99 lines
2.3 KiB
Python
99 lines
2.3 KiB
Python
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"""
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A (toy) tool for emitting Python ASTs as YAML formatted data.
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"""
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import ast
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import optparse
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import sys
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import yaml
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def propnames(node):
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"""return names of attributes specific for the current node"""
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props = {x for x in dir(node) if not x.startswith("_")}
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if isinstance(node, ast.Module):
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props -= {"body"}
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if isinstance(node, (ast.Expr, ast.Attribute)):
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props -= {"value"}
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if isinstance(node, ast.Constant):
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props -= {"n", "s"}
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if isinstance(node, ast.ClassDef):
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props -= {"body"}
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return props
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# Note that ast.NodeTransformer exists for mutations.
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# This is just for reads.
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class TreeDumper(ast.NodeVisitor):
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def __init__(self):
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super().__init__()
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self._stack = []
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def dump(self, node):
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self.visit(node)
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def visit(self, node):
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# nodetype = type(node)
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nodename = node.__class__.__name__
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indent = " " * len(self._stack) * 2
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print(indent + nodename)
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for n in propnames(node):
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print(indent + "%s: %s" % (n, node.__dict__[n]))
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self._stack.append(node)
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self.generic_visit(node)
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self._stack.pop()
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class YAMLTreeDumper(ast.NodeVisitor):
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def __init__(self):
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super().__init__()
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self._stack = []
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def node2yml(self, node):
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try:
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# nodetype = type(node)
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nodename = node.__class__.__name__
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return {
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"op": nodename,
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"props": {n: node.__dict__[n] for n in propnames(node)},
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"children": [],
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}
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except Exception:
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print(repr(node), propnames(node), dir(node))
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def visit(self, node):
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yml_node = self.node2yml(node)
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self._stack.append(yml_node)
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old_stack = self._stack
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self._stack = yml_node["children"]
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self.generic_visit(node)
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self._stack = old_stack
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return yml_node
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if __name__ == "__main__":
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parser = optparse.OptionParser(usage="%prog [options] <filename.py>")
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opts, args = parser.parse_args()
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if len(args) == 0:
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parser.print_help()
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sys.exit(-1)
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filename = args[0]
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with open(filename) as f:
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root = ast.parse(f.read(), filename)
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print(
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yaml.dump(
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YAMLTreeDumper().visit(root), default_flow_style=False, sort_keys=False
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)
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)
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