Joe Gibbs Politz

@joepolitz.bsky.social

753 Followers 226 Following

https://jpolitz.github.io

I have done significant work on this already in multiple agent passes, with some hard-won lessons learned. Make sure to read this document in its entirety – this was not generated with bloated extraneous detail by a model, but carefully curated by me so every detail matters (or is “load-bearing”, in your parlance).
A screenshot of a prefix of the commit message at the link. Tighten isPyretNumber, fix latent leaks (log toFixnum violations for now) Joe says: Medium-interesting finding from Ben noticing a change to `num-to-fixnum` behavior on CPO. The key thing is NON-integer JS floats. They are *not* supposed to be able to be Pyret numbers. In various places we were lax about this and things worked out because of tostring conversions or === doing the right thing, etc. This commit tries to make some progress on catching our own mistakes here: - Correctly return `false` from the widely used `isPyretNumber` for values like 2.3 (~2.3 aka Roughnum.makeInstance(2.3) still returns true) - Add assertPyretNumber, currently used in one place (toFixnum), which based on its throwing of a DomainError clearly expects to get an actual Pyret number. The rest of the commit cleans up cases where we made mistakes and returned or passed JS floating-point across the boundary. assertPyretNumber *should* throw, not just console.error. But I'm too scared to do that because I'm not convinced our tests are exhaustive here at all, and an exception in the wild could be pretty breaking. So we console.error for now. Claude used this assert on toFixnum to find several errors, all of which come straight from our existing tests/compiler runs. Claude says: Specifics of the boundary cleanups, since they're spread across four files: - js-numbers.js atan2: the y=0 quadrants correctly wrapped Math.PI in a Roughnum, but the x>0 4th-quadrant and x<0 cases passed bare Math.PI and 2*Math.PI to add(), which short-circuits on two JS numbers and returns the raw JS sum. So num-atan2(0, -1) returned the JS double 3.141592653589793 rather than a Roughnum, with branch-dependent type tags visible to user code (num-is-roughnum was false). Wrapping the constants in Roughnum.makeInstance fixes it. Bug present since the original atan2 introduction in 2016.
How did standards like HTTP get decided? Broadly, two ways: Careful design by standards bodies who select their members from experts across academia and industry and then engage in a deliberative process to do the best thing for society and the future of engineering with a well-considered balance of interests Whoever gets something working first and spends the money to build it implicitly decides how it works and everyone else lives with it forever Sometimes a mix (and sometimes the experts just pick the second thing)
Second, at a more principled level, we (controversially!) view code availability as a valuable learning opportunity for students, in that it reflects modern software practice. Sites such as StackOverflow and blogs give programmers ready access to code for various tasks; the problem for users is to assess whether the code they find is worth copying. Captain- Teach anonymizes the work being reviewed, so students can- not rely on the reputation of authors when deciding whether to follow ideas seen in other students’ work; instead, they must judge the code itself. If they make a correct judge- ment, this demonstrates learning and a corresponding im- provement in their grade. However, they may also copy a wrong solution (even one we used to seed the system, which can look quite convincing!), so copying blindly is perilous.
A footnote from the linked paper “ The co-first authorship order was determined via the best of three rounds in Super Smash Bros. Both YB and BZ contributed equally and have the right to list their name first in their CV. All authors contributed to the article and approved the submitted version.”
A program listing 1 #include <unistd.h> 2 #include <stdio.h> 3 #include <stdlib.h> 4 #include <sys/wait.h> 5 6 int main() { 7 int vals[] = { 1, 2, 3}; 8 int pid = fork(); 9 10 if(pid) { 11 printf("[parent] %p\n", &vals); 12 wait(NULL); 13 printf("[parent] %p %d\n", &vals, vals[0]); // will this print 9999? 14 } 15 else { 16 printf("[child] %p\n", &vals); // will this print the same as line 11? 17 vals[0] = 9999; 18 printf("[child] %p %d\n", &vals, vals[0]); 19 } 20 } 21 22 // Possibilities: 23 24 /* 25 A Different address, parent prints 9999 26 B Different address, parent prints 1 27 C Same address, parent prints 9999 28 D Same address, parent prints 1 29 */
A screenshot of the legend of the so-called “chart crime” GPT figure labelled "Software Engineering" with two glyphs – “Without thinking” and “With thinking”
A listing of unicode capital greek letters: Omicron (code point 927), Pi (code point 928), Rho (code point 929), to Sigma (code point 931).
Ada and kiddo on a trail up Kwaay Peak
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Ada, a medium sized tan dog, sitting in front of receding waves with one ear flapping in the wind
Screenshot of Copilot suggested completion “// NOTE(joe): this is a bit of a hack, but we need to provide...”
Ada smiling in front of a fallen tree on a dirt embankment above a small stream.
Subsumption rule where \skull is the outcome of a subtyping operation. From https://cs.brown.edu/~sk/Publications/Papers/Published/pgk-sem-type-fc-member-name/
A screenshot of a lecture capture. On the left side of the screen is the class's implementation of a String struct including code for an append function called "plus", on the right is the production code for string append in CPython
Close up shot of Ada—a white and tan 40lb dog with ears like Dobby the House Elf—looking up intently.
A single-page handout showing a Rust program that compiles simple programs like (sub1 (sub1 (add1 73))) to x86-64 assembly.
Joe in a pirate costume gesturing with a toy sword towards a sorted array written on a whiteboard
Lecture handout. These are a few commonly-used commands. There are lots more! We could fill pages with them (examples of find, wc, grep, output redirection) Bluesky, also known as Bluesky Social, is a microblogging social platform and a public benefit corporation. The service is focused on microblogging, and has been called "Twitter-like". Bluesky Social was made open source under the MIT license in May 2023.[27] This is a big codebase! Hundreds of files. What questions could we ask that we can answer with these commands?
Symptom: The behavior you see (terminal output, error messages, web page contents) Bug: A flaw in a program that causes symptoms Failure-inducing input: Data, values, or other input(s) that demonstrate a bug's symptom(s) Consider the following EdStem posts. What information could these students provide to help give an actionable answer? What bugs are possible in each scenario? How could more information about input and symptoms help?
Question from Anita Kwikansaur – The server from lab 2 isn't working, it just says class not found.
There is a reason that Gandalf doesn’t just fly Frodo to Mount Doom with magic, then let him drop the ring in. Narratively, that just doesn’t work with the magic system. We don’t know what it can do, and so if the writer uses it to solve a lot of problems, then the tension in the novel ends up feeling weak. The magic undermines the plot instead enhancing it.
A commit message: Update webpack and babel to newest version It's hard to say exactly what the methodology was here. Some tabs I had open were: https://babeljs.io/docs/env/ https://www.npmjs.com/package/babel-preset-es2015 https://stackoverflow.com/questions/49182862/preset-files-are-not-allowed-to-export-objects https://webpack.js.org/configuration/module/#ruleuse https://stackoverflow.com/questions/42060243/invalid-configuration-object-webpack-has-been-initialised-using-a-configuration/49849670#49849670 https://babeljs.io/blog/2018/07/27/removing-babels-stage-presets https://stackoverflow.com/questions/58915152/cannot-find-module-babel-plugin-transform-decorators-legacy https://stackoverflow.com/questions/61888940/module-build-failed-cannot-find-module-babel-preset-env/61889105#61889105
World’s cutest baby
APM - 285, Lecturer with Security of Employment Series The policy is proposed to be revised and includes the following key revisions: Revised name of “Lecturer with Security of Employment” (LSOE) series and ranks to “Professor of Teaching.”
Google Sheets cells: Tue 9:00 Tue 9:30 Tue 10:00 Tue 9:60 Tue 9:90 Tue 10:01 Tue 9:120 Tue 9:150 Tue 10:02
A view of a file in Github with an error message "Error in user YAML: (<unknown>): did not find expected key while parsing a block mapping at line 15 column 7"
A student question on a message board: Anon Student 2h ago (Public Post) When I go to reset my course specific account password, I keep getting the error "You must enter a valid username". I am typing in "cse123fa23z00" as it appears on sal.ucsd.edu, but it isn't working when I try to reset it on password.ucsd.edu. I've tried a variety of different combinations but nothing is working As a tutor, you know that accounts generally look like cs123fa23xyz with the “xyz” differing per-student. How do you respond?