Turtle is a reimplementation of the Unix command line environment in Haskell so
that you can use Haskell as a scripting language or a shell. Think of turtle
as coreutils embedded within the Haskell language.
The turtle library focuses on being a "better Bash" by providing a typed and
light-weight shell scripting experience embedded within the Haskell language.
If you have a large shell script that is difficult to maintain, consider
translating it to a "turtle script" (i.e. a Haskell script using the turtle
library).
Among typed languages, Haskell possesses a unique combination of features that
greatly assist scripting:
Haskell has global type inference, so all type annotations are optional
Haskell is functional and not object-oriented, so boilerplate is minimal
Haskell can be type-checked and interpreted quickly (< 1 second startup time)
Features
Batteries included: Command an extended suite of predefined utilities
Interoperability: You can still run external shell commands
Portability: Works on Windows, OS X, and Linux
Exception safety: Safely acquire and release resources
Streaming: Transform or fold command output in constant space
Patterns: Use typed regular expressions that can parse structured values
Formatting: Type-safe printf-style text formatting
Modern: Supports text and system-filepath
Caveats
Unlike shelly, this package does not use a monad transformer to keep track of
state like the current working directory or environment variables. Instead, all
state changes are made to the process's global state.
Development Status
turtle's types and idioms are reasonably complete and I don't expect there
to be significant changes to the library's core API. The only major
functionality that I might add in the future would be to wrap
optparse-applicative in a simpler API.
The set of available tools currently covers as many filesystem utilities as I
could find across Hackage, but I would like to continue to add to the set of
available tools to minimally match coreutils.
Copyright (c) 2017 Gabriel Gonzalez
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