Method call_format

compiler/src/modules/vm/builtins/io.rs:101–119

`format(value [, spec])`.

(&mut self, op: u16, chunk: &crate::modules::parser::SSAChunk, slots: &mut [Val])

    // `format(value [, spec])`.
    pub fn call_format(&mut self, op: u16, chunk: &crate::modules::parser::SSAChunk, slots: &mut [Val]) -> Result<(), VmErr> {
        if op != 1 && op != 2 {
            return Err(cold_type("format() takes 1 or 2 arguments"));
        }
        let spec_val = if op == 2 { Some(self.pop()?) } else { None };
        let val = self.pop()?;
        let result = match spec_val {
            Some(sv) => {
                // `sv` may be a non-heap value (int/float); guard before indexing the heap.
                let spec = match sv.is_heap().then(|| self.heap.get(sv)) {
                    Some(HeapObj::Str(s)) => s.clone(),
                    _ => return Err(cold_type("format() spec must be a string")),
                };
                self.format_op(val, &spec, chunk, slots)?
            }
            None => self.display_op(val, chunk, slots)?,
        };
        self.alloc_and_push_str(result)
    }
}