Generators (PEP 255 “Simple Generators”) and Coroutines (PEP 342 “Coroutines via Enhanced Generators”) are the cleanest way I’ve come across so far to implement the concept of a “pipeline” in Python. First approximation A pipeline is made of: a Producer, that generates data; many Stages, that receive data from the previous stage and send it to [...]
Tagged coroutine, generator, pipeline, pythonHere is a simple shell script to change the engine of all the tables in a MySQL database: Just because, as usual, I keep forgetting these kind of things…
Tagged alter table, batch, engine, mysqlIf you have never used hsenv before, you should. It’s basically the Haskell’s equivalent of Python’s virtualenv. You can find a tweaked version of hsenv here: I’ve relaxed some requirements in order to make it install on newer GHC releases. Finally, if when using you hit this error: Then, you have a problem with your [...]
Tagged bug, haskell, hGetContents, hsenv, localeRecently, I’ve been challenged to write a Sudoku solver. Not knowing the rules and with only 30 minutes, I needed some help… So, in case someone asks me again, I’ve implemented the same algorithm in Haskell. I know that there are already a lot of other solutions, but, hey, it was fun!
Tagged haskell, sudokuIn order not to forget again how to setup http authentication in nginx here is a reminder. For https, follow these steps: $ sudo -s # cd /etc/nginx # openssl req -new -x509 -nodes -out server.crt -keyout server.key and add these lines to your server instance: server { listen 443; ssl on; ssl_certificate /etc/nginx/server.crt; ssl_certificate_key [...]
Tagged authentication, https, nginxI’ve been using so many code static checkers lately, that I decided to write a wrapper around the ones I use the most. I called it: Universal Lint, ulint for short. At the moment, Python, Javascript and Haskell files are supported, but adding new linters/extension is trivial. Download it and use it!
Now, this is embarassing… It looks like requesting a non-existent video on Youtube causes a “500 Internal Server Error”! For example: Valid url: http://www.youtube.com/watch?v=b5CeNunbHto Invalid url: http://www.youtube.com/watch?v=wtf Surely, a better response would be something like the one returned when the videoId is misisng: http://www.youtube.com/watch?v= Seems like predictions became true.
Few days ago, I rewrote sgrep in Haskell. I was curious to know how it compares to grep in term of execution speed. In particular, I was interested to verify that hsgrep scales as O(log n), instead of O(n), with n being the size of the file analyzed. First of all, in order to have [...]
Tagged benchmark, grep, haskellAs an exercise to learn Haskell, I wrote a specialized grep to work on sorted files. It uses binary search to scan a text file and print all the (consecutive) lines that start with a user defined string. My program is a rewrite of sgrep in Haskell: I called it HSGrep. Code is available on [...]
Tagged grep, haskell, sortedFollowing a recent discussion on HN, I decided to share my own git pre-commit hook. It’s a work-in-progress, so you can find the most updated version here. To use it, just drop it in your .git/hooks directory. At every git commit, it will run pep8 and pyflakes on .py files, and gjslint on .js files.
Tagged git, gjslint, hook, javascript, pep8, pyflakes, python