=== meta
title = "GEML — the full tour"
author = "the GEML team"
spec = "1.0"
parser = "1.10.1"
===

# {{title}} {#top}

GEML {{spec}}, reference parser {{parser}}. Seven chapters, each a real
`.geml` file next to this one — **this document writes none of them**. It points
at them, and what you are reading is the result: a tour assembled entirely by
cross-document transclusion, which is itself one of the things being toured.

In the playground, use the chapter bar above to edit any chapter on its own.
Opened as a raw file in the browser extension, the whole tour renders in place.

=== note {.tip #how}
Every reference below is checked when this document is parsed. Press **Break a
reference** and the validity pill flips red — a dangling pointer is never
rendered quietly.
===

## 1 — One document is one tree {#ch1}

=== embed {src=ch01-basics.geml#b-top}
===

## 2 — Facts and derivation are different jobs {#ch2}

=== embed {src=ch02-relation.geml#r-top}
===

## 3 — A unit inside a block has an address {#ch3}

=== embed {src=ch03-coordinates.geml#c-top}
===

## 4 — One block, three engines {#ch4}

=== embed {src=ch04-data.geml#d-top}
===

## 5 — Charts, formulas, and a call graph that reads itself {#ch5}

=== embed {src=ch05-visual.geml#v-top}
===

## 6 — Reuse without copying {#ch6}

=== embed {src=ch06-reuse.geml#u-top}
===

## 7 — One source, many languages {#ch7}

=== embed {src=ch07-projection.geml#p-top}
===

%% A %% line is a comment: kept in the model, never rendered.

=== note {#refs}
Seven files, one page, zero duplication. Change a chapter and this tour changes
with it — which is the whole argument for addressing content instead of copying
it.
===