Attempts to include all type params #1425
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bindgen can handle a large fraction of C++ code, even with templates, and autocxx can in turn handle a very large fraction of bindgen output. Pretty much the only things autocxx can't handle are: * bindgen opaque types passed by value * Types with unused template parameters This change, with its associated bindgen change, tries to make progress to removing this second category of unhandled thing. It alters bindgen such that it always uses all template parameters, adding a PhantomData field where necessary. It's not quite right yet.
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Downstream postprocessors such as autocxx may want to use bindgen's representation of types to generate additional C++ code. bindgen is remarkably faithful at passing through enough information to make this possible - but for some C++ types, bindgen chooses to elide some template parameters. It's not safe for additional C++ code to be generated which references that type. This adds a callback by which such tools can recognize types where template parameters have been elided like this, so that extra C++ is avoided. This information could be provided in the existing `new_item_found` callback, but it's very niche and unlikely to be used by the majority of consumers, so a new callback is added instead. An alternative approach here is to provide a mode to bindgen where it *always* uses all template params, by adding additional PhantomData fields to structs where those params are not currently used. This is being prototyped in google/autocxx#1425 but is unlikely to be successful, on the assumption that lots of the templated types can't actually be properly represented by bindgen/Rust, so the current strategy of discarding them is more likely to work in the broad strokes. Part of google/autocxx#124
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I'm not likely to progress this soon - closing for now. |
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bindgen can handle a large fraction of C++ code, even with templates, and
autocxx can in turn handle a very large fraction of bindgen output. Pretty much
the only things autocxx can't handle are:
This change, with its associated bindgen change, tries to make progress to
removing this second category of unhandled thing.
It alters bindgen such that it always uses all template parameters, adding a
PhantomData field where necessary.
It's not quite right yet.