feat(repl): ghci repl integration

CHANGELOG.md

@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- GHCi repl integration: Automagically detect the command to start GHCi and load the current buffer.
+- Interact with the GHCi repl from any buffer using lua functions.
 ### Changed
 - Do not close Hoogle Telescope prompt on `<C-b>` (open hackage docs in browser).
 ### Fixed

README.md

@@ -58,11 +58,12 @@ To get started quickly with the default setup, add the following to your neovim
 
 ```lua
 local ht = require('haskell-tools')
+local def_opts = { noremap = true, silent = true, }
 ht.setup {
   hls = {
     -- See nvim-lspconfig's  suggested configuration for keymaps, etc.
     on_attach = function(client, bufnr)    
-      local opts = { noremap = true, silent = true, buffer = bufnr }
+      local opts = vim.tbl_extend('keep', def_opts, { buffer = bufnr, })
       -- haskell-language-server relies heavily on codeLenses,
       -- so auto-refresh (see advanced configuration) is enabled by default
       vim.keymap.set('n', '<space>ca', vim.lsp.codelens.run, opts)
@@ -71,6 +72,14 @@ ht.setup {
     end,
   },
 }
+-- Suggested keymaps that do not depend on haskell-language-server
+-- Toggle a GHCi repl for the current package
+vim.keymap.set('n', '<leader>rr', ht.repl.toggle, def_opts)
+-- Toggle a GHCi repl for the current buffer
+vim.keymap.set('n', '<leader>rf', funciton()
+  ht.repl.toggle(vim.api.nvim_buf_get_name(0))
+end, def_opts)
+vim.keymap.set('n', '<leader>rq', ht.repl.quit, def_opts)
 ```
 
 If using a local `hoogle` installation, [follow these instructions](https://github.com/ndmitchell/hoogle/blob/master/docs/Install.md#generate-a-hoogle-database)
@@ -126,6 +135,17 @@ With the `<C-r>` keymap, the Hoogle search telescope integration can be used to
 
 [![asciicast](https://asciinema.org/a/xEWKbTELrnJD0wNbC5t6jL6Tw.svg)](https://asciinema.org/a/xEWKbTELrnJD0wNbC5t6jL6Tw?t=0:04)
 
+#### GHCi repl
+
+Start a GHCi repl for the current project / buffer.
+
+* Automagically detects the appropriate command (`cabal new-repl`, `stack ghci` or `ghci`) for your project.
+* Choose between a builtin handler or [`toggleterm.nvim`](https://github.com/akinsho/toggleterm.nvim).
+* Dynamically create a repl command for [`iron.nvim`](https://github.com/hkupty/iron.nvim) (see [advanced configuration](#advanced-configuration)).
+* Interact with the repl from any buffer using a lua API.
+
+[![asciicast](https://asciinema.org/a/HtTdq1tqxoRVjt4hEf22tInLV.svg)](https://asciinema.org/a/HtTdq1tqxoRVjt4hEf22tInLV)
+
 ### Planned
 
 For planned features, refer to the [issues](https://github.com/MrcJkb/haskell-tools.nvim/issues?q=is%3Aopen+is%3Aissue+label%3Aenhancement).
@@ -150,6 +170,17 @@ require('haskell-tools').setup {
       -- 'browser': Open hoogle search in the default browser.
       mode = 'auto', 
     },
+    repl = {
+      -- 'builtin': Use the simple builtin repl
+      -- 'toggleterm': Use akinsho/toggleterm.nvim
+      handler = 'builtin',
+      builtin = {
+        create_repl_window = function(view)
+          -- create_repl_split | create_repl_vsplit | create_repl_tabnew | create_repl_cur_win
+          return view.create_repl_split { size = vim.o.lines / 3 }
+        end
+      },
+    },
   },
   hls = { -- LSP client options
     -- ...
@@ -202,6 +233,49 @@ hls = {
 },
 ```
 
+### Set up [`iron.nvim`](https://github.com/hkupty/iron.nvim) to use `haskell-tools.nvim`
+
+Depends on [iron.nvim/#300](https://github.com/hkupty/iron.nvim/pull/300).
+
+```lua
+local iron = require("iron.core")
+iron.setup {
+  config = {
+    repl_definition = {
+      haskell = {
+        command = function(meta)
+          local file = vim.api.nvim_buf_get_name(meta.current_bufnr)
+          -- call `require` in case iron is set up before haskell-tools
+          return require('haskell-tools').repl.mk_repl_cmd(file)
+        end,
+      },
+    },
+  },
+}
+```
+
+### Available functions
+
+```lua
+local ht = require('haskell-tools')
+
+-- Run a hoogle signature for the value under the cursor
+ht.hoogle.hoogle_signature()
+
+-- Toggle a GHCi repl
+ht.repl.toggle()
+-- Toggle a GHCi repl for `file`
+ht.repl.toggle(file)
+-- Quit the repl
+ht.repl.quit()
+-- Paste a command to the repl from register `reg`. (`reg` defaults to '"')
+ht.repl.paste(reg)
+-- Query the repl for the type of register `reg`. (`reg` defaults to '"')
+ht.repl.paste_type(reg)
+-- Query the repl for the type of word under the cursor
+ht.repl.cword_type()
+```
+
 ## Troubleshooting
 
 #### LSP features not working

lua/haskell-tools/config.lua

@@ -35,6 +35,17 @@ local defaults = {
       -- -- TODO: Fall back to a hoogle search if goToDefinition fails
       -- goToDefinitionFallback = false, 
     },
+    repl = {
+      -- 'builtin': Use the simple builtin repl
+      -- 'toggleterm': Use akinsho/toggleterm.nvim
+      handler = 'builtin',
+      builtin = {
+        create_repl_window = function(view)
+          -- create_repl_split | create_repl_vsplit | create_repl_tabnew | create_repl_cur_win
+          return view.create_repl_split { size = vim.o.lines / 3 }
+        end
+      },
+    },
   },
   hls = {
     on_attach = function(...) end,

lua/haskell-tools/deps.lua

@@ -53,4 +53,12 @@ function M.require_lspconfig(modname)
   return M.require_or_err(modname, 'neovim/nvim-lspconfig')
 end
 
+function M.require_toggleterm(modname)
+  return M.require_or_err(modname, 'akinsho/toggleterm')
+end
+
+function M.require_iron(modname)
+  return M.require_or_err(modname, 'hkupty/iron.nvim')
+end
+
 return M

lua/haskell-tools/init.lua

@@ -2,6 +2,7 @@ local M = {
   config = nil,
   lsp = nil,
   hoogle = nil,
+  repl = nil,
 }
 
 function M.setup(opts)
@@ -11,10 +12,13 @@ function M.setup(opts)
   M.lsp = lsp
   local hoogle = require('haskell-tools.hoogle')
   M.hoogle = hoogle
+  local repl = require('haskell-tools.repl')
+  M.repl = repl
 
   config.setup(opts)
   lsp.setup()
   hoogle.setup()
+  repl.setup()
 end
 
 return M

lua/haskell-tools/project-util.lua

@@ -1,6 +1,7 @@
 local deps = require('haskell-tools.deps')
 
--- Utility functions for analysing a project
+-- Utility functions for analysing a project.
+-- This module is not public API.
 local M = {}
 
 local function root_pattern(...)
@@ -31,22 +32,24 @@ function M.get_root_dir(path)
   local lspconfig = deps.require_lspconfig('lspconfig')
   return lspconfig.hls.get_root_dir(path)
 end
-
 -- Is `path` part of a cabal project?
--- @param string?: path to check for
--- @return boolean
+-- @param string: path to check for
+-- @return boolean | nil if `path` is not a writable file
 function M.is_cabal_project(path)
-  path = path or vim.fn.expand('%')
   local get_root = root_pattern('*.cabal', 'cabal.project') 
   return get_root(path) ~= nil
 end
 
 -- Is `path` part of a stack project?
--- @param string?: path to check for
--- @return boolean
+-- @param string: path to check for
+-- @return boolean | nil if `path` is not a writable file
 function M.is_stack_project(path)
-  path = path or vim.fn.expand('%')
   return M.match_stack_project_root(path) ~= nil
 end
 
+function M.get_package_name(path)
+  local package_path = M.match_package_root(path)
+  return package_path and vim.fn.fnamemodify(package_path, ':t')
+end
+
 return M

lua/haskell-tools/repl.lua

@@ -0,0 +1,125 @@
+local ht = require('haskell-tools')
+local project = require('haskell-tools.project-util')
+
+-- Tools for interaction with a ghci repl
+local M = {
+}
+
+-- Extend a repl command for `file`.
+-- If `file` is `nil`, create a repl the nearest package.
+-- @param cmd: table: the command to extend
+-- @param file: string | nil
+-- @param on_no_package: function(table) | nil: handler in case no package is found
+-- @return table | nil
+local function extend_repl_cmd(cmd, file, on_no_package)
+  on_no_package = on_no_package or function(_) return nil end
+  if file == nil then
+    file = vim.api.nvim_buf_get_name(0)
+    local pkg = project.get_package_name(file)
+    if pkg then
+      table.insert(cmd, pkg)
+      return cmd
+    else
+      return on_no_package(cmd)
+    end
+  end
+  local pkg = project.get_package_name(file)
+  if not pkg then return on_no_package(cmd) end
+  if vim.endswith(file, '.hs') then
+    table.insert(cmd, file)
+  else
+    table.insert(cmd, pkg)
+  end
+  return cmd
+end
+
+-- Create a cabal repl command for `file`.
+-- If `file` is `nil`, create a repl the nearest package.
+-- @param string | nil: file
+-- @return table | nil
+local function mk_cabal_repl_cmd(file)
+  return extend_repl_cmd({ 'cabal', 'new-repl', }, file)
+end
+
+-- Create a stack repl command for `file`.
+-- If `file` is `nil`, create a repl the nearest package.
+-- @param string | nil: file
+-- @return table | nil
+local function mk_stack_repl_cmd(file)
+  return extend_repl_cmd({ 'stack', 'ghci', }, file, function(cmd) return cmd end)
+end
+
+-- Create the command to create a repl for a file.
+-- If `file` is `nil`, create a repl the nearest package.
+-- @param string | nil: file
+-- @return table | nil
+function M.mk_repl_cmd(file)
+  local chk_path = file
+  if not chk_path then
+    chk_path = vim.api.nvim_buf_get_name(0)
+    if vim.fn.filewritable(chk_path) == 0 then
+      return nil
+    end
+  end
+  if project.is_cabal_project(chk_path) then
+    return mk_cabal_repl_cmd(file)
+  end
+  if project.is_stack_project(chk_path) then
+    return mk_stack_repl_cmd(file)
+  end
+  if vim.fn.executable('ghci') == 1 then
+    return vim.tbl_flatten { 'ghci', file and { file } or {}}
+  end
+  return nil
+end
+
+-- Create the command to create a repl for the current buffer.
+-- @return table | nil
+function M.buf_mk_repl_cmd()
+  local file = vim.api.nvim_buf_get_name(0)
+  return M.mk_repl_cmd(file)
+end
+
+function M.setup()
+  local opts = ht.config.options.tools.repl
+  local handler = {}
+  if opts.handler == 'toggleterm' then
+    local toggleterm = require('haskell-tools.repl.toggleterm')
+    toggleterm.setup(M.mk_repl_cmd)
+    handler = toggleterm
+  else
+    local builtin = require('haskell-tools.repl.builtin')
+    builtin.setup(M.mk_repl_cmd, opts.builtin)
+    handler = builtin
+  end
+  -- Toggle a GHCi repl
+  -- @param string?: optional file path
+  M.toggle = handler.toggle
+
+  -- Quit the repl
+  M.quit = handler.quit
+
+  -- Paste from register `reg` to the repl
+  -- @param string?: register (defaults to '"')
+  function M.paste(reg)
+    local data = vim.fn.getreg(reg or '"')
+    handler.send_cmd(data)
+  end
+
+  -- Query the repl for the type of register `reg`
+  -- @param string?: register (defaults to '"')
+  function M.paste_type(reg)
+    local data = vim.fn.getreg(reg or '"')
+    handler.send_cmd(':t ' .. data)
+  end
+
+  -- Query the repl for the type of word under the cursor
+  -- @param string?: register (defaults to '"')
+  function M.cword_type()
+    local cword = vim.fn.expand('<cword>')
+    handler.send_cmd(':t ' .. cword)
+  end
+
+end
+
+return M