- LSP Explained (in 5 Minutes)
# Notes
# The Five W's of LSP
- Who?
- When?
- What?
- Where?
- Why?
# LSP: Who?
Created by Microsoft, alongside collaboration with Red Hat and Codenvy
# LSP: When?
Open sourced in June of 2016
# LSP: What?
Language Server Protocol
> The Language Server Protocol (LSP) defines the protocol used between an editor and
> a language server that provides language features like auto complete, go to definition etc.
# LSP: Where?
In your editor!!
<!-- stop -->
(Ok... this one is a bit more of a stretch, but here me out)
# LSP: Where?
In your editor!!
- A `Language Server` communicates with a `Client` (your editor)
# LSP: Where?
## Notification
> "Hey, I changed the contents of a file"
```
|
| `textDocument/didChange`
| +--------------+ +--------------+
| | |----->| |
| | Client | | Server |
| | | | |
| +--------------+ +--------------+
|
```
# LSP: Where? (Notification)
```json
{
"method": "textDocument/didChange",
"params": {
"textDocument": {
"uri": "file:///path/to/the/file.js",
"version": 2
},
"contentChanges": [
{
"range": {
"start": { "line": 0, "character": 0 },
"end": { "line": 0, "character": 1 }
},
"rangeLength": 1,
"text": "console.log('Hello, World!');\n"
}
]
}
}
```
# LSP: Where?
## Request
> "Hey, Please tell me where this thing is defined"
```
|
| `textDocument/definition`
| +--------------+ +--------------+
| | |----->| |
| | Client | | Server |
| | |<-----| |
| +--------------+ +--------------+
| `Location`
|
```
# LSP: Where? (Request)
```json
{
"id": 1,
"method": "textDocument/definition",
"params": {
"textDocument": {
"uri": "file:///path/to/the/file.js"
},
"position": { "line": 10, "character": 5 }
}
}
```
# LSP: Where? (Response)
```json
{
"id": 1,
"result": [
{
"uri": "file:///path/to/the/definition/file.js",
"range": {
"start": { "line": 15, "character": 4 },
"end": { "line": 15, "character": 22 }
}
}
]
}
```
# LSP: Where?
## Notification
> "Yo, your code is bad!!"
```
|
| +--------------+ +--------------+
| | | | |
| | Client | | Server |
| | |<-----| |
| +--------------+ +--------------+
| `textDocument/publishDiagnostics`
|
```
# LSP: Where? (Notification)
```json
{
"method": "textDocument/publishDiagnostics",
"params": {
"uri": "file:///path/to/the/file.js",
"diagnostics": [
{ "range": { ... },
"severity": 1,
"code": "1000",
"message": "Missing semicolon."
},
{ "range": { ... },
"severity": 2,
"code": "1001",
"message": "Undefined variable 'abc'."
}
]
}
}
```
# LSP: Why?
It is one method of trying to make a large `M x N` problem into a `M + N` problem.
- `M` editors
- `N` languages
# How's LSP?
People always ask "What's LSP?" but they never ask "How's LSP?".
# How's LSP?
People always ask "What's LSP?" but they never ask "How's LSP?".
It seems to me it's doing quite well these days!
(maybe [[casting.c]] goes here?)