37 lines
907 B
Rust
37 lines
907 B
Rust
use enve::estr::SepVec;
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type MinusVec<T> = SepVec<T, '-'>;
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type PlusVec<T> = SepVec<T, '+'>;
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type MulVec<T> = SepVec<T, '*'>;
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const HELP_MESSAGE: &str = "
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USAGE:
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E=10+10*2+4 cargo run --example calc --all-features
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";
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fn main() -> Result<(), enve::Error> {
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let res: f32 = enve::get::<PlusVec<MinusVec<MulVec<f32>>>>("E")
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.map_err(|err| {
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match err {
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enve::Error::NotPresent => eprintln!("The expression was not found"),
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rest => eprintln!("ERROR: {}", rest),
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}
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eprintln!("{}", HELP_MESSAGE);
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std::process::exit(0);
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})
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.unwrap()
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.iter()
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.map(|p| {
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p.iter()
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.map(|m| m.iter().product::<f32>())
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.reduce(|acc, v| acc - v)
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.unwrap_or_default()
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})
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.sum::<f32>();
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println!("result: {}", res);
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Ok(())
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}
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