Struct SymbolTable 

pub struct SymbolTable { /* private fields */ }

SymbolTable holds different variables. There are three types of variables: Numberic variables, strings and numeric vectors of fixed size. (see the documentation). Many but not all of the methods of the ExprTk symbol_table were implemented, and the API is sometimes different.

Implementations

impl SymbolTable

pub fn new() -> SymbolTable

pub fn add_constant( &mut self, name: &str, value: c_double, ) -> Result<bool, InvalidName>

pub fn add_variable( &mut self, name: &str, value: c_double, ) -> Result<Option<usize>, InvalidName>

Adds a new variable. Returns the variable ID that can later be used for set_value or None if a variable with the same name was already present. The behavior of this function differs from the one of the underlying library by not providing the (optional) is_constant option. Use add_constant() instead.

pub fn value(&self, var_id: usize) -> c_double

Returns the value of a variable given its variable ID

Panics

This function will panic if the var_id refers to an invalid (too large) variable ID.

pub fn value_mut(&mut self, var_id: usize) -> &mut c_double

Returns a mutable reference to the value of a registered variable.

Panics

This function will panic if the var_id refers to an invalid (too large) variable ID.

Example:

use std::f64::consts::PI;
use exprtk_rs::*;

let mut symbol_table = SymbolTable::new();
let x_id = symbol_table.add_variable("x", 0.).expect("Invalid name").expect("Already present");
let mut expr = Expression::new("sin(x)", symbol_table).expect("Compile error");
assert_eq!(expr.value(), 0.);

let mut x = 0.;
while expr.symbols().value(x_id) <= 2. * PI {
    *expr.symbols_mut().value_mut(x_id) += 0.1;
    let y = expr.value();
}

pub fn value_cell(&self, var_id: usize) -> &Cell<c_double>

Returns the value of a registered variable as modifiable std::cell::Cell. This is an alternative access to value_mut and allows changing the values easily. If the reference to the Cell is kept around, its value can be changed multiple times.

Panics

This function will panic if the var_id refers to an invalid (too large) variable ID.

Example:

use exprtk_rs::*;

let mut symbol_table = SymbolTable::new();
let id = symbol_table.add_variable("a", 2.).expect("Invalid name").expect("Already present");
let mut expr = Expression::new("a - 1", symbol_table).expect("Compile error");
assert_eq!(expr.value(), 1.);

let value = expr.symbols().value_cell(id);
value.set(4.);
assert_eq!(expr.value(), 3.);

pub fn value_from_name(&self, name: &str) -> Result<c_double, InvalidName>

Returns the value of a variable (whether constant or not)

Panics

This function will panic if the name refers to an unknown variable.

pub fn add_stringvar( &mut self, name: &str, text: &str, ) -> Result<Option<usize>, InvalidName>

Adds a new string variable. Returns the variable ID that can later be used for set_string or None if a variable with the same name was already present.

pub fn set_string(&mut self, var_id: usize, text: &str) -> bool

pub fn string(&self, var_id: usize) -> &StringValue

Returns a reference to a string variable given its ID.

Panics

This function will panic if the var_id refers to an invalid (too large) variable ID.

pub fn string_mut(&mut self, var_id: usize) -> &mut StringValue

Returns a mutable reference to a string variable given its ID.

Panics

This function will panic if the var_id refers to an invalid (too large) variable ID.

pub fn add_vector( &mut self, name: &str, vec: &[c_double], ) -> Result<Option<usize>, InvalidName>

Adds a new vector variable. Returns the variable ID that can later be used for vector or None if a variable with the same name was already present.

pub fn vector(&self, var_id: usize) -> &[c_double]

Returns a reference to a vector given its variable ID.

Panics

This function will panic if the var_id refers to an invalid (too large) variable ID.

pub fn vector_mut(&mut self, var_id: usize) -> &mut [c_double]

Returns an mutable reference to a vector given its variable ID.

Panics

This function will panic if the var_id refers to an invalid (too large) variable ID.

pub fn vector_of_cells(&self, var_id: usize) -> &[Cell<c_double>]

Returns a reference to a vector given its variable ID. The values are of the type std::cell::Cell, and can thus be modified without mutable access to SymbolTable

pub fn get_var_id(&self, name: &str) -> Result<Option<usize>, InvalidName>

Returns the ‘ID’ of a variable or None if not found. The function will return Err(InvalidName) if the name is not entirely composed of ASCII characters.

pub fn get_string_id(&self, name: &str) -> Result<Option<usize>, InvalidName>

Returns the ‘ID’ of a string or None if not found. The function will return Err(InvalidName) if the name is not entirely composed of ASCII characters.

pub fn get_vec_id(&self, name: &str) -> Result<Option<usize>, InvalidName>

Returns the ‘ID’ of a vector or None if not found. The function will return Err(InvalidName) if the name is not entirely composed of ASCII characters.

pub fn clear_variables(&mut self)

pub fn clear_strings(&mut self)

pub fn clear_vectors(&mut self)

pub fn clear_local_constants(&mut self)

pub fn clear_functions(&mut self)

pub fn variable_count(&self) -> usize

pub fn stringvar_count(&self) -> usize

pub fn vector_count(&self) -> usize

pub fn function_count(&self) -> usize

pub fn add_constants(&mut self) -> bool

pub fn add_pi(&mut self) -> bool

pub fn add_epsilon(&mut self) -> bool

pub fn add_infinity(&mut self) -> bool

pub fn get_variable_names(&self) -> Vec<String>

pub fn get_stringvar_names(&self) -> Vec<String>

pub fn get_vector_names(&self) -> Vec<String>

pub fn symbol_exists(&self, name: &str) -> Result<bool, InvalidName>

pub fn is_constant_node(&self, name: &str) -> Result<bool, InvalidName>

pub fn is_constant_string(&self, name: &str) -> Result<bool, InvalidName>

impl SymbolTable

pub fn add_func1<F>(&mut self, name: &str, func: F) -> Result<bool, InvalidName>

where F: Fn(c_double) -> c_double + Clone,

Add a function with 1 scalar arguments. Returns true if the function was added / false if the name was already present.

impl SymbolTable

pub fn add_func2<F>(&mut self, name: &str, func: F) -> Result<bool, InvalidName>

where F: Fn(c_double, c_double) -> c_double + Clone,

Add a function with 2 scalar arguments. Returns true if the function was added / false if the name was already present.

impl SymbolTable

pub fn add_func3<F>(&mut self, name: &str, func: F) -> Result<bool, InvalidName>

where F: Fn(c_double, c_double, c_double) -> c_double + Clone,

Add a function with 3 scalar arguments. Returns true if the function was added / false if the name was already present.

impl SymbolTable

pub fn add_func4<F>(&mut self, name: &str, func: F) -> Result<bool, InvalidName>

where F: Fn(c_double, c_double, c_double, c_double) -> c_double + Clone,

Add a function with 4 scalar arguments. Returns true if the function was added / false if the name was already present.

impl SymbolTable

pub fn add_func5<F>(&mut self, name: &str, func: F) -> Result<bool, InvalidName>

where F: Fn(c_double, c_double, c_double, c_double, c_double) -> c_double + Clone,

Add a function with 5 scalar arguments. Returns true if the function was added / false if the name was already present.

impl SymbolTable

pub fn add_func6<F>(&mut self, name: &str, func: F) -> Result<bool, InvalidName>

where F: Fn(c_double, c_double, c_double, c_double, c_double, c_double) -> c_double + Clone,

Add a function with 6 scalar arguments. Returns true if the function was added / false if the name was already present.

impl SymbolTable

pub fn add_func7<F>(&mut self, name: &str, func: F) -> Result<bool, InvalidName>

where F: Fn(c_double, c_double, c_double, c_double, c_double, c_double, c_double) -> c_double + Clone,

Add a function with 7 scalar arguments. Returns true if the function was added / false if the name was already present.

impl SymbolTable

pub fn add_func8<F>(&mut self, name: &str, func: F) -> Result<bool, InvalidName>

where F: Fn(c_double, c_double, c_double, c_double, c_double, c_double, c_double, c_double) -> c_double + Clone,

Add a function with 8 scalar arguments. Returns true if the function was added / false if the name was already present.

impl SymbolTable

pub fn add_func9<F>(&mut self, name: &str, func: F) -> Result<bool, InvalidName>

where F: Fn(c_double, c_double, c_double, c_double, c_double, c_double, c_double, c_double, c_double) -> c_double + Clone,

Add a function with 9 scalar arguments. Returns true if the function was added / false if the name was already present.

impl SymbolTable

pub fn add_func10<F>( &mut self, name: &str, func: F, ) -> Result<bool, InvalidName>

where F: Fn(c_double, c_double, c_double, c_double, c_double, c_double, c_double, c_double, c_double, c_double) -> c_double + Clone,

Add a function with 10 scalar arguments. Returns true if the function was added / false if the name was already present.

Trait Implementations

impl Clone for SymbolTable

fn clone(&self) -> SymbolTable

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SymbolTable

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

Formats the value using the given formatter.

impl Default for SymbolTable

fn default() -> Self

Returns the “default value” for a type.

impl Drop for SymbolTable

fn drop(&mut self)

Executes the destructor for this type.

impl Send for SymbolTable

impl Sync for SymbolTable