The language server protocol

Your favourite language in you favourite Editor

How does it work

Client Editor

LSP Server

How does it work

Client Editor

LSP Server

object Main{
  def adding(a : Int, b : Int) = a + b
  val additional = ""
  val one = 1
  val two = 2
  addi_
}

How does it work

Client Editor

LSP Server

Completions

object Main{
  def adding(a : Int, b : Int) = a + b
  val additional = ""
  val one = 1
  val two = 2
  addi_
}

How does it work

Client Editor

LSP Server

Completions

object Main{
  def adding(a : Int, b : Int) = a + b
  val additional = ""
  val one = 1
  val two = 2
  addi_
}

How does it work

Client Editor

LSP Server

object Main{
  def adding(a : Int, b : Int) = a + b
  val additional = ""
  val one = 1
  val two = 2
  addi_
}

How does it work

Client Editor

LSP Server

- adding()

- additional

object Main{
  def adding(a : Int, b : Int) = a + b
  val additional = ""
  val one = 1
  val two = 2
  addi_
}

How does it work

Client Editor

LSP Server

- adding()

- additional

object Main{
  def adding(a : Int, b : Int) = a + b
  val additional = ""
  val one = 1
  val two = 2
  addi_
}

How does it work

Client Editor

LSP Server

object Main{
  def adding(a : Int, b : Int) = a + b
  val additional = ""
  val one = 1
  val two = 2
  addi_
}

How does it work

Client Editor

LSP Server

object Main{
  def adding(a : Int, b : Int) = a + b
  val additional = ""
  val one = 1
  val two = 2
  adding(_)
}

The build server protocol

The universe of Build tools

Mill

Seed

The universe of Build tools

Mill

Seed

Metals

Mill

Seed

The universe of Build tools

Bloop

LSP Server

BLOOP AND BSP

Bloop

LSP Server

What is this code a part of!

BLOOP AND BSP

Bloop

LSP Server

Which project?

BLOOP AND BSP

Bloop

LSP Server

BLOOP AND BSP

Which project?

Bloop

LSP Server

BLOOP AND BSP

Bloop

LSP Server

Project Foo

BLOOP AND BSP

Bloop

LSP Server

Project Foo

BLOOP AND BSP

Bloop

LSP Server

I don't know how to compile it!

BLOOP AND BSP

Bloop

LSP Server

Compile Foo!

BLOOP AND BSP

Bloop

LSP Server

Compile Foo!

BLOOP AND BSP

Bloop

LSP Server

BLOOP AND BSP

Bloop

LSP Server

Error report

BLOOP AND BSP

Bloop

LSP Server

Error report

BLOOP AND BSP

Bloop

LSP Server

Diagnostics

BLOOP AND BSP

SemanticDB

$ metap .
Test.scala
----------

Summary:
Schema => SemanticDB v4
Uri => Test.scala
Text => empty
Language => Scala
Symbols => 3 entries
Occurrences => 7 entries

Symbols:
_empty_/Test. => final object Test extends AnyRef { +1 decls }
_empty_/Test.main(). => method main(args: Array[String]): Unit
_empty_/Test.main().(args) => param args: Array[String]

Occurrences:
[0:7..0:11) <= _empty_/Test.
[1:6..1:10) <= _empty_/Test.main().
[1:11..1:15) <= _empty_/Test.main().(args)
[1:17..1:22) => scala/Array#
[1:23..1:29) => scala/Predef.String#
[1:33..1:37) => scala/Unit#
[2:4..2:11) => scala/Predef.println(+1).

Used in:

ReferenceProvider

ImplementationProvider

SyntheticDecorationsProvider

Anything that work file wide

Scalameta parser

- used for syntax based feature

- does not require versions specific feature

- easy to implement new features for all ScalaVersions

- FoldingProvider, DocumentSymbolProvider, some code actions

Scala presentation compiler

Scala Presentation Compiler (mtags)

2.13.4 / 2.12.13 / 2.12.12 / 3.0.0-RC1 ...

Java Interfaces

Metals Server (mtags)

Used for anything that needs to work on newest unsaved version of the code
Can work in non-compiling code
Implements one off features that work for a single point
HoverProvider, SignatureHelpProvider, DefinitionProvider (fallback)