Struct DateFn 

pub struct DateFn;

Returns the serial number for a calendar date from year, month, and day.

DATE normalizes out-of-range month and day values to produce a valid calendar date.

Remarks

• Years in the range 0..=1899 are interpreted as 1900..=3799 for Excel compatibility.
• The returned serial is date-system aware and depends on the active workbook system (1900 vs 1904).
• In the 1900 system, serial mapping preserves Excel’s historical phantom 1900-02-29 behavior.

Examples

title: "Build a standard date"
formula: "=DATE(2024, 1, 15)"
expected: 45306

title: "Normalize overflowing month input"
formula: "=DATE(2024, 13, 5)"
expected: 45662

related:
  - DATEVALUE
  - YEAR
  - EDATE
faq:
  - q: "Does DATE follow the workbook 1900/1904 date system?"
    a: "Yes. DATE emits a serial in the active workbook date system, so the same calendar date can map to different serials across 1900 vs 1904 mode."

Trait Implementations

impl Debug for DateFn

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

Formats the value using the given formatter.

impl Function for DateFn

[formualizer-docgen:schema:start] Name: DATE Type: DateFn Min args: 3 Max args: 3 Variadic: false Signature: DATE(arg1: number@scalar, arg2: number@scalar, arg3: number@scalar) Arg schema: arg1{kinds=number,required=true,shape=scalar,by_ref=false,coercion=NumberLenientText,max=None,repeating=None,default=false}; arg2{kinds=number,required=true,shape=scalar,by_ref=false,coercion=NumberLenientText,max=None,repeating=None,default=false}; arg3{kinds=number,required=true,shape=scalar,by_ref=false,coercion=NumberLenientText,max=None,repeating=None,default=false} Caps: PURE [formualizer-docgen:schema:end]

fn caps(&self) -> FnCaps

Capability flags for this function

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

fn min_args(&self) -> usize

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

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 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.