November 29, 2017

url encoding safe relational operators

I was catching up on Jesse Wilson’s blog this morning, and in particular his post URL Encoding Is Material. In that article, he says My advice If you’re defining your own URLs, you’ll save a lot of trouble by avoiding characters like <, >, {, }, +, ^, &, |, and ;. I came across this problem in one of my projects at work: I wanted a page to display some recent records with 1) a name field provided by the user and 2) a value field that match $l \leq \text{value} \leq b$, where $l$ and $b$ are given by the user.

November 13, 2017

snack buying

I got this text message from my father-in-law: Ok. Soda 1.50 Chocolate bar 1.00 Gum 0.10 Jelly Bean .05 Have to buy exactly 14 items and spend $10 At least one of each. There are 4 diff combos. (Order: soda, chocolate, gum and jelly bean) Got 5-2-3-4 3-5-4-2 Can’t get others. Any ideas? :) I whipped up this solution to check in python: #!/usr/bin/python3 # created_at: 2017-11-13 13:53:19 -0800 def main(): solutions = 0 for si in range(1,7): for ci in range(1,11): for gi in range(1,101): for ji in range(1,201): total = si*150 + ci*100 + gi*10 + ji*5 items = si + ci + gi + ji if total == 1000 and items == 14: print(si,ci,gi,ji, total, items) solutions += 1 print(solutions) if __name__ == "__main__": main() The core of this solution is the check

November 7, 2017

even the ceo doesn't get an office

Square is a fantastic place to work, and has been for my entire time here. One thing I’m not such a fan of, though, is the open office layout we have – and share with many other startups. Somehow I have the distinct memory of thinking, “Wow, even the CEO doesn’t get an office here! That’s really cool!” I had an important realization today, though. It’s not that the CEO of companies with open offices don’t get an office – it’s that they don’t want one.

October 27, 2017

500 Million Dollars!

I watched Destin’s $500 Million Dollars video: and had a few thoughts: my highschool CS education My highschool had computer teachers, but no computer science teachers. Luckily, we did have a teacher (Dick Van Kirk!) that was willing to sponsor an independent study of some computer science topics. I read the AP Computer Science A study guides and a bunch of the Java: How to Program (Deitel & Deitel) book and managed to get through the AP test with a top score.

September 12, 2017

confident women are getting bypassed by overconfident men

Really interesting youtube talk: confident women are getting bypassed by overconfident men

August 31, 2017

python attrs

I came across a very interesting library in a HN thread: the python attrs library. In particular, this seems like a great way to do the “dumb data objects” they talk about in the end of object inheritance, and also related to (but maybe lighter weight than) zope.interface. This also seems very similar to what I use autovalue for at work. One particularly interesting application is a “code database” – using static, checked-in-to-version-control definitions of some data model as a sort of very-fast-to-read, very-slow-to-update “Data Model”.

July 17, 2017

klr650 planned upgrades

I’m planning on “civilizing” my KLR650 just a tiny bit, since it is coming up on 1500 miles and I haven’t made it offroad at all yet. There are two (fairly minor) issues with the stock setup, as far as I’m currently concerned: First, I’d prefer the gearing to be just a little bit taller so I don’t have to wind it up quite as much. The engine just runs a little faster than I’d like at freeway speeds, and even driving around town it just feels slightly off.

May 5, 2017

relational java explorations with sqlite3 vtab

One idea i have been mulling over lately is exposing a java codebase relationally, with queries like: SELECT * FROM classes c JOIN annotations a ON a.class_id = c.id WHERE a.name = 'MyAnnotationClass'; The idea here is that you could search a codebase by pretending that you had tables for a whole bunch of things like: classes annotations variables literals methods This would be a useful thing because instead of relying on an IDE like IntelliJ to do “find usages” operations, you could actually script those interactions.

April 19, 2017

toy/life data models

I’ve been experimenting a lot with some kinda “toy” data models based on random things that I wish there was a database to query, but isn’t. For example: What was my average arrival time this week? How much of my equity has vested before a certain date? When was the last time we had spaghetti for dinner? I’ve been doing this with flat JSON files. This is a bit of an odd choice for me; I actually love schematizing data models in protobuf and MySQL and designing proper indices for the data models I work on during work hours.

April 3, 2017

_useful

I often create a directory/file called _useful/_useful.org/_useful.txt. I have one in my Dropbox, for example, that contains: My apartment lease My car/motorcycle insurance details A textfile with my vehicle plate numbers/VINs/insurance policy numbers. At work, I have one with the top visited links for logs/metrics/admin interfaces for the services I work with most a list of links of “typical” or “exemplar” things links to our internal tool views for typical payments, merchants, etc typical size (in bytes) of various protobuf messages we use a lot, size of 1M messages, #messages in 1MB/GB common coding idioms, like several variants of @RunWith that we use in various cases in our test code.