spec | ||
BSD-LICENSE.txt | ||
inspect.lua | ||
README.md |
inspect.lua
This function transform any Lua table into a human-readable representation of that table.
The objective here is human understanding (i.e. for debugging), not serialization or compactness.
Examples of use
"Array-like" tables are rendered horizontally:
inspect({1,2,3,4}) == "{ 1, 2, 3, 4 }"
"dictionary-like" tables are rendered with one element per line:
inspect({a=1,b=2}) == [[{
a = 1,
b = 2
}]]
The keys will be sorted alphanumerically when possible.
"Hybrid" tables will have the array part on the first line, and the dictionary part just below them:
inspect({1,2,3,b=2,a=1}) == [[{ 1, 2, 3,
a = 1,
b = 2
}]]
Tables can be nested, and will be indented with two spaces per level.
inspect({a={b=2}}) == [[{
a = {
b = 2
}
}]]
inspect
's second parameter allows controlling the maximum depth that will be printed out. When the max depth is reached, it'll just return {...}
:
local t5 = {a = {b = {c = {d = {e = 5}}}}}
inspect(t5, 4) == [[{
a = {
b = {
c = {
d = {...}
}
}
}
}]]
inspect(t5, 2) == [[{
a = {
b = {...}
}
}]])
Functions, userdata and threads are simply rendered as <function x>
, <userdata x>
and <thread x>
respectively:
inspect({ f = print, ud = some_user_data, thread = a_thread} ) == [[{
f = <function 1>,
u = <userdata 1>,
thread = <thread 1>
}]])
If the table has a metatable, inspect will include it at the end, in a special field called <metatable>
:
inspect(setmetatable({a=1}, {b=2}) == [[{
a = 1
<metatable> = {
b = 2
}
}]])
inspect
can handle tables with loops inside them. It will print <id>
right before the table is printed out the first time, and replace the whole table with <table id>
from then on, preventing infinite loops.
a = {1, 2}
b = {3, 4, a}
a[3] = b -- a references b, and b references a
inspect(a) = "<1>{ 1, 2, { 3, 4, <table 1> } }"
Notice that since both a
appears more than once in the expression, it is prefixed by <1>
and replaced by <table 1>
every time it appears later on.
h1. Gotchas / Warnings
This method is not appropiate for saving/restoring tables. It is ment to be used by the programmer mainly while debugging a program.
h1. Installation
Just copy the inspect.lua file somewhere in your projects (maybe inside a /lib/ folder) and require it accordingly.
Remember to store the value returned by require somewhere! (I suggest a local variable named inspect, altough others might like table.inspect)
local inspect = require 'inspect' -- or -- table.inspect = require 'inspect'
Also, make sure to read the license file; the text of that license file must appear somewhere in your projects' files.
h1. Specs
This project uses "telescope":https://github.com/norman/telescope for its specs. If you want to run the specs, you will have to install telescope first. Then just execute the following from the root inspect folder:
tsc -f spec/*