Enum Value 

pub enum Value {
    Float(Float),
    Integer(Integer),
    Complex(Complex),
    Boolean(bool),
    Unit,
    List(Rc<RefCell<Vec<Value>>>),
    Range(Box<Value>, RangeKind, Box<Value>),
    Function(Function),
}

Represents any value that can be stored in a variable.

Variants

Float(Float)

A floating-point value.

Integer(Integer)

An integer value.

Complex(Complex)

A complex number value.

Boolean(bool)

A boolean.

Unit

The unit type, analogous to () in Rust.

List(Rc<RefCell<Vec<Value>>>)

A list of values.

In cas-rs, a list is a reference to a vector of values. This is done to allow efficient cloning of lists, as well as mutation of lists in-place. References are passed around by default, which can result in somewhat confusing behavior, for example:

a = [1, 2, 3]
b = a
b[0] = 4
print(a) // prints [4, 2, 3]

TODO: In the future, a clone method may be added to cas-rs to allow the user to explicitly clone the list instead of copying the reference.

Range(Box<Value>, RangeKind, Box<Value>)

A range representing a sequence of values, either half-open or closed.

Function(Function)

A function.

Functions are treated as values just like any other value in cas-rs; they can be stored in variables, passed as arguments to other functions, and returned from functions.

Implementations

impl Value

pub fn typename(&self) -> &'static str

Returns the typename of this value.

pub fn coerce_float(self) -> Self

Consumes and attempts to coerce the value to a real number. Note that this coercion can be lossy if converting an arbitrary-precision integer to a fixed-width float. To preserve precision, see Value::coerce_integer and Value::coerce_number.

This conversion only occurs if one of the following is true:

• The value is an integer.
• The value is a complex number with a zero imaginary part.

This is useful for when evaluation of an expression results in a Value::Complex with a zero value for the imaginary part. Using a complex number for certain operators, such as the bitwise operators, will result in an error, so we will need to coerce those values to Value::Float instead.

pub fn coerce_integer(self) -> Self

Consumes and attempts to coerce the value to an integer. This coercion is lossless.

This conversion only occurs if one of the following is true:

• The value is a float with a zero fractional part.
• The value is a complex number with a zero imaginary part, and a real part with a zero fractional part.

pub fn coerce_number(self) -> Self

Consumes and attempts to coerce the value to a real number or an integer, preferring integers if possible. This coercion is lossless.

This conversion follows these rules:

• If the value is an integer, it is returned as-is.
• If the value is a float with a zero fractional part, it is converted to an integer. Otherwise, it is returned as-is.
• If the value is a complex number with a zero imaginary part, either an integer or float is returned if the real part is an integer or float, respectively. Otherwise, it is returned as-is.

pub fn coerce_complex(self) -> Self

Consumes and attempts to coerce the value to a complex number. This coercion is lossless.

pub fn into_degrees(self) -> Self

Converts this value from radians to degrees. If it is a real number, it is converted as usual. If it is a complex number, the real and imaginary parts are converted separately.

pub fn into_radians(self) -> Self

Converts this value from degrees to radians. If it is a real number, it is converted as usual. If it is a complex number, the real and imaginary parts are converted separately.

pub fn is_float(&self) -> bool

Returns true if this value is a real number, or can be coerced to one.

pub fn is_integer(&self) -> bool

Returns true if this value is an integer, or can be coerced to one.

pub fn is_complex(&self) -> bool

Returns true if this value is a complex number, or can be coerced to one.

pub fn is_boolean(&self) -> bool

Returns true if this value is a boolean.

pub fn is_unit(&self) -> bool

Returns true if this value is a unit type.

pub fn is_list(&self) -> bool

Returns true if this value is a list.

pub fn is_truthy(&self) -> bool

Returns true if this value is truthy.

For each type, the following values are considered “truthy”:

• Float: any value except 0.0 and NaN
• Integer: any value except 0
• Complex: any value except 0.0 + 0.0i and NaN + NaNi
• Bool: true
• Unit: never true; always false
• List: lists with at least one element; element(s) does not have to be truthy
• Range: ranges with at least one element; element(s) does not have to be truthy
• Function: always true

pub fn fmt(&self, options: FormatOptions) -> ValueFormatter<'_>

Returns a formatter for the value with the given options.

Trait Implementations

impl Clone for Value

fn clone(&self) -> Value

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Value

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

Formats the value using the given formatter.

impl Display for Value

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

Formats the value using the given formatter.

impl From<()> for Value

fn from(_: ()) -> Self

Converts to this type from the input type.

impl From<Complex> for Value

fn from(c: Complex) -> Self

Converts to this type from the input type.

impl From<Float> for Value

fn from(n: Float) -> Self

Converts to this type from the input type.

impl From<Integer> for Value

fn from(n: Integer) -> Self

Converts to this type from the input type.

impl From<Vec<Value>> for Value

fn from(values: Vec<Value>) -> Self

Converts to this type from the input type.

impl From<bool> for Value

fn from(b: bool) -> Self

Converts to this type from the input type.

impl From<f64> for Value

fn from(n: f64) -> Self

Converts to this type from the input type.

impl From<i64> for Value

fn from(n: i64) -> Self

Converts to this type from the input type.

impl PartialEq for Value

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl StructuralPartialEq for Value