Crate default_constructor

default-constructor

Macros for creating pseudo-dsls that constructs structs through default construction and field conversion.

Motivation

This crates is primary designed for bevy where constructing large bundles with ..Default::default() is common.

Syntax

Take construct! that uses Into.

construct! {
    Student {
        name: "Timmy",
        age: 10,
    }
}

This converts to

Student {
    name: Into::into("Timmy"),
    age: Into::into(10.into()),
    ..Default::default()
}

Meta Constructor

The meta constructor macro allows you to define your own macro with custom configurations. See documentation on meta_default_constructor! for detail.

InferInto

InferInto allows the user to bypass the orphan rule to create conversions.

By default we provide i32 -> f32 and i64 -> f64 conversions in addition to the standard From and Into.

If multiple conversion paths are found, the conversion will fail, thus failing the infer_construct macro.

Missing Features

[ ] Allow paths as type name. [ ] Tuple structs support.

Possible Features

[ ] Generics parsing.

Macros

• construct
  A standard constructor that uses Into.
• infer_construct
  A standard constructor that uses InferInto.
• meta_default_constructor
  The meta macro.

Traits

• InferInto
  Into with relaxed orphan rule, you can define non-owned conversion with a owned Marker. Keep in mind this inference will fail if multiple conversion paths are found.
• StandardConverters
  Provides conversion from integer literal i32 to other numerical types.

Functions

• infer_into
  Convert via InferInto