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> Post script is Turing complete.

That's irrelevant. Turing machines are pretty benign. They can't read or write to your files. The worst they could do is to run forever.

The problem with PostScript is that it allows to much OS interaction, such as file IO. But that has nothing to do with Turing completeness.

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I see your point in the second argument. That said, a Turing complete language, with out os-level checks, is not. For a language thought up to print and display things, it's hard to argue that postscript is as harmless as HTML, for example.

The problem with Turing complete implementations is that it is impossible to decide what the code is going to do without running it.

It's not a problem. If there are no commands for file IO, then there can be no file IO. The only thing you can not decide in the general case is if there are file IO commands if they will get executed or not. But even that is no problem, as you can just block/not implement the file IO commands.

But Turing Completeness! ;)

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