globals

[tehn]

see #425

• reset globals created by scripts between loads - fixed by [experiment] script state metatable #436
• clean up system globals clean up system globals #559
• consider adding underscores to system globals
• consider putting c functions into a table - see stop the globalocalypse #425 (comment)
• disable overwriting system globals - see [experiment] script state metatable #436 (comment) @pq
• protect some specific tables (ie engine) protect system tables from (accidental) overwrite #912 @pq

[pq]

disable overwriting system globals - see #436 (comment) @pq

on a little more investigation, i don't think disabling overwrites is possible without going more in the "sandbox scripts" direction (as explored in #426). alternatively, if the goal is more to limit the impact of overwriting globals, we could take an easier tack and piggy-back on what we're already doing in Script.clear and choose to additionally restore chosen globals to a good initial state.

for example,

norns/lua/script.lua

Lines 27 to 29 in dada0b7

	-- reset midi callbacks
	midi.add = norns.none
	midi.remove = norns.none

resets midi callbacks. taking a similar approach we could restore tables like metro, midi, etc.

@tehn: do we have a sense for what globals we want to protect and what we want to preserve across scripts?

list of globals...

globals = { }
for k,v in pairs(_G) do table.insert(globals, k..' : '..tostring(v)) end
for _,v in ipairs(globals) do print(v) end

_G : table: 0x538b8
_VERSION : Lua 5.3
_reset_lvm : function: 0x1be28
assert : function: 0x76c2e7bc
audio_dir : /home/we/dust/audio/
audio_input_level : function: 0x1b1b4
audio_monitor_level : function: 0x1b114
audio_monitor_mono : function: 0x1a5b4
audio_monitor_off : function: 0x1a584
audio_monitor_on : function: 0x1a594
audio_monitor_stereo : function: 0x1a5a4
audio_output_level : function: 0x1b164
audio_pitch_off : function: 0x1a564
audio_pitch_on : function: 0x1a574
bit32 : table: 0x54898
clamped_value : 0.052140721099196
cleanup : function: 0x759a8
collectgarbage : function: 0x76c2e250
controlspec : table: 0x63a80
coroutine : table: 0x54418
data_dir : /home/we/dust/data/
debug : table: 0x55b98
dofile : function: 0x76c2e734
enc : function: 0x759a8
engine : table: 0x5fdc0
error : function: 0x76c2e1d0
fileselect : table: 0xef690
gain_hp : function: 0x1b5f8
gain_in : function: 0x1b590
get_time : function: 0x1a5c4
getmetatable : function: 0x76c2e6e4
globals : table: 0x97708
grid : table: 0xaf500
grid_all_led : function: 0x1bf94
grid_cols : function: 0x1be6c
grid_refresh : function: 0x1bf34
grid_rows : function: 0x1bed0
grid_set_led : function: 0x1c00c
hid : table: 0x664b0
home_dir : /home/we
init : function: 0x759a8
io : table: 0x55398
ipairs : function: 0x76c2e4b0
key : function: 0x759a8
line : network >
load : function: 0x76c2e53c
load_engine : function: 0x1b438
loadfile : function: 0x76c2e674
math : table: 0x56830
metro : table: 0xa3330
metro_set_time : function: 0x1b380
metro_start : function: 0x1a608
metro_stop : function: 0x1b3e8
midi : table: 0xb6188
midi_send : function: 0x1b488
mix : table: 0x6a020
next : function: 0x76c2e060
norns : table: 0x5aef0
os : table: 0x55128
osc : table: 0xee528
osc_send : function: 0x1aa84
osc_send_crone : function: 0x1a8d0
package : table: 0x53808
pairs : function: 0x76c2e490
params : table: 0xf2a78
paramset : table: 0x78fc8
pcall : function: 0x76c2d9a4
poll : table: 0x66260
print : function: 0x76c2dedc
rawequal : function: 0x76c2de9c
rawget : function: 0x76c2de04
rawlen : function: 0x76c2de44
rawset : function: 0x76c2ddb8
redraw : function: 0x759a8
report_engines : function: 0x1a8c0
request_poll_value : function: 0x1b21c
require : function: 0x544d8
restart_audio : function: 0x1a4a0
s : 249255
s_aa : function: 0x1bd3c
s_arc : function: 0x1b7a8
s_circle : function: 0xad858
s_clear : function: 0x1c1b4
s_close : function: 0x1c0b4
s_curve : function: 0x1b91c
s_curve_rel : function: 0x1b858
s_extents : function: 0x1b644
s_fill : function: 0x1c174
s_font_face : function: 0x1bddc
s_font_size : function: 0x1bd88
s_level : function: 0x1bcf0
s_line : function: 0x1bad0
s_line_cap : function: 0x1bc54
s_line_join : function: 0x1bc04
s_line_rel : function: 0x1b9e0
s_line_width : function: 0x1bca4
s_miter_limit : function: 0x1bbb8
s_move : function: 0x1bb44
s_move_rel : function: 0x1ba5c
s_rect : function: 0x1b70c
s_stroke : function: 0x1c134
s_text : function: 0x1b6bc
s_text_center : function: 0xac270
s_text_right : function: 0xac258
s_update : function: 0x1c0f4
screen : table: 0xac7b0
script_dir : /home/we/dust/scripts/
select : function: 0x76c2da48
send_command : function: 0x1a6d4
set_aux_fx_input_level : function: 0x1b018
set_aux_fx_input_pan : function: 0x1afbc
set_aux_fx_off : function: 0x1a4e4
set_aux_fx_on : function: 0x1a4f4
set_aux_fx_output_level : function: 0x1af78
set_aux_fx_param : function: 0x1aed4
set_aux_fx_return_level : function: 0x1af34
set_insert_fx_mix : function: 0x1ae90
set_insert_fx_off : function: 0x1a4c4
set_insert_fx_on : function: 0x1a4d4
set_insert_fx_param : function: 0x1ae30
set_poll_time : function: 0x1b26c
setmetatable : function: 0x76c2e334
sound_file_inspect : function: 0x1ada8
start_audio : function: 0x1a4b4
start_poll : function: 0x1c1f4
startup : function: 0x760a0
state : table: 0x666b0
stop_poll : function: 0x1b2d4
string : table: 0x539c0
tab : table: 0x57ef8
table : table: 0x54ee0
tape_new : function: 0x1b0c4
tape_open : function: 0x1b074
tape_pause : function: 0x1a514
tape_pause_rec : function: 0x1a544
tape_play : function: 0x1a524
tape_start_rec : functi
on: 0x1a554
tape_stop : function: 0x1a504
tape_stop_rec : function: 0x1a534
textentry : table: 0xdf838
tonumber : function: 0x76c2db18
tostring : function: 0x76c2da20
type : function: 0x76c2d94c
us : 1537564476
usleep : function: 0x1b328
utf8 : table: 0x57458
util : table: 0x6b748
wifi : table: 0xe5420
xpcall : function: 0x76c2d8bc

[pq]

@tehn: do we have a sense for what globals we want to protect and what we want to preserve across scripts?

this is related to the general cleanup task i guess. there may not actually be much left to protect / restore when norns is less leaky...