parent
6b1706f68f
commit
8c6228c3d9
18
README.md
18
README.md
@ -62,23 +62,21 @@ And you can use **variables** and **functions** in expressions like this:
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```rust
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```rust
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use evalexpr::*;
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use evalexpr::*;
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use evalexpr::error::expect_number;
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let context = context_map! {
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let context = context_map! {
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"five" => 5,
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"five" => 5,
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"twelve" => 12,
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"twelve" => 12,
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"f" => Function::new(Some(1) /* argument amount */, Box::new(|arguments| {
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"f" => Function::new(Box::new(|argument| {
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if let Value::Int(int) = arguments[0] {
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if let Ok(int) = argument.as_int() {
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Ok(Value::Int(int / 2))
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Ok(Value::Int(int / 2))
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} else if let Value::Float(float) = arguments[0] {
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} else if let Ok(float) = argument.as_float() {
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Ok(Value::Float(float / 2.0))
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Ok(Value::Float(float / 2.0))
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} else {
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} else {
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Err(EvalexprError::expected_number(arguments[0].clone()))
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Err(EvalexprError::expected_number(argument.clone()))
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}
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}
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})),
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})),
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"avg" => Function::new(Some(2) /* argument amount */, Box::new(|arguments| {
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"avg" => Function::new(Box::new(|argument| {
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expect_number(&arguments[0])?;
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let arguments = argument.as_tuple()?;
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expect_number(&arguments[1])?;
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if let (Value::Int(a), Value::Int(b)) = (&arguments[0], &arguments[1]) {
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if let (Value::Int(a), Value::Int(b)) = (&arguments[0], &arguments[1]) {
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Ok(Value::Int((a + b) / 2))
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Ok(Value::Int((a + b) / 2))
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@ -342,7 +340,6 @@ The implementation expects a [serde `string`](https://serde.rs/data-model.html)
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Example parsing with [ron format](docs.rs/ron):
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Example parsing with [ron format](docs.rs/ron):
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```rust
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```rust
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# #[cfg(feature = "serde_support")] {
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extern crate ron;
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extern crate ron;
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use evalexpr::*;
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use evalexpr::*;
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@ -356,9 +353,8 @@ match ron::de::from_str::<Node>(serialized_free) {
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Ok(free) => assert_eq!(free.eval_with_context(&context), Ok(Value::from(25))),
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Ok(free) => assert_eq!(free.eval_with_context(&context), Ok(Value::from(25))),
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Err(error) => {
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Err(error) => {
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() // Handle error
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() // Handle error
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},
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}
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}
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# }
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}
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```
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```
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With `serde`, expressions can be integrated into arbitrarily complex data.
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With `serde`, expressions can be integrated into arbitrarily complex data.
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