Macro define_dbg 

macro_rules! define_dbg {
    ( $( #[$meta:meta] )* $name:ident, $($args:tt)* ) => { ... };
}

Defines dbg macro that prints and returns the value of a given expression for quick and dirty debugging.

The implementation of the generated dbg-like macro is based on std::dbg macro implementation, but the exact output printed by std::dbg should not be relied upon and is subject to future changes.

The first argument specifies the generated macro name. The writer itself is specified by the rest arguments with the define_writer macros.

Use define_try_dbg if you need to define a fallible dbg macros.

Examples

let mut string = String::new();
custom_print::define_dbg!(cdbg, concat, |value: &str| string += value);

assert_eq!(cdbg!("value"), "value");
assert!(string.contains("\"value\""));