program-transformation | 易学教程

How can i use MVars to move paddles on my pingpong haskell game?

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问题 I already have a function that moves 2 paddles in a ping pong game in haskell. I want to change so it uses MVars now. I know that i need to change wHeld, sHeld, downHeld and upHeld to MVars but any ideas on how to change movePaddle to deal with MVars? Also when i declare wHeld an MVars it shows a error on deriving show (Non instance for (Show MVar Bool)) data PongGame = Game { ballLoc :: (Float, Float) -- ^ Pong ball (x, y) location. , ballVel :: (Float, Float) -- ^ Pong ball (x, y) velocity.

Converting C source to C++

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问题 How would you go about converting a reasonably large (>300K), fairly mature C codebase to C++? The kind of C I have in mind is split into files roughly corresponding to modules (i.e. less granular than a typical OO class-based decomposition), using internal linkage in lieu private functions and data, and external linkage for public functions and data. Global variables are used extensively for communication between the modules. There is a very extensive integration test suite available, but no

Parallel Dynamic Programming

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问题 Are there any good papers discussing how to take a dynamic program and parallelize it? 回答1: IIRC, what you typically do with dynamic programming is to recursively divide a problem into subproblems, and assemble optimal solutions from optimal subsolutions. What makes it effective is that all optimal subsolutions are built into a cache so they need not be recomputed. If the problem can be divided several ways, you can fork the solver for each subsolution. If each(sub) problem averages 1+epsilon

Converting C source to C++

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How would you go about converting a reasonably large (>300K), fairly mature C codebase to C++? The kind of C I have in mind is split into files roughly corresponding to modules (i.e. less granular than a typical OO class-based decomposition), using internal linkage in lieu private functions and data, and external linkage for public functions and data. Global variables are used extensively for communication between the modules. There is a very extensive integration test suite available, but no unit (i.e. module) level tests. I have in mind a general strategy: Compile everything in C++'s C

What is tail-recursion elimination?

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Steve Yegge mentioned it in a blog post and I have no idea what it means, could someone fill me in? Is it the same thing as tail call optimization ? Tail call elimination is an optimization that saves stack space. It replaces a function call with a goto . Tail recursion elimination is the same thing, but with the added constraint that the function is calling itself. Basically, if the very last thing a function A does is return A(params...) then you can eliminate the allocation of a stack frame and instead set the appropriate registers and jump directly into the body of the function. Consider

What is tail-recursion elimination?

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问题 Steve Yegge mentioned it in a blog post and I have no idea what it means, could someone fill me in? Is it the same thing as tail call optimization? 回答1: Tail call elimination is an optimization that saves stack space. It replaces a function call with a goto . Tail recursion elimination is the same thing, but with the added constraint that the function is calling itself. Basically, if the very last thing a function A does is return A(params...) then you can eliminate the allocation of a stack