Function arguments are always passed by reference, so they need to be real. But print's not a function. Keep in mind that the builtin functions are often called "named operators" and that Deparse shows a "print" op, not a "entersub" op. I suspect it's more along the lines of print and other builtins have their arguments built specially.

Just guessing.

By the way, I was getting similar results to print when using assignments.

In reply to Re^3: Keys() required to autovivify? by ikegami
in thread Keys() required to autovivify? by jrw

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