https://github.com/nhynes/default-env

The `env!` macro but with a default value.
https://github.com/nhynes/default-env

env rust

Last synced: 10 days ago
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The `env!` macro but with a default value.

• Host: GitHub
• URL: https://github.com/nhynes/default-env
• Owner: nhynes
• Created: 2019-06-21T02:27:43.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2023-06-21T19:43:22.000Z (over 1 year ago)
• Last Synced: 2024-10-12T12:17:17.793Z (26 days ago)
• Topics: env, rust
• Language: Rust
• Size: 2.93 KB
• Stars: 1
• Watchers: 2
• Forks: 2
• Open Issues: 2
• Metadata Files:
  • Readme: README.md

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README

        
# default-env

`default_env!` is a macro like [`env!`](https://doc.rust-lang.org/std/macro.env.html) that returns a default value if the environment variable is not found.

Unlike [`option_env!`](https://doc.rust-lang.org/std/macro.option_env.html), the output of `default_env!` can be used in macros (because who doesn't love macros in their macros?).

## Example

```rust

macro_rules! long_str {

  () => {

    concat!(

        "Hello, ", default_env!("USER", "anonymous user"), ".",

        "Today is ", default_env!("WEEKDAY", compile_error!("You exist in a land beyond time."))

      )

  }

}

```