I'm not really versed in the idioms/social mores of Python, so please take the following with a grain of salt:

This seems like it usefully solves a problem, but the invocation pattern is suspect to me -- Instead of "glom" taking the target for picking-apart plus a magic little bit of DSL, what if "glom" took a single parameter, the aforementioned DSL, and returned a function that would perform the corresponding search when called on a target? Even if Python or this package optimises away repeatedly searching (by the same spec|in the same manner), the convention the package prescribes is odd to me, right after the first few paragraphs of intro.