Awesome  Rust

Awesome Rust

1647699252

McFly: Fly Through Your Shell History Written in Rust

McFly replaces your default ctrl-r shell history search with an intelligent search engine that takes into account your working directory and the context of recently executed commands. McFly's suggestions are prioritized in real time with a small neural network.

TL;DR: an upgraded ctrl-r where history results make sense for what you're working on right now.

Features

  • Rebinds ctrl-r to bring up a full-screen reverse history search prioritized with a small neural network.
  • Augments your shell history to track command exit status, timestamp, and execution directory in a SQLite database.
  • Maintains your normal shell history file as well so that you can stop using McFly whenever you want.
  • Unicode support throughout.
  • Includes a simple action to scrub any history item from the McFly database and your shell history files.
  • Designed to be extensible for other shells in the future.
  • Written in Rust, so it's fast and safe.
  • You can type % to match any number of characters when searching.

Prioritization

The key feature of McFly is smart command prioritization powered by a small neural network that runs in real time. The goal is for the command you want to run to always be one of the top suggestions.

When suggesting a command, McFly takes into consideration:

  • The directory where you ran the command. You're likely to run that command in the same directory in the future.
  • What commands you typed before the command (e.g., the command's execution context).
  • How often you run the command.
  • When you last ran the command.
  • If you've selected the command in McFly before.
  • The command's historical exit status. You probably don't want to run old failed commands.

Installation

Install with Homebrew (on OS X or Linux)

  1. Install the tap:
brew tap cantino/mcfly

2.   Install mcfly:

brew install mcfly

3.   Add the following to the end of your ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish file:

Bash:

eval "$(mcfly init bash)"

Zsh:

eval "$(mcfly init zsh)"

Fish:

mcfly init fish | source

Run . ~/.bashrc / . ~/.zshrc / source ~/.config/fish/config.fish or restart your terminal emulator.

Uninstalling with Homebrew

  1. Remove mcfly:
brew uninstall mcfly

2.   Remove the tap:

brew untap cantino/mcfly

3.   Remove the lines you added to ~/.bashrc / ~/.zshrc / ~/.config/fish/config.fish.

Install with MacPorts (on OS X)

  1. Update the ports tree
sudo port selfupdate

2.   Install mcfly:

sudo port install mcfly

3.  Add the following to the end of your ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish file, as appropriate:

Bash:

eval "$(mcfly init bash)"

Zsh:

eval "$(mcfly init zsh)"

Fish:

mcfly init fish | source

Run . ~/.bashrc / . ~/.zshrc / source ~/.config/fish/config.fish or restart your terminal emulator.

Uninstalling with MacPorts

  1. Remove mcfly:
sudo port uninstall mcfly

2.   Remove the lines you added to ~/.bashrc / ~/.zshrc / ~/.config/fish/config.fish.

Installing using our install script

  1. curl -LSfs https://raw.githubusercontent.com/cantino/mcfly/master/ci/install.sh | sh -s -- --git cantino/mcfly
  2. Add the following to the end of your ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish file, respectively:

Bash:

eval "$(mcfly init bash)"

Zsh:

eval "$(mcfly init zsh)"

Fish:

mcfly init fish | source

3.   Run . ~/.bashrc / . ~/.zshrc / source ~/.config/fish/config.fish or restart your terminal emulator.

Installing manually from GitHub

  1. Download the latest release from GitHub.
  2. Install to a location in your $PATH. (For example, you could create a directory at ~/bin, copy mcfly to this location, and add export PATH="$PATH:$HOME/bin" to your .bashrc / .zshrc, or run set -Ua fish_user_paths "$HOME/bin" for fish.)
  3. Add the following to the end of your ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish file, respectively:

Bash:

eval "$(mcfly init bash)"

Zsh:

eval "$(mcfly init zsh)"

Fish:

mcfly init fish | source

4.  Run . ~/.bashrc / . ~/.zshrc / source ~/.config/fish/config.fish or restart your terminal emulator.

Install manually from source

  1. Install Rust 1.40 or later
  2. Run git clone https://github.com/cantino/mcfly and cd mcfly
  3. Run cargo install --path .
  4. Ensure ~/.cargo/bin is in your $PATH.
  5. Add the following to the end of your ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish file, respectively:

Bash:

eval "$(mcfly init bash)"

Zsh:

eval "$(mcfly init zsh)"

Fish:

mcfly init fish | source

6.   Run . ~/.bashrc / . ~/.zshrc / source ~/.config/fish/config.fish or restart your terminal emulator.

Install by Zinit

  • Add below code to your zshrc.
zinit ice lucid wait"0a" from"gh-r" as"program" atload'eval "$(mcfly init zsh)"' 
zinit light cantino/mcfly 
  • It will download mcfly and install for you.
  • $(mcfly init zsh) will be executed after prompt

iTerm2

To avoid McFly's UI messing up your scrollback history in iTerm2, make sure this option is unchecked:

iterm2 UI instructions

Settings

A number of settings can be set via environment variables. To set a setting you should add the following snippets to your ~/.bashrc / ~/.zshrc / ~/.config/fish/config.fish.

Light Mode

To swap the color scheme for use in a light terminal, set the environment variable MCFLY_LIGHT.

bash / zsh:

export MCFLY_LIGHT=TRUE

fish:

set -gx MCFLY_LIGHT TRUE

Tip: on macOS you can use the following snippet for color scheme to be configured based on system-wide settings:

bash / zsh:

if [[ "$(defaults read -g AppleInterfaceStyle 2&>/dev/null)" != "Dark" ]]; then
    export MCFLY_LIGHT=TRUE
fi

VIM Key Scheme

By default Mcfly uses an emacs inspired key scheme. If you would like to switch to the vim inspired key scheme, set the environment variable MCFLY_KEY_SCHEME.

bash / zsh:

export MCFLY_KEY_SCHEME=vim

fish:

set -gx MCFLY_KEY_SCHEME vim

Fuzzy Searching

To enable fuzzy searching, set MCFLY_FUZZY to an integer. 0 is off; higher numbers weight toward shorter matches. Values in the 2-5 range get good results so far; try a few and report what works best for you!

bash / zsh:

export MCFLY_FUZZY=2

fish:

set -gx MCFLY_FUZZY 2

Results Count

To change the maximum number of results shown, set MCFLY_RESULTS (default: 10).

bash / zsh:

export MCFLY_RESULTS=50

fish:

set -gx MCFLY_RESULTS 50

Interface view

To change interface view, set MCFLY_INTERFACE_VIEW (default: TOP). Available options: TOP and BOTTOM

bash / zsh:

export MCFLY_INTERFACE_VIEW=BOTTOM

fish:

set -gx MCFLY_INTERFACE_VIEW BOTTOM

Disable menu interface

To disable the menu interface, set the environment variable MCFLY_DISABLE_MENU.

bash / zsh:

export MCFLY_DISABLE_MENU=TRUE

fish:

set -gx MCFLY_DISABLE_MENU TRUE

Results sorting

To change the sorting of results shown, set MCFLY_RESULTS_SORT (default: RANK). Possible values RANK and LAST_RUN

bash / zsh:

export MCFLY_RESULTS_SORT=LAST_RUN

fish:

set -gx MCFLY_RESULTS_SORT LAST_RUN

Slow startup

If you have a very large history database and you notice that McFly launches slowly, you can set MCFLY_HISTORY_LIMIT to something like 10000 to limit how many records are considered when searching. In this example, McFly would search only the latest 10,000 entries.

Possible Future Features

  • Add a screencast to README.
  • Learn common command options and autocomplete them in the suggestion UI?
  • Sort command line args when coming up with the template matching string.
  • Possible prioritization improvements:
    • Cross validation & explicit training set selection.
    • Learn command embeddings

Development

Contributing

Contributions and bug fixes are encouraged! However, we may not merge PRs that increase complexity significantly beyond what is already required to maintain the project. If you're in doubt, feel free to open an issue and ask.

Running tests

cargo test

Releasing (notes for @cantino)

  1. Edit Cargo.toml and bump the version.
  2. Edit CHANGELOG.txt
  3. Run cargo clippy and cargo fmt.
  4. Recompile (cargo build).
  5. git add -p
  6. git ci -m 'Bumping to vx.x.x'
  7. git tag vx.x.x
  8. git push origin head --tags
  9. Let the build finish.
  10. Edit the new Release on Github.
  11. Edit pkg/brew/mcfly.rb and update the version and SHAs. (shasum -a 256 ...)
  12. Edit ../homebrew-mcfly/pkg/brew/mcfly.rb too.
  13. cp pkg/brew/mcfly.rb ../homebrew-mcfly/pkg/brew/mcfly.rb
  14. Compare with diff ../homebrew-mcfly/pkg/brew/mcfly.rb ../mcfly/pkg/brew/mcfly.rb ; diff ../homebrew-mcfly/HomebrewFormula/mcfly.rb ../mcfly/HomebrewFormula/mcfly.rb
  15. git add -p && git ci -m 'Update homebrew' && git push
  16. cd ../homebrew-mcfly && git add -p && git ci -m 'Update homebrew' && git push && cd ../mcfly
  17. cargo publish

Download Details:
Author: cantino
Source Code: https://github.com/cantino/mcfly
License: MIT License

#rust 

What is GEEK

Buddha Community

McFly: Fly Through Your Shell History Written in Rust

Serde Rust: Serialization Framework for Rust

Serde

*Serde is a framework for serializing and deserializing Rust data structures efficiently and generically.*

You may be looking for:

Serde in action

Click to show Cargo.toml. Run this code in the playground.

[dependencies]

# The core APIs, including the Serialize and Deserialize traits. Always
# required when using Serde. The "derive" feature is only required when
# using #[derive(Serialize, Deserialize)] to make Serde work with structs
# and enums defined in your crate.
serde = { version = "1.0", features = ["derive"] }

# Each data format lives in its own crate; the sample code below uses JSON
# but you may be using a different one.
serde_json = "1.0"

 

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize, Debug)]
struct Point {
    x: i32,
    y: i32,
}

fn main() {
    let point = Point { x: 1, y: 2 };

    // Convert the Point to a JSON string.
    let serialized = serde_json::to_string(&point).unwrap();

    // Prints serialized = {"x":1,"y":2}
    println!("serialized = {}", serialized);

    // Convert the JSON string back to a Point.
    let deserialized: Point = serde_json::from_str(&serialized).unwrap();

    // Prints deserialized = Point { x: 1, y: 2 }
    println!("deserialized = {:?}", deserialized);
}

Getting help

Serde is one of the most widely used Rust libraries so any place that Rustaceans congregate will be able to help you out. For chat, consider trying the #rust-questions or #rust-beginners channels of the unofficial community Discord (invite: https://discord.gg/rust-lang-community), the #rust-usage or #beginners channels of the official Rust Project Discord (invite: https://discord.gg/rust-lang), or the #general stream in Zulip. For asynchronous, consider the [rust] tag on StackOverflow, the /r/rust subreddit which has a pinned weekly easy questions post, or the Rust Discourse forum. It's acceptable to file a support issue in this repo but they tend not to get as many eyes as any of the above and may get closed without a response after some time.

Download Details:
Author: serde-rs
Source Code: https://github.com/serde-rs/serde
License: View license

#rust  #rustlang 

Awesome  Rust

Awesome Rust

1647699252

McFly: Fly Through Your Shell History Written in Rust

McFly replaces your default ctrl-r shell history search with an intelligent search engine that takes into account your working directory and the context of recently executed commands. McFly's suggestions are prioritized in real time with a small neural network.

TL;DR: an upgraded ctrl-r where history results make sense for what you're working on right now.

Features

  • Rebinds ctrl-r to bring up a full-screen reverse history search prioritized with a small neural network.
  • Augments your shell history to track command exit status, timestamp, and execution directory in a SQLite database.
  • Maintains your normal shell history file as well so that you can stop using McFly whenever you want.
  • Unicode support throughout.
  • Includes a simple action to scrub any history item from the McFly database and your shell history files.
  • Designed to be extensible for other shells in the future.
  • Written in Rust, so it's fast and safe.
  • You can type % to match any number of characters when searching.

Prioritization

The key feature of McFly is smart command prioritization powered by a small neural network that runs in real time. The goal is for the command you want to run to always be one of the top suggestions.

When suggesting a command, McFly takes into consideration:

  • The directory where you ran the command. You're likely to run that command in the same directory in the future.
  • What commands you typed before the command (e.g., the command's execution context).
  • How often you run the command.
  • When you last ran the command.
  • If you've selected the command in McFly before.
  • The command's historical exit status. You probably don't want to run old failed commands.

Installation

Install with Homebrew (on OS X or Linux)

  1. Install the tap:
brew tap cantino/mcfly

2.   Install mcfly:

brew install mcfly

3.   Add the following to the end of your ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish file:

Bash:

eval "$(mcfly init bash)"

Zsh:

eval "$(mcfly init zsh)"

Fish:

mcfly init fish | source

Run . ~/.bashrc / . ~/.zshrc / source ~/.config/fish/config.fish or restart your terminal emulator.

Uninstalling with Homebrew

  1. Remove mcfly:
brew uninstall mcfly

2.   Remove the tap:

brew untap cantino/mcfly

3.   Remove the lines you added to ~/.bashrc / ~/.zshrc / ~/.config/fish/config.fish.

Install with MacPorts (on OS X)

  1. Update the ports tree
sudo port selfupdate

2.   Install mcfly:

sudo port install mcfly

3.  Add the following to the end of your ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish file, as appropriate:

Bash:

eval "$(mcfly init bash)"

Zsh:

eval "$(mcfly init zsh)"

Fish:

mcfly init fish | source

Run . ~/.bashrc / . ~/.zshrc / source ~/.config/fish/config.fish or restart your terminal emulator.

Uninstalling with MacPorts

  1. Remove mcfly:
sudo port uninstall mcfly

2.   Remove the lines you added to ~/.bashrc / ~/.zshrc / ~/.config/fish/config.fish.

Installing using our install script

  1. curl -LSfs https://raw.githubusercontent.com/cantino/mcfly/master/ci/install.sh | sh -s -- --git cantino/mcfly
  2. Add the following to the end of your ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish file, respectively:

Bash:

eval "$(mcfly init bash)"

Zsh:

eval "$(mcfly init zsh)"

Fish:

mcfly init fish | source

3.   Run . ~/.bashrc / . ~/.zshrc / source ~/.config/fish/config.fish or restart your terminal emulator.

Installing manually from GitHub

  1. Download the latest release from GitHub.
  2. Install to a location in your $PATH. (For example, you could create a directory at ~/bin, copy mcfly to this location, and add export PATH="$PATH:$HOME/bin" to your .bashrc / .zshrc, or run set -Ua fish_user_paths "$HOME/bin" for fish.)
  3. Add the following to the end of your ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish file, respectively:

Bash:

eval "$(mcfly init bash)"

Zsh:

eval "$(mcfly init zsh)"

Fish:

mcfly init fish | source

4.  Run . ~/.bashrc / . ~/.zshrc / source ~/.config/fish/config.fish or restart your terminal emulator.

Install manually from source

  1. Install Rust 1.40 or later
  2. Run git clone https://github.com/cantino/mcfly and cd mcfly
  3. Run cargo install --path .
  4. Ensure ~/.cargo/bin is in your $PATH.
  5. Add the following to the end of your ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish file, respectively:

Bash:

eval "$(mcfly init bash)"

Zsh:

eval "$(mcfly init zsh)"

Fish:

mcfly init fish | source

6.   Run . ~/.bashrc / . ~/.zshrc / source ~/.config/fish/config.fish or restart your terminal emulator.

Install by Zinit

  • Add below code to your zshrc.
zinit ice lucid wait"0a" from"gh-r" as"program" atload'eval "$(mcfly init zsh)"' 
zinit light cantino/mcfly 
  • It will download mcfly and install for you.
  • $(mcfly init zsh) will be executed after prompt

iTerm2

To avoid McFly's UI messing up your scrollback history in iTerm2, make sure this option is unchecked:

iterm2 UI instructions

Settings

A number of settings can be set via environment variables. To set a setting you should add the following snippets to your ~/.bashrc / ~/.zshrc / ~/.config/fish/config.fish.

Light Mode

To swap the color scheme for use in a light terminal, set the environment variable MCFLY_LIGHT.

bash / zsh:

export MCFLY_LIGHT=TRUE

fish:

set -gx MCFLY_LIGHT TRUE

Tip: on macOS you can use the following snippet for color scheme to be configured based on system-wide settings:

bash / zsh:

if [[ "$(defaults read -g AppleInterfaceStyle 2&>/dev/null)" != "Dark" ]]; then
    export MCFLY_LIGHT=TRUE
fi

VIM Key Scheme

By default Mcfly uses an emacs inspired key scheme. If you would like to switch to the vim inspired key scheme, set the environment variable MCFLY_KEY_SCHEME.

bash / zsh:

export MCFLY_KEY_SCHEME=vim

fish:

set -gx MCFLY_KEY_SCHEME vim

Fuzzy Searching

To enable fuzzy searching, set MCFLY_FUZZY to an integer. 0 is off; higher numbers weight toward shorter matches. Values in the 2-5 range get good results so far; try a few and report what works best for you!

bash / zsh:

export MCFLY_FUZZY=2

fish:

set -gx MCFLY_FUZZY 2

Results Count

To change the maximum number of results shown, set MCFLY_RESULTS (default: 10).

bash / zsh:

export MCFLY_RESULTS=50

fish:

set -gx MCFLY_RESULTS 50

Interface view

To change interface view, set MCFLY_INTERFACE_VIEW (default: TOP). Available options: TOP and BOTTOM

bash / zsh:

export MCFLY_INTERFACE_VIEW=BOTTOM

fish:

set -gx MCFLY_INTERFACE_VIEW BOTTOM

Disable menu interface

To disable the menu interface, set the environment variable MCFLY_DISABLE_MENU.

bash / zsh:

export MCFLY_DISABLE_MENU=TRUE

fish:

set -gx MCFLY_DISABLE_MENU TRUE

Results sorting

To change the sorting of results shown, set MCFLY_RESULTS_SORT (default: RANK). Possible values RANK and LAST_RUN

bash / zsh:

export MCFLY_RESULTS_SORT=LAST_RUN

fish:

set -gx MCFLY_RESULTS_SORT LAST_RUN

Slow startup

If you have a very large history database and you notice that McFly launches slowly, you can set MCFLY_HISTORY_LIMIT to something like 10000 to limit how many records are considered when searching. In this example, McFly would search only the latest 10,000 entries.

Possible Future Features

  • Add a screencast to README.
  • Learn common command options and autocomplete them in the suggestion UI?
  • Sort command line args when coming up with the template matching string.
  • Possible prioritization improvements:
    • Cross validation & explicit training set selection.
    • Learn command embeddings

Development

Contributing

Contributions and bug fixes are encouraged! However, we may not merge PRs that increase complexity significantly beyond what is already required to maintain the project. If you're in doubt, feel free to open an issue and ask.

Running tests

cargo test

Releasing (notes for @cantino)

  1. Edit Cargo.toml and bump the version.
  2. Edit CHANGELOG.txt
  3. Run cargo clippy and cargo fmt.
  4. Recompile (cargo build).
  5. git add -p
  6. git ci -m 'Bumping to vx.x.x'
  7. git tag vx.x.x
  8. git push origin head --tags
  9. Let the build finish.
  10. Edit the new Release on Github.
  11. Edit pkg/brew/mcfly.rb and update the version and SHAs. (shasum -a 256 ...)
  12. Edit ../homebrew-mcfly/pkg/brew/mcfly.rb too.
  13. cp pkg/brew/mcfly.rb ../homebrew-mcfly/pkg/brew/mcfly.rb
  14. Compare with diff ../homebrew-mcfly/pkg/brew/mcfly.rb ../mcfly/pkg/brew/mcfly.rb ; diff ../homebrew-mcfly/HomebrewFormula/mcfly.rb ../mcfly/HomebrewFormula/mcfly.rb
  15. git add -p && git ci -m 'Update homebrew' && git push
  16. cd ../homebrew-mcfly && git add -p && git ci -m 'Update homebrew' && git push && cd ../mcfly
  17. cargo publish

Download Details:
Author: cantino
Source Code: https://github.com/cantino/mcfly
License: MIT License

#rust 

Awesome  Rust

Awesome Rust

1654894080

Serde JSON: JSON Support for Serde Framework

Serde JSON

Serde is a framework for serializing and deserializing Rust data structures efficiently and generically.

[dependencies]
serde_json = "1.0"

You may be looking for:

JSON is a ubiquitous open-standard format that uses human-readable text to transmit data objects consisting of key-value pairs.

{
    "name": "John Doe",
    "age": 43,
    "address": {
        "street": "10 Downing Street",
        "city": "London"
    },
    "phones": [
        "+44 1234567",
        "+44 2345678"
    ]
}

There are three common ways that you might find yourself needing to work with JSON data in Rust.

  • As text data. An unprocessed string of JSON data that you receive on an HTTP endpoint, read from a file, or prepare to send to a remote server.
  • As an untyped or loosely typed representation. Maybe you want to check that some JSON data is valid before passing it on, but without knowing the structure of what it contains. Or you want to do very basic manipulations like insert a key in a particular spot.
  • As a strongly typed Rust data structure. When you expect all or most of your data to conform to a particular structure and want to get real work done without JSON's loosey-goosey nature tripping you up.

Serde JSON provides efficient, flexible, safe ways of converting data between each of these representations.

Operating on untyped JSON values

Any valid JSON data can be manipulated in the following recursive enum representation. This data structure is serde_json::Value.

enum Value {
    Null,
    Bool(bool),
    Number(Number),
    String(String),
    Array(Vec<Value>),
    Object(Map<String, Value>),
}

A string of JSON data can be parsed into a serde_json::Value by the serde_json::from_str function. There is also from_slice for parsing from a byte slice &[u8] and from_reader for parsing from any io::Read like a File or a TCP stream.

use serde_json::{Result, Value};

fn untyped_example() -> Result<()> {
    // Some JSON input data as a &str. Maybe this comes from the user.
    let data = r#"
        {
            "name": "John Doe",
            "age": 43,
            "phones": [
                "+44 1234567",
                "+44 2345678"
            ]
        }"#;

    // Parse the string of data into serde_json::Value.
    let v: Value = serde_json::from_str(data)?;

    // Access parts of the data by indexing with square brackets.
    println!("Please call {} at the number {}", v["name"], v["phones"][0]);

    Ok(())
}

The result of square bracket indexing like v["name"] is a borrow of the data at that index, so the type is &Value. A JSON map can be indexed with string keys, while a JSON array can be indexed with integer keys. If the type of the data is not right for the type with which it is being indexed, or if a map does not contain the key being indexed, or if the index into a vector is out of bounds, the returned element is Value::Null.

When a Value is printed, it is printed as a JSON string. So in the code above, the output looks like Please call "John Doe" at the number "+44 1234567". The quotation marks appear because v["name"] is a &Value containing a JSON string and its JSON representation is "John Doe". Printing as a plain string without quotation marks involves converting from a JSON string to a Rust string with as_str() or avoiding the use of Value as described in the following section.

The Value representation is sufficient for very basic tasks but can be tedious to work with for anything more significant. Error handling is verbose to implement correctly, for example imagine trying to detect the presence of unrecognized fields in the input data. The compiler is powerless to help you when you make a mistake, for example imagine typoing v["name"] as v["nmae"] in one of the dozens of places it is used in your code.

Parsing JSON as strongly typed data structures

Serde provides a powerful way of mapping JSON data into Rust data structures largely automatically.

use serde::{Deserialize, Serialize};
use serde_json::Result;

#[derive(Serialize, Deserialize)]
struct Person {
    name: String,
    age: u8,
    phones: Vec<String>,
}

fn typed_example() -> Result<()> {
    // Some JSON input data as a &str. Maybe this comes from the user.
    let data = r#"
        {
            "name": "John Doe",
            "age": 43,
            "phones": [
                "+44 1234567",
                "+44 2345678"
            ]
        }"#;

    // Parse the string of data into a Person object. This is exactly the
    // same function as the one that produced serde_json::Value above, but
    // now we are asking it for a Person as output.
    let p: Person = serde_json::from_str(data)?;

    // Do things just like with any other Rust data structure.
    println!("Please call {} at the number {}", p.name, p.phones[0]);

    Ok(())
}

This is the same serde_json::from_str function as before, but this time we assign the return value to a variable of type Person so Serde will automatically interpret the input data as a Person and produce informative error messages if the layout does not conform to what a Person is expected to look like.

Any type that implements Serde's Deserialize trait can be deserialized this way. This includes built-in Rust standard library types like Vec<T> and HashMap<K, V>, as well as any structs or enums annotated with #[derive(Deserialize)].

Once we have p of type Person, our IDE and the Rust compiler can help us use it correctly like they do for any other Rust code. The IDE can autocomplete field names to prevent typos, which was impossible in the serde_json::Value representation. And the Rust compiler can check that when we write p.phones[0], then p.phones is guaranteed to be a Vec<String> so indexing into it makes sense and produces a String.

The necessary setup for using Serde's derive macros is explained on the Using derive page of the Serde site.

Constructing JSON values

Serde JSON provides a json! macro to build serde_json::Value objects with very natural JSON syntax.

use serde_json::json;

fn main() {
    // The type of `john` is `serde_json::Value`
    let john = json!({
        "name": "John Doe",
        "age": 43,
        "phones": [
            "+44 1234567",
            "+44 2345678"
        ]
    });

    println!("first phone number: {}", john["phones"][0]);

    // Convert to a string of JSON and print it out
    println!("{}", john.to_string());
}

The Value::to_string() function converts a serde_json::Value into a String of JSON text.

One neat thing about the json! macro is that variables and expressions can be interpolated directly into the JSON value as you are building it. Serde will check at compile time that the value you are interpolating is able to be represented as JSON.

let full_name = "John Doe";
let age_last_year = 42;

// The type of `john` is `serde_json::Value`
let john = json!({
    "name": full_name,
    "age": age_last_year + 1,
    "phones": [
        format!("+44 {}", random_phone())
    ]
});

This is amazingly convenient, but we have the problem we had before with Value: the IDE and Rust compiler cannot help us if we get it wrong. Serde JSON provides a better way of serializing strongly-typed data structures into JSON text.

Creating JSON by serializing data structures

A data structure can be converted to a JSON string by serde_json::to_string. There is also serde_json::to_vec which serializes to a Vec<u8> and serde_json::to_writer which serializes to any io::Write such as a File or a TCP stream.

use serde::{Deserialize, Serialize};
use serde_json::Result;

#[derive(Serialize, Deserialize)]
struct Address {
    street: String,
    city: String,
}

fn print_an_address() -> Result<()> {
    // Some data structure.
    let address = Address {
        street: "10 Downing Street".to_owned(),
        city: "London".to_owned(),
    };

    // Serialize it to a JSON string.
    let j = serde_json::to_string(&address)?;

    // Print, write to a file, or send to an HTTP server.
    println!("{}", j);

    Ok(())
}

Any type that implements Serde's Serialize trait can be serialized this way. This includes built-in Rust standard library types like Vec<T> and HashMap<K, V>, as well as any structs or enums annotated with #[derive(Serialize)].

Performance

It is fast. You should expect in the ballpark of 500 to 1000 megabytes per second deserialization and 600 to 900 megabytes per second serialization, depending on the characteristics of your data. This is competitive with the fastest C and C++ JSON libraries or even 30% faster for many use cases. Benchmarks live in the serde-rs/json-benchmark repo.

Getting help

Serde is one of the most widely used Rust libraries, so any place that Rustaceans congregate will be able to help you out. For chat, consider trying the #rust-questions or #rust-beginners channels of the unofficial community Discord (invite: https://discord.gg/rust-lang-community), the #rust-usage or #beginners channels of the official Rust Project Discord (invite: https://discord.gg/rust-lang), or the #general stream in Zulip. For asynchronous, consider the [rust] tag on StackOverflow, the /r/rust subreddit which has a pinned weekly easy questions post, or the Rust Discourse forum. It's acceptable to file a support issue in this repo, but they tend not to get as many eyes as any of the above and may get closed without a response after some time.

No-std support

As long as there is a memory allocator, it is possible to use serde_json without the rest of the Rust standard library. This is supported on Rust 1.36+. Disable the default "std" feature and enable the "alloc" feature:

[dependencies]
serde_json = { version = "1.0", default-features = false, features = ["alloc"] }

For JSON support in Serde without a memory allocator, please see the serde-json-core crate.

Link: https://crates.io/crates/serde_json

#rust  #rustlang  #encode   #json 

Nat  Grady

Nat Grady

1658354220

Shell-history: Get The Command History Of The User's Shell

shell-history

Get the command history of the user's shell

Install

$ npm install shell-history

Usage

import {shellHistory, shellHistoryPath} from 'shell-history';

console.log(shellHistory());
//=> ['ava', 'echo unicorn', 'node', 'npm test', …]

console.log(shellHistoryPath());
//=> '/Users/sindresorhus/.history'

API

shellHistory()

Get an array of commands.

On Windows, unless the HISTFILE environment variable is set, this will only return commands from the current session.

shellHistoryPath()

Get the path of the file containing the shell history.

On Windows, this will return either the HISTFILE environment variable or undefined.

parseShellHistory(string)

Parse a shell history string into an array of commands.

Related

Author: Sindresorhus
Source Code: https://github.com/sindresorhus/shell-history 
License: MIT license

#electron #shell #history 

Rust Lang Course For Beginner In 2021: Guessing Game

 What we learn in this chapter:
- Rust number types and their default
- First exposure to #Rust modules and the std::io module to read input from the terminal
- Rust Variable Shadowing
- Rust Loop keyword
- Rust if/else
- First exposure to #Rust match keyword

=== Content:
00:00 - Intro & Setup
02:11 - The Plan
03:04 - Variable Secret
04:03 - Number Types
05:45 - Mutability recap
06:22 - Ask the user
07:45 - First intro to module std::io
08:29 - Rust naming conventions
09:22 - Read user input io:stdin().read_line(&mut guess)
12:46 - Break & Understand
14:20 - Parse string to number
17:10 - Variable Shadowing
18:46 - If / Else - You Win, You Loose
19:28 - Loop
20:38 - Match
23:19 - Random with rand
26:35 - Run it all
27:09 - Conclusion and next episode

#rust