Difference between revisions of "Talk:Open research problems"
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(Acoiding the I/O problem using the FFI) |
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| − | == Denotative languages and the I/O problem == |
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| + | You can <span style="color:brown;">search for this page title</span> in other pages, |
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| + | <span style="color:brown;">search the related logs</span>, |
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| − | <div style="border-left:1px solid lightgray; padding: 1em" alt="blockquote"> |
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| + | or <span style="color:brown;">create this page</span>. |
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| − | My view is that the next logical step for programming is to split into two non-overlapping programming domains: |
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| − | * runtime building for … |
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| − | * … mathematical programming languages |
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| − | <tt>[https://www.haskellforall.com/2021/04/the-end-of-history-for-programming.html Gabriella Gonzalez].</tt> |
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| − | </div> |
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| − | Let's assume: |
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| − | * a denotative language exists - here, it's called <i>DL</i>. |
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| − | * the implementation of <i>DL</i> is written in an imperative language - let's call that <i>IL</i>. |
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| − | Let's also assume: |
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| − | * <i>DL</i> is initially successfull. |
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| − | * solid-state Turing machines remain in use, so <i>IL</i> is still needed. |
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| − | As time goes on, technology advances which means an ever-expanding list of hardware to cater for. Unfortunately, the computing architecture remains mired in state and effects - supporting the new hardware usually means a visit to <i>IL</i> to add the extra subroutines/procedures (or modify existing ones) in the implementation. |
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| − | <i>DL</i> will still attract some interest: |
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| − | * Parts of the logic required to support hardware can be more usefully written as <i>DL</i> definitions, to be called by the implementation where needed - there's no problem with imperative code calling denotative code. |
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| − | * periodic refactoring of the implementation reveals suitable candidates for replacement with calls to <i>DL</i> expressions. |
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| − | * <i>DL</i> is occasionally extended to cater for new patterns of use - mostly in the form of new abstractions and their supporting libraries, or (more rarely) the language itself and therefore its implementation in <i>IL</i>. |
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| − | ...in any case, <i>DL</i> remains denotative - if you want a computer to do something new to its surroundings, that usually means using <i>IL</i> to modify the implementation of <i>DL</i>. |
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| − | So the question is this: which language will programmers use more often, out of habit - <i>DL</i> or <i>IL</i>? |
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| − | Here's a clue: |
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| − | <div style="border-left:1px solid lightgray; padding: 1em" alt="blockquote"> |
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| − | They [monadic types] are especially useful for structuring large systems. In fact, there's a danger of programming in this style too much (I know I do), and almost forgetting about the 'pure' style of Haskell. |
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| − | <tt>[[Monad tutorials timeline|Noel Winstanley]].</tt> |
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| − | </div> |
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| − | Instead of [http://conal.net/blog/posts/can-functional-programming-be-liberated-from-the-von-neumann-paradigm looking at the whole system in a consistently denotational style (with simple & precise semantics)] by using <i>DL</i> alone, most users would be working on the implementation using <i>IL</i> - being denotative makes for nice libraries, but getting the job done means being imperative. Is this an improvement over the current situation in Haskell? No - instead of having the denotative/imperative division in Haskell by way of types, users would be contending with that division <i>at the language level</i> in the forms of differing syntax and semantics, annoying foreign calls, and so forth. |
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| − | The advent of Haskell's FFI is an additional aggravation - it allows countless more effect-centric operations to be accessed. Moving <b>all</b> of them into a <i>finite</i> implementation isn't just impractical - it's impossible. |
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| − | But if you still think being denotative is worth all that bother (or you just want to prove me wrong :-) [https://www.ioccc.org/2019/lynn/hint.html this] could be a useful place to start: |
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| − | <div style="border-left:1px solid lightgray; padding: 1em" alt="blockquote"> |
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| − | * <tt>OneHundredPercentPure</tt>: Gone is the catch-all lawless <code>IO</code> monad. And no trace of those scary <code>unsafeThisAndThat</code> functions. All functions must be pure. |
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| − | </div> |
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| − | — [[User:Atravers|Atravers]] Fri Oct 22 06:36:41 UTC 2021 |
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| − | == Outsourcing the I/O problem == |
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| − | ...it's quite simple really: |
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| − | * just extend the FFI enough to replace the ''usually''-abstract I/O definitions with calls to foreign definitions: |
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| − | :{| |
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| − | | |
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| − | instance Monad IO where |
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| − | return = primUnitIO |
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| − | (>>=) = primBindIO |
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| − | foreign import ccall unsafe primUnitIO :: a -> IO a |
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| − | foreign import ccall unsafe primBindIO :: IO a -> (a -> IO b) -> IO b |
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| − | ⋮ |
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| − | |} |
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| − | * the <code>IO</code> type is then just a type-level tag, as specified in the Haskell 2010 report: |
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| − | :{| |
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| − | data IO a -- that's all folks! |
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| − | |} |
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| − | ''Voilà!'' In this example, the I/O problem has been outsourced to C - if you're not happy with C's solution to the I/O problem, just use another programming language for the Haskell implementation: there's plenty of them to choose from (...but don't use Haskell, to avoid going <code>⊥</code>-up ;-). |
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| − | — [[User:Atravers|Atravers]] Thu Dec 9 01:55:47 UTC 2021 |
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Latest revision as of 07:30, 3 March 2022
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