foo++->bar

[Akuli]

https://github.com/Akuli/jou/blob/a3f82bc3d8d5cc228d278a4dfb6feb2f55bb9778/self_hosted/parser.jou#L31

Ideally foo++->bar would be valid syntax. When foo is a pointer to a struct, this increments the pointer and retrieves bar field from the instance where the pointer pointed before incrementing. But it doesn't work.

[littlewhitecloud]

Perhaps, operator precedence?

[Akuli]

The way operator precedence is implemented now is super simple: if a function parse_foo() calls parse_bar(), then bar has higher precedence than foo, because parse_bar() parses as much bar as it can, and all that occurs inside a foo.

The -> operator has higher precedence than ++, so that foo->bar++ works properly. But it means that foo++->bar doesn't work. The two functions for parsing ++ and -> should either be combined together, or they could call each other recursively.

[Moosems]

Functions and parentheses mark precedence for the interior otherwise left to right? This would allow functions called in a function to get called in proper order and statements can get done properly (i.e. 5(3+(5-6)) is equal to 10) but statements that want to be read left to right are the default. You could also make parentheses evaluate earlier so you do something like (foo++)->bar?

[Akuli]

(foo++)->bar is already supported.

Now that I look at this again, IMO it's pefectly fine if the compiler doesn't understand foo++->bar. Someone new to Jou could easily struggle with understanding that:

• ++-> means ++ then ->
• -> does not mean - then >
• ++ does not mean + then + again.

That said, the compiler's error message isn't great. For this file

def main() -> int:
    foo++->bar
    return 0

it produces:

compiler error in file "a.jou", line 2: expected end of line, got '->'