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566d934745
SF patch #1015989 The basic idea of this patch is to compute lineno attributes for all AST nodes. The actual implementation lead to a lot of restructing and code cleanup. The generated AST nodes now have an optional lineno argument to constructor. Remove the top-level asList(), since it didn't seem to serve any purpose. Add an __iter__ to ast nodes. Use isinstance() instead of explicit type tests. Change transformer to use the new lineno attribute, which replaces three lines of code with one. Use universal newlines so that we can get rid of special-case code for line endings. Use lookup_node() in a few more frequently called, but simple com_xxx methods(). Change string exception to class exception.
286 lines
9.1 KiB
Python
286 lines
9.1 KiB
Python
"""Generate ast module from specification
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This script generates the ast module from a simple specification,
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which makes it easy to accomodate changes in the grammar. This
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approach would be quite reasonable if the grammar changed often.
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Instead, it is rather complex to generate the appropriate code. And
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the Node interface has changed more often than the grammar.
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"""
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import fileinput
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import getopt
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import re
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import sys
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from StringIO import StringIO
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SPEC = "ast.txt"
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COMMA = ", "
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def load_boilerplate(file):
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f = open(file)
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buf = f.read()
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f.close()
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i = buf.find('### ''PROLOGUE')
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j = buf.find('### ''EPILOGUE')
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pro = buf[i+12:j].strip()
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epi = buf[j+12:].strip()
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return pro, epi
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def strip_default(arg):
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"""Return the argname from an 'arg = default' string"""
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i = arg.find('=')
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if i == -1:
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return arg
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t = arg[:i].strip()
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return t
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P_NODE = 1
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P_OTHER = 2
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P_NESTED = 3
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P_NONE = 4
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class NodeInfo:
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"""Each instance describes a specific AST node"""
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def __init__(self, name, args):
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self.name = name
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self.args = args.strip()
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self.argnames = self.get_argnames()
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self.argprops = self.get_argprops()
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self.nargs = len(self.argnames)
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self.init = []
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def get_argnames(self):
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if '(' in self.args:
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i = self.args.find('(')
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j = self.args.rfind(')')
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args = self.args[i+1:j]
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else:
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args = self.args
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return [strip_default(arg.strip())
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for arg in args.split(',') if arg]
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def get_argprops(self):
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"""Each argument can have a property like '*' or '!'
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XXX This method modifies the argnames in place!
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"""
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d = {}
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hardest_arg = P_NODE
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for i in range(len(self.argnames)):
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arg = self.argnames[i]
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if arg.endswith('*'):
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arg = self.argnames[i] = arg[:-1]
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d[arg] = P_OTHER
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hardest_arg = max(hardest_arg, P_OTHER)
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elif arg.endswith('!'):
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arg = self.argnames[i] = arg[:-1]
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d[arg] = P_NESTED
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hardest_arg = max(hardest_arg, P_NESTED)
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elif arg.endswith('&'):
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arg = self.argnames[i] = arg[:-1]
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d[arg] = P_NONE
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hardest_arg = max(hardest_arg, P_NONE)
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else:
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d[arg] = P_NODE
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self.hardest_arg = hardest_arg
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if hardest_arg > P_NODE:
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self.args = self.args.replace('*', '')
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self.args = self.args.replace('!', '')
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self.args = self.args.replace('&', '')
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return d
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def gen_source(self):
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buf = StringIO()
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print >> buf, "class %s(Node):" % self.name
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self._gen_init(buf)
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print >> buf
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self._gen_getChildren(buf)
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print >> buf
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self._gen_getChildNodes(buf)
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print >> buf
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self._gen_repr(buf)
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buf.seek(0, 0)
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return buf.read()
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def _gen_init(self, buf):
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if self.args:
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print >> buf, " def __init__(self, %s, lineno=None):" % self.args
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else:
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print >> buf, " def __init__(self, lineno=None):"
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if self.argnames:
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for name in self.argnames:
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print >> buf, " self.%s = %s" % (name, name)
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print >> buf, " self.lineno = lineno"
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if self.init:
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print >> buf, "".join([" " + line for line in self.init])
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def _gen_getChildren(self, buf):
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print >> buf, " def getChildren(self):"
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if len(self.argnames) == 0:
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print >> buf, " return ()"
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else:
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if self.hardest_arg < P_NESTED:
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clist = COMMA.join(["self.%s" % c
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for c in self.argnames])
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if self.nargs == 1:
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print >> buf, " return %s," % clist
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else:
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print >> buf, " return %s" % clist
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else:
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if len(self.argnames) == 1:
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print >> buf, " return tuple(flatten(self.%s))" % self.argnames[0]
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else:
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print >> buf, " children = []"
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template = " children.%s(%sself.%s%s)"
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for name in self.argnames:
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if self.argprops[name] == P_NESTED:
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print >> buf, template % ("extend", "flatten(",
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name, ")")
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else:
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print >> buf, template % ("append", "", name, "")
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print >> buf, " return tuple(children)"
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def _gen_getChildNodes(self, buf):
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print >> buf, " def getChildNodes(self):"
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if len(self.argnames) == 0:
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print >> buf, " return ()"
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else:
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if self.hardest_arg < P_NESTED:
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clist = ["self.%s" % c
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for c in self.argnames
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if self.argprops[c] == P_NODE]
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if len(clist) == 0:
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print >> buf, " return ()"
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elif len(clist) == 1:
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print >> buf, " return %s," % clist[0]
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else:
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print >> buf, " return %s" % COMMA.join(clist)
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else:
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print >> buf, " nodelist = []"
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template = " nodelist.%s(%sself.%s%s)"
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for name in self.argnames:
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if self.argprops[name] == P_NONE:
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tmp = (" if self.%s is not None:\n"
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" nodelist.append(self.%s)")
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print >> buf, tmp % (name, name)
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elif self.argprops[name] == P_NESTED:
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print >> buf, template % ("extend", "flatten_nodes(",
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name, ")")
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elif self.argprops[name] == P_NODE:
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print >> buf, template % ("append", "", name, "")
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print >> buf, " return tuple(nodelist)"
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def _gen_repr(self, buf):
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print >> buf, " def __repr__(self):"
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if self.argnames:
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fmt = COMMA.join(["%s"] * self.nargs)
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if '(' in self.args:
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fmt = '(%s)' % fmt
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vals = ["repr(self.%s)" % name for name in self.argnames]
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vals = COMMA.join(vals)
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if self.nargs == 1:
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vals = vals + ","
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print >> buf, ' return "%s(%s)" %% (%s)' % \
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(self.name, fmt, vals)
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else:
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print >> buf, ' return "%s()"' % self.name
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rx_init = re.compile('init\((.*)\):')
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def parse_spec(file):
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classes = {}
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cur = None
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for line in fileinput.input(file):
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if line.strip().startswith('#'):
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continue
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mo = rx_init.search(line)
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if mo is None:
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if cur is None:
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# a normal entry
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try:
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name, args = line.split(':')
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except ValueError:
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continue
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classes[name] = NodeInfo(name, args)
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cur = None
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else:
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# some code for the __init__ method
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cur.init.append(line)
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else:
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# some extra code for a Node's __init__ method
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name = mo.group(1)
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cur = classes[name]
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return sorted(classes.values(), key=lambda n: n.name)
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def main():
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prologue, epilogue = load_boilerplate(sys.argv[-1])
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print prologue
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print
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classes = parse_spec(SPEC)
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for info in classes:
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print info.gen_source()
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print epilogue
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if __name__ == "__main__":
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main()
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sys.exit(0)
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### PROLOGUE
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"""Python abstract syntax node definitions
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This file is automatically generated by Tools/compiler/astgen.py
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"""
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from consts import CO_VARARGS, CO_VARKEYWORDS
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def flatten(list):
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l = []
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for elt in list:
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t = type(elt)
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if t is tuple or t is list:
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for elt2 in flatten(elt):
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l.append(elt2)
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else:
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l.append(elt)
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return l
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def flatten_nodes(list):
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return [n for n in flatten(list) if isinstance(n, Node)]
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nodes = {}
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class Node:
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"""Abstract base class for ast nodes."""
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def getChildren(self):
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pass # implemented by subclasses
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def __iter__(self):
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for n in self.getChildren():
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yield n
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def asList(self): # for backwards compatibility
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return self.getChildren()
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def getChildNodes(self):
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pass # implemented by subclasses
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class EmptyNode(Node):
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pass
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class Expression(Node):
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# Expression is an artificial node class to support "eval"
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nodes["expression"] = "Expression"
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def __init__(self, node):
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self.node = node
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def getChildren(self):
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return self.node,
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def getChildNodes(self):
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return self.node,
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def __repr__(self):
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return "Expression(%s)" % (repr(self.node))
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### EPILOGUE
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for name, obj in globals().items():
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if isinstance(obj, type) and issubclass(obj, Node):
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nodes[name.lower()] = obj
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