Hi,

I'm heavily using .p8 files as headless scripts to automate my export pipeline. It's great, as all commands are available and when running headlessly, you can even save/load which fail in normal GUI mode.

However, I noticed that errors are completely silent (unlike GUI mode, which shows error messages). How can I catch PICO-8 errors from within the .p8 script or, as last resort, from the bash script I'm using to pico8 -x the .p8 script?

The most commonly failing commands are save("game.p8.png") when the PNG is too big, and export("game.bin/html") where we're missing an icon or label. When that happens, I must re-run the commands in GUI mode and inspect every error one-by-one. Besides, the commands I manually type are generally slightly different from the script ones (which are very complete with all options) so I'm not exactly sure if I'm reproducing it right.

My suggestions:
a. access error code of last native PICO-8 command (like, save, load and export) with a simple function (e.g. err() which returns an int). We could go further by getting the error message too (e.g. errmsg())
b. make all commands return a success bool. Currently, only load does this (undocumented). save and export return nil so I cannot verify success of the operation.
c. Less convenient, but let a bash/shell script running pico8 -x check the final result of the operations (1 for error, 0 for success) and read error messages in some way. This is less convenient as it doesn't pinpoint where the error occurred in the script. Currently, pico-8 cartridge..p8 -export "... game.bin" does print error messages; but it doesn't return 1 on failure (e.g. missing label) so we cannot check that in a bash script.
d. An option for pico8 -x that prints all native command errors as we would see them in the GUI (load -> "could not load" or better "could not load [filename]", export -> "no icon found, please capture a label or use -i")