pub struct Function { /* private fields */ }
Expand description
A user-defined function.
Functions can be used in expressions by storing them in a Context
.
use evalexpr::*;
let mut context = HashMapContext::new();
context.set_function("id".into(), Function::new(|argument| {
Ok(argument.clone())
})).unwrap(); assert_eq!(eval_with_context("id(4)", &context), Ok(Value::from(4)));
Creates a user-defined function.
The function
is boxed for storage.
Performs copy-assignment from
source
.
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Formats the value using the given formatter.
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Immutably borrows from an owned value.
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Mutably borrows from an owned value.
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Returns the argument unchanged.
Calls U::from(self)
.
That is, this conversion is whatever the implementation of
From<T> for U
chooses to do.
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning.
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Uses borrowed data to replace owned data, usually by cloning.
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The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.