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// usage: cargo run --release --example ns_vec_btreemap_string
use std::collections::BTreeMap;
fn main() -> Result<(), fasteval::Error> {
let mut layer1 = BTreeMap::new();
layer1.insert("x".to_string(), 2.0);
layer1.insert("y".to_string(), 3.0);
let mut layers : Vec<BTreeMap<String,f64>> = vec![layer1];
let val = fasteval::ez_eval("x * y", &mut layers)?;
assert_eq!(val, 6.0);
// Let's add another layer which shadows the previous one:
let mut layer2 = BTreeMap::new();
layer2.insert("x".to_string(), 3.0);
layers.push(layer2);
let val = fasteval::ez_eval("x * y", &mut layers)?;
assert_eq!(val, 9.0);
// Remove the top layer and we'll be back to what we had before:
layers.pop();
let val = fasteval::ez_eval("x * y", &mut layers)?;
assert_eq!(val, 6.0);
Ok(())
}
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