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In METAFONT, run interactively, is it possible to give a new value to a point variable?

If you just try to equate a point to a new point, the equation will be inconsistent with other equations. If you try to assign a new value, MF says that := is ''improper''. And you can't wipe out z5 by pair z5; without taking all the other points with you.

Toothrot
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1 Answers1

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In MetaFont, z5 etc. is just a shorthand for (x5,y5). Now (x5,y5):=(...) wouldn't be allowed, so z5:=(...) isn't either.

To assign a new value, you can change both parts separably: To reset z5 to it's initial set and allow new assignments, write

x5:=whatever; y5:=whatever;

Then z5=(3,4) etc. works again.

Marcel Krüger
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