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46 lines
1.4 KiB
Python
46 lines
1.4 KiB
Python
"""Check for errs in the AST.
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The Python parser does not catch all syntax errors. Others, like
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assignments with invalid targets, are caught in the code generation
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phase.
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The compiler package catches some errors in the transformer module.
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But it seems clearer to write checkers that use the AST to detect
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errors.
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"""
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from compiler import ast, walk
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def check(tree, multi=None):
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v = SyntaxErrorChecker(multi)
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walk(tree, v)
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return v.errors
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class SyntaxErrorChecker:
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"""A visitor to find syntax errors in the AST."""
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def __init__(self, multi=None):
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"""Create new visitor object.
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If optional argument multi is not None, then print messages
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for each error rather than raising a SyntaxError for the
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first.
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"""
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self.multi = multi
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self.errors = 0
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def error(self, node, msg):
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self.errors = self.errors + 1
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if self.multi is not None:
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print "%s:%s: %s" % (node.filename, node.lineno, msg)
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else:
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raise SyntaxError, "%s (%s:%s)" % (msg, node.filename, node.lineno)
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def visitAssign(self, node):
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# the transformer module handles many of these
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pass
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## for target in node.nodes:
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## if isinstance(target, ast.AssList):
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## if target.lineno is None:
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## target.lineno = node.lineno
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## self.error(target, "can't assign to list comprehension")
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