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What is the purpose of the reader monad?
The reader monad is so complex and seems to be useless. In an imperative language like Java or C++, there is no equivalent concept for the reader monad, if I am not mistaken.
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Any reason why scala does not explicitly support dependent types?
There are path dependent types and I think it is possible to express almost all the features of such languages as Epigram or Agda in Scala, but I'm wondering why Scala does not support this more explicitly like it does very nicely in other areas (say, DSLs) ?
Anything I'm missing like "it is not n...
Scala: Abstract types vs generics
...s Type System
A Conversation with Martin Odersky, Part III
by Bill Venners and Frank Sommers (May 18, 2009)
Update (October2009): what follows below has actually been illustrated in this new article by Bill Venners:
Abstract Type Members versus Generic Type Parameters in Scala (see summary at the ...
数据存储组件 · App Inventor 2 中文网
...应用程序。兼容模式可用于旧的应用程序（新约束之前）Android 上的文件访问。
行数据
获取当前已加载的源文件的行数据列表。
源文件
设置数据解析的源文件，然后异步解析文件。结果存储在 列数据 、行数据 及 列名列...
Repeat String - Javascript
...
Note to new readers: This answer is old and and not terribly practical - it's just "clever" because it uses Array stuff to get
String things done. When I wrote "less process" I definitely meant
"less code" because, as others have noted in subsequent answers, it...
mmap() vs. reading blocks
...ontain sets of variable length records. I've got a first implementation up and running and am now looking towards improving performance, particularly at doing I/O more efficiently since the input file gets scanned many times.
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A monad is just a monoid in the category of endofunctors, what's the problem?
...r phrasing is by James Iry, from his highly entertaining Brief, Incomplete and Mostly Wrong History of Programming Languages, in which he fictionally attributes it to Philip Wadler.
The original quote is from Saunders Mac Lane in Categories for the Working Mathematician, one of the foundational text...
What's so bad about Template Haskell?
... Tough luck, you'll only see that when actually using your code generator, and only under the circumstances that trigger the generation of that particular code. It is very difficult to unit test, too.
TH is also outright dangerous:
Code that runs at compile-time can do arbitrary IO, including la...
JavaScript + Unicode regexes
...egex. See Unicode-aware regular expressions in ES6.
Until ES 6 is finished and widely adopted among browser vendors you're still on your own, though. Update: There is now a transpiler named regexpu that translates ES6 Unicode regular expressions into equivalent ES5. It can be used as part of your bu...
Fastest way to iterate over all the chars in a String
... as byte[] by default.
SECOND UPDATE: As of 2016-10-25, on my AMDx64 8core and source 1.8, there is no difference between using 'charAt' and field access. It appears that the jvm is sufficiently optimized to inline and streamline any 'string.charAt(n)' calls.
THIRD UPDATE: As of 2020-09-07, on my Ry...