| 1 | """Check for errs in the AST.
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| 2 |
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| 3 | The Python parser does not catch all syntax errors. Others, like
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| 4 | assignments with invalid targets, are caught in the code generation
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| 5 | phase.
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| 6 |
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| 7 | The compiler package catches some errors in the transformer module.
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| 8 | But it seems clearer to write checkers that use the AST to detect
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| 9 | errors.
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| 10 | """
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| 11 |
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| 12 | from . import ast
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| 13 | from .visitor import walk
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| 14 |
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| 15 |
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| 16 | def check(tree, multi=None):
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| 17 | v = SyntaxErrorChecker(multi)
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| 18 | walk(tree, v)
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| 19 | return v.errors
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| 20 |
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| 21 | class SyntaxErrorChecker:
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| 22 | """A visitor to find syntax errors in the AST."""
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| 23 |
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| 24 | def __init__(self, multi=None):
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| 25 | """Create new visitor object.
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| 26 |
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| 27 | If optional argument multi is not None, then print messages
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| 28 | for each error rather than raising a SyntaxError for the
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| 29 | first.
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| 30 | """
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| 31 | self.multi = multi
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| 32 | self.errors = 0
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| 33 |
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| 34 | def error(self, node, msg):
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| 35 | self.errors = self.errors + 1
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| 36 | if self.multi is not None:
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| 37 | print("%s:%s: %s" % (node.filename, node.lineno, msg))
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| 38 | else:
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| 39 | raise SyntaxError, "%s (%s:%s)" % (msg, node.filename, node.lineno)
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| 40 |
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| 41 | def visitAssign(self, node):
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| 42 | # the transformer module handles many of these
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| 43 | pass
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| 44 | ## for target in node.nodes:
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| 45 | ## if isinstance(target, ast.AssList):
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| 46 | ## if target.lineno is None:
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| 47 | ## target.lineno = node.lineno
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| 48 | ## self.error(target, "can't assign to list comprehension")
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