ref: d7b52500f32c3e540cdb79ad72e5e9e86f4cd31e
dir: /sys/lib/python/compiler/syntax.py/
"""Check for errs in the AST.
The Python parser does not catch all syntax errors. Others, like
assignments with invalid targets, are caught in the code generation
phase.
The compiler package catches some errors in the transformer module.
But it seems clearer to write checkers that use the AST to detect
errors.
"""
from compiler import ast, walk
def check(tree, multi=None):
v = SyntaxErrorChecker(multi)
walk(tree, v)
return v.errors
class SyntaxErrorChecker:
"""A visitor to find syntax errors in the AST."""
def __init__(self, multi=None):
"""Create new visitor object.
If optional argument multi is not None, then print messages
for each error rather than raising a SyntaxError for the
first.
"""
self.multi = multi
self.errors = 0
def error(self, node, msg):
self.errors = self.errors + 1
if self.multi is not None:
print "%s:%s: %s" % (node.filename, node.lineno, msg)
else:
raise SyntaxError, "%s (%s:%s)" % (msg, node.filename, node.lineno)
def visitAssign(self, node):
# the transformer module handles many of these
pass
## for target in node.nodes:
## if isinstance(target, ast.AssList):
## if target.lineno is None:
## target.lineno = node.lineno
## self.error(target, "can't assign to list comprehension")