Macro pahs::sequence_with

macro_rules! sequence_with {
    ($pd:expr, $pos:expr, {let $x:pat = $parser:expr; $($rest:tt)*}, $creator:expr) => { ... };
    ($pd:expr, $pos:expr, {$x:pat = $parser:expr; $($rest:tt)*}, $creator:expr) => { ... };
    ($pd:expr, $pos:expr, {}, $creator:expr) => { ... };
}

Runs parsers one after another, optionally saving their results. Then, calls the creator function that builds a value based on the saved results.

Short-circuits if any parser fails.