Exit Lane Rise Bundle Order

Gallery / Inter-section Routing

A section taller than the one it feeds, so its RIGHT exit port sits a lane above its own trunk and the two-line bundle climbs to reach it. One line arrives level from the same row and the other descends from the row above, which fixes the pair's lane order at the entry; the climb carries that order through to the exit rather than crossing the two lines on the rise (issue #1770).

Mermaid source

%% Regression fixture for issue #1770.  The `mid` section is taller than the
%% `dest` section it feeds, and both are top-aligned in the row, so mid's trunk
%% sits below its own RIGHT exit port: the two-line bundle out of `m_merge`
%% climbs a lane to reach the port.  `alpha` arrives level from `feed` while
%% `beta` descends from `upper`, so the entry-port phases re-slot the bundle
%% after the exit port has already taken its own order; the climb must carry
%% that re-slot through instead of crossing the pair on the rise.
%%metro title: Exit-lane rise bundle order
%%metro style: dark
%%metro diamond_style: symmetric
%%metro file: mid_report | HTML | Mid report
%%metro line: alpha | Alpha | #e6007e
%%metro line: beta | Beta | #2db572
%%metro grid: upper | 0,0
%%metro grid: feed | 0,1
%%metro grid: mid | 1,1
%%metro grid: dest | 2,1

graph LR
    subgraph upper [Upper]
        u1[U1]
    end

    subgraph feed [Feed]
        f1[F1]
    end

    subgraph mid [Mid]
        m_prep[Prep]
        m_a[A]
        m_b[B]
        m_merge[Merge]

        m_prep -->|alpha,beta| m_a
        m_prep -->|alpha,beta| m_b
        m_a -->|alpha,beta| m_merge
        m_b -->|alpha,beta| m_merge
        m_merge -->|alpha,beta| mid_report
    end

    subgraph dest [Dest]
        d1[D1]
    end

    u1 -->|beta| m_prep
    f1 -->|alpha| m_prep
    m_merge -->|alpha,beta| d1

CLI command

nf-metro render examples/topologies/exit_lane_rise_bundle_order.mmd -o exit_lane_rise_bundle_order.svg

Rendered map