I have parsed the following sentence in the Stanford CoreNLP demo page and the Stanford parser demo page. Although both result in a parse that can imply purpose semantics (hinging on the
advcl and the
sbar accordingly), clearly the parsers don't capture "in order to" as an expression whose meaning much transcends the relationships between its own word constituents (as in an idiom).
he went to the shop in order to buy food
What kind of parsing, or pre-processing stage, may yield "in order to" as a single unit of meaning, thus making it amenable to semantics derivation same as a preposition affords? e.g. "for" may commonly imply purpose semantics, and having "for" parse as a preposition assists in deriving purpose semantics.