feat: grapple.nvim integration (#29)

* feat: grapple integration
* feat(grapple): update command completion
* readme: update for grapple integration
* fix(harpoon): use portal log for errors instead of a raw error

README.md

@@ -185,6 +185,34 @@ require("portal.builtin").changelist.tunnel()
 
 </details>
 
+#### `grapple`
+
+Filter, match, and iterate over tagged files from [harpoon](https://github.com/cbochs/grapple).
+
+**Defaults**
+
+- **`opts.start`**: `1`
+- **`opts.direction`**: `"forward"`
+- **`opts.max_results`**: `#settings.labels`
+
+**Content**
+
+- **`type`**: `"harpoon"`
+- **`buffer`**: the tags's `bufnr`
+- **`cursor`**: the tags's `row` and `col`
+- **`select`**: uses `grapple#select`
+- **`key`**: the tags's key
+
+<details>
+<summary><b>Examples</b></summary>
+
+```lua
+-- Open a default search for grapples's tags
+require("portal.builtin").grapple.tunnel()
+```
+
+</details>
+
 #### `harpoon`
 
 Filter, match, and iterate over marked files from [harpoon](https://github.com/ThePrimeagen/harpoon).
@@ -200,7 +228,7 @@ Filter, match, and iterate over marked files from [harpoon](https://github.com/T
 - **`type`**: `"harpoon"`
 - **`buffer`**: the mark's `bufnr`
 - **`cursor`**: the mark's `row` and `col`
-- **`select`**: uses `harpoon.ui#nav_file` to select
+- **`select`**: uses `harpoon.ui#nav_file`
 - **`index`**: the mark's index
 
 <details>

lua/portal/builtin/grapple.lua

@@ -0,0 +1,75 @@
+---@type Portal.QueryGenerator
+local function generator(opts, settings)
+    local Iterator = require("portal.iterator")
+    local Search = require("portal.search")
+
+    local ok, _ = require("grapple")
+    if not ok then
+        require("portal.log").error("Unable to load 'grapple'. Please ensure that grapple.nvim is installed.")
+    end
+
+    local tags = require("grapple").tags()
+
+    opts = vim.tbl_extend("force", {
+        direction = "forward",
+        max_results = #settings.labels,
+    }, opts or {})
+
+    if settings.max_results then
+        opts.max_results = math.min(opts.max_results, settings.max_results)
+    end
+
+    -- stylua: ignore
+    local iter = Iterator:new(tags)
+        :take(settings.lookback)
+
+    if opts.start then
+        iter = iter:start_at(opts.start)
+    end
+    if opts.direction == Search.direction.backward then
+        iter = iter:reverse()
+    end
+
+    iter = iter:map(function(v, _)
+        local buffer
+        if vim.fn.bufexists(v.file_path) ~= 0 then
+            buffer = vim.fn.bufnr(v.file_path)
+        else
+            buffer = vim.fn.bufadd(v.file_path)
+        end
+
+        if buffer == vim.fn.bufnr() then
+            return nil
+        end
+
+        return {
+            type = "grapple",
+            buffer = buffer,
+            cursor = { row = v.cursor[1], col = v.cursor[2] },
+            select = function(content)
+                require("grapple").select({ key = content.key })
+            end,
+            key = v.key,
+        }
+    end)
+
+    iter = iter:filter(function(v)
+        return vim.api.nvim_buf_is_valid(v.buffer)
+    end)
+    if settings.filter then
+        iter = iter:filter(settings.filter)
+    end
+    if opts.filter then
+        iter = iter:filter(opts.filter)
+    end
+    if not opts.slots then
+        iter = iter:take(opts.max_results)
+    end
+
+    return {
+        source = iter,
+        slots = opts.slots,
+    }
+end
+
+return generator

lua/portal/builtin/harpoon.lua

@@ -5,7 +5,7 @@ local function generator(opts, settings)
 
     local ok, _ = require("harpoon")
     if not ok then
-        error("harpoon is not installed")
+        require("portal.log").error("Unable to load 'harpoon'. Please ensure that harpoon is installed.")
     end
 
     local marks = require("harpoon").get_mark_config().marks

lua/portal/commands.lua

@@ -13,6 +13,7 @@ function Commands.create()
         complete = function(_, cmd_line, _)
             local builtins = {
                 "changelist",
+                "grapple",
                 "harpoon",
                 "jumplist",
                 "quickfix",