IDE packages for pulsar

pulsar-ide.md

Pulsar IDE

Pulsar doesn’t have a cohesive IDE experience out of the box, but various packages can collaborate to provide it:

• On the backend, any package that uses atom-languageclient, or any language server configured for use with generic-lsp, can provide any of the services listed below.
• On the frontend, any package that consumes the services listed below can give the user a UI for the given feature.

The services

In general, a backend provides a service and a frontend consumes it. Here are the major services that are provided by atom-languageclient and similar sources, along with the packages in PPM that can consume them:

• intentions:list: Pops up a small menu at a given point in the editor.
  • Consumed by intentions
• symbol.provider: Shows a filterable list of symbols for the current file or for the entire project. Can also support go-to-reference behavior.
  • Consumed by symbols-view-redux (eventually built-in; I've added support for this service to my fork of atom-languageclient)
• autocomplete-provider: Lets providers offer context-specific completions for what the user is typing.
  • Consumed by autocomplete-plus (built-in)
• code-actions: Offers a list of code actions (automatic refactors/reformats) for a given buffer context.
  • Consumed by none (atom-ide-code-actions is not standalone)
  • (The intentions package can fill most of this gap; I’ve added that to my fork of atom-languageclient)
• code-format.range: Allows a provider to reformat an arbitrary section of a buffer
  • Consumed by atom-ide-code-format
• code-highlight: Allows a provider to provide a list of buffer ranges for the UI to bring attention to; used for things like “highlight references to X”
  • Note: very similar to find-references, but the LSP spec says they're purposefully separate because this one “is allowed to be more fuzzy”
  • Consumed by none (atom-ide-code-highlight is not standalone)
• definitions: Provides “go to definition” functionality
  • Consumed by atom-ide-definitions, atom-refs
• find-references: The opposite of definitions; given a symbol, returns all the ranges where that symbol is referenced
  • Consumed by pulsar-find-references, atom-refs
• outline-view: Shows a hierarchical/filterable symbol view in a sidebar for a given buffer
  • Consumed by atom-ide-outline (which somehow caused my editor to crash when I tried it), pulsar-outline-view.

The services listed above are “pull”-style services: the frontend initiates all interaction. Several others are “push”-style services in which the backend triggers all UI updates. These services invert the provider/consumer relationship: the UI package will provide a function that the backend can call with data whenever appropriate.

• linter-indie: Shows diagnostic messages — linting and other code suggestions.
  • Provided by linter (which also exposes more traditional “pull”-style linting services)
• datatip: Shows documentation for a given token when the user hovers over it (or puts the cursor inside of it).
  • Provided by atom-ide-datatip
• signature-help: Shows the signature of a method while the cursor is inside of the method’s arguments.
  • Provided by atom-ide-signature-help

I’ve omitted atom-ide-ui here because (a) it’s not currently working in Pulsar, though nobody has really investigated why; and (b) it’s an opinionated monolith. The two services that have no standalone consumers have implementations inside of atom-ide-ui that we could consult if we wanted to implement our own versions.

The vast majority of atom-ide-ui got broken into smaller atom-ide-* packages by atom-community; users can install those packages piecemeal or just install atom-ide-base to get it all at once.

Other LSP capabilities that Pulsar could support

• Call hierarchy is in the LSP Spec and seems to be implemented in atom-languageclient.
• Rename requests — renaming a symbol across all references in a project — is in the LSP Spec and seems to be implemented in atom-languageclient.
  • I took a first pass at a package that implemented the refactor service described in atom-languageclient, and it manages to implement rename requests perfectly. I might publish this in the package repo if I can write some specs.