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Surely Rust can infer the type in your example? It just doesn't provide Zig's syntax to use the inferred type to manually initialize. If you wrote some_fn() her

Surely Rust can infer the type in your example? It just doesn't provide Zig's syntax to use the inferred type to manually initialize. If you wrote some_fn() here where some_fn's return type was genericised, Rust would ask for the appropriately typed some_fn not say it doesn't know the type.

flohofwoe 1y ago
> Surely Rust can infer the type in your example? Well in Rust code like this: pass_action.colors[0] = sg::ColorAttachmentAction { load_action: sg::LoadAction::Clear, clear_value: sg::Color { r: 0.25, g: 0.5, b: 0.75, a: 1.0 }, ..Default::default() }; ...I cannot write: pass_action.colors[0] = { load_action: sg::LoadAction::Clear, clear_value: { r: 0.25, g: 0.5, b: 0.75, a: 1.0 }, ..Default::default() }; ...even though the Rust compiler has all the type information it needs (from the 'left-hand-side'). For comparison, in Zig it would look like this: pass_action.colors[0] = .{ .load_action = .Clear, .clear_value = .{ .r=0.25, .g=0.5, .b=0.75, .a=1.0 }, }; ...Zig is still only halfway there compared to C99 (e.g. Zig doesn't allow designator chaining and is much less flexible for initializing nested arrays - in those areas it's closer to Rust than C).
- tialaramex 1y ago
  Right but your call to Default::default() gives the game away that we do have inference. Default::default() is generic, if we didn't have inference we'd need to tell it which of the enormous number of implementations of that trait it should call. Would you take syntax like clear_value: _ { r: 0.25, g: 0.5, g: 0.75, a: 1.0 } ?? Then we're saying that we know we need to pick a type here but the type can be inferred where our underscore was, just like when we let words: Vec<_> = "A sentence broken by spaces".split_whitespace().collect();

flohofwoe 1y ago

> Surely Rust can infer the type in your example? Well in Rust code like this: pass_action.colors[0] = sg::ColorAttachmentAction { load_action: sg::LoadAction::Clear, clear_value: sg::Color { r: 0.25, g: 0.5, b: 0.75, a: 1.0 }, ..Default::default() }; ...I cannot write: pass_action.colors[0] = { load_action: sg::LoadAction::Clear, clear_value: { r: 0.25, g: 0.5, b: 0.75, a: 1.0 }, ..Default::default() }; ...even though the Rust compiler has all the type information it needs (from the 'left-hand-side'). For comparison, in Zig it would look like this: pass_action.colors[0] = .{ .load_action = .Clear, .clear_value = .{ .r=0.25, .g=0.5, .b=0.75, .a=1.0 }, }; ...Zig is still only halfway there compared to C99 (e.g. Zig doesn't allow designator chaining and is much less flexible for initializing nested arrays - in those areas it's closer to Rust than C).

tialaramex 1y ago
Right but your call to Default::default() gives the game away that we do have inference. Default::default() is generic, if we didn't have inference we'd need to tell it which of the enormous number of implementations of that trait it should call. Would you take syntax like clear_value: _ { r: 0.25, g: 0.5, g: 0.75, a: 1.0 } ?? Then we're saying that we know we need to pick a type here but the type can be inferred where our underscore was, just like when we let words: Vec<_> = "A sentence broken by spaces".split_whitespace().collect();