fixed-macro

This library provides fixed!, a proc-macro that allows easily creating fixed-point constants for all of the fixed-point types provided in fixed crate.

toml [dependencies] fixed-macro = "1.0"

Compiler support: same as fixed crate, rustc 1.44+ as of the time of writing.

Details

• The syntax of the macro is as follows:

  rust fixed!(<value>: <type>)

  where <value> is an integer literal or a float literal, and <type> is either of the form I<i>F<f> or U<i>F<f>, matching one of the type aliases provided in fixed::types. Note in particular that <value> has to be a literal and not an arbitrary arithmetic expression, and that <type> is considered a special identifier, so that it doesn't have to be imported first.

• Create a fixed-point constant which is parsed at compile time (the same syntax for int and float literals is supported as in Rust itself, including underscores and scientific notation):

  ```rust use fixed_macro::fixed; use fixed::types::U8F8;

  let x1 = fixed!(-1.23: I32F32); // float literal (note, the type is not in scope) const X2: U8F8 = fixed!(1.2: U8F8); // can be used to initialize const values let x3 = fixed!(123: U8F8); // decimal integers work as well let x4 = fixed!(0x7B: U8F8); // and hex/oct/bin integers too let x5 = fixed!(1234.567890: I32F32); // underscores are ignored, same as in rustc let x7 = fixed!(0.12e+01: U8F8); // scientific notation is also supported ```

• For each type alias from fixed::types, there is a macro with a matching name in fixed_macro::types which you can use without specifying the type name:

  ```rust use fixed_macro::types::I16F48;

  let a1 = I16F48!(-1.23); ```

  Both the macro and the type can happily coexist in the same scope:

  ```rust use fixed::types::I16F48; use fixed_macro::types::I16F48;

  const B1: I16F48 = I16F48!(1.23e-2); ```

  You can choose to import both under different (or same) user-defined names:

  ```rust use fixed::types::{I16F48 as Decimal}; use fixed_macro::types::{I16F48 as dec};

  let c1 = dec!(12345); const C2: Decimal = dec!(-0.123456); ```

License

<sup>Licensed under either of Apache License, Version 2.0 or MIT license at your option.</sup>

<sub>Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.</sub>