I might not be following you correctly... But what you describe sounds pretty much like Ruby's Inline gem/module/library/whatever-name-you-fashion, which allows you to mix snippets of C within the body of Ruby code.
Of course, Ruby is not prone to be a speed demon, but this also helps get the critical code done in a fast language.
Posted Feb 24, 2013 11:30 UTC (Sun) by JanC_ (guest, #34940)
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Cython allows you to write Python-like code that has (optional) type annotations and other ways to help the Cython compiler to create faster code than would be possible when compiling pure Python without a JIT (a JIT as used in PyPy can take advantage of knowing what type is used at runtime).
So it's not about inlining C code, but an alternative to writing C modules/gems/whatever.