Struct evalexpr::Node

pub struct Node { /* private fields */ }

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)));

Implementations

impl Node

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

Returns an iterator over all nodes in this tree.

pub fn iter_operators_mut(&mut self) -> impl Iterator<Item = &mut Operator>

Returns a mutable iterator over all operators 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_identifiers_mut(&mut self) -> impl Iterator<Item = &mut String>

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

Examples

use evalexpr::*;

let mut tree = build_operator_tree("a + b + c * f()").unwrap(); // Do proper error handling here

for identifier in tree.iter_identifiers_mut() {
    *identifier = String::from("x");
}

let mut iter = tree.iter_identifiers();

assert_eq!(iter.next(), Some("x"));
assert_eq!(iter.next(), Some("x"));
assert_eq!(iter.next(), Some("x"));
assert_eq!(iter.next(), Some("x"));
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_variable_identifiers_mut( &mut self ) -> impl Iterator<Item = &mut String>

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

Examples

use evalexpr::*;

let mut tree = build_operator_tree("a + b + c * f()").unwrap(); // Do proper error handling here

for identifier in tree.iter_variable_identifiers_mut() {
    *identifier = String::from("x");
}

let mut iter = tree.iter_identifiers();

assert_eq!(iter.next(), Some("x"));
assert_eq!(iter.next(), Some("x"));
assert_eq!(iter.next(), Some("x"));
assert_eq!(iter.next(), Some("f"));
assert_eq!(iter.next(), None);

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

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

Examples

use evalexpr::*;

let tree = build_operator_tree("d = a + f(b + c)").unwrap(); // Do proper error handling here
let mut iter = tree.iter_read_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_read_variable_identifiers_mut( &mut self ) -> impl Iterator<Item = &mut String>

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

Examples

use evalexpr::*;

let mut tree = build_operator_tree("d = a + f(b + c)").unwrap(); // Do proper error handling here

for identifier in tree.iter_read_variable_identifiers_mut() {
    *identifier = String::from("x");
}

let mut iter = tree.iter_identifiers();

assert_eq!(iter.next(), Some("d"));
assert_eq!(iter.next(), Some("x"));
assert_eq!(iter.next(), Some("f"));
assert_eq!(iter.next(), Some("x"));
assert_eq!(iter.next(), Some("x"));
assert_eq!(iter.next(), None);

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

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

Examples

use evalexpr::*;

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

pub fn iter_write_variable_identifiers_mut( &mut self ) -> impl Iterator<Item = &mut String>

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

Examples

use evalexpr::*;

let mut tree = build_operator_tree("d = a + f(b + c)").unwrap(); // Do proper error handling here

for identifier in tree.iter_write_variable_identifiers_mut() {
    *identifier = String::from("x");
}

let mut iter = tree.iter_identifiers();

assert_eq!(iter.next(), Some("x"));
assert_eq!(iter.next(), Some("a"));
assert_eq!(iter.next(), Some("f"));
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 iter_function_identifiers_mut( &mut self ) -> impl Iterator<Item = &mut String>

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

Examples

use evalexpr::*;

let mut tree = build_operator_tree("d = a + f(b + c)").unwrap(); // Do proper error handling here

for identifier in tree.iter_function_identifiers_mut() {
    *identifier = String::from("x");
}

let mut iter = tree.iter_identifiers();

assert_eq!(iter.next(), Some("d"));
assert_eq!(iter.next(), Some("a"));
assert_eq!(iter.next(), Some("x"));
assert_eq!(iter.next(), Some("b"));
assert_eq!(iter.next(), Some("c"));
assert_eq!(iter.next(), None);

pub fn eval_with_context<C: Context>( &self, context: &C ) -> 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<C: ContextWithMutableVariables>( &self, context: &mut C ) -> 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.

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

pub fn eval_string_with_context<C: Context>( &self, context: &C ) -> 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<C: Context>( &self, context: &C ) -> 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<C: Context>( &self, context: &C ) -> 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<C: Context>( &self, context: &C ) -> 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<C: Context>( &self, context: &C ) -> 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<C: Context>( &self, context: &C ) -> 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<C: Context>( &self, context: &C ) -> 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<C: ContextWithMutableVariables>( &self, context: &mut C ) -> 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<C: ContextWithMutableVariables>( &self, context: &mut C ) -> 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<C: ContextWithMutableVariables>( &self, context: &mut C ) -> 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<C: ContextWithMutableVariables>( &self, context: &mut C ) -> 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<C: ContextWithMutableVariables>( &self, context: &mut C ) -> 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<C: ContextWithMutableVariables>( &self, context: &mut C ) -> 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<C: ContextWithMutableVariables>( &self, context: &mut C ) -> 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.

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.

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.

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. 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.

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.

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.

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

pub fn children(&self) -> &[Node]

Returns the children of this node as a slice.

pub fn operator(&self) -> &Operator

Returns the operator associated with this node.

pub fn children_mut(&mut self) -> &mut Vec<Node>

Returns a mutable reference to the vector containing the children of this node.

WARNING: Writing to this might have unexpected results, as some operators require certain amounts and types of arguments.

pub fn operator_mut(&mut self) -> &mut Operator

Returns a mutable reference to the operator associated with this node.

WARNING: Writing to this might have unexpected results, as some operators require different amounts and types of arguments.

Trait Implementations

impl Clone for Node

fn clone(&self) -> Node

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Node

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

Formats the value using the given formatter.

impl Display for Node

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

Formats the value using the given formatter.

impl PartialEq<Node> for Node

fn eq(&self, other: &Node) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Node