Convert code elements from strings to native Python types.

def native_types(code):
    """Convert code elements from strings to native Python types."""
    out = []
    for c in code:
        if isconstant(c, quoted=True):
            if isstring(c, quoted=True):
                v = c[1:-1]
            elif isbool(c):
                v = to_bool(c)
            elif isnumber(c):
                v = c
            else:
                raise CompileError("Unknown type %s: %s" % (type(c).__name__, c))

            # Instead of pushing constants in the code, we always push callable
            # Python functions, for fast dispatching:
            out.append(make_embedded_push(v))
        else:
            try:
                out.append(instructions.lookup(c))
            except KeyError:
                raise CompileError("Unknown word '%s'" % c)
    return out