# icecream-rs

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Print debugging with inspection for Rust, inspired by [icecream](https://github.com/gruns/icecream) for Python.

I tend to use a lot of print debugging when writing Rust. `icecream` provides the `ic!()` and `ice!()` macros to make print debugging more convenient, by formatting print statements with helpful information like:
- line number
- calling function
- module name
- file name


### Debugging with `ic!()`

```rust
// src/example.rs
#[macro_use]
extern crate icecream;

mod a_module {
    fn some_function() {
        let x = Some(99);
        ic!();
        ic!(x);
        ic!(x.unwrap() + 1);
        ice!();
    }
}
```

#### Plain
`ic!()` prints the filename and line number.
```
example.rs:8 ❯
```

#### Matching on an identifier
`ic!(x)` prints the name of the variable and the value formatted with `std::fmt::Debug`.
```
example.rs:9 ❯ x = Some(99)
```

#### Matching on an expression
`ic!(x.unwrap() + 1)` evaluates the inner expression and prints the resulting value.

```
example.rs:10 ❯ x.unwrap() + 1 = 100
```

#### Printing more information
`ice!()` prints a longer output that includes the calling module and function.
```
example.rs::a_module::some_function:11 ❯
```

### Configuring `ic!()`

You can also configure the characters used for symbols in the print output.

```rs
// main.rs
#[macro_use]
extern crate icecream;

fn main() {
    icecream::set_equals_symbol(" -> ");
    let x = 1;
    ic!(x);
}
```

```
main.rs:7 ❯ x -> 1
```

### Tests

Tests *must* be run single-threaded with the `--nocapture` flag.

```
RUST_TEST_THREADS=1 cargo test -- --nocapture
```