class/static methods. |
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250 | 250 | |
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251 | 251 | It supports alias expansion of symbol and funciton-call styles:: |
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252 | 252 | |
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253 | 253 | # decl = defn |
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254 | 254 | h = heads(default) |
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255 | 255 | b($1) = ancestors($1) - ancestors(default) |
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256 | 256 | """ |
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257 | 257 | # typically a config section, which will be included in error messages |
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258 | 258 | _section = None |
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259 | 259 | # tags of symbol and function nodes |
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260 | 260 | _symbolnode = 'symbol' |
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261 | 261 | _funcnode = 'func' |
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262 | 262 | |
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263 | 263 | def __new__(cls): |
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264 | 264 | raise TypeError("'%s' is not instantiatable" % cls.__name__) |
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265 | 265 | |
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266 | 266 | @staticmethod |
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267 | 267 | def _parse(spec): |
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268 | 268 | """Parse an alias name, arguments and definition""" |
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269 | 269 | raise NotImplementedError |
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270 | 270 | |
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271 | 271 | @staticmethod |
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272 | 272 | def _getlist(tree): |
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273 | 273 | """Extract a list of arguments from parsed tree""" |
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274 | 274 | raise NotImplementedError |
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275 | 275 | |
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276 | 276 | @classmethod |
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277 | 277 | def _builddecl(cls, decl): |
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278 | 278 | """Parse an alias declaration into ``(name, tree, args, errorstr)`` |
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279 | 279 | |
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280 | 280 | This function analyzes the parsed tree. The parsing rule is provided |
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281 | 281 | by ``_parse()``. |
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282 | 282 | |
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283 | 283 | - ``name``: of declared alias (may be ``decl`` itself at error) |
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284 | 284 | - ``tree``: parse result (or ``None`` at error) |
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285 | 285 | - ``args``: list of argument names (or None for symbol declaration) |
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286 | 286 | - ``errorstr``: detail about detected error (or None) |
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287 | 287 | |
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288 | 288 | >>> sym = lambda x: ('symbol', x) |
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289 | 289 | >>> symlist = lambda *xs: ('list',) + tuple(sym(x) for x in xs) |
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290 | 290 | >>> func = lambda n, a: ('func', sym(n), a) |
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291 | 291 | >>> parsemap = { |
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292 | 292 | ... 'foo': sym('foo'), |
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293 | 293 | ... '$foo': sym('$foo'), |
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294 | 294 | ... 'foo::bar': ('dagrange', sym('foo'), sym('bar')), |
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295 | 295 | ... 'foo()': func('foo', None), |
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296 | 296 | ... '$foo()': func('$foo', None), |
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297 | 297 | ... 'foo($1, $2)': func('foo', symlist('$1', '$2')), |
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298 | 298 | ... 'foo(bar_bar, baz.baz)': |
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299 | 299 | ... func('foo', symlist('bar_bar', 'baz.baz')), |
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300 | 300 | ... 'foo(bar($1, $2))': |
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301 | 301 | ... func('foo', func('bar', symlist('$1', '$2'))), |
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302 | 302 | ... 'foo($1, $2, nested($1, $2))': |
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303 | 303 | ... func('foo', (symlist('$1', '$2') + |
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304 | 304 | ... (func('nested', symlist('$1', '$2')),))), |
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305 | 305 | ... 'foo("bar")': func('foo', ('string', 'bar')), |
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306 | 306 | ... 'foo($1, $2': error.ParseError('unexpected token: end', 10), |
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307 | 307 | ... 'foo("bar': error.ParseError('unterminated string', 5), |
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308 | 308 | ... 'foo($1, $2, $1)': func('foo', symlist('$1', '$2', '$1')), |
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309 | 309 | ... } |
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310 | 310 | >>> def parse(expr): |
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311 | 311 | ... x = parsemap[expr] |
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312 | 312 | ... if isinstance(x, Exception): |
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313 | 313 | ... raise x |
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314 | 314 | ... return x |
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315 | 315 | >>> def getlist(tree): |
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316 | 316 | ... if not tree: |
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317 | 317 | ... return [] |
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318 | 318 | ... if tree[0] == 'list': |
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319 | 319 | ... return list(tree[1:]) |
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320 | 320 | ... return [tree] |
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321 | 321 | >>> class aliasrules(basealiasrules): |
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322 | 322 | ... _parse = staticmethod(parse) |
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323 | 323 | ... _getlist = staticmethod(getlist) |
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324 | 324 | >>> builddecl = aliasrules._builddecl |
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325 | 325 | >>> builddecl('foo') |
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326 | 326 | ('foo', ('symbol', 'foo'), None, None) |
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327 | 327 | >>> builddecl('$foo') |
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328 | 328 | ('$foo', None, None, "'$' not for alias arguments") |
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329 | 329 | >>> builddecl('foo::bar') |
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330 | 330 | ('foo::bar', None, None, 'invalid format') |
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331 | 331 | >>> builddecl('foo()') |
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332 | 332 | ('foo', ('func', ('symbol', 'foo')), [], None) |
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333 | 333 | >>> builddecl('$foo()') |
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334 | 334 | ('$foo()', None, None, "'$' not for alias arguments") |
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335 | 335 | >>> builddecl('foo($1, $2)') |
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336 | 336 | ('foo', ('func', ('symbol', 'foo')), ['$1', '$2'], None) |
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337 | 337 | >>> builddecl('foo(bar_bar, baz.baz)') |
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338 | 338 | ('foo', ('func', ('symbol', 'foo')), ['bar_bar', 'baz.baz'], None) |
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339 | 339 | >>> builddecl('foo($1, $2, nested($1, $2))') |
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340 | 340 | ('foo($1, $2, nested($1, $2))', None, None, 'invalid argument list') |
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341 | 341 | >>> builddecl('foo(bar($1, $2))') |
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342 | 342 | ('foo(bar($1, $2))', None, None, 'invalid argument list') |
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343 | 343 | >>> builddecl('foo("bar")') |
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344 | 344 | ('foo("bar")', None, None, 'invalid argument list') |
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345 | 345 | >>> builddecl('foo($1, $2') |
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346 | 346 | ('foo($1, $2', None, None, 'at 10: unexpected token: end') |
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347 | 347 | >>> builddecl('foo("bar') |
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348 | 348 | ('foo("bar', None, None, 'at 5: unterminated string') |
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349 | 349 | >>> builddecl('foo($1, $2, $1)') |
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350 | 350 | ('foo', None, None, 'argument names collide with each other') |
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351 | 351 | """ |
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352 | 352 | try: |
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353 | 353 | tree = cls._parse(decl) |
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354 | 354 | except error.ParseError as inst: |
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355 | 355 | return (decl, None, None, parseerrordetail(inst)) |
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356 | 356 | |
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357 | 357 | if tree[0] == cls._symbolnode: |
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358 | 358 | # "name = ...." style |
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359 | 359 | name = tree[1] |
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360 | 360 | if name.startswith('$'): |
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361 | 361 | return (decl, None, None, _("'$' not for alias arguments")) |
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362 | 362 | return (name, tree, None, None) |
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363 | 363 | |
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364 | 364 | if tree[0] == cls._funcnode and tree[1][0] == cls._symbolnode: |
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365 | 365 | # "name(arg, ....) = ...." style |
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366 | 366 | name = tree[1][1] |
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367 | 367 | if name.startswith('$'): |
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368 | 368 | return (decl, None, None, _("'$' not for alias arguments")) |
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369 | 369 | args = [] |
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370 | 370 | for arg in cls._getlist(tree[2]): |
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371 | 371 | if arg[0] != cls._symbolnode: |
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372 | 372 | return (decl, None, None, _("invalid argument list")) |
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373 | 373 | args.append(arg[1]) |
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374 | 374 | if len(args) != len(set(args)): |
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375 | 375 | return (name, None, None, |
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376 | 376 | _("argument names collide with each other")) |
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377 | 377 | return (name, tree[:2], args, None) |
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378 | 378 | |
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379 | 379 | return (decl, None, None, _("invalid format")) |
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380 | 380 | |
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381 | 381 | @classmethod |
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382 | 382 | def _relabelargs(cls, tree, args): |
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383 | 383 | """Mark alias arguments as ``_aliasarg``""" |
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384 | 384 | if not isinstance(tree, tuple): |
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385 | 385 | return tree |
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386 | 386 | op = tree[0] |
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387 | 387 | if op != cls._symbolnode: |
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388 | 388 | return (op,) + tuple(cls._relabelargs(x, args) for x in tree[1:]) |
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389 | 389 | |
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390 | 390 | assert len(tree) == 2 |
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391 | 391 | sym = tree[1] |
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392 | 392 | if sym in args: |
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393 | 393 | op = '_aliasarg' |
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394 | 394 | elif sym.startswith('$'): |
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395 | 395 | raise error.ParseError(_("'$' not for alias arguments")) |
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396 | 396 | return (op, sym) |
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397 | 397 | |
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398 | 398 | @classmethod |
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399 | 399 | def _builddefn(cls, defn, args): |
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400 | 400 | """Parse an alias definition into a tree and marks substitutions |
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401 | 401 | |
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402 | 402 | This function marks alias argument references as ``_aliasarg``. The |
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403 | 403 | parsing rule is provided by ``_parse()``. |
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404 | 404 | |
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405 | 405 | ``args`` is a list of alias argument names, or None if the alias |
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406 | 406 | is declared as a symbol. |
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407 | 407 | |
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408 | 408 | >>> parsemap = { |
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409 | 409 | ... '$1 or foo': ('or', ('symbol', '$1'), ('symbol', 'foo')), |
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410 | 410 | ... '$1 or $bar': ('or', ('symbol', '$1'), ('symbol', '$bar')), |
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411 | 411 | ... '$10 or baz': ('or', ('symbol', '$10'), ('symbol', 'baz')), |
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412 | 412 | ... '"$1" or "foo"': ('or', ('string', '$1'), ('string', 'foo')), |
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413 | 413 | ... } |
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414 | 414 | >>> class aliasrules(basealiasrules): |
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415 | 415 | ... _parse = staticmethod(parsemap.__getitem__) |
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416 | 416 | ... _getlist = staticmethod(lambda x: []) |
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417 | 417 | >>> builddefn = aliasrules._builddefn |
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418 | 418 | >>> def pprint(tree): |
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419 | 419 | ... print prettyformat(tree, ('_aliasarg', 'string', 'symbol')) |
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420 | 420 | >>> args = ['$1', '$2', 'foo'] |
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421 | 421 | >>> pprint(builddefn('$1 or foo', args)) |
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422 | 422 | (or |
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423 | 423 | ('_aliasarg', '$1') |
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424 | 424 | ('_aliasarg', 'foo')) |
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425 | 425 | >>> try: |
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426 | 426 | ... builddefn('$1 or $bar', args) |
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427 | 427 | ... except error.ParseError as inst: |
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428 | 428 | ... print parseerrordetail(inst) |
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429 | 429 | '$' not for alias arguments |
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430 | 430 | >>> args = ['$1', '$10', 'foo'] |
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431 | 431 | >>> pprint(builddefn('$10 or baz', args)) |
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432 | 432 | (or |
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433 | 433 | ('_aliasarg', '$10') |
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434 | 434 | ('symbol', 'baz')) |
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435 | 435 | >>> pprint(builddefn('"$1" or "foo"', args)) |
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436 | 436 | (or |
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437 | 437 | ('string', '$1') |
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438 | 438 | ('string', 'foo')) |
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439 | 439 | """ |
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440 | 440 | tree = cls._parse(defn) |
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441 | 441 | if args: |
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442 | 442 | args = set(args) |
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443 | 443 | else: |
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444 | 444 | args = set() |
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445 | 445 | return cls._relabelargs(tree, args) |
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446 | 446 | |
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447 | 447 | @classmethod |
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448 | 448 | def build(cls, decl, defn): |
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449 | 449 | """Parse an alias declaration and definition into an alias object""" |
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450 | 450 | repl = efmt = None |
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451 | 451 | name, tree, args, err = cls._builddecl(decl) |
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452 | 452 | if err: |
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453 | 453 | efmt = _('failed to parse the declaration of %(section)s ' |
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454 | 454 | '"%(name)s": %(error)s') |
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455 | 455 | else: |
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456 | 456 | try: |
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457 | 457 | repl = cls._builddefn(defn, args) |
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458 | 458 | except error.ParseError as inst: |
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459 | 459 | err = parseerrordetail(inst) |
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460 | 460 | efmt = _('failed to parse the definition of %(section)s ' |
|
461 | 461 | '"%(name)s": %(error)s') |
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462 | 462 | if err: |
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463 | 463 | err = efmt % {'section': cls._section, 'name': name, 'error': err} |
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464 | 464 | return alias(name, tree, args, err, repl) |
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465 | 465 | |
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466 | 466 | @classmethod |
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467 | 467 | def buildmap(cls, items): |
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468 | 468 | """Parse a list of alias (name, replacement) pairs into a dict of |
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469 | 469 | alias objects""" |
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470 | 470 | aliases = {} |
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471 | 471 | for decl, defn in items: |
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472 | 472 | a = cls.build(decl, defn) |
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473 | 473 | aliases[a.name] = a |
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474 | 474 | return aliases |
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475 | 475 | |
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476 | 476 | @classmethod |
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477 | 477 | def _getalias(cls, aliases, tree): |
|
478 | 478 | """If tree looks like an unexpanded alias, return it. Return None |
|
479 | 479 | otherwise. |
|
480 | 480 | """ |
|
481 | 481 | if not isinstance(tree, tuple): |
|
482 | 482 | return None |
|
483 | 483 | if tree[0] == cls._symbolnode: |
|
484 | 484 | name = tree[1] |
|
485 | 485 | a = aliases.get(name) |
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486 | 486 | if a and a.args is None and a.tree == tree: |
|
487 | 487 | return a |
|
488 | 488 | if tree[0] == cls._funcnode and tree[1][0] == cls._symbolnode: |
|
489 | 489 | name = tree[1][1] |
|
490 | 490 | a = aliases.get(name) |
|
491 | 491 | if a and a.args is not None and a.tree == tree[:2]: |
|
492 | 492 | return a |
|
493 | 493 | return None |
|
494 | 494 | |
|
495 | 495 | @classmethod |
|
496 | 496 | def _expandargs(cls, tree, args): |
|
497 | 497 | """Replace _aliasarg instances with the substitution value of the |
|
498 | 498 | same name in args, recursively. |
|
499 | 499 | """ |
|
500 | 500 | if not isinstance(tree, tuple): |
|
501 | 501 | return tree |
|
502 | 502 | if tree[0] == '_aliasarg': |
|
503 | 503 | sym = tree[1] |
|
504 | 504 | return args[sym] |
|
505 | 505 | return tuple(cls._expandargs(t, args) for t in tree) |
|
506 | 506 | |
|
507 | 507 | @classmethod |
|
508 | 508 | def _expand(cls, aliases, tree, expanding, cache): |
|
509 | 509 | if not isinstance(tree, tuple): |
|
510 | 510 | return tree |
|
511 | 511 | a = cls._getalias(aliases, tree) |
|
512 |
if a is |
|
|
512 | if a is None: | |
|
513 | return tuple(cls._expand(aliases, t, expanding, cache) | |
|
514 | for t in tree) | |
|
513 | 515 |
|
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514 | 516 |
|
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515 | 517 |
|
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516 | 518 |
|
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517 | 519 |
|
|
518 |
|
|
|
519 | 'name': a.name}) | |
|
520 | % {'section': cls._section, 'name': a.name}) | |
|
520 | 521 |
|
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521 | 522 |
|
|
522 | 523 |
|
|
523 | 524 |
|
|
524 | 525 |
|
|
525 | 526 |
|
|
526 |
|
|
|
527 | if a.args is None: | |
|
528 | return result | |
|
527 | 529 |
|
|
528 | 530 |
|
|
529 | 531 |
|
|
530 | 532 |
|
|
531 | 533 |
|
|
532 |
|
|
|
533 | else: | |
|
534 | result = tuple(cls._expand(aliases, t, expanding, cache) | |
|
535 | for t in tree) | |
|
536 | return result | |
|
534 | return cls._expandargs(result, dict(zip(a.args, l))) | |
|
537 | 535 | |
|
538 | 536 | @classmethod |
|
539 | 537 | def expand(cls, aliases, tree): |
|
540 | 538 | """Expand aliases in tree, recursively. |
|
541 | 539 | |
|
542 | 540 | 'aliases' is a dictionary mapping user defined aliases to alias objects. |
|
543 | 541 | """ |
|
544 | 542 | return cls._expand(aliases, tree, [], {}) |
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