Enum NumberArg 

pub enum NumberArg {
    Literal(LitInt),
    ConstExpr {
        const_token: Const,
        kind: NumberKind,
        block: Block,
    },
    Constant {
        kind: NumberKind,
        dbl_colon: PathSep,
        ident: MinOrMax,
    },
}

Represents a numerical argument obtained from parsing proc macro input tokens.

NumberArg can represent three kinds of numerical data:

• A literal value directly specified in the input.
• A primitive number constant, which is a predefined constant value.
• An expression that is evaluated at compile time using the Rhai scripting engine.

This enum is designed to work within the context of procedural macros, where it helps in interpreting and manipulating numerical inputs. It provides flexibility in handling both simple numerical values and complex expressions that need to be evaluated.

The NumberArg can be converted into a NumberValue type through the into_value method. This conversion allows for direct operations on the underlying numerical value, supporting various primitive number types (e.g., u8, u16, i32, usize, etc.).

Example usage:

let num_arg: NumberArg = parse_macro_input!(input as NumberArg);
let num_value: NumberValue = num_arg.into_value(NumberKind::U32);
// Now `num_value` can be used for further numerical operations.

Note: The into_value method panics if the conversion fails, so it should be used within a context where panicking is acceptable or handled appropriately.

Variants

Literal(LitInt)

ConstExpr

Fields

const_token: Const

kind: NumberKind

block: Block

Constant

Fields

kind: NumberKind

dbl_colon: PathSep

ident: MinOrMax

Implementations

impl NumberArg

pub const LIMITS_INIT: (Option<Self>, Option<Self>)

pub fn new_min_constant(kind: NumberKind) -> Self

Create a new NumberArg instance for a NumberKind’s minimum value.

pub fn new_max_constant(kind: NumberKind) -> Self

Create a new NumberArg instance for a NumberKind’s maximum value.

pub fn from_expr(expr: &Expr) -> Self

Helper method to create a NumberArg instance from a syn::Expr. Mostly useful for testing.

pub fn from_lit(lit: &LitInt) -> Self

Helper method to create a NumberArg instance from a syn::LitInt. Mostly useful for testing.

pub fn from_range_expr(kind: NumberKind, expr: &ExprRange) -> (Self, Self)

Helper method to create a pair of NumberArg instances from a syn::ExprRange. Mostly useful for testing.

pub fn min(&self, other: &Self, kind: NumberKind) -> Self

Create a new NumberArg instance from the lesser of two inputs.

pub fn max(&self, other: &Self, kind: NumberKind) -> Self

Create a new NumberArg instance from the greater of two inputs.

pub fn into_value(&self, kind: NumberKind) -> NumberValue

Convert the NumberArg into a NumberValue instance.

pub fn into_literal_as_tokens(&self, kind: NumberKind) -> TokenStream

Output the value as a bare literal number in a token stream.

pub fn base10_parse<N>(&self) -> Result<N>

where N: FromStr, N::Err: Display,

Parse the value as a base 10 number.

Trait Implementations

impl Clone for NumberArg

fn clone(&self) -> NumberArg

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for NumberArg

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

Formats the value using the given formatter.

impl Display for NumberArg

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

Formats the value using the given formatter.

impl Parse for NumberArg

fn parse(input: ParseStream<'_>) -> Result<Self>

impl ToTokens for NumberArg

fn to_tokens(&self, tokens: &mut TokenStream)

Write self to the given TokenStream.

fn to_token_stream(&self) -> TokenStream

Convert self directly into a TokenStream object.

fn into_token_stream(self) -> TokenStream

where Self: Sized,

Convert self directly into a TokenStream object.