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Comment by gdp | Hacker News Reader

When you say "I think in pseudo-code", what are the semantics of this pseudo-code?

'cause it's actually a bit of a non-answer, when you think about it. Saying 'pseudo code' means that the language you think in has some informality in its syntax - but presumably you still have some fixed understanding of what it does?

If it has no fixed syntax and no fixed semantics, then is it actually helpful as a mental model? I would argue that it is not.

(Note: I'm not just being antagonistic here, I'm genuinely curious. I don't think in terms of "syntax", so this is all a bit alien to me).

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It's perfectly possible to express solutions at a high level without much regard for formal semantics. Knuth's The Art of Computer Programming expresses most of its algorithms in a combination of informal English and ad-hoc pseudocode. It's usually not difficult to translate them into languages with semantics varying from machine code to Haskell.

I didn't say "formal semantics", I said "fixed semantics", as in "something you understand and can apply consistently within a context". Within the context of a single code-fragment, the semantics are not changing. They might change from example to example, but that's perfectly reasonable.

My assertion is that when people say "I think in pseudo-code", they actually mean "an idealised version of language X", where language X is some paradigm or language they understand well.

I just wrote a blog post about this very subject, based on the flood of comments (shameless self-promotion follows):

http://news.ycombinator.org/item?id=802780

For example, if someone asked me to do the fizzbuzz test (http://www.codinghorror.com/blog/archives/000781.html), I might think to myself in pseudocode:

  Loop from 1-100:
    if the current number is a multiple of 3, print "fizz"
    if the current number is a multiple of 5, print "buzz"
    otherwise, print the number
    print newline

Then I might turn that into PHP:

  <?php
    for($i=1;$i<=100;$i++) {
      if($i % 3 == 0) {echo("Fizz");}
      if($i % 5 == 0) {echo("Buzz");}
      if($i % 3 != 0 && $i % 5 != 0) {echo($i);}
      echo("<br />");
    }
  ?>

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