Dumper

A small library for dumping lua variables quickly. This library is typically used for quick debugging values to the terminal where one would use print but want more information about the value (like table content), output to stderr by default (or other file handle) and optionally time elapsed.

Installation

luarocks install dumper

Example Usage

Example using:

local dumper = require 'dumper'

local s, i, b, t = 'string', 1, true, {}

-- dumping
dumper.dump(s, i, b, t)
-- outputs: string  1       true    {}

-- inspected dumping
dumper.idump(s, i, b, t)
-- outputs: "string"        1       true    {}

-- timed dumping
dumper.tdump() -- reset time
for _=1,1000 do
  -- (do stuff)
end
dumper.tdump("for loop")
-- outputs: 0.050853 ms     for loop

-- import dump functions to _G and set default output to stdout
require 'dumper'.import(io.stdout)
dump('test')
-- outputs: test

Tipically I setup this in my .bashrc:

export LUA_INIT="require 'dumper'.import()"

This make dumper functions available as global variables when running any lua script in your machine. Then in lua script simply run dump(something) to debug lua values with nicer format.

Documentation

setoutput(output)

Set dumper output file handle. You can pass here a file handle like io.stdout, io.stderr or a temporary file using io.tmpfile(). If value is nil or false dump will not output to any file, instead it will only return a formated string.

dump(...)

Dump any value using tostring function except for tables that does not have __tostring metamethod, in this case inspect library is used, however metatables are filtered from inspect output. Returns the formated string.

idump(...)

Dump any value using inspect library. Returns the formated string.

tdump(...)

Dump any value using dump and printing the time elapsed since last call, all calls resets the timer, calling with no values can be used to just reset the timer. Returns the formated string plus the elapsed time in nanoseconds.

bdump(...)

Dump any value using dump and printing traceback. Returns the formated string plus the traceback.

import(output)

Import dump, idump, bdump, tdump functions to _G. Optionally an optiona argument output specifies the default output when printing. function dumper.import(out)

License

MIT