Afterword

The preface made one promise in three clauses: read a pipeline aloud on day one, write one on day two, and still have it after a year away. If you have come through the book, the first clause was settled by the reading practice and the second by the writing practice, on the same day if you wanted. The third clause cannot be settled by a book at all, and this page is about being honest with what remains.

The ten questions

Here is the only exercise this book assigns, and it is the whole test. For the next ten working days, bring one question a day from your own data, not the cast’s, and answer it in one sentence. Small questions count. A total you already know from a dashboard is a fine question, because checking a known answer is how you learn to trust a new tool with an unknown one.

Two rules make it a fair trial. Write the sentence before opening this book, and only then look anything up. Recall is the skill, and looking up after an attempt strengthens it where looking up before replaces it. And read each finished sentence aloud once. By day ten you should be writing sentences this book never showed you, which is the only outcome that would prove you learned the grammar rather than the examples.

The year away

Then the real test, which neither you nor this book can hurry: put it down. Work takes you where it takes you, and some month next year a table will land in front of you again. The measure of this grammar is what happens in that minute, before any manual is open. Does keep the rows where, total by, sort, take ten come back as a sentence you can say? Everything in the design, the closed vocabulary, the one-way spellings, the words that repeat, was aimed at that minute. The author cannot be there for it, and that is exactly why the laws exist in writing.

If it breaks, say so

This book made falsifiable claims, on purpose, and you now know enough to falsify them. A thing you can say two ways. A refusal that names no repair. A sentence that reads differently in the two languages. A page whose tabs disagree. Any of these is a defect, none of them is yours to route around, and a report of one is worth more to this project than praise. The repository takes issues at https://github.com/psychometrician/god, and the margin of every page has a link.

The grammar is young, and the version number the coverage appendix records means what it says. What it will not do is grow casually. Every word that enters answers to the laws, and the vocabulary you learned here is intended to be the vocabulary, not this year’s draft of it. Stability is a feature you were promised, and it binds the road ahead.

Thanks

dplyr and tidyr showed that data manipulation could read as sentences, and god’s debt to them is on every page here. DuckDB and Spark do the actual work, superbly, for free. The sibling project’s book taught this one how to be a book. And whoever read this far: the grammar only becomes real when somebody says its sentences to a table the author has never seen. That is you, tomorrow morning, with the first of ten questions.

Say it once. Run it anywhere.