honest dome
const compFn = switch (direction) {
.Right => Position.generateCompFn("x", .Less),
.Down => Position.generateCompFn("y", .Less),
.Left => Position.generateCompFn("x", .Greater),
.Up => Position.generateCompFn("y", .Greater),
};
direction is runtime, all results can be comptime -calculated.
but Zig doesn't want me to:
value with comptime-only type 'fn (void, main.Position, main.Position) bool' depends on runtime control flow
why?
coarse ridge
the result of each switch prong is comptime known but the final result of compFn isnt
put & in front of either the switch or the functions to get a function pointer which can be runtime known
honest dome
thank you! it helped for that case. but I wanted to also switch and use different sorting methods, can you enlighten me why this approach is not enough here?
const sortFn = &switch (direction) {
.Right, .Down => std.sort.min,
.Left, .Up => std.sort.max,
};
i assume because those functions are generic, theyre inherently comptime only
honest dome
ah, you're correct
they accept comptime args
hmm, but now I cannot pass/use that const pointer to function in a call to min/max:
error: expected type 'fn (void, main.Position, main.Position) bool', found '*const fn (void, main.Position, main.Position) bool'
.Right, .Down => std.sort.min(Position, matching_walls.items, {}, compFn),
like so:
const wall = switch (direction) {
.Right, .Down => std.sort.min(Position, matching_walls.items, {}, compFn),
.Left, .Up => std.sort.max(Position, matching_walls.items, {}, compFn),
};
and I cannot dereference it either
I'm too beginner for what I'm trying to do but I don't want to write repeated code.