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But what's in that string? That still counts. What I should have done was put an additional restriction on what IO is available. Otherwise, something like "eval

But what's in that string? That still counts. What I should have done was put an additional restriction on what IO is available. Otherwise, something like "eval `cat f`" or something could be all powerful. My first attempt shows Ruby simulating a cyclic tag system with only 15 unique characters including newlines and spaces: https://github.com/elitheeli/oddities/raw/master/only_a_few_characters.rb https://github.com/elitheeli/oddities/raw/master/only_a_few_... EDIT: down to 14 characters.

jerf 16y ago
"But what's in that string? That still counts." Sure, but it counts regardless of what you're talking about. We don't generally talk about charging data against the TM because they all need data of some sort to do anything interesting. "eval" still gets you there. (Pedantic.)
- elitheeli 16y ago
  I should have phrased as "what is the minimum number of characters that need to be seen by a Ruby parser in order to have something Turing equivalent to Ruby without a limited character set?"