4 ms·

Ask HN: Particularly elegant programs to study?

44 points by sz 16y ago

Examples help tremendously in learning any abstract subject. What are some famously well-written programs whose source is available to look at?

nomurrcy 16y ago
Lua (The programming language) is very well written and well worth reading and understanding. http://www.lua.org/ http://www.lua.org/
- davidsiems 16y ago
  I have to disagree. The language spec and the docs on the Lua website are well written but the VM itself is a mess. It's a trainwreck of ambiguously named variables, minimal documentation, and overuse of macros to force inline code. The Lua VM is a good example of something that isn't well written from a reading / understanding point of view, but is something that is well written from the 'it works' point of view.
- pygy_ 16y ago
  Here are the source code reading order recommendations by Mike Pall (the author of LuaJIT). http://www.reddit.com/r/programming/comments/63hth/ask_reddit_which_oss_codebases_out_there_are_so/c02ppb8 http://www.reddit.com/r/programming/comments/63hth/ask_reddi...
techbio 16y ago
I searched for "russian doll pseudocode" hoping to discover something elegant, but the clearest "code" there is a nicely colored Venn-ish diagram. http://ijcai.org/papers09/Papers/IJCAI09-106.pdf http://ijcai.org/papers09/Papers/IJCAI09-106.pdf
michael_dorfman 16y ago
TeX. Or, any of Knuth's other Literate Programs. Also, the book "Beautiful Code" is an attempt along these lines, but personally, I don't find the programs there as beautiful as Knuth's.
plinkplonk 16y ago
Code from Peter Norvig's "Paradigms of Artificial Intelligence Programming"
d4rt 16y ago
sqlite is both beautiful and has a significant test suite. http://www.sqlite.org/ http://www.sqlite.org/
- jamii 16y ago
  The sqlite test suite is a fantastic example of how to produce solid software. I wish it were used as a case study for all software engineering courses.
petercooper 16y ago
This is very Ruby specific (so mostly not "famous" stuff) but if that's your scene, I asked the same question to Rubyists recently and got some good suggestions: http://www.rubyflow.com/items/1817 http://www.rubyflow.com/items/1817
jamii 16y ago
I don't know about famous, but Conal Elliots ideas about denotational semantics have led to some beautifully elegant libraries - http://conal.net/blog/posts/denotational-design-with-type-class-morphisms/ http://conal.net/blog/posts/denotational-design-with-type-cl... Don't be put off by the academic tone, at its heart the paper is about how to design abstractions.
- sz 16y ago
  This looks awesome, thanks. How to design abstractions was what I had in mind when posing the question.
  - jamii 16y ago
    I really enjoy reading Conals work. This paper is a particularly good example of how denotational semantics can guide the design of a library - http://conal.net/blog/posts/paper-beautiful-differentiation/ http://conal.net/blog/posts/paper-beautiful-differentiation/
abyssknight 16y ago
c99shell. No, really, it's very well written.
jashmenn 16y ago
Léon Bottou's implementation of Stochastic Gradient SVMs is the most concise implementation of an SVM that you'll find: http://leon.bottou.org/projects/sgd http://leon.bottou.org/projects/sgd
- sz 16y ago
  (since I had to look it up what a SVM was) "Support vector machines (SVMs) are a set of related supervised learning methods... The standard SVM takes a set of input data, and predicts, for each given input, which of two possible classes the input is a member of... Intuitively, an SVM model is a representation of the examples as points in space, mapped so that the examples of the separate categories are divided by a clear gap that is as wide as possible. New examples are then mapped into that same space and predicted to belong to a category based on which side of the gap they fall on." [wikipedia]
doublez 16y ago
The Lift framework core has some rather lithe Scala in it. Do mind that it's an actively developed, actively deployed framework - functionality sometimes takes priority ... ;)
- doublez 16y ago
  https://github.com/lift/lift https://github.com/lift/lift
dkurth 16y ago
Here's Peter Norvig's toy spelling corrector (in Python), along with some helpful explanation: http://norvig.com/spell-correct.html http://norvig.com/spell-correct.html
pierrefar 16y ago
I've heard good things about the code of Redis and Tokyo Tyrant.
variety 16y ago
The djb way: "straight, no chaser": http://cr.yp.to/ qmail in particular, and also (if you like math) primegen. BTW, his code is not easy to understand (quite the opposite) -- there are few source comments, and most of these are snarky, cryptic or both; and not only does he explain almost nothing on a global scale but oftentimes what he is doing might look, at first blush, kinda wrong, obtuse even. But that's precisely the point -- there are a lot of idioms in there that most C programmers just wouldn't think of, especially if you're into minimalism (when it comes to things like dealing with strings, error handling, forking, etc).
- kazuya 16y ago
  > and not only does he explain almost nothing on a global scale but oftentimes what he is doing might look, at first blush, kinda wrong, obtuse even. Can you give some examples?
dawsdesign 16y ago
I've heard that Postfix is as close to perfect you can get, but I haven't dived in personally.
jbarham 16y ago
http://code.google.com/p/go/source/browse/ http://code.google.com/p/go/source/browse/ is the source for the Go compilers and standard library. Very clean, clear code in the Bell Labs tradition.
srean 16y ago
I am surprised that nobody has pointed to http://news.usethesource.com/ http://news.usethesource.com/ yet.
- deleted 16y ago
  [deleted]

44 points by sz 16y ago

Examples help tremendously in learning any abstract subject. What are some famously well-written programs whose source is available to look at?

nomurrcy 16y ago

Lua (The programming language) is very well written and well worth reading and understanding. http://www.lua.org/ http://www.lua.org/

davidsiems 16y ago
I have to disagree. The language spec and the docs on the Lua website are well written but the VM itself is a mess. It's a trainwreck of ambiguously named variables, minimal documentation, and overuse of macros to force inline code. The Lua VM is a good example of something that isn't well written from a reading / understanding point of view, but is something that is well written from the 'it works' point of view.
pygy_ 16y ago
Here are the source code reading order recommendations by Mike Pall (the author of LuaJIT). http://www.reddit.com/r/programming/comments/63hth/ask_reddit_which_oss_codebases_out_there_are_so/c02ppb8 http://www.reddit.com/r/programming/comments/63hth/ask_reddi...

techbio 16y ago

I searched for "russian doll pseudocode" hoping to discover something elegant, but the clearest "code" there is a nicely colored Venn-ish diagram. http://ijcai.org/papers09/Papers/IJCAI09-106.pdf http://ijcai.org/papers09/Papers/IJCAI09-106.pdf

michael_dorfman 16y ago

TeX. Or, any of Knuth's other Literate Programs. Also, the book "Beautiful Code" is an attempt along these lines, but personally, I don't find the programs there as beautiful as Knuth's.

plinkplonk 16y ago

Code from Peter Norvig's "Paradigms of Artificial Intelligence Programming"

d4rt 16y ago

sqlite is both beautiful and has a significant test suite. http://www.sqlite.org/ http://www.sqlite.org/

jamii 16y ago
The sqlite test suite is a fantastic example of how to produce solid software. I wish it were used as a case study for all software engineering courses.

petercooper 16y ago

This is very Ruby specific (so mostly not "famous" stuff) but if that's your scene, I asked the same question to Rubyists recently and got some good suggestions: http://www.rubyflow.com/items/1817 http://www.rubyflow.com/items/1817

jamii 16y ago

I don't know about famous, but Conal Elliots ideas about denotational semantics have led to some beautifully elegant libraries - http://conal.net/blog/posts/denotational-design-with-type-class-morphisms/ http://conal.net/blog/posts/denotational-design-with-type-cl... Don't be put off by the academic tone, at its heart the paper is about how to design abstractions.

sz 16y ago
This looks awesome, thanks. How to design abstractions was what I had in mind when posing the question.
- jamii 16y ago
  I really enjoy reading Conals work. This paper is a particularly good example of how denotational semantics can guide the design of a library - http://conal.net/blog/posts/paper-beautiful-differentiation/ http://conal.net/blog/posts/paper-beautiful-differentiation/

abyssknight 16y ago

c99shell. No, really, it's very well written.

jashmenn 16y ago

Léon Bottou's implementation of Stochastic Gradient SVMs is the most concise implementation of an SVM that you'll find: http://leon.bottou.org/projects/sgd http://leon.bottou.org/projects/sgd

sz 16y ago
(since I had to look it up what a SVM was) "Support vector machines (SVMs) are a set of related supervised learning methods... The standard SVM takes a set of input data, and predicts, for each given input, which of two possible classes the input is a member of... Intuitively, an SVM model is a representation of the examples as points in space, mapped so that the examples of the separate categories are divided by a clear gap that is as wide as possible. New examples are then mapped into that same space and predicted to belong to a category based on which side of the gap they fall on." [wikipedia]

doublez 16y ago

The Lift framework core has some rather lithe Scala in it. Do mind that it's an actively developed, actively deployed framework - functionality sometimes takes priority ... ;)

doublez 16y ago
https://github.com/lift/lift https://github.com/lift/lift

dkurth 16y ago

Here's Peter Norvig's toy spelling corrector (in Python), along with some helpful explanation: http://norvig.com/spell-correct.html http://norvig.com/spell-correct.html

pierrefar 16y ago

I've heard good things about the code of Redis and Tokyo Tyrant.

variety 16y ago

The djb way: "straight, no chaser": http://cr.yp.to/ qmail in particular, and also (if you like math) primegen. BTW, his code is not easy to understand (quite the opposite) -- there are few source comments, and most of these are snarky, cryptic or both; and not only does he explain almost nothing on a global scale but oftentimes what he is doing might look, at first blush, kinda wrong, obtuse even. But that's precisely the point -- there are a lot of idioms in there that most C programmers just wouldn't think of, especially if you're into minimalism (when it comes to things like dealing with strings, error handling, forking, etc).

kazuya 16y ago
> and not only does he explain almost nothing on a global scale but oftentimes what he is doing might look, at first blush, kinda wrong, obtuse even. Can you give some examples?

dawsdesign 16y ago

I've heard that Postfix is as close to perfect you can get, but I haven't dived in personally.

jbarham 16y ago

http://code.google.com/p/go/source/browse/ http://code.google.com/p/go/source/browse/ is the source for the Go compilers and standard library. Very clean, clear code in the Bell Labs tradition.

srean 16y ago

I am surprised that nobody has pointed to http://news.usethesource.com/ http://news.usethesource.com/ yet.

deleted 16y ago
[deleted]