Use a mock sentinel for MARK instead of a gensym #216
Merged
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Gensyms just resolve to strings, and shouldn't be used literally anywhere they might collide with adversarial input, which commonly come in the form of unsanitized strings. User input could theoretically change where a MARK is, altering behavior.
sentinel
s normally shouldn't be used outside of tests, but the standalone property limits my options. At run time a simpleobject()
would do, but unpickling the sameobject()
created at read time twice wouldn't preserve equality in this case. A sentinel can do that.I've used
getattr
to create a sentinel with a non-identifier string, which are almost never used, so this is unlikely to interfere with tests. For good measure, I prependedhissp.
to the]
as an ad-hoc namespace.