The Test.QuickCheck.Monadic module lets you test monadic code, even things that run in IO. A monadic property test is of type PropertyM m a, where m is the monad the test runs in and a is ultimately ignored. In the case of PropertyM IO a, you convert the monadic test to a Property by using … Read more
On linux, the two AIO implementations are fundamentally different. The POSIX AIO is a user-level implementation that performs normal blocking I/O in multiple threads, hence giving the illusion that the I/Os are asynchronous. The main reason to do this is that: it works with any filesystem it works (essentially) on any operating system (keep in … Read more
Assume you were: Reading a network file and got disconnected. Reading a local file that was no longer available. Using some stream to read data and some other process closed the stream. Trying to read/write a file, but don’t have permission. Trying to write to a file, but disk space was no longer available. There … Read more
to output to a file: git log > filename.log To specify a format, like you want everything on one line git log –pretty=oneline >filename.log or you want it a format to be emailed via a program like sendmail git log –pretty=email |email-sending-script.sh to generate JSON, YAML or XML it looks like you need to do … Read more
In general, there’s no way to make arbitrary edits in the middle of a file. It’s not a deficiency of Ruby. It’s a limitation of the file system: Most file systems make it easy and efficient to grow or shrink the file at the end, but not at the beginning or in the middle. So … Read more
flush() just makes sure that any buffered data is written to disk (in this case – more generally, flushed through whatever IO channel you’re using). You can still write to the stream (or writer) afterwards. close() flushes the data and indicates that there isn’t any more data. It closes any file handles, sockets or whatever. … Read more
I looked at the ruby documentation for StringIO, and it looks like what you want is StringIO#string, not StringIO#to_s Thus, change your code to: s = StringIO.new s << ‘foo’ s << ‘bar’ s.string
Consider the specific example of IOT Maybe. How would you write a Monad instance for that? You could start with something like this: instance Monad (IOT Maybe) where return x = IOT (Just (return x)) IOT Nothing >>= _ = IOT Nothing IOT (Just m) >>= k = IOT $ error “what now?” where m’ … Read more
You want to call the method without any OpenOption arguments. Files.write(path, content.getBytes()); From the Javadoc: The options parameter specifies how the the file is created or opened. If no options are present then this method works as if the CREATE, TRUNCATE_EXISTING, and WRITE options are present. In other words, it opens the file for writing, … Read more
Rust 1.x (see documentation): use std::io; use std::io::prelude::*; fn main() { let stdin = io::stdin(); for line in stdin.lock().lines() { println!(“{}”, line.unwrap()); } } Rust 0.10–0.12 (see documentation): use std::io; fn main() { for line in io::stdin().lines() { print!(“{}”, line.unwrap()); } } Rust 0.9 (see 0.9 documentation): use std::io; use std::io::buffered::BufferedReader; fn main() { let … Read more