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One of the main difficulties I've had using parser generators has been the difficulty of figuring out why a grammar didn't work. Fixing shift-reduce and reduce-reduce conflicts seemed like voodoo to me, and though I slightly understand better how to Fix such things now it's still a different mode of thinking that I don't want to try to get into when I just want to parse something simple. PyMeta uses a variation on the Parsing Expression Grammar (PEG) approach to parsing. The chief consequence of this is there's no possibility of ambiguity in a parse: a successful parse will yield exactly one result, and you can trace the control flow through the grammar to figure out how it got there.

RRDTool is a really good back-end for storing time-series data. If you are developing tools that need a data repository and graphing capabilities, this provides you both. You create an RRD and then you begin inserting data values at regular intervals. You then call the graphing API to have a graph displayed. The neat thing about this data storage is its “round robin” nature. You define various time spans, and the granularity at which you want them stored. A fixed binary file is created, which never grows in size over time. As you insert more data, it is inserted into each span. As results are collected, they are averaged and rolled into successive time spans. It makes a much more efficient system than using your own complex data structures, relational database, or file system storage.

Following my thoughts yesterday, here are some VIM python scripts to add python breakpoint and debugging features to VIM. With this set up the F7 key will set a breakpoint on a line of code, Shift-F7 will remove all breakpoints and Shift-F12 will execute a script in the python debugger. This only runs on windows as far as I know, because it uses the 'start' command to launch the debugger in a seperate process without VIM waiting for it to finish. This allows you to look through the source code (and fix it) while the debugging is still in progress.

This script mimics rsync which is available for the unix platform and have been ported to win32 one. It is a sort of advanced version of xcopy. Its aim is to selectively synchronize folders. More precisely it copy selective parts of a folder to a destination folder and in addition can remove parts of the destination folder that do not correspond to parts of the original folder. I like its capability to avoid copying files through the .cvsignore mechanism or the pattern matching mechanism and its capability to delete files that are no longer relevant, not to mention that because it's a python script anyone can easily fix or improve it as he whish.