Function exec_stmts 

pub fn exec_stmts(
    stmts: &[StmtEntry],
    env: &mut Env,
    io: &mut IoContext,
    fmt: &FormatMode,
    base: Base,
    compact: bool,
) -> Result<Option<Signal>, String>

Execute a sequence of parsed statements, handling flow control signals.

Returns Ok(None) on normal completion, Ok(Some(Signal::Break/Continue)) when those flow-control statements escape a loop, or Err(e) on runtime error. Loop implementations (For, While) catch Break/Continue internally; a signal that reaches the top-level caller should be reported as an error.