Snippet support (#72)

To know more about snippet integration, please visit `:h snippet-integration`, or https://github.com/danymat/neogen#snippet-support !

Co-authored-by: danymat <d.danymat@gmail.com>

lua/neogen/generator.lua

@@ -13,6 +13,7 @@ local granulator = require("neogen.granulator")
 local mark = require("neogen.mark")
 local nodes = require("neogen.utilities.nodes")
 local default_locator = require("neogen.locators.default")
+local snippet = require("neogen.snippet")
 local JUMP_TEXT = "$1"
 
 local function get_parent_node(filetype, typ, language)
@@ -33,7 +34,7 @@ end
 ---@param n integer
 ---@return string
 local function prefix_generator(template, commentstring, n)
-    local prefix = (" "):rep(n)
+    local prefix = (vim.bo.expandtab and " " or "\t"):rep(n)
 
     -- Do not append the comment string if not wanted
     if template.use_default_comment ~= false then
@@ -155,7 +156,7 @@ local function generate_content(parent, data, template, required_type)
 end
 
 return setmetatable({}, {
-    __call = function(_, filetype, typ)
+    __call = function(_, filetype, typ, return_snippet)
         if filetype == "" then
             notify("No filetype detected", vim.log.levels.WARN)
             return
@@ -210,19 +211,42 @@ return setmetatable({}, {
             end
         end
 
-        -- Append content to row
-        vim.api.nvim_buf_set_lines(0, row, row, true, content)
+        if return_snippet then
+            -- User just wants the snippet, so we give him the snippet plus placement informations
+            local generated_snippet = snippet.to_snippet(content, marks_pos, { row, 0 })
+            return generated_snippet, row
+        end
 
-        if #marks_pos > 0 then
-            -- Start session of marks
-            mark:start()
-            for _, pos in ipairs(marks_pos) do
-                mark:add_mark(pos)
+        local snippet_engine = conf.snippet_engine
+        if snippet_engine then
+            -- User want to use a snippet engine instead of native handling
+            local engines = snippet.engines
+            if not vim.tbl_contains(vim.tbl_keys(engines), snippet_engine) then
+                notify(string.format("Snippet engine '%s' not supported", snippet_engine), vim.log.levels.ERROR)
+                return
+            end
+
+            -- Converts the content to a lsp compatible snippet
+            local generated_snippet = snippet.to_snippet(content, marks_pos, { row, 0 })
+            -- Calls the snippet expand function for required snippet engine
+            engines[snippet_engine](generated_snippet, { row, 0 })
+            return
+        else
+            -- We use default marks for jumping between annotations
+            -- Append content to row
+            vim.api.nvim_buf_set_lines(0, row, row, true, content)
+
+            if #marks_pos > 0 then
+                -- Start session of marks
+                mark:start()
+                for _, pos in ipairs(marks_pos) do
+                    mark:add_mark(pos)
+                end
+                vim.cmd("startinsert")
+                mark:jump()
+                -- Add range mark after first jump
+                mark:add_range_mark({ row, 0, row + #template_content, 1 })
             end
-            vim.cmd("startinsert")
-            mark:jump()
-            -- Add range mark after first jump
-            mark:add_range_mark({ row, 0, row + #template_content, 1 })
         end
     end,
 })

lua/neogen/init.lua

@@ -91,12 +91,15 @@ end
 ---
 --- - to configure a language, just add your configurations in the `languages` table.
 ---   For example, for the `lua` lang:
----   >
+--- >
 ---    languages = {
 ---      lua = { -- Configuration here }
 ---    }
----   <
----   Default configurations for a languages can be found in `lua/neogen/configurations/<you_language>.lua`
+--- <
+---   Default configurations for a languages can be found in `lua/neogen/configurations/<your_language>.lua`
+---
+---  - To know which snippet engines are supported, take a look at |snippet-integration|.
+---    Example: `snippet_engine = "luasnip"`
 ---
 ---@toc_entry Configure the setup
 ---@tag neogen-configuration
@@ -109,6 +112,9 @@ neogen.configuration = {
 
     -- Configuration for default languages
     languages = {},
+
+    -- Use a snippet engine to generate annotations.
+    snippet_engine = nil,
 }
 --minidoc_afterlines_end
 
@@ -120,9 +126,15 @@ neogen.configuration = {
 --- For example, if you are inside a function, and called `generate({ type = "func" })`,
 --- Neogen will go until the start of the function and start annotating for you.
 ---
----@param opts table Options to change default behaviour of generation.
----  - {opts.type} `(string?, default: "func")` Which type we are trying to use for generating annotations.
+---@param opts table Optional configs to change default behaviour of generation.
+---  - {opts.type} `(string, default: "func")` Which type we are trying to use for generating annotations.
 ---    Currently supported: `func`, `class`, `type`, `file`
+---  - {opts.return_snippet} `boolean` if true, will return 3 values from the function call.
+---  This option is useful if you want to get the snippet to use with a unsupported snippet engine
+---  Below are the returned values:
+---  - 1: (type: `string[]`) the resulting lsp snippet
+---  - 2: (type: `number`) the `row` to insert the annotations
+---  - 3: (type: `number`) the `col` to insert the annotations
 ---@toc_entry Generate annotations
 neogen.generate = function(opts)
     if not conf or not conf.enabled then
@@ -130,7 +142,7 @@ neogen.generate = function(opts)
         return
     end
 
-    require("neogen.generator")(vim.bo.filetype, opts and opts.type)
+    return require("neogen.generator")(vim.bo.filetype, opts and opts.type, opts and opts.return_snippet)
 end
 
 -- Expose more API  ============================================================
@@ -204,6 +216,10 @@ end
 ---
 --- Note: We will only document `major` and `minor` versions, not `patch` ones.
 ---
+--- ## 2.3.0~
+---   - Added bundled support with snippet engines !
+---     Check out |snippet-integration| for basic setup
+---     For more information of possible options, check out |neogen.generate()|
 --- ## 2.2.0~
 ---   ### Python~
 ---     - Add support for `*args` and `**kwargs`

lua/neogen/snippet.lua

@@ -0,0 +1,53 @@
+local notify = require("neogen.utilities.helpers").notify
+
+---
+--- To use a snippet engine, pass the option into neogen setup:
+--- >
+---  require('neogen').setup({
+---    snippet_engine = "luasnip",
+---    ...
+---  })
+--- <
+--- Some snippet engines come out of the box bundled with neogen:
+--- - `"luasnip"` (https://github.com/L3MON4D3/LuaSnip)
+---@tag snippet-integration
+---@toc_entry Use popular snippet engines
+local snippet = {}
+snippet.engines = {}
+
+--- Converts a template to a lsp-compatible snippet
+---@param template string[] the generated annotations to parse
+---@param marks table generated marks for the annotations
+---@param pos table a tuple of row,col
+---@return table resulting snippet lines
+---@private
+snippet.to_snippet = function(template, marks, pos)
+    local offset = {}
+    for i, m in ipairs(marks) do
+        local r, col = m[1] - pos[1] + 1, m[2]
+        if offset[r] then
+            offset[r] = offset[r] + tostring(i - 1):len() + 1
+        else
+            offset[r] = 0
+        end
+        local pre = template[r]:sub(1, col + offset[r])
+        template[r] = pre .. "$" .. i .. template[r]:sub(col + 1 + offset[r])
+    end
+    return template
+end
+
+--- Expand snippet for luasnip engine
+---@param snip string the snippet to expand
+---@param pos table a tuple of row, col
+---@private
+snippet.engines.luasnip = function(snip, pos)
+    local ok, luasnip = pcall(require, "luasnip")
+    if not ok then
+        notify("Luasnip not found, aborting...", vim.log.levels.ERROR)
+        return
+    end
+    vim.fn.append(pos[1], "")
+    luasnip.lsp_expand(table.concat(snip, "\n"), { pos = { pos[1], pos[2] } })
+end
+
+return snippet