---
name: superderive
description: >-
  Create or refine stepwise algebraic derivation figures — rewrite
  steps, justification rails, cancel and substitute highlights.
  Use when a rewrite must be seen (cancel-visual, subst-visual, or
  more than four steps), or the user asks for $superderive. Not for
  architecture (superfig), tensor faces (supertensor), or a full
  paper-note job (use superpaper; short rewrites stay as align).
---

# superderive

Turn one rewrite sequence into one slide-ready figure with three zones:

1. **Top — claim.** The identity being justified.
2. **Middle — steps.** `\sdstep` / `\sdcancel` / `\sdsubst` / `\sdreason`.
3. **Bottom — meaning.** Idea, rewrite, caveat.

Draw with the package. Do not hand-roll TikZ unless the linter allows it.

## When to use

- A cancel or substitution that is the claim.
- More than four rewrite steps that must stay aligned as a picture.
- An illegal vs legal pair (`\sdcol`, one per figure).

If `expand: true` and steps ≤ 4 and there is no cancel/subst visual,
superpaper still uses `align`. This package is for when the rewrite
must be *seen*.

## Workflow

1. `./scripts/preflight.sh`
2. One rewrite path. Drop equivalent expansions.
3. Roles: `keep` / `rewrite` / `cancel` / `intro` (already declared).
4. Smallest grammar: `\sdstep` + `\sdreason`; add `\sdcancel` / `\sdsubst` only when they carry information.
5. `./scripts/build.sh fig.tex` then audit `references/checklist.md`.

## Output

Editable TikZ. Build emits PDF, SVG, PNG, transparent PNG, thumbnail.

Chinese: `\usepackage[cjk]{superderive}`. English: `[en]`.