├── .gitignore ├── COPYING ├── Cargo.toml ├── LINKING_EXCEPTION ├── README.md └── src ├── constructors.rs ├── iomonad.rs ├── lib.rs └── realworld.rs /.gitignore: -------------------------------------------------------------------------------- 1 | target 2 | Cargo.lock 3 | -------------------------------------------------------------------------------- /COPYING: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. 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It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | 635 | Copyright (C) 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | Copyright (C) 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | -------------------------------------------------------------------------------- /Cargo.toml: -------------------------------------------------------------------------------- 1 | [package] 2 | name = "burrito" 3 | version = "0.1.0" 4 | authors = ["Lee "] 5 | license = "GPLv3.0+ WITH Classpath-exception-2.0" 6 | description = "A monadic IO interface." 7 | documentation = "https://withoutboats.github.io/burrito/" 8 | repository = "https://github.com/withoutboats/burrito/" 9 | -------------------------------------------------------------------------------- /LINKING_EXCEPTION: -------------------------------------------------------------------------------- 1 | Linking this library statically or dynamically with other modules is making a 2 | combined work based on this library. Thus, the terms and conditions of the GNU 3 | General Public License cover the whole combination. 4 | 5 | As a special exception, the copyright holders of this library give you 6 | permission to link this library with independent modules to produce an 7 | executable, regardless of the license terms of these independent modules, and 8 | to copy and distribute the resulting executable under terms of your choice, 9 | provided that you also meet, for each linked independent module, the terms and 10 | conditions of the license of that module. An independent module is a module 11 | which is not derived from or based on this library. If you modify this library, 12 | you may extend this exception to your version of the library, but you are not 13 | obligated to do so. If you do not wish to do so, delete this exception 14 | statement from your version. 15 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Burrito: a monadic IO interface. 2 | 3 | Burrito is a monad. Monads are [basically burritoes](http://blog.plover.com/prog/burritos.html). 4 | This monad wraps an IO handle, hiding its potential state of failure from you 5 | for as long as you want. This isn't _exactly_ like the IO monad from Haskell, 6 | but its very similar conceptually. 7 | 8 | [Documentation!](https://withoutboats.github.io/burrito/) 9 | 10 | ### Creating a Burrito 11 | 12 | You can instantiate a burrito one of several ways: 13 | 14 | * The `burrito()` function will return a Burrito wrapping the stdio handles. 15 | * `Burrito::wrap()` takes an `io::Result` to create a burrito wrapping that 16 | `T`. `io::Result` is the return type of most functions which create IO 17 | handles. 18 | * `Burrito::wrap_func()` takes a function which returns an `io::Result` and 19 | wraps the IO handle returned by that function. 20 | * Several standard IO types implement the traits `FromPath` or `FromAddr`. 21 | `Burrito::from_path` and `Burrito::from_addr` will transform a path or socket 22 | address into an IO handle and wrap a burrito around it. 23 | 24 | Note that `File`'s implementation of `FromPath` will open a file with read, 25 | write, and create all set to `true`. If you wish to open a file with different 26 | options, you will want to use `Burrito::wrap()`. 27 | 28 | ### Using a Burrito 29 | 30 | If the handle inside the burrito implements `Read`, `Write`, `Seek`, or 31 | `BufRead`, the burrito will implement similar methods to those defined on that 32 | trait, though the signatures will differ. The return value of those functions 33 | will then be stored inside the burrito, accessible through the `and_then()` 34 | method which burrito implements. As a simple example, this code will echo once 35 | on stdin/stdout. 36 | 37 | ```rust 38 | burrito().read_line().and_then(|echo, burrito| burrito.print_line(&echo)); 39 | ``` 40 | 41 | More information is available in the API docs. 42 | 43 | ### Non-blocking IO 44 | 45 | Burrito currently is built on top of the standard library's io module, which 46 | is intended for blocking IO. Extensions may be forthcoming which will implement 47 | non-blocking burritoes, probably on top of `mio`. 48 | 49 | ### Licensing. 50 | 51 | This library is licensed under the GPL version 3 or greater with the CLASSPATH 52 | linking exception. 53 | 54 | ### Jokes 55 | 56 | This library is a joke. But you can also use it actually. Like it works and 57 | stuff. 58 | -------------------------------------------------------------------------------- /src/constructors.rs: -------------------------------------------------------------------------------- 1 | use std::convert::AsRef; 2 | use std::fs; 3 | use std::net::{self, ToSocketAddrs}; 4 | use std::path::Path; 5 | use std::io; 6 | 7 | pub trait FromPath { 8 | fn from_path>(P) -> io::Result; 9 | } 10 | 11 | pub trait FromAddr { 12 | fn from_addr(A) -> io::Result; 13 | } 14 | 15 | impl FromPath for fs::File { 16 | fn from_path>(path: P) -> io::Result { 17 | fs::OpenOptions::new().read(true).write(true).create(true).open(path) 18 | } 19 | } 20 | 21 | impl FromAddr for net::TcpStream { 22 | fn from_addr(addr: A) -> io::Result { 23 | net::TcpStream::connect(addr) 24 | } 25 | } 26 | 27 | -------------------------------------------------------------------------------- /src/iomonad.rs: -------------------------------------------------------------------------------- 1 | use std::fmt; 2 | use std::io::{self, Read, Write, Seek, BufRead}; 3 | 4 | use realworld::RealWorld; 5 | use self::Io::*; 6 | 7 | pub enum Io { 8 | Good(A, T), 9 | Bad(io::Error), 10 | } 11 | 12 | impl Io where T: Read { 13 | 14 | pub fn read(self, n: usize) -> Io, T> { 15 | match self { 16 | Good(_, mut r) => { 17 | let mut buf = vec![0; n]; 18 | match r.read(&mut buf) { 19 | Ok(n) => { 20 | buf.truncate(n); 21 | Good(buf, r) 22 | } 23 | Err(err) => Bad(err), 24 | } 25 | } 26 | Bad(err) => Bad(err) 27 | } 28 | } 29 | 30 | pub fn read_to_end(self) -> Io, T> { 31 | match self { 32 | Good(_, mut r) => { 33 | let mut buf = Vec::new(); 34 | match r.read_to_end(&mut buf) { 35 | Ok(..) => Good(buf, r), 36 | Err(err) => Bad(err), 37 | } 38 | } 39 | Bad(err) => Bad(err) 40 | } 41 | } 42 | 43 | pub fn read_to_string(self) -> Io { 44 | match self { 45 | Good(_, mut r) => { 46 | let mut buf = String::new(); 47 | match r.read_to_string(&mut buf) { 48 | Ok(..) => Good(buf, r), 49 | Err(err) => Bad(err), 50 | } 51 | } 52 | Bad(err) => Bad(err) 53 | } 54 | } 55 | 56 | } 57 | 58 | impl Io where T: Write { 59 | 60 | /// Write from inside the burrito. 61 | pub fn write(self, buf: &[u8]) -> Io { 62 | match self { 63 | Good(_, mut w) => { 64 | match w.write(buf) { 65 | Ok(n) => Good(n, w), 66 | Err(err) => Bad(err), 67 | } 68 | } 69 | Bad(err) => Bad(err) 70 | } 71 | } 72 | 73 | pub fn write_all(self, buf: &[u8]) -> Io<(), T> { 74 | match self { 75 | Good(_, mut w) => { 76 | match w.write_all(buf) { 77 | Ok(..) => Good((), w), 78 | Err(err) => Bad(err), 79 | } 80 | } 81 | Bad(err) => Bad(err) 82 | } 83 | } 84 | 85 | pub fn write_fmt(self, fmt: fmt::Arguments) -> Io<(), T> { 86 | match self { 87 | Good(_, mut w) => { 88 | match w.write_fmt(fmt) { 89 | Ok(..) => Good((), w), 90 | Err(err) => Bad(err), 91 | } 92 | } 93 | Bad(err) => Bad(err) 94 | } 95 | } 96 | 97 | } 98 | 99 | impl Io where T: Seek { 100 | 101 | pub fn seek(self, pos: io::SeekFrom) -> Io { 102 | match self { 103 | Good(_, mut s) => { 104 | match s.seek(pos) { 105 | Ok(n) => Good(n, s), 106 | Err(err) => Bad(err), 107 | } 108 | } 109 | Bad(err) => Bad(err) 110 | } 111 | } 112 | 113 | } 114 | 115 | impl Io where T: BufRead { 116 | 117 | pub fn fill_buf(self) -> Io<(), T> { 118 | match self { 119 | Good(_, mut r) => { 120 | match r.fill_buf() { 121 | Ok(..) => Good((), r), 122 | Err(err) => Bad(err), 123 | } 124 | } 125 | Bad(err) => Bad(err) 126 | } 127 | } 128 | 129 | pub fn consume(self, amt: usize) -> Io<(), T> { 130 | match self { 131 | Good(_, mut r) => { 132 | r.consume(amt); 133 | Good((), r) 134 | } 135 | Bad(err) => Bad(err) 136 | } 137 | } 138 | 139 | pub fn read_until(self, byte: u8) -> Io, T> { 140 | match self { 141 | Good(_, mut r) => { 142 | let mut buf = Vec::new(); 143 | match r.read_until(byte, &mut buf) { 144 | Ok(..) => Good(buf, r), 145 | Err(err) => Bad(err), 146 | } 147 | } 148 | Bad(err) => Bad(err) 149 | } 150 | } 151 | 152 | pub fn read_line(self) -> Io { 153 | match self { 154 | Good(_, mut r) => { 155 | let mut buf = String::new(); 156 | match r.read_line(&mut buf) { 157 | Ok(..) => Good(buf, r), 158 | Err(err) => Bad(err), 159 | } 160 | } 161 | Bad(err) => Bad(err) 162 | } 163 | } 164 | 165 | pub fn split(self, byte: u8) -> io::Result> { 166 | match self { 167 | Good(_, r) => Ok(r.split(byte)), 168 | Bad(err) => Err(err) 169 | } 170 | } 171 | 172 | pub fn lines(self) -> io::Result> { 173 | match self { 174 | Good(_, r) => Ok(r.lines()), 175 | Bad(err) => Err(err), 176 | } 177 | } 178 | 179 | } 180 | 181 | impl Io { 182 | 183 | pub fn print_line(self, buf: &str) -> Io<(), RealWorld> { 184 | match self { 185 | Good(_, rw) => { 186 | let result = rw.stdout.lock().write_all(format!("{}\n", buf).as_bytes()); 187 | match result { 188 | Ok(..) => Good((), rw), 189 | Err(err) => Bad(err), 190 | } 191 | } 192 | Bad(err) => Bad(err) 193 | } 194 | } 195 | 196 | pub fn read_line(self) -> Io { 197 | match self { 198 | Good(_, mut rw) => { 199 | let mut buf = String::new(); 200 | match rw.stdin.read_line(&mut buf) { 201 | Ok(..) => Good(buf, rw), 202 | Err(err) => Bad(err), 203 | } 204 | } 205 | Bad(err) => Bad(err) 206 | } 207 | } 208 | 209 | pub fn write_to_err(self, buf: &[u8]) -> Io { 210 | match self { 211 | Good(_, rw) => { 212 | let result = rw.stderr.lock().write(buf); 213 | match result { 214 | Ok(n) => Good(n, rw), 215 | Err(err) => Bad(err), 216 | } 217 | } 218 | Bad(err) => Bad(err) 219 | } 220 | } 221 | 222 | pub fn write_all_to_err(self, buf: &[u8]) -> Io<(), RealWorld> { 223 | match self { 224 | Good(_, rw) => { 225 | let result = rw.stderr.lock().write_all(buf); 226 | match result { 227 | Ok(..) => Good((), rw), 228 | Err(err) => Bad(err), 229 | } 230 | } 231 | Bad(err) => Bad(err) 232 | } 233 | } 234 | 235 | pub fn write_fmt_to_err(self, fmt: fmt::Arguments) -> Io<(), RealWorld> { 236 | match self { 237 | Good(_, rw) => { 238 | let result = rw.stderr.lock().write_fmt(fmt); 239 | match result { 240 | Ok(..) => Good((), rw), 241 | Err(err) => Bad(err), 242 | } 243 | } 244 | Bad(err) => Bad(err) 245 | } 246 | } 247 | 248 | } 249 | -------------------------------------------------------------------------------- /src/lib.rs: -------------------------------------------------------------------------------- 1 | //! `Burrito` is a monadic IO interface, similar to Haskell's IO monad. 2 | //! 3 | //! A single `Burrito` type wraps a single IO handle, whether its the stdio, a file on the system, 4 | //! or a socket address. There are several ways to create a `Burrito`. 5 | //! 6 | //! * `burrito()` creates an stdio `Burrito.` 7 | //! * `Burrito::wrap()` wraps a Result, where T is an IO handle. 8 | //! * `Burrito::wrap_func()` wraps a function which returns a Result, where T is an IO handle. 9 | //! * Types which implement `FromPath` can be wrapped using `Burrito::from_path()` 10 | //! * Types which implement `FromAddr` can be wrapped using `Burrito::from_addr()` 11 | //! 12 | //! IO actions can be performed directly on the `Burrito`; the result of these actions can be 13 | //! accessed using the `and_then` method. IO failure can be handled using the `or_else` method. 14 | //! 15 | //! As a simple example of a `Burrito` in action, this code will echo stdin on stdout. 16 | //! 17 | //! ```no_run 18 | //! # extern crate burrito; 19 | //! # fn main() { 20 | //! use burrito::burrito; 21 | //! 22 | //! burrito().read_line().and_then(|echo, burrito| burrito.print_line(&echo)); 23 | //! # } 24 | //! ``` 25 | //! 26 | //! # The `RealWorld` type 27 | //! 28 | //! The default `Burrito`, which is returned by `burrito()`, wraps a type called `RealWorld`. This 29 | //! encapsulates the handles to stdin, stdout, stderr. It does not lock these handles; it will 30 | //! attempt to lock them each time they are written to / read from. 31 | //! 32 | //! The `RealWorld` type is not directly accessible except wrapped inside of the `Burrito` returned 33 | //! by `burrito()`. 34 | //! 35 | //! # Using the monadic interface 36 | //! 37 | //! Every `Burrito` has two type parameters. The `T` type is the type of the IO handle it wraps. 38 | //! The `A` type, however, is the type of the data returned by the most recent IO call. 39 | //! 40 | //! All of the IO calls implemented on `Burrito` consume the object and return a new `Burrito`; if 41 | //! that call returned data of some kind, that data is stored inside that new `Burrito`. 42 | //! 43 | //! ## `and_then()` 44 | //! 45 | //! The prefered way to access the data inside a burrito is the `and_then` method. `and_then` 46 | //! takes a function of `A` and `Burrito<(), T>` to any `Burrito`, and applies that function to the 47 | //! `A` data inside the `Burrito` and a new `Burrito` wrapped around the IO handle. 48 | //! 49 | //! A common pattern when using `Burrito`s is a back and forth between IO methods and `and_then` 50 | //! calls, possibly including IO methods on the burrito and the end of the `and_then`. 51 | //! 52 | //! ``` 53 | //! # extern crate burrito; 54 | //! # fn main() { 55 | //! use burrito::burrito; 56 | //! 57 | //! burrito().read_line().and_then(|input, burrito| { 58 | //! let output = // Generate output based on the input in some way. 59 | //! # &input; 60 | //! burrito.print_line(output) 61 | //! }).read_line().and_then(|input, burrito| { 62 | //! // Do more stuff with the next input. 63 | //! burrito 64 | //! }); 65 | //! # } 66 | //! ``` 67 | //! 68 | //! Note that the function passed to `and_then` is only called in the event that the `Burrito` is 69 | //! not in a state of failure. 70 | //! 71 | //! ## `and()` 72 | //! 73 | //! The `and()` method is less powerful than the `and_then()` method because it does not provide 74 | //! access to the data inside the `Burrito`. Its main use is to close this IO handle when its done 75 | //! being used and to open another one, which could possibly be of a different type. It is not 76 | //! lazy, and the IO handle will actually be opened even if the `Burrito` is in a state of failure. 77 | //! 78 | //! ## `or_else()` 79 | //! 80 | //! The `or_else()` method provides access to the inner error in the event that the `Burrito` 81 | //! represents an IO handle in a state of failure. As soon as any IO method on that handle returns 82 | //! a failure, the `Burrito` remains in a state of failure until re-instantiated. This method must 83 | //! either create a `Burrito` of the same type (presumably replacing the original `Burrito`) or 84 | //! else diverge, e.g. by exiting or panicking. 85 | //! 86 | //! ## `or()` 87 | //! 88 | //! The `or()` method enables replacing the `Burrito` with another of the same types, but does not 89 | //! provide access to the inner error. It is not lazy, and will actually open the handle even if 90 | //! the `Burrito` is not in a state of failure. 91 | 92 | use std::convert::AsRef; 93 | use std::default::Default; 94 | use std::fmt; 95 | use std::path::Path; 96 | use std::io::{self, Read, Write, Seek, BufRead}; 97 | use std::net::ToSocketAddrs; 98 | 99 | mod realworld; 100 | mod iomonad; 101 | mod constructors; 102 | 103 | use realworld::RealWorld; 104 | use iomonad::Io; 105 | use iomonad::Io::*; 106 | pub use constructors::{FromPath, FromAddr}; 107 | 108 | /// Create a default burrito (wrapping the stdio handles). 109 | pub fn burrito() -> Burrito<(), RealWorld> { Burrito::default() } 110 | 111 | /// The fundamental monadic type of the burrito library. 112 | /// 113 | /// `Burrito` implements different IO methods depending on the traits implemented by the IO handle 114 | /// it wraps. These methods have the same name as the methods associated with that trait, though 115 | /// their signature differs somewhat. 116 | pub struct Burrito(Io); 117 | 118 | /// These methods construct `Burrito`s of arbitrary types. 119 | impl Burrito<(), T> { 120 | 121 | /// The basic constructor for `Burrito`. This takes an `io::Result`, where `T` is the type 122 | /// being wrapped by the `Burrito`, `io::Result` is the return type of the constructor for 123 | /// most IO handle types. 124 | /// 125 | /// ``` 126 | /// # extern crate burrito; 127 | /// # fn main() { 128 | /// use std::fs::File; 129 | /// use burrito::Burrito; 130 | /// 131 | /// let burrito = Burrito::wrap(File::create("/foo/bar/baz")); 132 | /// # } 133 | /// ``` 134 | pub fn wrap(inner: io::Result) -> Burrito<(), T> { 135 | match inner { 136 | Ok(io) => Burrito(Good((), io)), 137 | Err(err) => Burrito(Bad(err)), 138 | } 139 | } 140 | 141 | /// A constructor for `Burrito` which takes a function and wraps the result of that function. 142 | /// 143 | /// ``` 144 | /// # extern crate burrito; 145 | /// # fn main() { 146 | /// use std::fs::{self, File}; 147 | /// use burrito::Burrito; 148 | /// 149 | /// let burrito = Burrito::wrap_func(|| { 150 | /// try!(fs::metadata("/foo/bar/baz")); 151 | /// File::open("/foo/bar/baz") 152 | /// }); 153 | /// # } 154 | /// ``` 155 | pub fn wrap_func io::Result>(f: F) -> Burrito<(), T> { 156 | match f() { 157 | Ok(io) => Burrito(Good((), io)), 158 | Err(err) => Burrito(Bad(err)), 159 | } 160 | } 161 | 162 | } 163 | 164 | /// These two functions are constructors for types which can be constructed from paths and socket 165 | /// addresses. 166 | impl Burrito<(), ()> { 167 | 168 | /// Constructs an IO handle using the path argument, according to that IO handle's 169 | /// implementation of FromPath, then wraps that handle in a `Burrito`. It is a good idea to 170 | /// type annotate this call to ensure the correct kind of handle is constructed. 171 | /// 172 | /// ```rust 173 | /// # extern crate burrito; 174 | /// # fn main() { 175 | /// use std::fs::File; 176 | /// use burrito::{Burrito, FromPath}; 177 | /// 178 | /// let burrito = Burrito::from_path::<_, File>("/foo/bar/baz"); 179 | /// # } 180 | /// ``` 181 | pub fn from_path, T: FromPath>(path: P) -> Burrito<(), T> { 182 | match T::from_path(path) { 183 | Ok(io) => Burrito(Good((), io)), 184 | Err(err) => Burrito(Bad(err)), 185 | } 186 | } 187 | 188 | /// Constructs an IO handle using the addr argument, according to that IO handle's 189 | /// implementation of FromAddr, then wraps that handle in a `Burrito`. It is a good idea to 190 | /// type annotate this call to ensure the correct kind of handle is constructed. 191 | /// 192 | /// ```rust 193 | /// # extern crate burrito; 194 | /// # fn main() { 195 | /// use std::net::TcpStream; 196 | /// use burrito::{Burrito, FromAddr}; 197 | /// 198 | /// let burrito = Burrito::from_addr::<_, TcpStream>("localhost:12345"); 199 | /// # } 200 | /// ``` 201 | pub fn from_addr(addr: A) -> Burrito<(), T> { 202 | match T::from_addr(addr) { 203 | Ok(io) => Burrito(Good((), io)), 204 | Err(err) => Burrito(Bad(err)), 205 | } 206 | } 207 | 208 | } 209 | 210 | /// These methods are defined for all `Burrito`s. 211 | impl Burrito { 212 | 213 | /// Allows you to 'pivot' to a new `Burrito` if this one is good, or to remain in a state of 214 | /// failure if this `Burrito` has failed. See the module level documentation for more info. 215 | pub fn and(self, alternative: Burrito) -> Burrito { 216 | match self { 217 | Burrito(Good(..)) => alternative, 218 | Burrito(Bad(err)) => Burrito(Bad(err)), 219 | } 220 | } 221 | 222 | /// Allows access to data returned by the most recent IO call on this `Burrito`; this function 223 | /// must return another `Burrito` of some kind or else diverge. See the module level 224 | /// documentation for more info. 225 | pub fn and_then(self, f: F) -> Burrito 226 | where F: FnOnce(A, Burrito<(), T>) -> Burrito { 227 | match self { 228 | Burrito(Good(data, io)) => f(data, Burrito(Good((), io))), 229 | Burrito(Bad(err)) => Burrito(Bad(err)) 230 | } 231 | } 232 | 233 | /// Allows you to substitute this `Burrito` for another of the same type if it has gone bad. 234 | pub fn or(self, alternative: Burrito) -> Burrito { 235 | match self { 236 | Burrito(Bad(..)) => alternative, 237 | _ => self, 238 | } 239 | } 240 | 241 | /// Allows access to the error thrown if this `Burrito` has gone bad. This function must return 242 | /// another `Burrito` of the same type or else diverge. See the module level documentation for 243 | /// more info. 244 | pub fn or_else(self, f: F) -> Burrito 245 | where F: FnOnce(io::Error) -> Burrito { 246 | match self { 247 | Burrito(Bad(err)) => f(err), 248 | _ => self 249 | } 250 | } 251 | 252 | /// Drops any data returned by the most recent IO call. 253 | pub fn ignore(self) -> Burrito<(), T> { 254 | match self { 255 | Burrito(Good(_, io)) => Burrito(Good((), io)), 256 | Burrito(Bad(err)) => Burrito(Bad(err)) 257 | } 258 | } 259 | 260 | /// Returns true if the `Burrito` has not failed. 261 | pub fn is_good(&self) -> bool { 262 | match *self { 263 | Burrito(Good(..)) => true, 264 | Burrito(Bad(..)) => false, 265 | } 266 | } 267 | 268 | /// Returns true if the `Burrito` has failed. 269 | pub fn is_bad(&self) -> bool { !self.is_good() } 270 | 271 | /// Converts the `Burrito` to a `Result` of both the handle and the most recently returned 272 | /// data. 273 | pub fn ok(self) -> io::Result<(A, T)> { 274 | match self { 275 | Burrito(Good(data, io)) => Ok((data, io)), 276 | Burrito(Bad(err)) => Err(err), 277 | } 278 | } 279 | 280 | /// Converts the `Burrito` to a `Result` of the most recently returned data. 281 | pub fn to_data(self) -> io::Result { 282 | match self { 283 | Burrito(Good(data, _)) => Ok(data), 284 | Burrito(Bad(err)) => Err(err), 285 | } 286 | } 287 | 288 | /// Converts the `Burrito` to a `Result` of the IO handle wrapped within. 289 | pub fn to_handle(self) -> io::Result { 290 | match self { 291 | Burrito(Good(_, io)) => Ok(io), 292 | Burrito(Bad(err)) => Err(err), 293 | } 294 | } 295 | 296 | } 297 | 298 | impl Default for Burrito<(), RealWorld> { 299 | fn default() -> Burrito<(), RealWorld> { Burrito(Good((), RealWorld::default())) } 300 | } 301 | 302 | impl Burrito where T: Read { 303 | /// Performs a read on the IO handle inside the burrito. Will read into a buffer of _n_ bytes. 304 | /// 305 | /// Though the buffer passed to `Read::read()` can be stack allocated, this function allocates 306 | /// the buffer on the heap, so that its length can be determined by the function call. The 307 | /// `Vec` returned by this type will contain all of the bytes read from the call; if that 308 | /// is less than _n_, it will not include any null bytes. 309 | pub fn read(self, n: usize) -> Burrito, T> { Burrito(self.0.read(n)) } 310 | /// Reads to the end of the handle inside the burrito, returning a `Vec` of bytes. 311 | pub fn read_to_end(self) -> Burrito, T> { Burrito(self.0.read_to_end()) } 312 | /// Reads everything from the handle into a `String`. 313 | pub fn read_to_string(self) -> Burrito { Burrito(self.0.read_to_string()) } 314 | } 315 | 316 | impl Burrito where T: Write { 317 | /// Writes the content of the buf to the IO handle; returns the number of bytes written. 318 | pub fn write(self, buf: &[u8]) -> Burrito { Burrito(self.0.write(buf)) } 319 | /// Writes the content of the buf to the IO handle; will write all of the bytes unless it 320 | /// fails. 321 | pub fn write_all(self, buf: &[u8]) -> Burrito<(), T> { Burrito(self.0.write_all(buf)) } 322 | /// Writes formatted text to the IO handle. 323 | pub fn write_fmt(self, buf: fmt::Arguments) -> Burrito<(), T> { 324 | Burrito(self.0.write_fmt(buf)) 325 | } 326 | } 327 | 328 | impl Burrito where T: Seek { 329 | /// Seeks to a position in the IO handle; returns the actual position that has been `seek`ed 330 | /// to. 331 | pub fn seek(self, pos: io::SeekFrom) -> Burrito { Burrito(self.0.seek(pos)) } 332 | } 333 | 334 | impl Burrito where T: BufRead { 335 | /// Fills the buffer on the buffered reader. Unlike the underlying fill_buf macro, this does 336 | /// not return a reference to the bytes in the buffer. 337 | pub fn fill_buf(self) -> Burrito<(), T> { Burrito(self.0.fill_buf()) } 338 | /// Marks `amt` bytes in the buffer as consumed. 339 | pub fn consume(self, amt: usize) -> Burrito<(), T> { Burrito(self.0.consume(amt)) } 340 | /// Reads from the buffered reader until the `byte` is reached. 341 | pub fn read_until(self, byte: u8) -> Burrito, T> { Burrito(self.0.read_until(byte)) } 342 | /// Reads a line from the buffered reader. 343 | pub fn read_line(self) -> Burrito { Burrito(self.0.read_line()) } 344 | /// Generates a Split Iterator of the underlying buffered reader. This will be wrapped in a 345 | /// result because the IO handle may have failed at some point in the past. 346 | pub fn split(self, byte: u8) -> io::Result> { self.0.split(byte) } 347 | /// Generates a Lines Iterator of the underlying buffered reader. This will be wrapped in a 348 | /// result because the IO handle may have failed at some point in the past. 349 | pub fn lines(self) -> io::Result> { self.0.lines() } 350 | } 351 | 352 | /// These methods are implemented only for the stdio `Burrito`. Note that `RealWorld` implements 353 | /// both `Read` and `Write`, and so the stdio `Burrito` also has all methods for `Burrito`s 354 | /// wrapping handles which implement those traits; the methods associated with the `Write` trait 355 | /// write to stdout, whereas a set of special `to_err()` methods write to stderr. 356 | impl Burrito { 357 | 358 | /// Prints a string to stdout, with a newline affixed to the end. Internally, it calls 359 | /// `write_all`; to use it like the `println!()` macro, you can use a reference to a format 360 | /// macro - that is `&format!()`. 361 | /// 362 | /// ``` 363 | /// # extern crate burrito; 364 | /// # fn main() { 365 | /// use burrito::burrito; 366 | /// 367 | /// burrito().print_line(&format!("2 + 2 = {}", 4)); 368 | /// # } 369 | /// ``` 370 | pub fn print_line(self, buf: &str) -> Burrito<(), RealWorld> { 371 | Burrito(self.0.print_line(buf)) 372 | } 373 | 374 | /// Reads a line from stdin. This has the same behavior as the read_line() method on io::Stdin. 375 | /// 376 | /// ```no_run 377 | /// # extern crate burrito; 378 | /// # fn main() { 379 | /// use burrito::burrito; 380 | /// 381 | /// let input = burrito().read_line().to_data(); 382 | /// # } 383 | /// ``` 384 | pub fn read_line(self) -> Burrito { 385 | Burrito(self.0.read_line()) 386 | } 387 | 388 | /// Performs a write to stderr instead of stdout. 389 | pub fn write_to_err(self, buf: &[u8]) -> Burrito { 390 | Burrito(self.0.write_to_err(buf)) 391 | } 392 | 393 | /// Performs a write_all to stderr instead of stdout. 394 | pub fn write_all_to_err(self, buf: &[u8]) -> Burrito<(), RealWorld> { 395 | Burrito(self.0.write_all_to_err(buf)) 396 | } 397 | 398 | /// Performs a write_fmt to stderr instead of stdout. 399 | pub fn write_fmt_to_err(self, fmt: fmt::Arguments) -> Burrito<(), RealWorld> { 400 | Burrito(self.0.write_fmt_to_err(fmt)) 401 | } 402 | 403 | } 404 | -------------------------------------------------------------------------------- /src/realworld.rs: -------------------------------------------------------------------------------- 1 | use std::io::{self, Read, Write}; 2 | 3 | pub struct RealWorld { 4 | pub stdin: io::Stdin, 5 | pub stdout: io::Stdout, 6 | pub stderr: io::Stderr, 7 | } 8 | 9 | impl Default for RealWorld { 10 | fn default() -> RealWorld { 11 | RealWorld { 12 | stdin: io::stdin(), 13 | stdout: io::stdout(), 14 | stderr: io::stderr(), 15 | } 16 | } 17 | } 18 | 19 | impl Read for RealWorld { 20 | fn read(&mut self, buf: &mut [u8]) -> io::Result { 21 | self.stdin.lock().read(buf) 22 | } 23 | } 24 | 25 | impl Write for RealWorld { 26 | fn write(&mut self, buf: &[u8]) -> io::Result { 27 | self.stdout.lock().write(buf) 28 | } 29 | fn flush(&mut self) -> io::Result<()> { Ok(()) } 30 | } 31 | --------------------------------------------------------------------------------