Struct MonthFn 

pub struct MonthFn;

Extracts the month number (1 to 12) from a date serial.

Remarks

• Fractional time is ignored; only the date portion contributes.
• Serials are interpreted with Excel 1900 date semantics.
• The result always uses January=1 through December=12.

Examples

title: "Extract month from January date"
formula: "=MONTH(44927)"
expected: 1

title: "Extract month from leap-day serial"
formula: "=MONTH(45351)"
expected: 2

related:
  - YEAR
  - DAY
  - EOMONTH
faq:
  - q: "Can MONTH return values outside 1 through 12?"
    a: "No. MONTH always returns an integer from 1 to 12 after serial-to-date conversion."

Trait Implementations

impl Debug for MonthFn

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

Formats the value using the given formatter.

impl Function for MonthFn

[formualizer-docgen:schema:start] Name: MONTH Type: MonthFn Min args: 1 Max args: 1 Variadic: false Signature: MONTH(arg1: number@scalar) Arg schema: arg1{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.