[webapp] very long expressions may break formatting of truth table

[ryukinix]

Example: https://logic.manoel.dev/?prop=%28%28~c%20-%3E%20b%29%20-%3E%20%28%28b%20-%3E%20a%29%20-%3E%20%28%28c%20-%3E%20a%29%20-%3E%20a%29%29%29%20-%3E%20%28%28d%20-%3E%20%28~c%20-%3E%20b%29%29%20-%3E%20%28%28b%20-%3E%20a%29%20-%3E%20%28%28c%20-%3E%20a%29%20-%3E%20%28d%20-%3E%20a%29%29%29%29

Expression:

((~c -> b) -> ((b -> a) -> ((c -> a) -> a))) -> ((d -> (~c -> b)) -> ((b -> a) -> ((c -> a) -> (d -> a))))

The same happens in the terminal version too, so indeed is a problem related with print-truth-table formatting.

That's not caused because #46

[ryukinix]

Minimal example of the bug:

https://logic.manoel.dev/?prop=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa%20-%3E%20bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb

reducing one character from one of the variables it will print properly:

https://logic.manoel.dev/?prop=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa%20-%3E%20bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb

I'm considering that the reason behind of the bug is the princ-to-string function that runs format behind the header print, probably around these lines:

lisp-inference/src/truth-table.lisp

Lines 190 to 192 in 35f9036

	(printable-header (loop for x in header
	for p = (princ-to-string x)
	collect (concatenate 'string " " p " |")))

[ryukinix]

Well, well, well...

[ryukinix]

related: https://www.reddit.com/r/lisp/comments/112zjb4/anyone_know_why_newlines_get_randomly_inserted/

basically all these functions pretty print lisp human-readable objects and can insert random newlines arbitrary:

• princ-to-string
• princ
• prin1
• format with ~A, ~s

Setting *pretty-print* to nil should solve this.