https://github.com/williamvenner/env_ast

env! but it outputs tokens instead of a string literal
https://github.com/williamvenner/env_ast

env env-vars environment environment-variables gh-actions github-actions macro proc-macro rust

Last synced: 7 months ago
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env! but it outputs tokens instead of a string literal

• Host: GitHub
• URL: https://github.com/williamvenner/env_ast
• Owner: WilliamVenner
• License: mit
• Created: 2022-02-08T15:38:50.000Z (over 3 years ago)
• Default Branch: master
• Last Pushed: 2022-02-08T15:58:13.000Z (over 3 years ago)
• Last Synced: 2024-10-11T11:33:43.031Z (about 1 year ago)
• Topics: env, env-vars, environment, environment-variables, gh-actions, github-actions, macro, proc-macro, rust
• Language: Rust
• Homepage: https://docs.rs/env_ast/
• Size: 2.93 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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# env_ast

Dead simple procedural macro that mimics [`env!`](https://doc.rust-lang.org/std/env/index.html) but outputs AST tokens instead of a string literal.

**WARNING:** This macro is potentially DANGEROUS and can introduce arbitrary code execution (ACE) if used improperly. If you need this macro, make sure you REALLY need it.

# Usage

Simply add to your [Cargo.toml](https://doc.rust-lang.org/cargo/reference/manifest.html) file:

```toml

[dependencies]

env_ast = "*"

```

And in your code:

```rust

#[macro_use] extern crate env_ast;

fn it_works() {}

fn default_works() {}

fn main() {

    env_ast!("MY_ENV_VAR")(); // For this to compile, MY_ENV_VAR must be set to `it_works` at build time

    env_ast!("ENV_VAR_THAT_IS_NOT_SET", default_works)(); // You can provide a default set of tokens if the environment variable is not found

}

```