feat: extend lz.n with custom handlers (#17)

added require('lz.n').register_handler(lz.n.HandlerSpec)

added lz.n.Plugin.extras for extra spec items from custom handlers.

feat: extend lz.n with custom handlers

feat: extend lz.n with custom handlers

added tests

Update spec/register_handler_spec.lua



Update spec/register_handler_spec.lua



feat: extend lz.n with custom handlers

Update README.md



Update lua/lz/n/handler/init.lua

Co-authored-by: Marc Jakobi <mrcjkb89@outlook.com>

README.md

@@ -315,6 +315,42 @@ Or
   ├── init.lua
 ```
 
+### Custom Handlers
+
+You may register your own handlers to lazy-load plugins via
+other triggers not already covered by the plugin spec.
+
+You should register all handlers before calling `require('lz.n').load`,
+because they will not be retroactively applied to
+the `load` calls that occur before they are registered.
+
+The `register_handler` function returns a boolean that indicates success.
+
+`require("lz.n").register_handler(handler: lz.n.Handler): boolean`
+
+#### lz.n.Handler
+
+<!-- markdownlint-disable MD013 -->
+| Property | Type | Description |
+|----------|------|-------------|
+| spec_field | `string` | the `lz.n.PluginSpec` field defined by the handler |
+| add | `fun(plugin: lz.n.Plugin)` | adds a plugin to the handler |
+| del | `fun(plugin: lz.n.Plugin)?` | removes a plugin from the handler |
+<!-- markdownlint-enable MD013 -->
+
+When writing custom handlers,
+you can load the plugin and run the hooks from
+the spec with the following function:
+
+```lua
+  ---@type fun(plugins: string | lz.n.Plugin | string[] | lz.n.Plugin[])
+  require('lz.n').trigger_load
+```
+
+The function accepts plugin names or parsed plugin specs.
+It will call the handler's `del` function (if it exists) after the `before` hooks,
+and before `load` of the plugin's spec.
+
 ## :green_heart: Contributing
 
 All contributions are welcome!

lua/lz/n/handler/cmd.lua

@@ -5,7 +5,7 @@ local loader = require("lz.n.loader")
 ---@type lz.n.CmdHandler
 local M = {
     pending = {},
-    type = "cmd",
+    spec_field = "cmd",
 }
 
 ---@param cmd string

lua/lz/n/handler/colorscheme.lua

@@ -6,8 +6,8 @@ local loader = require("lz.n.loader")
 ---@type lz.n.ColorschemeHandler
 local M = {
     pending = {},
-    type = "colorscheme",
     augroup = nil,
+    spec_field = "colorscheme",
 }
 
 ---@param plugin lz.n.Plugin

lua/lz/n/handler/event.lua

@@ -23,7 +23,7 @@ local M = {
     pending = {},
     events = {},
     group = vim.api.nvim_create_augroup("lz_n_handler_event", { clear = true }),
-    type = "event",
+    spec_field = "event",
     ---@param spec lz.n.EventSpec
     parse = function(spec)
         local ret = lz_n_events[spec]

lua/lz/n/handler/ft.lua

@@ -6,7 +6,7 @@ local event = require("lz.n.handler.event")
 ---@type lz.n.FtHandler
 local M = {
     pending = {},
-    type = "ft",
+    spec_field = "ft",
     ---@param value string
     ---@return lz.n.Event
     parse = function(value)

lua/lz/n/handler/init.lua

@@ -1,20 +1,5 @@
----@class lz.n.Handler
----@field type lz.n.HandlerTypes
----@field pending table<string, table<string, string>> -- key: plugin_name: plugin_name
----@field add fun(plugin: lz.n.Plugin)
----@field del? fun(plugin: lz.n.Plugin)
-
 local M = {}
 
----@enum lz.n.HandlerTypes
-M.types = {
-    cmd = "cmd",
-    event = "event",
-    ft = "ft",
-    keys = "keys",
-    colorscheme = "colorscheme",
-}
-
 local handlers = {
     cmd = require("lz.n.handler.cmd"),
     event = require("lz.n.handler.event"),
@@ -23,6 +8,31 @@ local handlers = {
     colorscheme = require("lz.n.handler.colorscheme"),
 }
 
+---@param spec lz.n.PluginSpec
+---@return boolean
+function M.is_lazy(spec)
+    ---@diagnostic disable-next-line: undefined-field
+    return spec.lazy or vim.iter(handlers):any(function(spec_field, _)
+        return spec[spec_field] ~= nil
+    end)
+end
+
+---@param handler lz.n.Handler
+---@return boolean success
+function M.register_handler(handler)
+    if handlers[handler.spec_field] == nil then
+        handlers[handler.spec_field] = handler
+        return true
+    else
+        vim.notify(
+            "Handler already exists for " .. handler.spec_field .. ". Refusing to register new handler.",
+            vim.log.levels.ERROR,
+            { title = "lz.n" }
+        )
+        return false
+    end
+end
+
 ---@param plugin lz.n.Plugin
 local function enable(plugin)
     for _, handler in pairs(handlers) do
@@ -32,7 +42,7 @@ end
 
 function M.disable(plugin)
     for _, handler in pairs(handlers) do
-        if type(handler.del) == "function" then
+        if handler.del then
             handler.del(plugin)
         end
     end

lua/lz/n/handler/keys.lua

@@ -5,7 +5,7 @@ local loader = require("lz.n.loader")
 ---@type lz.n.KeysHandler
 local M = {
     pending = {},
-    type = "keys",
+    spec_field = "keys",
     ---@param value string|lz.n.KeysSpec
     ---@param mode? string
     ---@return lz.n.Keys

lua/lz/n/init.lua

@@ -14,6 +14,12 @@ local deferred_ui_enter = vim.schedule_wrap(function()
     vim.api.nvim_exec_autocmds("User", { pattern = "DeferredUIEnter", modeline = false })
 end)
 
+---@type fun(handler: lz.n.Handler): boolean
+M.register_handler = require("lz.n.handler").register_handler
+
+---@type fun(plugins: string | lz.n.Plugin | string[] | lz.n.Plugin[])
+M.trigger_load = require("lz.n.loader").load
+
 ---@overload fun(spec: lz.n.Spec)
 ---@overload fun(import: string)
 function M.load(spec)

lua/lz/n/meta.lua

@@ -88,5 +88,10 @@ error("Cannot import a meta module")
 --- Takes the plugin name (not the module name). Defaults to |packadd| if not set.
 --- @field load? fun(name: string)
 
+--- @class lz.n.Handler
+--- @field spec_field string
+--- @field add fun(plugin: lz.n.Plugin)
+--- @field del? fun(plugin: lz.n.Plugin)
+
 --- @type lz.n.Config
 vim.g.lz_n = vim.g.lz_n

lua/lz/n/spec.lua

@@ -144,11 +144,7 @@ local function parse(spec)
             table.insert(result.colorscheme, _colorscheme_spec)
         end
     end
-    result.lazy = result.lazy
-        or result.event ~= nil
-        or result.keys ~= nil
-        or result.cmd ~= nil
-        or result.colorscheme ~= nil
+    result.lazy = require("lz.n.handler").is_lazy(spec)
     return result
 end
 

spec/register_handler_spec.lua

@@ -0,0 +1,47 @@
+---@diagnostic disable: invisible
+vim.g.lz_n = {
+    load = function() end,
+}
+local lz_n = require("lz.n")
+local spy = require("luassert.spy")
+
+describe("handlers.custom", function()
+    ---@class TestHandler: lz.n.Handler
+    ---@type TestHandler
+    local hndl = {
+        spec_field = "testfield",
+        add = function(_) end,
+        del = function(_) end,
+    }
+    local addspy = spy.on(hndl, "add")
+    local delspy = spy.on(hndl, "del")
+    it("Duplicate handlers fail to register", function()
+        local notispy = spy.new(function() end)
+        -- NOTE: teardown fails if you don't temporarily replace vim.notify
+        local og_notify = vim.notify
+        vim.notify = notispy
+        assert.False(lz_n.register_handler(require("lz.n.handler.ft")))
+        assert.spy(notispy).called(1)
+        vim.notify = og_notify
+    end)
+    it("can add plugins to the handler", function()
+        assert.True(lz_n.register_handler(hndl))
+        lz_n.load({
+            "testplugin",
+            testfield = { "a", "b" },
+        })
+        assert.spy(addspy).called_with({
+            name = "testplugin",
+            testfield = { "a", "b" },
+            lazy = true,
+        })
+    end)
+    it("loading a plugin removes it from the handler", function()
+        lz_n.trigger_load("testplugin")
+        assert.spy(delspy).called_with({
+            name = "testplugin",
+            testfield = { "a", "b" },
+            lazy = true,
+        })
+    end)
+end)