Consider switching to libpg_query for faster builds (vs PostgreSQL source download)

[lfittl]

First of all, thanks for the note on pganalyze in the README & happy to that you've found that blog post back then useful!

I've actually recently optimized that approach a bit more, so you don't have to download and build all of PostgreSQL when all you want is access to the parser.

You can find the latest in this C library: https://github.com/lfittl/libpg_query

See pg_query.h for how to access it, and src/postgres for the parts of the source it uses - extracted by this script using LLVM/clang.

I could also see adding an explicit pg_syntax_check or similar, to avoid unnecessary parse tree JSON generation. Let me know if that'd be useful :)

[sfackler]

Nice, this looks like it'll be way nicer to work with than waiting 15 minutes for all of Postgres to build!

[sfackler]

One thing - I can't bind to pg_query_fingerprint_with_opts because the libc crate doesn't have a type corresponding to stdbool.h's bool. Doesn't really matter for this crate though.

[lfittl]

@sfackler Ah, that method doesn't actually need to be exposed - its just used for the tests in the C library. I've removed it from the pg_query.h header file :)

[jbg]

@sfackler is your work on this in a branch somewhere? I would be happy to lend a hand if needed. Wanting to use this library for a project and would prefer the lighter-weight approach proposed here.

[sfackler]

There's some in progress work here on binding to libpg_query: https://github.com/sfackler/rust-pg_query

[lfittl]

@jbg @sfackler Let me know if there is any further improvements I can make to the base library that would be useful to you.

As a side node, I have some upcoming work to rebase the library to the Postgres 10 query parser, but that'll be in a branch separate from 9.5-latest.