diff --git a/library/lua/gui/widgets.lua b/library/lua/gui/widgets.lua
index 7d81e9888..3aecd43b2 100644
--- a/library/lua/gui/widgets.lua
+++ b/library/lua/gui/widgets.lua
@@ -199,7 +199,7 @@ function parse_label_text(obj)
     for _,v in ipairs(text) do
         local vv
         if type(v) == 'string' then
-            vv = utils.split_string(v, NEWLINE)
+            vv = v:split(NEWLINE)
         else
             vv = { v }
         end
@@ -803,7 +803,7 @@ function FilteredList:setFilter(filter, pos)
     self.edit.text = filter
 
     if filter ~= '' then
-        local tokens = utils.split_string(filter, ' ')
+        local tokens = filter:split()
         local ipos = pos
 
         choices = {}
diff --git a/library/lua/utils.lua b/library/lua/utils.lua
index ba769bc24..99ca87c6e 100644
--- a/library/lua/utils.lua
+++ b/library/lua/utils.lua
@@ -482,16 +482,7 @@ end
 
 -- Split the string by the given delimiter
 function split_string(self, delimiter)
-    local result = { }
-    local from  = 1
-    local delim_from, delim_to = string.find( self, delimiter, from  )
-    while delim_from do
-        table.insert( result, string.sub( self, from , delim_from-1 ) )
-        from  = delim_to + 1
-        delim_from, delim_to = string.find( self, delimiter, from  )
-    end
-    table.insert( result, string.sub( self, from  ) )
-    return result
+    return self:split(delimiter)
 end
 
 -- Ask a yes-no question
@@ -545,9 +536,9 @@ end
 
 -- Normalize directory separator slashes across platforms to '/' and collapse
 -- adjacent slashes into a single slash.
-local platformSlash = package.config:sub(1,1)
+local PLATFORM_SLASH = package.config:sub(1,1)
 function normalizePath(path)
-    return path:gsub(platformSlash, '/'):gsub('/+', '/')
+    return path:gsub(PLATFORM_SLASH, '/'):gsub('/+', '/')
 end
 
 function invert(tab)
@@ -618,7 +609,7 @@ function df_expr_to_ref(expr)
     expr = expr:gsub('%["(.-)"%]', function(field) return '.' .. field end)
         :gsub('%[\'(.-)\'%]', function(field) return '.' .. field end)
         :gsub('%[(%d+)]', function(field) return '.' .. field end)
-    local parts = split_string(expr, '%.')
+    local parts = expr:split('.', true)
     local obj = df_env[parts[1]]
     for i = 2, #parts do
         local key = tonumber(parts[i]) or parts[i]
diff --git a/plugins/lua/blueprint.lua b/plugins/lua/blueprint.lua
index bd0df0a7e..b06b69e9e 100644
--- a/plugins/lua/blueprint.lua
+++ b/plugins/lua/blueprint.lua
@@ -1,5 +1,6 @@
 local _ENV = mkmodule('plugins.blueprint')
 
+local argparse = require('argparse')
 local utils = require('utils')
 
 -- the info here is very basic and minimal, so hopefully we won't need to change
@@ -43,17 +44,11 @@ local valid_phase_list = {
 valid_phases = utils.invert(valid_phase_list)
 
 local function parse_cursor(opts, arg)
-    local _, _, x, y, z = arg:find('^(%d+),(%d+),(%d+)$')
-    if not x then
-        qerror(('invalid argument for --cursor option: "%s"; expected format' ..
-                ' is "<x>,<y>,<z>", for example: "30,60,150"'):format(arg))
-    end
+    local cursor = argparse.coords(arg)
     -- be careful not to replace struct members when called from C++, but also
     -- create the table as needed when called from lua
     if not opts.start then opts.start = {} end
-    opts.start.x = tonumber(x)
-    opts.start.y = tonumber(y)
-    opts.start.z = tonumber(z)
+    utils.assign(opts.start, cursor)
 end
 
 local function parse_positionals(opts, args, start_argidx)
@@ -93,7 +88,7 @@ local function process_args(opts, args)
         return
     end
 
-    return utils.processArgsGetopt(args, {
+    return argparse.processArgsGetopt(args, {
             {'c', 'cursor', hasArg=true,
              handler=function(optarg) parse_cursor(opts, optarg) end},
             {'h', 'help', handler=function() opts.help = true end},
diff --git a/plugins/lua/stockflow.lua b/plugins/lua/stockflow.lua
index ca484d831..91a3284ff 100644
--- a/plugins/lua/stockflow.lua
+++ b/plugins/lua/stockflow.lua
@@ -922,31 +922,6 @@ function matchall(haystack, needles)
     return true
 end
 
-function splitstring(full, pattern)
-    local last = string.len(full)
-    local result = {}
-    local n = 1
-    while n <= last do
-        local start, stop = string.find(full, pattern, n)
-        if not start then
-            result[#result+1] = string.sub(full, n)
-            break
-        elseif start > n then
-            result[#result+1] = string.sub(full, n, start - 1)
-        end
-
-        if stop < n then
-            -- The pattern matches an empty string.
-            -- Avoid an infinite loop.
-            break
-        end
-
-        n = stop + 1
-    end
-
-    return result
-end
-
 function screen:refilter()
     -- Determine which rows to show, and in which colors.
     -- Todo: The official one now has three categories of search results:
@@ -956,7 +931,7 @@ function screen:refilter()
     self.page_size = self.frame_rect.height - ExtraLines
 
     local filtered = {}
-    local needles = splitstring(self.search_string, " ")
+    local needles = self.search_string:split()
     for key, value in ipairs(reaction_list) do
         if matchall(string.upper(value.name), needles) then
             filtered[#filtered+1] = {