Struct RandFn 

pub struct RandFn;

Trait Implementations

impl Debug for RandFn

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

Formats the value using the given formatter.

impl Function for RandFn

Returns a uniformly distributed pseudo-random number in the interval [0, 1).

RAND is volatile and recalculates whenever dependent formulas recalculate.

Remarks

• The result is always greater than or equal to 0 and strictly less than 1.
• Because the function is volatile, repeated evaluations can return different values.
• The engine seeds randomness per evaluation context for reproducible execution flows.

Examples

title: "RAND stays within bounds"
formula: "=LET(n, RAND(), AND(n>=0, n<1))"
expected: true

title: "Derived integer bucket from RAND"
formula: "=LET(n, INT(RAND()*10), AND(n>=0, n<=9))"
expected: true

related:
  - RANDBETWEEN
  - LET
  - INT
faq:
  - q: "Can RAND return the same value on every recalculation?"
    a: "Not by default. RAND is volatile, so recalculation can produce a different sample each time."
  - q: "If RAND is used twice in one formula, do both uses share one sample?"
    a: "Only if you bind it once (for example with LET). Two separate RAND calls are two separate draws."
  - q: "Why does RAND look deterministic in some engine runs?"
    a: "Randomness is seeded per evaluation context, which keeps a run reproducible while still treating RAND as volatile across recalculations."

[formualizer-docgen:schema:start] Name: RAND Type: RandFn Min args: 0 Max args: 0 Variadic: false Signature: RAND() Arg schema: [] Caps: VOLATILE [formualizer-docgen:schema:end]

fn caps(&self) -> FnCaps

Capability flags for this function

fn name(&self) -> &'static str

fn min_args(&self) -> usize

fn eval<'a, 'b, 'c>( &self, _args: &'c [ArgumentHandle<'a, 'b>], ctx: &dyn FunctionContext<'b>, ) -> Result<CalcValue<'b>, ExcelError>

The unified evaluation path.

fn namespace(&self) -> &'static str

fn variadic(&self) -> bool

fn volatile(&self) -> bool

fn arg_schema(&self) -> &'static [ArgSchema]

fn aliases(&self) -> &'static [&'static str]

Optional list of additional alias names (case-insensitive) that should resolve to this function. Default: empty slice. Implementors can override to expose legacy names. Returned slice must have ’static lifetime (typically a static array reference).

fn function_salt(&self) -> u64

fn eval_reference<'a, 'b, 'c>( &self, _args: &'c [ArgumentHandle<'a, 'b>], _ctx: &dyn FunctionContext<'b>, ) -> Option<Result<ReferenceType, ExcelError>>

Optional reference result path. Only called by the interpreter/engine when the callsite expects a reference (e.g., range combinators, by-ref argument positions, or spill sources).

fn dispatch<'a, 'b, 'c>( &self, args: &'c [ArgumentHandle<'a, 'b>], ctx: &dyn FunctionContext<'b>, ) -> Result<CalcValue<'b>, ExcelError>

Dispatch to the unified evaluation path with automatic argument validation.