Eta IDE Support

Overview.md

Eta REPL already provides functionality for getting several bits of information about loaded source code, most of which is available after running :set +c.

• :load will do a -O0 compilation of the specified file and directly load the class files into the underlying eta-serv's JVM process's heap.

Documentation: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghci.html#ghci-cmd-:load

Implementation: https://github.com/typelead/eta/blob/master/eta/Eta/REPL/UI.hs#L1721-L1723

• :reload will detect any changes and recompile accordingly and only reload the transitively changed modules.

Documentation: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghci.html#ghci-cmd-:reload

Implementation: https://github.com/typelead/eta/blob/master/eta/Eta/REPL/UI.hs#L1802-L1807

• :loc-at command will, given a source span, provide the original definition site of the identifier in the source span.

Documentation: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghci.html#ghci-cmd-:loc-at

Implementation: https://github.com/typelead/eta/blob/master/eta/Eta/REPL/UI.hs#L2024-L2031

• :all-types will provide source spans mapped to types indicated a particular subexpression has the given type.

Documentation: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghci.html#ghci-cmd-:all-types

Implementation: https://github.com/typelead/eta/blob/master/eta/Eta/REPL/UI.hs#L2034-L2049

• :type-at will provide a type given a source span

Documentation: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghci.html#ghci-cmd-:all-types

Implementation: https://github.com/typelead/eta/blob/master/eta/Eta/REPL/UI.hs#L2003-L2011

• :uses will provide all the uses of given source span in the current module

Documentation: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghci.html#ghci-cmd-:uses

Implementation: https://github.com/typelead/eta/blob/master/eta/Eta/REPL/UI.hs#L2014-L2021

• :info will provide information like the type and the definition (if it exists)

Documentation: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghci.html#ghci-cmd-:info

Implementation: https://github.com/typelead/eta/blob/master/eta/Eta/REPL/UI.hs#L1423-L1431

• :type will provide the type the provided expression

Documentation: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghci.html#ghci-cmd-:type

Implementation: https://github.com/typelead/eta/blob/master/eta/Eta/REPL/UI.hs#L1993-L2000

• :kind! will provide the kind of the reduce type

Documentation: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghci.html#ghci-cmd-:kind

Implementation: https://github.com/typelead/eta/blob/master/eta/Eta/REPL/UI.hs#L2124-L2128

• :browse will list out all the exported functions/types of the given module

Documentation: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghci.html#ghci-cmd-:browse

Server.md

The idea is to create a new server process called eta-ide which will be distributed with every Eta binary distribution and which provides all the facilities for IDE usage.

eta-ide will be a server that implements all the functionality mentioned above, but takes JSON input and returns JSON output.

This most likely means we should have a common library that provides the functionality (eta-ide-core) and have the Eta compiler/REPL + eta-ide depend on it.