truecalc-core 1.0.1

Spreadsheet formula engine — parser and evaluator for Excel-compatible formulas
Documentation 
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use chrono::{Local, Timelike};
use crate::eval::functions::{check_arity_len, EvalCtx};
use crate::eval::functions::date::serial::{date_to_serial, time_to_serial};
use crate::parser::ast::Expr;
use crate::types::Value;

/// `NOW()` — returns the current local datetime as a spreadsheet serial number.
/// Integer part = date serial; fractional part = time-of-day.
///
/// Volatile. Registered lazy so it can read the evaluation context: when the
/// context carries a pinned `now_serial` (set via `Engine::evaluate_at`,
/// P1.4 issue #526) it returns that serial verbatim — deterministic.
/// Without a pin it falls back to the ambient local clock.
pub fn now_fn(args: &[Expr], ctx: &mut EvalCtx<'_>) -> Value {
    if let Some(e) = check_arity_len(args.len(), 0, 0) {
        return e;
    }
    let serial = match ctx.ctx.now_serial {
        Some(now) => now,
        None => {
            let now = Local::now().naive_local();
            date_to_serial(now.date()) + time_to_serial(now.hour(), now.minute(), now.second())
        }
    };
    Value::Number(serial)
}

#[cfg(test)]
mod tests;