New code injection special

fennel-lua.lua

-- (lua "print('hello!')") -> prints hello, evaluates to nil
-- (lua "print 'hello!'" "10") -> prints hello, evaluates to the number 10
-- (lua nil "{1,2,3}") -> Evaluates to a table literal
SPECIALS['lua'] = function(ast, scope, parent)
    assertCompile(#ast == 2 or #ast == 3,
        "expected 2 or 3 arguments in 'lua' special form", ast)
    if ast[2] ~= nil then
        table.insert(parent, {leaf = tostring(ast[2]), ast = ast})
    end
    if #ast == 3 then
        return tostring(ast[3])
    end
end