Struct evalexpr::Node

pub struct Node { /* fields omitted */ }

A node in the operator tree. The operator tree is created by the crate-level build_operator_tree method. It can be evaluated for a given context with the Node::eval method.

The advantage of constructing the operator tree separately from the actual evaluation is that it can be evaluated arbitrarily often with different contexts.

Examples

use evalexpr::*;

let mut context = HashMapContext::new();
context.set_value("alpha".into(), 2.into()).unwrap(); // Do proper error handling here
let node = build_operator_tree("1 + alpha").unwrap(); // Do proper error handling here
assert_eq!(node.eval_with_context(&context), Ok(Value::from(3)));

Methods

impl Node

pub fn iter(&self) -> impl Iterator<Item = &Node>

Returns an iterator over all nodes in this tree.

impl Node

pub fn iter_identifiers(&self) -> impl Iterator<Item = &str>

Returns an iterator over all identifiers in this expression. Each occurrence of an identifier is returned separately.

Examples

use evalexpr::*;

let tree = build_operator_tree("a + b + c * f()").unwrap(); // Do proper error handling here
let mut iter = tree.iter_identifiers();
assert_eq!(iter.next(), Some("a"));
assert_eq!(iter.next(), Some("b"));
assert_eq!(iter.next(), Some("c"));
assert_eq!(iter.next(), Some("f"));
assert_eq!(iter.next(), None);

pub fn iter_variable_identifiers(&self) -> impl Iterator<Item = &str>

Returns an iterator over all variable identifiers in this expression. Each occurrence of a variable identifier is returned separately.

Examples

use evalexpr::*;

let tree = build_operator_tree("a + f(b + c)").unwrap(); // Do proper error handling here
let mut iter = tree.iter_variable_identifiers();
assert_eq!(iter.next(), Some("a"));
assert_eq!(iter.next(), Some("b"));
assert_eq!(iter.next(), Some("c"));
assert_eq!(iter.next(), None);

pub fn iter_function_identifiers(&self) -> impl Iterator<Item = &str>

Returns an iterator over all function identifiers in this expression. Each occurrence of a function identifier is returned separately.

Examples

use evalexpr::*;

let tree = build_operator_tree("a + f(b + c)").unwrap(); // Do proper error handling here
let mut iter = tree.iter_function_identifiers();
assert_eq!(iter.next(), Some("f"));
assert_eq!(iter.next(), None);

pub fn eval_with_context(&self, context: &dyn Context) -> EvalexprResult<Value>

Evaluates the operator tree rooted at this node with the given context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_with_context_mut(
    &self,
    context: &mut dyn Context
) -> EvalexprResult<Value>

Evaluates the operator tree rooted at this node with the given mutable context.

Fails, if one of the operators in the expression tree fails.

pub fn eval(&self) -> EvalexprResult<Value>

Evaluates the operator tree rooted at this node with an empty context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_string_with_context(
    &self,
    context: &dyn Context
) -> EvalexprResult<String>

Evaluates the operator tree rooted at this node into a string with an the given context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_float_with_context(
    &self,
    context: &dyn Context
) -> EvalexprResult<FloatType>

Evaluates the operator tree rooted at this node into a float with an the given context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_int_with_context(
    &self,
    context: &dyn Context
) -> EvalexprResult<IntType>

Evaluates the operator tree rooted at this node into an integer with an the given context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_number_with_context(
    &self,
    context: &dyn Context
) -> EvalexprResult<FloatType>

Evaluates the operator tree rooted at this node into a float with an the given context. If the result of the expression is an integer, it is silently converted into a float.

Fails, if one of the operators in the expression tree fails.

pub fn eval_boolean_with_context(
    &self,
    context: &dyn Context
) -> EvalexprResult<bool>

Evaluates the operator tree rooted at this node into a boolean with an the given context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_tuple_with_context(
    &self,
    context: &dyn Context
) -> EvalexprResult<TupleType>

Evaluates the operator tree rooted at this node into a tuple with an the given context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_empty_with_context(
    &self,
    context: &dyn Context
) -> EvalexprResult<EmptyType>

Evaluates the operator tree rooted at this node into an empty value with an the given context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_string_with_context_mut(
    &self,
    context: &mut dyn Context
) -> EvalexprResult<String>

Evaluates the operator tree rooted at this node into a string with an the given mutable context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_float_with_context_mut(
    &self,
    context: &mut dyn Context
) -> EvalexprResult<FloatType>

Evaluates the operator tree rooted at this node into a float with an the given mutable context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_int_with_context_mut(
    &self,
    context: &mut dyn Context
) -> EvalexprResult<IntType>

Evaluates the operator tree rooted at this node into an integer with an the given mutable context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_number_with_context_mut(
    &self,
    context: &mut dyn Context
) -> EvalexprResult<FloatType>

Evaluates the operator tree rooted at this node into a float with an the given mutable context. If the result of the expression is an integer, it is silently converted into a float.

Fails, if one of the operators in the expression tree fails.

pub fn eval_boolean_with_context_mut(
    &self,
    context: &mut dyn Context
) -> EvalexprResult<bool>

Evaluates the operator tree rooted at this node into a boolean with an the given mutable context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_tuple_with_context_mut(
    &self,
    context: &mut dyn Context
) -> EvalexprResult<TupleType>

Evaluates the operator tree rooted at this node into a tuple with an the given mutable context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_empty_with_context_mut(
    &self,
    context: &mut dyn Context
) -> EvalexprResult<EmptyType>

Evaluates the operator tree rooted at this node into an empty value with an the given mutable context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_string(&self) -> EvalexprResult<String>

Evaluates the operator tree rooted at this node into a string with an empty context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_float(&self) -> EvalexprResult<FloatType>

Evaluates the operator tree rooted at this node into a float with an empty context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_int(&self) -> EvalexprResult<IntType>

Evaluates the operator tree rooted at this node into an integer with an empty context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_number(&self) -> EvalexprResult<FloatType>

Evaluates the operator tree rooted at this node into a float with an empty context. If the result of the expression is an integer, it is silently converted into a float.

Fails, if one of the operators in the expression tree fails.

pub fn eval_boolean(&self) -> EvalexprResult<bool>

Evaluates the operator tree rooted at this node into a boolean with an empty context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_tuple(&self) -> EvalexprResult<TupleType>

Evaluates the operator tree rooted at this node into a tuple with an empty context.

Fails, if one of the operators in the expression tree fails.

pub fn eval_empty(&self) -> EvalexprResult<EmptyType>

Evaluates the operator tree rooted at this node into an empty value with an empty context.

Fails, if one of the operators in the expression tree fails.

Trait Implementations

impl Display for Node

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl Debug for Node

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.