| 1 | """Generate ast module from specification
|
|---|
| 2 |
|
|---|
| 3 | This script generates the ast module from a simple specification,
|
|---|
| 4 | which makes it easy to accomodate changes in the grammar. This
|
|---|
| 5 | approach would be quite reasonable if the grammar changed often.
|
|---|
| 6 | Instead, it is rather complex to generate the appropriate code. And
|
|---|
| 7 | the Node interface has changed more often than the grammar.
|
|---|
| 8 | """
|
|---|
| 9 |
|
|---|
| 10 | import fileinput
|
|---|
| 11 | import re
|
|---|
| 12 | import sys
|
|---|
| 13 | from StringIO import StringIO
|
|---|
| 14 |
|
|---|
| 15 | SPEC = "ast.txt"
|
|---|
| 16 | COMMA = ", "
|
|---|
| 17 |
|
|---|
| 18 | def load_boilerplate(file):
|
|---|
| 19 | f = open(file)
|
|---|
| 20 | buf = f.read()
|
|---|
| 21 | f.close()
|
|---|
| 22 | i = buf.find('### ''PROLOGUE')
|
|---|
| 23 | j = buf.find('### ''EPILOGUE')
|
|---|
| 24 | pro = buf[i+12:j].strip()
|
|---|
| 25 | epi = buf[j+12:].strip()
|
|---|
| 26 | return pro, epi
|
|---|
| 27 |
|
|---|
| 28 | def strip_default(arg):
|
|---|
| 29 | """Return the argname from an 'arg = default' string"""
|
|---|
| 30 | i = arg.find('=')
|
|---|
| 31 | if i == -1:
|
|---|
| 32 | return arg
|
|---|
| 33 | t = arg[:i].strip()
|
|---|
| 34 | return t
|
|---|
| 35 |
|
|---|
| 36 | P_NODE = 1
|
|---|
| 37 | P_OTHER = 2
|
|---|
| 38 | P_NESTED = 3
|
|---|
| 39 | P_NONE = 4
|
|---|
| 40 |
|
|---|
| 41 | class NodeInfo:
|
|---|
| 42 | """Each instance describes a specific AST node"""
|
|---|
| 43 | def __init__(self, name, args):
|
|---|
| 44 | self.name = name
|
|---|
| 45 | self.args = args.strip()
|
|---|
| 46 | self.argnames = self.get_argnames()
|
|---|
| 47 | self.argprops = self.get_argprops()
|
|---|
| 48 | self.nargs = len(self.argnames)
|
|---|
| 49 | self.init = []
|
|---|
| 50 |
|
|---|
| 51 | def get_argnames(self):
|
|---|
| 52 | if '(' in self.args:
|
|---|
| 53 | i = self.args.find('(')
|
|---|
| 54 | j = self.args.rfind(')')
|
|---|
| 55 | args = self.args[i+1:j]
|
|---|
| 56 | else:
|
|---|
| 57 | args = self.args
|
|---|
| 58 | return [strip_default(arg.strip())
|
|---|
| 59 | for arg in args.split(',') if arg]
|
|---|
| 60 |
|
|---|
| 61 | def get_argprops(self):
|
|---|
| 62 | """Each argument can have a property like '*' or '!'
|
|---|
| 63 |
|
|---|
| 64 | XXX This method modifies the argnames in place!
|
|---|
| 65 | """
|
|---|
| 66 | d = {}
|
|---|
| 67 | hardest_arg = P_NODE
|
|---|
| 68 | for i in range(len(self.argnames)):
|
|---|
| 69 | arg = self.argnames[i]
|
|---|
| 70 | if arg.endswith('*'):
|
|---|
| 71 | arg = self.argnames[i] = arg[:-1]
|
|---|
| 72 | d[arg] = P_OTHER
|
|---|
| 73 | hardest_arg = max(hardest_arg, P_OTHER)
|
|---|
| 74 | elif arg.endswith('!'):
|
|---|
| 75 | arg = self.argnames[i] = arg[:-1]
|
|---|
| 76 | d[arg] = P_NESTED
|
|---|
| 77 | hardest_arg = max(hardest_arg, P_NESTED)
|
|---|
| 78 | elif arg.endswith('&'):
|
|---|
| 79 | arg = self.argnames[i] = arg[:-1]
|
|---|
| 80 | d[arg] = P_NONE
|
|---|
| 81 | hardest_arg = max(hardest_arg, P_NONE)
|
|---|
| 82 | else:
|
|---|
| 83 | d[arg] = P_NODE
|
|---|
| 84 | self.hardest_arg = hardest_arg
|
|---|
| 85 |
|
|---|
| 86 | if hardest_arg > P_NODE:
|
|---|
| 87 | self.args = self.args.replace('*', '')
|
|---|
| 88 | self.args = self.args.replace('!', '')
|
|---|
| 89 | self.args = self.args.replace('&', '')
|
|---|
| 90 |
|
|---|
| 91 | return d
|
|---|
| 92 |
|
|---|
| 93 | def gen_source(self):
|
|---|
| 94 | buf = StringIO()
|
|---|
| 95 | print >> buf, "class %s(Node):" % self.name
|
|---|
| 96 | self._gen_init(buf)
|
|---|
| 97 | print >> buf
|
|---|
| 98 | self._gen_getChildren(buf)
|
|---|
| 99 | print >> buf
|
|---|
| 100 | self._gen_getChildNodes(buf)
|
|---|
| 101 | print >> buf
|
|---|
| 102 | self._gen_repr(buf)
|
|---|
| 103 | buf.seek(0, 0)
|
|---|
| 104 | return buf.read()
|
|---|
| 105 |
|
|---|
| 106 | def _gen_init(self, buf):
|
|---|
| 107 | if self.args:
|
|---|
| 108 | argtuple = '(' in self.args
|
|---|
| 109 | args = self.args if not argtuple else ''.join(self.argnames)
|
|---|
| 110 | print >> buf, " def __init__(self, %s, lineno=None):" % args
|
|---|
| 111 | else:
|
|---|
| 112 | print >> buf, " def __init__(self, lineno=None):"
|
|---|
| 113 | if self.argnames:
|
|---|
| 114 | if argtuple:
|
|---|
| 115 | for idx, name in enumerate(self.argnames):
|
|---|
| 116 | print >> buf, " self.%s = %s[%s]" % (name, args, idx)
|
|---|
| 117 | else:
|
|---|
| 118 | for name in self.argnames:
|
|---|
| 119 | print >> buf, " self.%s = %s" % (name, name)
|
|---|
| 120 | print >> buf, " self.lineno = lineno"
|
|---|
| 121 | # Copy the lines in self.init, indented four spaces. The rstrip()
|
|---|
| 122 | # business is to get rid of the four spaces if line happens to be
|
|---|
| 123 | # empty, so that reindent.py is happy with the output.
|
|---|
| 124 | for line in self.init:
|
|---|
| 125 | print >> buf, (" " + line).rstrip()
|
|---|
| 126 |
|
|---|
| 127 | def _gen_getChildren(self, buf):
|
|---|
| 128 | print >> buf, " def getChildren(self):"
|
|---|
| 129 | if len(self.argnames) == 0:
|
|---|
| 130 | print >> buf, " return ()"
|
|---|
| 131 | else:
|
|---|
| 132 | if self.hardest_arg < P_NESTED:
|
|---|
| 133 | clist = COMMA.join(["self.%s" % c
|
|---|
| 134 | for c in self.argnames])
|
|---|
| 135 | if self.nargs == 1:
|
|---|
| 136 | print >> buf, " return %s," % clist
|
|---|
| 137 | else:
|
|---|
| 138 | print >> buf, " return %s" % clist
|
|---|
| 139 | else:
|
|---|
| 140 | if len(self.argnames) == 1:
|
|---|
| 141 | print >> buf, " return tuple(flatten(self.%s))" % self.argnames[0]
|
|---|
| 142 | else:
|
|---|
| 143 | print >> buf, " children = []"
|
|---|
| 144 | template = " children.%s(%sself.%s%s)"
|
|---|
| 145 | for name in self.argnames:
|
|---|
| 146 | if self.argprops[name] == P_NESTED:
|
|---|
| 147 | print >> buf, template % ("extend", "flatten(",
|
|---|
| 148 | name, ")")
|
|---|
| 149 | else:
|
|---|
| 150 | print >> buf, template % ("append", "", name, "")
|
|---|
| 151 | print >> buf, " return tuple(children)"
|
|---|
| 152 |
|
|---|
| 153 | def _gen_getChildNodes(self, buf):
|
|---|
| 154 | print >> buf, " def getChildNodes(self):"
|
|---|
| 155 | if len(self.argnames) == 0:
|
|---|
| 156 | print >> buf, " return ()"
|
|---|
| 157 | else:
|
|---|
| 158 | if self.hardest_arg < P_NESTED:
|
|---|
| 159 | clist = ["self.%s" % c
|
|---|
| 160 | for c in self.argnames
|
|---|
| 161 | if self.argprops[c] == P_NODE]
|
|---|
| 162 | if len(clist) == 0:
|
|---|
| 163 | print >> buf, " return ()"
|
|---|
| 164 | elif len(clist) == 1:
|
|---|
| 165 | print >> buf, " return %s," % clist[0]
|
|---|
| 166 | else:
|
|---|
| 167 | print >> buf, " return %s" % COMMA.join(clist)
|
|---|
| 168 | else:
|
|---|
| 169 | print >> buf, " nodelist = []"
|
|---|
| 170 | template = " nodelist.%s(%sself.%s%s)"
|
|---|
| 171 | for name in self.argnames:
|
|---|
| 172 | if self.argprops[name] == P_NONE:
|
|---|
| 173 | tmp = (" if self.%s is not None:\n"
|
|---|
| 174 | " nodelist.append(self.%s)")
|
|---|
| 175 | print >> buf, tmp % (name, name)
|
|---|
| 176 | elif self.argprops[name] == P_NESTED:
|
|---|
| 177 | print >> buf, template % ("extend", "flatten_nodes(",
|
|---|
| 178 | name, ")")
|
|---|
| 179 | elif self.argprops[name] == P_NODE:
|
|---|
| 180 | print >> buf, template % ("append", "", name, "")
|
|---|
| 181 | print >> buf, " return tuple(nodelist)"
|
|---|
| 182 |
|
|---|
| 183 | def _gen_repr(self, buf):
|
|---|
| 184 | print >> buf, " def __repr__(self):"
|
|---|
| 185 | if self.argnames:
|
|---|
| 186 | fmt = COMMA.join(["%s"] * self.nargs)
|
|---|
| 187 | if '(' in self.args:
|
|---|
| 188 | fmt = '(%s)' % fmt
|
|---|
| 189 | vals = ["repr(self.%s)" % name for name in self.argnames]
|
|---|
| 190 | vals = COMMA.join(vals)
|
|---|
| 191 | if self.nargs == 1:
|
|---|
| 192 | vals = vals + ","
|
|---|
| 193 | print >> buf, ' return "%s(%s)" %% (%s)' % \
|
|---|
| 194 | (self.name, fmt, vals)
|
|---|
| 195 | else:
|
|---|
| 196 | print >> buf, ' return "%s()"' % self.name
|
|---|
| 197 |
|
|---|
| 198 | rx_init = re.compile('init\((.*)\):')
|
|---|
| 199 |
|
|---|
| 200 | def parse_spec(file):
|
|---|
| 201 | classes = {}
|
|---|
| 202 | cur = None
|
|---|
| 203 | for line in fileinput.input(file):
|
|---|
| 204 | if line.strip().startswith('#'):
|
|---|
| 205 | continue
|
|---|
| 206 | mo = rx_init.search(line)
|
|---|
| 207 | if mo is None:
|
|---|
| 208 | if cur is None:
|
|---|
| 209 | # a normal entry
|
|---|
| 210 | try:
|
|---|
| 211 | name, args = line.split(':')
|
|---|
| 212 | except ValueError:
|
|---|
| 213 | continue
|
|---|
| 214 | classes[name] = NodeInfo(name, args)
|
|---|
| 215 | cur = None
|
|---|
| 216 | else:
|
|---|
| 217 | # some code for the __init__ method
|
|---|
| 218 | cur.init.append(line)
|
|---|
| 219 | else:
|
|---|
| 220 | # some extra code for a Node's __init__ method
|
|---|
| 221 | name = mo.group(1)
|
|---|
| 222 | cur = classes[name]
|
|---|
| 223 | return sorted(classes.values(), key=lambda n: n.name)
|
|---|
| 224 |
|
|---|
| 225 | def main():
|
|---|
| 226 | prologue, epilogue = load_boilerplate(sys.argv[-1])
|
|---|
| 227 | print prologue
|
|---|
| 228 | print
|
|---|
| 229 | classes = parse_spec(SPEC)
|
|---|
| 230 | for info in classes:
|
|---|
| 231 | print info.gen_source()
|
|---|
| 232 | print epilogue
|
|---|
| 233 |
|
|---|
| 234 | if __name__ == "__main__":
|
|---|
| 235 | main()
|
|---|
| 236 | sys.exit(0)
|
|---|
| 237 |
|
|---|
| 238 | ### PROLOGUE
|
|---|
| 239 | """Python abstract syntax node definitions
|
|---|
| 240 |
|
|---|
| 241 | This file is automatically generated by Tools/compiler/astgen.py
|
|---|
| 242 | """
|
|---|
| 243 | from consts import CO_VARARGS, CO_VARKEYWORDS
|
|---|
| 244 |
|
|---|
| 245 | def flatten(seq):
|
|---|
| 246 | l = []
|
|---|
| 247 | for elt in seq:
|
|---|
| 248 | t = type(elt)
|
|---|
| 249 | if t is tuple or t is list:
|
|---|
| 250 | for elt2 in flatten(elt):
|
|---|
| 251 | l.append(elt2)
|
|---|
| 252 | else:
|
|---|
| 253 | l.append(elt)
|
|---|
| 254 | return l
|
|---|
| 255 |
|
|---|
| 256 | def flatten_nodes(seq):
|
|---|
| 257 | return [n for n in flatten(seq) if isinstance(n, Node)]
|
|---|
| 258 |
|
|---|
| 259 | nodes = {}
|
|---|
| 260 |
|
|---|
| 261 | class Node:
|
|---|
| 262 | """Abstract base class for ast nodes."""
|
|---|
| 263 | def getChildren(self):
|
|---|
| 264 | pass # implemented by subclasses
|
|---|
| 265 | def __iter__(self):
|
|---|
| 266 | for n in self.getChildren():
|
|---|
| 267 | yield n
|
|---|
| 268 | def asList(self): # for backwards compatibility
|
|---|
| 269 | return self.getChildren()
|
|---|
| 270 | def getChildNodes(self):
|
|---|
| 271 | pass # implemented by subclasses
|
|---|
| 272 |
|
|---|
| 273 | class EmptyNode(Node):
|
|---|
| 274 | pass
|
|---|
| 275 |
|
|---|
| 276 | class Expression(Node):
|
|---|
| 277 | # Expression is an artificial node class to support "eval"
|
|---|
| 278 | nodes["expression"] = "Expression"
|
|---|
| 279 | def __init__(self, node):
|
|---|
| 280 | self.node = node
|
|---|
| 281 |
|
|---|
| 282 | def getChildren(self):
|
|---|
| 283 | return self.node,
|
|---|
| 284 |
|
|---|
| 285 | def getChildNodes(self):
|
|---|
| 286 | return self.node,
|
|---|
| 287 |
|
|---|
| 288 | def __repr__(self):
|
|---|
| 289 | return "Expression(%s)" % (repr(self.node))
|
|---|
| 290 |
|
|---|
| 291 | ### EPILOGUE
|
|---|
| 292 | for name, obj in globals().items():
|
|---|
| 293 | if isinstance(obj, type) and issubclass(obj, Node):
|
|---|
| 294 | nodes[name.lower()] = obj
|
|---|
