pending-wrap-resolution

## Context The SadConsole terminal Writer uses a deferred-wrap model (PendingWrap flag) per ECMA-48 §7.1. When the cursor reaches the right margin, the wrap is deferred until the next printable character. Cursor-movement handlers must decide whether to just clear the flag (most handlers) or resolve the wrap first (advance to next line, col 0). ## Pattern: Forward-Movement PendingWrap Resolution Any handler that moves the cursor **forward along the line** (increasing column) must **resolve** PendingWrap, not just clear it. Without resolution, forward movement from the right margin is clamped to `width-1` → a no-op. ### Detection Rule A handler is AT RISK if: 1. It moves the cursor forward (increasing column index) 2. The movement is relative to the current position 3. The target is clamped at `width - 1` ### Fix Template ```csharp case 'X': // Forward-moving handler if (State.PendingWrap && State.AutoWrap) { State.PendingWrap = false; State.CursorColumn = 0; LineFeed(); } else { State.PendingWrap = false; } ApplyForwardMovement(Param(parameters, 0, 1)); break; ``` ### Handlers That Need This - CUF (CSI C) — forward cursor movement - CHT (CSI I) — forward tab - C0 HT (0x09) — tab character ### Handlers That Do NOT Need This - Absolute positioning (CUP, CHA, VPA, DECSTBM, DECOM) — target is independent of current position - Backward/vertical relative (CUU, CUD, CUB, CNL, CPL, CBT) — movement from right margin is meaningful, not clamped ## Anti-Patterns - **Blanket PendingWrap=false in dispatcher epilogue** — this is the opt-out model that caused the original b5-ans01.ans bug. Each handler manages its own PendingWrap clearing. - **Just clearing PendingWrap for forward movement** — clearing without resolution makes forward movement from the right margin a no-op. ## Examples See `Writer.cs` CUF handler (case 'C'), CHT handler (case 'I'), and C0 HT in OnC0Control for the canonical implementations.