feat(extras): Insert repeat node when duplicated keys occur

DOC.md

@@ -124,6 +124,11 @@ only apply to some nodes (`user_args` for both function and dynamicNode).
 These `opts` are only mentioned if they accept options that are not common to
 all nodes.
 
+## Node-Api:
+
+- `get_jump_index()`: this method returns the jump-index of a node. If a node 
+  doesn't have a jump-index, this method returns `nil` instead.
+
 # SNIPPETS
 
 The most direct way to define snippets is `s`:
@@ -237,7 +242,7 @@ which is passed to the function.
 (in most cases `parent == parent.snippet`, but the `parent` of the dynamicNode
 is not always the surrounding snippet, it could be a `snippetNode`).
 
-## Api:
+## Snippet-Api:
 
 - `invalidate()`: call this method to effectively remove the snippet. The
   snippet will no longer be able to expand via `expand` or `expand_auto`. It
@@ -1204,6 +1209,13 @@ ls.add_snippets("all", {
   }, {
     delimiters = "<>"
   })),
+  s("example4", fmt([[
+  repeat {a} with the same key {a}
+  ]], {
+    a = i(1, "this will be repeat")
+  }, {
+    repeat_duplicates = true
+  }))
 })
 ```
 
@@ -1238,6 +1250,9 @@ any way, correspond to the jump-index of the nodes!
   	when passing multiline strings via `[[]]` (default true).
   * `dedent`: remove indent common to all lines in `format`. Again, makes
   	passing multiline-strings a bit nicer (default true).
+  * `repeat_duplicates`: repeat nodes when a key is reused instead of copying
+        the node if it has a jump-index, refer to [jump-index](#jump-index) to
+        know which nodes have a jump-index (default false).
 
 There is also `require("luasnip.extras.fmt").fmta`. This only differs from `fmt`
 by using angle-brackets (`<>`) as the default-delimiter.

Makefile

@@ -1,4 +1,5 @@
 NVIM_PATH=deps/nvim
+TEST_FILE?=$(realpath tests)
 nvim:
 	git clone --depth 1 https://github.com/neovim/neovim ${NVIM_PATH} || (cd ${NVIM_PATH}; git fetch --depth 1; git checkout origin/master)
 
@@ -33,4 +34,4 @@ test: nvim jsregexp
 	# unset both to prevent env leaking into the neovim-build.
 	# add helper-functions to lpath.
 	# ";;" in CPATH appends default.
-	unset LUA_PATH LUA_CPATH; LUASNIP_SOURCE=$(shell pwd) JSREGEXP_PATH=$(shell pwd)/${JSREGEXP_PATH} TEST_FILE=$(realpath tests) BUSTED_ARGS=--lpath=$(shell pwd)/tests/?.lua make -C ${NVIM_PATH} functionaltest
+	unset LUA_PATH LUA_CPATH; LUASNIP_SOURCE=$(shell pwd) JSREGEXP_PATH=$(shell pwd)/${JSREGEXP_PATH} TEST_FILE=$(realpath ${TEST_FILE}) BUSTED_ARGS=--lpath=$(shell pwd)/tests/?.lua make -C ${NVIM_PATH} functionaltest

doc/luasnip.txt

@@ -7,8 +7,9 @@ Table of Contents                                  *luasnip-table-of-contents*
   - Jump-index                                            |luasnip-jump-index|
   - Adding Snippets                                  |luasnip-adding-snippets|
 2. NODE                                                         |luasnip-node|
+  - Node-Api:                                              |luasnip-node-api:|
 3. SNIPPETS                                                 |luasnip-snippets|
-  - Api:                                                        |luasnip-api:|
+  - Snippet-Api:                                        |luasnip-snippet-api:|
 4. TEXTNODE                                                 |luasnip-textnode|
 5. INSERTNODE                                             |luasnip-insertnode|
 6. FUNCTIONNODE                                         |luasnip-functionnode|
@@ -193,6 +194,13 @@ only apply to some nodes (`user_args` for both function and dynamicNode). These
 `opts` are only mentioned if they accept options that are not common to all
 nodes.
 
+NODE-API:                                                  *luasnip-node-api:*
+
+
+- `get_jump_index()`: this method returns the jump-index of a node. If a node
+    doesn’t have a jump-index, this method returns `nil` instead.
+
+
 ==============================================================================
 3. SNIPPETS                                                 *luasnip-snippets*
 
@@ -304,7 +312,7 @@ where the snippet can be accessed through the immediate parent
 parent.snippet`, but the `parent` of the dynamicNode is not always the
 surrounding snippet, it could be a `snippetNode`).
 
-API:                                                            *luasnip-api:*
+SNIPPET-API:                                            *luasnip-snippet-api:*
 
 
 - `invalidate()`: call this method to effectively remove the snippet. The
@@ -1167,6 +1175,13 @@ Simple example:
       }, {
         delimiters = "<>"
       })),
+      s("example4", fmt([[
+      repeat {a} with the same key {a}
+      ]], {
+        a = i(1, "this will be repeat")
+      }, {
+        repeat_duplicates = true
+      }))
     })
 <
 
@@ -1197,6 +1212,9 @@ any way, correspond to the jump-index of the nodes!
         when passing multiline strings via `[[]]` (default true).
     - `dedent`: remove indent common to all lines in `format`. Again, makes
         passing multiline-strings a bit nicer (default true).
+    - `repeat_duplicates`: repeat nodes when a key is reused instead of copying
+        the node if it has a jump-index, refer to |luasnip-jump-index| to
+        know which nodes have a jump-index (default false).
 
 
 There is also `require("luasnip.extras.fmt").fmta`. This only differs from

lua/luasnip/extras/fmt.lua

@@ -2,6 +2,7 @@ local text_node = require("luasnip.nodes.textNode").T
 local wrap_nodes = require("luasnip.util.util").wrap_nodes
 local extend_decorator = require("luasnip.util.extend_decorator")
 local Str = require("luasnip.util.str")
+local rp = require("luasnip.extras").rep
 
 -- https://gist.github.com/tylerneylon/81333721109155b2d244
 local function copy3(obj, seen)
@@ -39,11 +40,13 @@ end
 --   opts:
 --     delimiters: string, 2 distinct characters (left, right), default "{}"
 --     strict: boolean, set to false to allow for unused `args`, default true
+--     repeat_duplicates: boolean, repeat nodes which have jump_index instead of copying them, default false
 -- Returns: a list of strings and elements of `args` inserted into placeholders
 local function interpolate(fmt, args, opts)
 	local defaults = {
 		delimiters = "{}",
 		strict = true,
+		repeat_duplicates = false,
 	}
 	opts = vim.tbl_extend("force", defaults, opts or {})
 
@@ -97,7 +100,12 @@ local function interpolate(fmt, args, opts)
 		-- The nodes are modified in-place as part of constructing the snippet,
 		-- modifying one node twice will lead to UB.
 		if used_keys[key] then
-			table.insert(elements, copy3(args[key]))
+			local jump_index = args[key]:get_jump_index() -- For nodes that don't have a jump index, copy it instead
+			if not opts.repeat_duplicates or jump_index == nil then
+				table.insert(elements, copy3(args[key]))
+			else
+				table.insert(elements, rp(jump_index))
+			end
 		else
 			table.insert(elements, args[key])
 			used_keys[key] = true
@@ -211,6 +219,7 @@ local function format_nodes(str, nodes, opts)
 		end
 	end, parts)
 end
+
 extend_decorator.register(format_nodes, { arg_indx = 3 })
 
 return {

lua/luasnip/nodes/node.lua

@@ -216,6 +216,7 @@ Node.update_dependents_static = Node._update_dependents_static
 Node.update_all_dependents_static = Node._update_dependents_static
 
 function Node:update() end
+
 function Node:update_static() end
 
 function Node:expand_tabs(tabwidth, indentstr)
@@ -298,6 +299,10 @@ function Node:get_static_args()
 	return get_args(self, "get_static_text")
 end
 
+function Node:get_jump_index()
+	return self.pos
+end
+
 function Node:set_ext_opts(name)
 	-- differentiate, either visited or unvisited needs to be set.
 	if name == "passive" then

tests/integration/fmt_spec.lua

@@ -0,0 +1,58 @@
+local helpers = require("test.functional.helpers")(after_each)
+local exec_lua, feed = helpers.exec_lua, helpers.feed
+local ls_helpers = require("helpers")
+local Screen = require("test.functional.ui.screen")
+
+describe("Fmt", function()
+	local screen
+
+	before_each(function()
+		helpers.clear()
+		ls_helpers.session_setup_luasnip()
+		screen = Screen.new(50, 3)
+		screen:attach()
+		screen:set_default_attr_ids({
+			[0] = { bold = true, foreground = Screen.colors.Blue },
+			[1] = { bold = true, foreground = Screen.colors.Brown },
+			[2] = { bold = true },
+			[3] = { background = Screen.colors.LightGray },
+		})
+	end)
+	after_each(function()
+		screen:detach()
+	end)
+
+	it("Repeat duplicate node with same key", function()
+		exec_lua([=[
+    ls.add_snippets("all", {
+      ls.s(
+        "repeat",
+        require("luasnip.extras.fmt").fmt([[
+        {a} repeat {a}
+        ]],
+        { a = ls.i(1) },
+        { repeat_duplicates = true }
+        )
+      )
+    })
+    ]=])
+		feed("irepeat")
+		exec_lua("ls.expand()")
+		screen:expect({
+			grid = [[
+      ^ repeat                                           |
+      {0:~                                                 }|
+      {2:-- INSERT --}                                      |
+      ]],
+		})
+		feed("asdf")
+		exec_lua("ls.jump()")
+		screen:expect({
+			grid = [[
+      ^asdf repeat asdf                                  |
+      {0:~                                                 }|
+      {2:-- INSERT --}                                      |
+      ]],
+		})
+	end)
+end)