rust-search-extension/README.md

![](assets/rustacean.gif)

# Rust Search Extension

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![](https://img.shields.io/badge/stable-1.31.0-yellow.svg)
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🦀 A handy browser extension to search crates and docs in address bar (omnibox).

### Installation

- Chrome Web Store

https://chrome.google.com/webstore/detail/rust-search-extension/ennpfpdlaclocpomkiablnmbppdnlhoh

- Mannually

Git clone to your computer, open `chrome://extension` page, and enable developer mode, then click `load unpakced` button, select the `extension` directory.

### Features

- Search Primitive Types and Modules
- Search Structs, Traits and Enums
- Search Functions, Methods and Macros
- Search crates on https://crates.io
- Both Chrome and Firefox are supported
- [ ] Search local Rust docs (`rustup docs --std`) 

### Usages

Input keyword **rs** in the address bar, press `Tab` or `Space` to activate the search bar. Then enter any word 
you want to search, the extension will response the related search results instantly.

![demonstration.gif](assets/demonstration.gif)

### How the extension works

#### 1. Build *search index*

The raw *search index* was generated by **rustc-doc**. The most important function is `build_index()` which 
located at [librustdoc/html/render.rs](https://github.com/rust-lang/rust/blob/master/src/librustdoc/html/render.rs).

The final *search index* is an object array like this:

```js
var searchIndex = [
    {
      crate: "std",
      desc: "A hash map implemented with linear probing and Robin Hood bucket stealing.",
      name: "HashMap",
      parent: undefined,
      path: "std::collections",
      ty: 3,
      type: null
    },
    {
      crate: "std",
      desc: "Applies function to the elements of iterator and returns the first non-none result.",
      name: "find_map",
      parent: {ty: 8, name: "Iterator"},
      path: "std::iter",
      ty: 11,
      type: [["self"],["f"]]
    }
    ...
];
```
 
#### 2. Build *search words array* based on *search index*

The *search words array* is the list of search words to query against which build from the raw *search index*.
It's just a plain name array of every Rust structs, traits, enums, functions, methods, macros, etc.
```js
var searchWords = [
    "result", 
    "option", 
    "hashmap", 
    "hashset", 
    "clone", 
    "copy", 
    "display", 
    "debug"
    ...
];
```

#### 3. Search keyword in *search words array*

Using *Levenshtein distance* algorithm to search matched words, the max Levenshtein distance is 2.

```js
// Max levenshtein distance.
var MAX_LEV_DISTANCE = 2;
```

#### 4. Sort *search result* 

Sort search result according to *Levenshtein distance*, lexicographical and others metrics.

#### 5. Transform *search result* to *suggestion result* to show in the address bar

Mapping the *search word* and *search index* to generate the *search result*, build Rust doc link for each result item.

```js
var suggestResults = [
    {
      content: "https://doc.rust-lang.org/std/ops/trait.Deref.html",
      description: "std::ops::<match>Deref</match> - <dim>Used for immutable dereferencing operations, like `*v`.</dim>"
    },
    {
      content: "https://doc.rust-lang.org/std/ops/trait.Deref.html#tymethod.deref",
      description: "std::ops::Deref::<match>deref</match> - <dim>Dereferences the value.</dim>"
    }
    ...
];
```