feat(comment): add support for: interface methods, struct fields, variables (#123)

* refactor(comment): dont use unnecessary function

* chore: quick way to open vim in dev mode

* feat(comment): add comment on on interface method

* feat(comment): add comment on a struct field

* feat(comment): add comment on a variable

* docs: add note about the generate function

* docs: gopher.TsResult

* fix(utils): handle case when indentation is wrong

Taskfile.yml

···
              -u ./scripts/minimal_init.lua \
              -c "lua MiniTest.run()" \
              -c ":qa!"
+  nvim:
+    cmd: nvim --clean -u "./scripts/minimal_init.lua" {{ .CLI_ARGS }}
 
   docgen:
     desc: generate vimhelp

lua/gopher/_utils/init.lua

···
 local utils = {}
 
 ---@param msg string
----@param lvl? number by default `vim.log.levels.INFO`
+---@param lvl? integer by default `vim.log.levels.INFO`
 function utils.notify(msg, lvl)
   lvl = lvl or vim.log.levels.INFO
   vim.notify(msg, lvl, {
···
 function utils.trimend(s)
   local r, _ = string.gsub(s, "%s+$", "")
   return r
+end
+
+-- Since indentation can be spaces or tabs, that's my hack around it
+---@param line string
+---@param indent integer
+---@return string
+function utils.indent(line, indent)
+  local char = string.sub(line, 1, 1)
+  if char ~= " " and char ~= "\t" then
+    char = " "
+  end
+  return string.rep(char, indent)
 end
 
 return utils

lua/gopher/_utils/ts.lua

···
        right: (expression_list (composite_literal
                                  type: (struct_type))))]
   ]],
+  struct_field = [[
+    (field_declaration name: (field_identifier) @_name)
+  ]],
   func = [[
     [(function_declaration name: (identifier)       @_name)
-     (method_declaration   name: (field_identifier) @_name)]
+     (method_declaration   name: (field_identifier) @_name)
+     (method_elem          name: (field_identifier) @_name)]
   ]],
   package = [[
     (package_identifier) @_name
···
       name: (type_identifier) @_name
       type: (interface_type))
   ]],
+  var = [[
+    [(var_declaration (var_spec name: (identifier) @_name))
+     (short_var_declaration
+       left: (expression_list (identifier) @_name @_var))]
+  ]],
 }
 
 ---@param parent_type string[]
 ---@param node TSNode
 ---@return TSNode?
-local function get_parrent_node(parent_type, node)
+local function get_parent_node(parent_type, node)
   ---@type TSNode?
   local current = node
   while current do
···
 end
 
 ---@class gopher.TsResult
----@field name string
----@field start integer
----@field end_ integer
----@field is_varstruct boolean
+---@field name string Name of the struct, function, etc
+---@field start integer Line number where the declaration starts
+---@field end_ integer Line number where the declaration ends
+---@field indent integer Number of spaces/tabs in the current cursor line
+---@field is_varstruct boolean Is struct declared as `var S struct{}` or `s := struct{}{}`
 
 ---@param bufnr integer
 ---@param parent_type string[]
···
     error "No treesitter parser found for go"
   end
 
-  local node = vim.treesitter.get_node {
-    bufnr = bufnr,
-  }
+  local node = vim.treesitter.get_node { bufnr = bufnr }
   if not node then
-    error "No nodes found under cursor"
+    error "No nodes found under the cursor"
   end
 
-  local parent_node = get_parrent_node(parent_type, node)
+  local parent_node = get_parent_node(parent_type, node)
   if not parent_node then
-    error "No parent node found under cursor"
+    error "No parent node found under the cursor"
   end
 
   local q = vim.treesitter.query.parse("go", query)
   local res = get_captures(q, parent_node, bufnr)
   assert(res.name ~= nil, "No capture name found")
 
-  local start_row, _, end_row, _ = parent_node:range()
+  local start_row, start_col, end_row, _ = parent_node:range()
+  res["indent"] = start_col
   res["start"] = start_row + 1
   res["end_"] = end_row + 1
 
···
 ---@param bufnr integer
 function ts.get_struct_under_cursor(bufnr)
   --- should be both type_spec and type_declaration
-  --- because in cases like `type ( T struct{}, U strict{} )`
-  --- i will be choosing always last struct in the list
+  --- because in cases like `type ( T struct{}, U struct{} )`
   ---
   --- var_declaration is for cases like `var x struct{}`
   --- short_var_declaration is for cases like `x := struct{}{}`
+  ---
+  --- it always chooses last struct type in the list
   return do_stuff(bufnr, {
     "type_spec",
     "type_declaration",
···
 end
 
 ---@param bufnr integer
+function ts.get_struct_field_under_cursor(bufnr)
+  return do_stuff(bufnr, { "field_declaration" }, queries.struct_field)
+end
+
+---@param bufnr integer
 function ts.get_func_under_cursor(bufnr)
   --- since this handles both and funcs and methods we should check for both parent nodes
-  return do_stuff(bufnr, { "function_declaration", "method_declaration" }, queries.func)
+  return do_stuff(bufnr, {
+    "method_elem",
+    "function_declaration",
+    "method_declaration",
+  }, queries.func)
 end
 
 ---@param bufnr integer
···
 ---@param bufnr integer
 function ts.get_interface_under_cursor(bufnr)
   return do_stuff(bufnr, { "type_declaration" }, queries.interface)
+end
+
+---@param bufnr integer
+function ts.get_variable_under_cursor(bufnr)
+  return do_stuff(bufnr, { "var_declaration", "short_var_declaration" }, queries.var)
 end
 
 return ts

lua/gopher/comment.lua

···
 
 local ts = require "gopher._utils.ts"
 local log = require "gopher._utils.log"
+local u = require "gopher._utils"
 local comment = {}
 
----@param name string
----@return string
----@dochide
-local function template(name)
-  return "// " .. name .. " "
-end
-
+--- NOTE: The order of functions executed inside this function is IMPORTANT.
+--- This function is extremely fragile; run tests after making any changes.
+---
 ---@param bufnr integer
+---@param line string
 ---@return string
 ---@dochide
-local function generate(bufnr)
+local function generate(bufnr, line)
+  local sf_ok, sf_res = pcall(ts.get_struct_field_under_cursor, bufnr)
+  if sf_ok then
+    return u.indent(line, sf_res.indent) .. "// " .. sf_res.name .. " "
+  end
+
   local s_ok, s_res = pcall(ts.get_struct_under_cursor, bufnr)
   if s_ok then
-    return template(s_res.name)
+    return u.indent(line, s_res.indent) .. "// " .. s_res.name .. " "
+  end
+
+  local v_ok, v_res = pcall(ts.get_variable_under_cursor, bufnr)
+  if v_ok then
+    return u.indent(line, v_res.indent) .. "// " .. v_res.name .. " "
   end
 
   local f_ok, f_res = pcall(ts.get_func_under_cursor, bufnr)
   if f_ok then
-    return template(f_res.name)
+    return u.indent(line, f_res.indent) .. "// " .. f_res.name .. " "
   end
 
   local i_ok, i_res = pcall(ts.get_interface_under_cursor, bufnr)
   if i_ok then
-    return template(i_res.name)
+    return u.indent(line, i_res.indent) .. "// " .. i_res.name .. " "
   end
 
   local p_ok, p_res = pcall(ts.get_package_under_cursor, bufnr)
···
 
 function comment.comment()
   local bufnr = vim.api.nvim_get_current_buf()
-  local cmt = generate(bufnr)
-  log.debug("generated comment: " .. cmt)
+  local lnum = vim.fn.getcurpos()[2]
+  local line = vim.fn.getline(lnum)
+  local cmt = generate(bufnr, line)
+  log.debug("generated comment:", {
+    comment = cmt,
+    line = line,
+  })
 
-  local pos = vim.fn.getcurpos()[2]
-  vim.fn.append(pos - 1, cmt)
-  vim.fn.setpos(".", { 0, pos, #cmt })
+  vim.fn.append(lnum - 1, cmt)
+  vim.fn.setpos(".", { bufnr, lnum, #cmt })
   vim.cmd "startinsert!"
 end
 

spec/fixtures/comment/interface_many_method_input.go

···
+package main
+
+type Testinger interface {
+	Get(id string) int
+	Set(id string, val int)
+}

spec/fixtures/comment/interface_many_method_output.go

···
+package main
+
+type Testinger interface {
+	Get(id string) int
+	// Set 
+	Set(id string, val int)
+}

spec/fixtures/comment/interface_method_input.go

···
+package main
+
+type Testinger interface {
+	Method(input string) error
+}

spec/fixtures/comment/interface_method_output.go

···
+package main
+
+type Testinger interface {
+	// Method 
+	Method(input string) error
+}

spec/fixtures/comment/many_structs_fields_input.go

···
+package main
+
+type (
+	TestOne struct {
+		Asdf string
+		ID   int
+	}
+
+	TestTwo struct {
+		Fesa int
+		A    bool
+	}
+
+	TestThree struct {
+		Asufj int
+		Fs    string
+	}
+)

spec/fixtures/comment/many_structs_fields_output.go

···
+package main
+
+type (
+	TestOne struct {
+		Asdf string
+		ID   int
+	}
+
+	TestTwo struct {
+		// Fesa 
+		Fesa int
+		A    bool
+	}
+
+	TestThree struct {
+		Asufj int
+		Fs    string
+	}
+)

spec/fixtures/comment/struct_fields_input.go

···
+package main
+
+type CommentStruct struct {
+	Name    string
+	Address string
+	Aliases []string
+}

spec/fixtures/comment/struct_fields_output.go

···
+package main
+
+type CommentStruct struct {
+	Name    string
+	// Address 
+	Address string
+	Aliases []string
+}

spec/fixtures/comment/svar_input.go

···
+package main
+
+func varTest() {
+	s := "something"
+}

spec/fixtures/comment/svar_output.go

···
+package main
+
+func varTest() {
+	// s 
+	s := "something"
+}

spec/fixtures/comment/var_input.go

···
+package main
+
+func test() {
+	var imAVar string
+}

spec/fixtures/comment/var_output.go

···
+package main
+
+func test() {
+	// imAVar 
+	var imAVar string
+}

spec/fixtures/comment/var_struct_fields_input.go

···
+package main
+
+func main() {
+	var s struct {
+		API string
+		Key string
+	}
+}

spec/fixtures/comment/var_struct_fields_output.go

···
+package main
+
+func main() {
+	var s struct {
+		API string
+		// Key 
+		Key string
+	}
+}

spec/integration/comment_test.lua

···
   do_the_test("struct", { 4, 1 })
 end
 
+comment["should add a comment on struct field"] = function()
+  do_the_test("struct_fields", { 5, 8 })
+end
+
+comment["should add a comment on var struct field"] = function()
+  do_the_test("var_struct_fields", { 6, 4 })
+end
+
+comment["should add a comment on one field of many structs"] = function()
+  do_the_test("many_structs_fields", { 10, 4 })
+end
+
 comment["should add comment to function"] = function()
   do_the_test("func", { 3, 1 })
 end
···
 
 comment["should add comment to interface"] = function()
   do_the_test("interface", { 3, 6 })
+end
+
+comment["should add comment on interface method"] = function()
+  do_the_test("interface_method", { 4, 2 })
+end
+
+comment["should add a comment on interface with many method"] = function()
+  do_the_test("interface_many_method", { 5, 2 })
+end
+
+comment["should add a comment on a var"] = function()
+  do_the_test("var", { 4, 2 })
+end
+
+comment["should add a comment on a short declared var"] = function()
+  do_the_test("svar", { 4, 8 })
 end
 
 comment["otherwise should add // above cursor"] = function()

spec/unit/utils_test.lua

···
   t.eq(u.trimend "  hi   ", "  hi")
 end
 
+utils["should add .indent() spaces"] = function()
+  local u = require "gopher._utils"
+  local line = "    func Test() error {"
+  local indent = 4
+
+  t.eq("    ", u.indent(line, indent))
+end
+
+utils["should add .indent() a tab"] = function()
+  local u = require "gopher._utils"
+  local line = "\tfunc Test() error {"
+  local indent = 1
+
+  t.eq("\t", u.indent(line, indent))
+end
+
+utils["should add .indent() 2 tabs"] = function()
+  local u = require "gopher._utils"
+  local line = "\t\tfunc Test() error {"
+  local indent = 2
+
+  t.eq("\t\t", u.indent(line, indent))
+end
+
 return T