add snippetType as option on snippet creation

snippetType shall be "autosnippet" or "snippet" (or nil -> unset -> take
default value from add_snippets). Note: snippetType is used for indexing
(it already is a string, which should be interned by lua)

First draft can be seen at
[this issue](#482 (comment)),
adapted because `selfpopulating tables` were merged in the meantime and
the option was renamed.

For a dicussion on naming the new option key see
[the comments here](#513 (comment))

Author: atticus-sullivan

DOC.md

@@ -117,6 +117,12 @@ entries:
   Snippets with high priority will be matched to a trigger before those with a
   lower one.
   The priority for multiple snippets can also be set in `add_snippets`.
+- `snippetType`: string, should be either `snippet` or `autosnippet` (ATTENTION:
+  singular form is used), decides whether this snippet has to be triggered by
+  `ls.expand()` or whether is triggered automatically (don't forget to set
+  `ls.config.setup({ enable_autosnippets = true })` if you want to use this
+  feature). If unset it depends on how the snippet is added of which type the
+  snippet will be.
 
 `s` can also be a single string, in which case it is used instead of `trig`, all
 other values being defaulted:
@@ -2228,7 +2234,10 @@ the lazy_load.
   If `ft` is `nil`, `snippets` should be a table containing lists of snippets,
   the keys are corresponding filetypes.  
   `opts` may contain the following keys:
-  - `type`: type of `snippets`, `"snippets"` or `"autosnippets"`.
+  - `type`: type of `snippets`, `"snippets"` or `"autosnippets"` (ATTENTION:
+	plural form used here). This serves as default value for the `snippetType`
+	key of each snippet added by this call see [SNIPPETS](#SNIPPETS).
+
   - `key`: Key that identifies snippets added via this call.  
 	If `add_snippets` is called with a key that was already used, the snippets
 	from that previous call will be removed.  

doc/luasnip.txt

@@ -1,4 +1,4 @@
-*luasnip.txt*          For NVIM v0.5.0          Last change: 2022 September 08
+*luasnip.txt*          For NVIM v0.5.0          Last change: 2022 September 13
 
 ==============================================================================
 Table of Contents                                  *luasnip-table-of-contents*
@@ -168,6 +168,12 @@ entries:
     Snippets with high priority will be matched to a trigger before those with a
     lower one.
     The priority for multiple snippets can also be set in `add_snippets`.
+- `snippetType`: string, should be either `snippet` or `autosnippet` (ATTENTION:
+    singular form is used), decides whether this snippet has to be triggered by
+    `ls.expand()` or whether is triggered automatically (don’t forget to set
+    `ls.config.setup({ enable_autosnippets = true })` if you want to use this
+    feature). If unset it depends on how the snippet is added of which type the
+    snippet will be.
 
 
 `s` can also be a single string, in which case it is used instead of `trig`,
@@ -2215,13 +2221,14 @@ empty the snippets table and the caches of the lazy_load.
     Makes `snippets` (list of snippets) available in `ft`. If `ft` is `nil`,
     `snippets` should be a table containing lists of snippets, the keys are
     corresponding filetypes. `opts` may contain the following keys:
-    - `type`: type of `snippets`, `"snippets"` or `"autosnippets"`.
-    - `key`: Key that identifies snippets added via this call.
-        If `add_snippets` is called with a key that was already used, the snippets
-        from that previous call will be removed.
-        This can be used to reload snippets: pass an unique key to each
-        `add_snippets` and just re-do the `add_snippets`-call when the snippets have
-        changed.
+    - `type`: type of `snippets`, `"snippets"` or `"autosnippets"` (ATTENTION: plural
+        form used here). This serves as default value for the `snippetType` key of each
+        snippet added by this call see |luasnip-snippets|.
+    - `key`: Key that identifies snippets added via this call. If `add_snippets` is
+        called with a key that was already used, the snippets from that previous call
+        will be removed. This can be used to reload snippets: pass an unique key to
+        each `add_snippets` and just re-do the `add_snippets`-call when the snippets
+        have changed.
     - `override_priority`: set priority for all snippets.
     - `default_priority`: set priority only for snippets without snippet-priority.
 - `clean_invalidated(opts: table or nil) -> bool`: clean invalidated snippets

lua/luasnip/nodes/snippet.lua

@@ -186,6 +186,20 @@ local function init_snippet_context(context)
 	-- might be nil, but whitelisted in snippetProxy.
 	context.priority = context.priority
 
+	-- might be nil, but whitelisted in snippetProxy.
+	-- shall be a string, allowed values: "snippet", "autosnippet"
+	assert(
+		not context.snippetType
+			or context.snippetType == "snippet"
+			or context.snippetType == "autosnippet",
+		"snippetType has to be either 'snippet' or 'autosnippet' (or unset)"
+	)
+	-- switch to plural forms so that we can use this for indexing
+	context.snippetType = context.snippetType == "autosnippet"
+			and "autosnippets"
+		or context.snippetType == "snippet" and "snippets"
+		or nil
+
 	-- maybe do this in a better way when we have more parameters, but this is
 	-- fine for now.
 

lua/luasnip/nodes/snippetProxy.lua

@@ -47,7 +47,7 @@ end
 
 -- some values of the snippet are nil by default, list them here so snippets
 -- aren't instantiated because of them.
-local license_to_nil = { priority = true }
+local license_to_nil = { priority = true, snippetType = true }
 
 -- context and opts are (almost) the same objects as in s(contex, nodes, opts), snippet is a string representing the snippet.
 -- opts can aditionally contain the key `parse_fn`, which will be used to parse

lua/luasnip/session/snippet_collection.lua

@@ -253,12 +253,21 @@ function M.add_snippets(snippets, opts)
 				or opts.default_priority
 				or 1000
 
+			-- if snippetType undefined by snippet, take default value from opts
+			snip.snippetType = snip.snippetType ~= nil and snip.snippetType
+				or opts.type
+			assert(
+				snip.snippetType == "autosnippets"
+					or snip.snippetType == "snippets",
+				"snipptType must be either 'autosnippets' or 'snippets'"
+			)
+
 			snip.id = current_id
 			current_id = current_id + 1
 
 			-- do the insertion
-			table.insert(by_prio[opts.type][snip.priority][ft], snip)
-			table.insert(by_ft[opts.type][ft], snip)
+			table.insert(by_prio[snip.snippetType][snip.priority][ft], snip)
+			table.insert(by_ft[snip.snippetType][ft], snip)
 			by_id[snip.id] = snip
 		end
 	end

tests/integration/add_snippets_spec.lua

@@ -193,4 +193,120 @@ describe("add_snippets", function()
 			{2:-- INSERT --}                                      |]],
 		})
 	end)
+
+	it("add autosnippets by option", function()
+		exec_lua("ls.config.setup({ enable_autosnippets = true })")
+		exec_lua([[
+			ls.add_snippets("all", {
+				ls.snippet({trig="triA", snippetType="autosnippet"}, {ls.text_node("helloAworld")}, {})
+			}, {
+				key = "a",
+			} )
+		]])
+		exec_lua([[
+			ls.add_snippets("all", {
+				ls.snippet({trig="triB", snippetType="snippet"}, {ls.text_node("helloBworld")}, {})
+			}, {
+				key = "b",
+			} )
+		]])
+		exec_lua([[
+			ls.add_snippets("all", {
+				ls.snippet({trig="triC", snippetType=nil}, {ls.text_node("helloCworld")}, {})
+			}, {
+				key = "c",
+				type="snippets"
+			} )
+		]])
+		exec_lua([[
+			ls.add_snippets("all", {
+				ls.snippet({trig="triD", snippetType=nil}, {ls.text_node("helloDworld")}, {})
+			}, {
+				key = "d",
+				type="autosnippets"
+			} )
+		]])
+		exec_lua([[
+			ls.add_snippets("all", {
+				ls.snippet({trig="triE", snippetType="snippet"}, {ls.text_node("helloEworld")}, {})
+			}, {
+				key = "e",
+				type="autosnippets"
+			} )
+		]])
+
+		-- check if snippet "a" is automatically triggered
+		feed("<ESC>cc") -- rewrite line
+		feed("triA")
+		screen:expect({
+			grid = [[
+			helloAworld^                                       |
+			{0:~                                                 }|
+			{2:-- INSERT --}                                      |]],
+		})
+
+		feed("<ESC>cc") -- rewrite line
+		feed("triB")
+		-- check if snippet "b" is NOT automatically triggered
+		screen:expect({
+			grid = [[
+			triB^                                              |
+			{0:~                                                 }|
+			{2:-- INSERT --}                                      |]],
+		})
+		-- check if snippet "b" is working
+		exec_lua("ls.expand()")
+		screen:expect({
+			grid = [[
+			helloBworld^                                       |
+			{0:~                                                 }|
+			{2:-- INSERT --}                                      |]],
+		})
+
+		feed("<ESC>cc") -- rewrite line
+		feed("triC")
+		-- check if snippet "c" is NOT automatically triggered
+		screen:expect({
+			grid = [[
+			triC^                                              |
+			{0:~                                                 }|
+			{2:-- INSERT --}                                      |]],
+		})
+		-- check if snippet "c" is working
+		exec_lua("ls.expand()")
+		screen:expect({
+			grid = [[
+			helloCworld^                                       |
+			{0:~                                                 }|
+			{2:-- INSERT --}                                      |]],
+		})
+
+		feed("<ESC>cc") -- rewrite line
+		feed("triD")
+		-- check if snippet "d" is automatically triggered
+		screen:expect({
+			grid = [[
+			helloDworld^                                       |
+			{0:~                                                 }|
+			{2:-- INSERT --}                                      |]],
+		})
+
+		feed("<ESC>cc") -- rewrite line
+		feed("triE")
+		-- check if snippet "e" is NOT automatically triggered
+		screen:expect({
+			grid = [[
+			triE^                                              |
+			{0:~                                                 }|
+			{2:-- INSERT --}                                      |]],
+		})
+		-- check if snippet "c" is working
+		exec_lua("ls.expand()")
+		screen:expect({
+			grid = [[
+			helloEworld^                                       |
+			{0:~                                                 }|
+			{2:-- INSERT --}                                      |]],
+		})
+	end)
 end)