Eclipse IDE for Scalathe 2.9 story

Iulian Dragos1

Credits2

Miles Sabin

Martin Odersky

Hubert Plociniczak

Eugene Vigdorchik

Mirko Stocker

and many more: Matt Russell, Josh Suereth, Daniel Ratiu, Donna Malayeri..

3David Bernard

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Goals

• work with large projects/files

• Scala compiler (80k LOC), 4-5000 LOC/file

• advanced use of the type system

• path-dependent types, self-types, mix-ins

• reliable (no crashes/lock ups)

• responsive (never wait when typing)

Howto?

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• mixed team with compiler and IDE expertise

• ScalaSolutions/Typesafe involvement started around September 2010

• Martin, Eugene and Iulian

• branch ‘wip_experiment’ in the scala-ide repo

• use the full-blown Scala compiler for:

• interactive error highlight, completion, hyperlinking

• turning Scala symbols into Java model elements

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• Why?

• reuse (type-checker == 1-2 person years)

• consistency

• Why not?

• SPEED

• (no) support for different Scala versions

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Presentation Compiler

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• asynchronous

• interruptible

• targeted

• stop after type-checking

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AskTypeAt

Work Queue

Presentation Compiler Thread

Eclipse Threads

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Work Queue

Presentation Compiler Thread

Eclipse Threads

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AskTypeCompletion

...

Work Queue

Presentation Compiler Thread

Eclipse Threads

AskTypeAt

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AskTypeCompletion

...

Work Queue

Presentation Compiler Thread

Eclipse Threads

AskTypeAt

Result is communicated through a SyncVar

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• All compiler activity happens on PC thread

• Background compile loaded files when work queue is empty

• Check work queue when type checker reaches “safe-points” in the AST

• Drop everything when a file is changed (AskReload)

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Implementation

• 1 type-checker run / instance --> 100s of type-check runs / minute

• memory leaks

• side-effects/state

• out-of-order and targeted type-checking

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• compiler changes needed

• 2.9 compiler has them

• what about 2.8?

• David Bernard ‘backports’

• 2.8.2 preview available now!

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• Reliability, responsiveness over features

• Create a solid foundation for adding features

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Goals, again

Versions

• wip_experiment

• feature freeze, focus on getting the basics right

• wip_exp_backports

• backported many patches

• new features (SoC - highlight implicits)

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Versioning

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2.8 2.9

wip_experiment

wip_exp_backport

2.0.0-beta-28 2.0.0-beta-29

1.0.0-milestones ?

Roadmap20

• MERGE the two code bases

• add features on the solid 2.x base

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• 2.0 final release

• SBT-based builder/SBT console

• REPL improvements

• Find References

• better testing

• sketch a Scala tools API

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• 2.1

• Scala aware debugger

• scalatest/specs integration

• Better refactoring

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