bee98999db
To achieve this, the function type wrapped by Function was changed to remove the `Box`. Relates to #73
44 lines
1.1 KiB
Rust
44 lines
1.1 KiB
Rust
use std::fmt;
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use crate::{error::EvalexprResult, value::Value};
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pub(crate) mod builtin;
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/// A user-defined function.
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/// Functions can be used in expressions by storing them in a `Context`.
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///
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/// # Examples
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///
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/// ```rust
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/// use evalexpr::*;
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///
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/// let mut context = HashMapContext::new();
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/// context.set_function("id".into(), Function::new(|argument| {
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/// Ok(argument.clone())
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/// })).unwrap(); // Do proper error handling here
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/// assert_eq!(eval_with_context("id(4)", &context), Ok(Value::from(4)));
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/// ```
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#[derive(Clone)]
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pub struct Function {
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function: fn(&Value) -> EvalexprResult<Value>,
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}
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impl Function {
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/// Creates a user-defined function.
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///
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/// The `function` is a boxed function that takes a `Value` and returns a `EvalexprResult<Value, Error>`.
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pub fn new(function: fn(&Value) -> EvalexprResult<Value>) -> Self {
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Self { function }
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}
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pub(crate) fn call(&self, argument: &Value) -> EvalexprResult<Value> {
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(self.function)(argument)
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}
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}
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impl fmt::Debug for Function {
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fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
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write!(f, "Function {{ [...] }}")
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}
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}
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