TCL is easy to embed!

tcl.cr

@[Link("tcl")]
lib LibTcl
  type Tcl_FreeProc = Void*
  fun Tcl_SetVar(interp : Tcl_Interp*, varName : LibC::Char*, newValue : LibC::Char*, flags : Int32) : LibC::Char*
  fun Tcl_Eval(interp : Tcl_Interp*, script : LibC::Char*) : Int32
  fun Tcl_CreateInterp : Tcl_Interp*

  struct Tcl_Interp
    result : LibC::Char*
    freeProc : Tcl_FreeProc
    errorLine : Int32
  end
end

my_string = "MagicWord"
puts("The secret is '#{my_string}'")
interp = LibTcl.Tcl_CreateInterp

variable_name = "my_string"
LibTcl.Tcl_SetVar(interp, variable_name, my_string, 0)

script = <<-END_SCRIPT
puts "Within this Tcl script, my_string has the value '$my_string'."
END_SCRIPT

LibTcl.Tcl_Eval interp, script