I like Lua, but after going all in on Gambit-C^1 for a bit, I'm not sure anything can top its level of integration. Besides compiling to C, it just lets you straight up write C inside of a .scm file.
I think all the arguments of the article still hold if one changes "Lua" to "Tcl". (well, the general arguments, not anything related to the Xedge framework).
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Using Lua for Embedded Development vs. Traditional C Code