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5.4 Evaluation Rules • 191S := {1, 2, 5}> convert( S, list );[1, 2, 5]The convert command can perform many other structural and mathematicalconversions. For more information, refer to ?convert.5.4 Evaluation RulesIn a symbolic mathematics program such as Maple you encounter theissue of evaluation. If you assign the value y to x, the value z to y, andthe value 5 to z, then to what should x evaluate?Levels of EvaluationMaple, in most cases, does full evaluation of names. That is, when you usea name or symbol, Maple checks if the name or symbol has an assignedvalue. If it has a value, Maple substitutes the value for the name. If thisvalue itself has an assigned value, Maple performs a substitution again,and so on, recursively, until no more substitutions are possible.> x := y;x := y> y := z;y := z> z := 5;z := 5Now Maple evaluates x fully. That is, Maple substitutes y for x, z fory, and finally, 5 for z.> x;