I've accumulated a bunch of little libraries via various evening and weekend hacking projects over the past year or so, in various states of completion. Most are things I'm at least half-considering for Phobos, though some belong as third-party libs. I definitely don't have time to finish/flesh out all of them anytime soon, so I've decided to ask the community what to prioritize. Below is a summary of everything I've been working on, with its current level of completion. Please let me know the following:
1. A relative ordering of how useful you think these libraries would be to the community. 2. In absolute terms, would you find this useful? 3. For the Phobos candidates, whether they're general enough to belong in the **standard** library. List in order from most to least finished: 1. Rational: A library for handling rational numbers exactly. Templated on integer type, can use BigInts for guaranteed accuracy, or fixed-width integers for more speed where the denominator and numerator will be small. Completion state: Mostly finished. Just need to fix a litte bit rot and submit for review. (Phobos candidate) 2. RandAA: A hash table implementation with deterministic memory management, based on randomized probing. Main advantage over builtin AAs is that it plays much nicer with the GC and multithreaded programs. Lookup times are also expected O(1) no matter how many collisions exist in modulus hash space, as long as there are few collisions in full 32- or 64-bit hash space. Completion state: Mostly finished. Just needs a little doc improvement, a few benchmarks and submission for review. (Phobos candidate) 3. TempAlloc: A memory allocator based on a thread-local segmented stack, useful for allocating large temporary buffers in things like numerics code. Also comes with a hash table, hash set and AVL tree optimized for this allocation scheme. The advantages over plain old stack allocation are that it's independent of function calls (meaning you can return pointers to TempAlloc-allocated memory from a function, etc.) and it's segmented, meaning you can allocate huge buffers w/o risking stack overflow. Its main weakness is that this stack is not scanned by the GC, meaning that you can't store the only reference to a GC-allocated piece of memory here. However, in practice large arrays of primitives are an extremely common case in performance-critical code. I find this module immensely useful in dstats and Lars Kyllingstad uses it in SciD. Getting it into Phobos would make it easy for other scientific/numerics code to use it. Completion state: Working and used. Needs a litte cleanup and documentation. (Phobos candidate) 4. Streaming CSV Parser: Parses CSV files as they're read in, a few convenience functions for extracting columns into structs. If Phobos every gets SQLite support I'll probably add sugar for turning a CSV file into an SQLite database, too. Completion state: Prototype working, needs testing, cleanup and documentation. (Phobos candidate) 5. Matrix operations: SciD improvements that allow you to write matrix operations that look like normal math/MATLAB and optimizes them via expression templates so that a minimal number of temporary matrices are created. Uses/will use BLAS for multiplication. Completion state: Addition implemented. Multiplication not. 6. Machine learning: Decision trees, KNN, Random Forest, Logistic Regression, SVM, Naive Bayes, etc. This would be a dstats module. Completion state: Decision trees prototyped, logistic regression working. 7. std.mixins: Mixins for commonly needed boilerplate code. I stopped working on this when Andrei suggested that making a collection of mixins into a module is a bad idea. I've thought about it some more and I respectfully disagree. std.mixins would be a one-stop shop for pretty much any boilerplate you need to inject, and most of this code doesn't fit in any other obvious place. Completion state: A few things (struct comparison, simple class constructors, Singleton pattern) prototyped. (Phobos candidate) 8. GZip support in std.file: I'll leave the stream stuff for someone else, but just simple stuff like read(), write(), append() IMHO belongs in std.file. Completion state: Not started, but this is the easiest of the bunch to implement. (Phobos candidate)
