Add log path getter, time format

DOC.md

@@ -3452,10 +3452,11 @@ hints towards what is going wrong.
 
 The log is stored in `<vim.fn.stdpath("log")>/luasnip.log`
 (`<vim.fn.stdpath("cache")>/luasnip.log` for Neovim versions where
-`stdpath("log")` does not exist), and can be opened by calling `ls.log.open()`.
+`stdpath("log")` does not exist), and can be opened by calling `ls.log.open()`. You can get the log path through `ls.log.log_location()`.
 The loglevel (granularity of reported events) can be adjusted by calling
 `ls.log.set_loglevel("error"|"warn"|"info"|"debug")`. `"debug"` has the highest
-granularity, `"error"` the lowest, the default is `"warn"`.  
+granularity, `"error"` the lowest, the default is `"warn"`.
+You can also adjust the datetime formatting through the `ls.log.time_fmt` variable. By default, it uses the `'%X'` formatting, which results in the full time (hour, minutes and seconds) being shown.
 
 Once this log grows too large (10MiB, currently not adjustable), it will be
 renamed to `luasnip.log.old`, and a new, empty log created in its place. If

lua/luasnip/util/log.lua

@@ -54,19 +54,24 @@ end
 
 local M = {}
 
+--- The file path we're currently logging into.
+function M.log_location()
+        return logpath
+end
+--- Time formatting for logs. Defaults to '%X'.
+M.time_fmt = '%X'
+
+local function make_log_level(level)
+        return function(msg)
+                log_line_append(string.format("%s | %s | %s", level, os.date(M.time_fmt), msg))
+        end
+end
+
 local log = {
-	error = function(msg)
-		log_line_append("ERROR | " .. msg)
-	end,
-	warn = function(msg)
-		log_line_append("WARN  | " .. msg)
-	end,
-	info = function(msg)
-		log_line_append("INFO  | " .. msg)
-	end,
-	debug = function(msg)
-		log_line_append("DEBUG | " .. msg)
-	end,
+	error = make_log_level('ERROR'),
+	warn = make_log_level('WARN'),
+	info = make_log_level('INFO'),
+	debug = make_log_level('DEBUG'),
 }
 
 -- functions copied directly by deepcopy.