major update to utility functions

README.md

@@ -4,6 +4,7 @@ It's like dotfiles, but no, it's just Lua scripts I find useful.
 ## Scripts
 - `popen-command-test.lua`: A badly-named WIP script for working with LLMs through WSL using [ollama](https://github.com/jmorganca/ollama).
 - `print-arguments.lua`: For testing how a Lua script receives arguments. (It can be platform-specific.)
+- `test.lua`: (Dev Test) Used repeatedly while working on these scripts to verify minor details I'm forgetful about.
 - `utility-functions.lua`: (Library) Required for many of these scripts to run.
 - `video-dl.lua`: A few premade command lines for using `yt-dlp` to download what I want quicker.
 

test.lua

@@ -0,0 +1,18 @@
+#!/usr/bin/env luajit
+
+-- if utility-functions.lua has an error, this won't show it, so for testing purposes, I don't use it here
+-- local error_occurred, utility = pcall(function() return require("utility-functions") end) if not error_occurred then error("This script is installed improperly. Follow instructions at https://github.com/TangentFoxy/.lua-files#installation") end
+utility = require("utility-functions")
+
+print("---")
+
+-- local ls = utility.ls()
+-- ls(function(file_name)
+--   print(file_name)
+-- end)
+
+utility.ls()(function(file_name)
+  print(file_name)
+end)
+
+print("---")

utility-functions.lua

@@ -1,21 +1,40 @@
 math.randomseed(os.time())
 
--- TODO look for popen command and fall back to outputting to file if its unavailable
-function os.command(command)
+local utility = {}
+
+if package.config:sub(1, 1) == "\\" then
+  utility.OS = "Windows"
+else
+  utility.OS = "UNIX-like"
+end
+
+-- TODO look for popen command and fall back to outputting to file if its unavailable (this should always output a warning!)
+function os.capture(command)
   local file = assert(io.popen(command, 'r'))
   local output = assert(file:read('*all'))
   file:close()
   return output
 end
 
+-- always uses outputting to a temporary file to guarantee safety
+function os.capture_safe(command, tmp_file_name)
+  local file_name = tmp_file_name or utility.tmp_file_name()
+  os.execute(command .. " > " .. file_name)
+
+  local file = io.open(file_name, "r")
+  local output = file:read("*all")
+  file:close()
+  os.execute("rm " .. file_name) -- NOTE may not work on all systems, I have a version somewhere that always does
+  return output
+end
+
 -- trim6 from Lua users wiki (best all-round pure Lua performance)
 function string.trim(s)
   return s:match'^()%s*$' and '' or s:match'^%s*(.*%S)'
 end
 
-local utility = {}
-
--- NOTE: This will print errors sometimes. :D
+-- TODO: This needs to use which on a non-Windows platform.
+-- NOTE: This will sometimes print errors that do not matter. Windows, am I right?
 utility.required_program = function(name)
   if os.execute("where " .. tostring(name)) ~= 0 then
     error(tostring(name) .. " must be installed and in the path")
@@ -37,9 +56,33 @@ utility.tmp_file_name = function()
 end
 
 utility.escape_quotes = function(input)
+  -- the order of these commands is important and must be preserved
   input = input:gsub("\\", "\\\\")
   input = input:gsub("\"", "\\\"")
   return input
 end
 
+utility.ls = function(path)
+  local command
+  if utility.OS == "Windows" then
+    command = "dir /w /b"
+  else
+    command = "ls -1"
+  end
+
+  local tmp_file_name = utility.tmp_file_name()
+  local output = os.capture_safe(command, tmp_file_name)
+  -- local output = os.capture_safe(command)
+  -- output = output:trim() -- verifying that even without trailing newlines, the gmatch below will work
+  -- print(output .. "\n---") -- DEBUG
+
+  return function(fn)
+    for line in output:gmatch("[^\r\n]+") do
+      if line ~= tmp_file_name then -- exclude temporary file name
+        fn(line)
+      end
+    end
+  end
+end
+
 return utility