Re: transpiling to low level C

On 22.12.2024 07:01, Waldek Hebisch wrote:
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Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:
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On 21.12.2024 02:28, Tim Rentsch wrote:
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Janis Papanagnou <janis_papanagnou+ng@hotmail.com> writes:
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On 16.12.2024 00:53, BGB wrote:
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[...]
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Pretty much all higher level control flow can be expressed via goto.

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A 'goto' may be used but it isn't strictly *necessary*. What *is*
necessary, though, that is an 'if' (some conditional branch), and
either 'goto' or recursive functions.

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Conditional branches, including 'if', '?:', etc., are not strictly
necessary either.

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No? - Can you give an example of your statement?

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Look at example that I posted (apparently neither you nor Tim
looked at my posts where I explained in detail how to translate
goto program (with conditional jumps) into program that contains
no goto and no conditional jumps).

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I'm not sure but may have just skimmed over your "C" example if it
wasn't of interest to the point I tried to make (at that stage).
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Or try to figure out how to do this knowing that C has function
pointers.

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I will retry to explain what I tried to say... - very simply put...
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There's "Recursive Functions" and the Turing Machines "equivalent".
The "Recursive Functions" is the most powerful class of algorithms.
Formal Recursive Functions are formally defined in terms of abstract
mathematical formulated properties;  one of these [three properties]
are the "Test Sets".  (Here I can already stop.)
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But since we're not in a theoretical CS newsgroup I'd just wanted
to see an example of some common, say, mathematical function and
see it implemented without 'if' and 'goto' or recursion. - Take a
simple one, say, fac(n) = n! , the factorial function.  I know how
I can implement that with 'if' and recursion, and I know how I can
implement that with 'while' (or 'goto').
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If I re-inspect your example upthread - I hope it was the one you
wanted to refer to - I see that you have removed the 'if' symbol
but not the conditional, the test function;  there's still the
predicate (the "Test Set") present in form of 'int c2 = i < n',
and it's there in the original code, in the goto transformed code,
and in the function-pointer code.  And you cannot get rid of that.