=== meta
title = "GEML feature tour"
author = "the GEML team"
release = "1.0"
===

# {{title}} {#top}

One document, written in GEML {{release}} by {{author}} — edit it, or hit
**Break a reference** to watch `geml check` fail the build. This opening is a
*flow* paragraph, so it carries inline markup: **strong**, ~~struck~~,
`inline code`, inline math $a^2 + b^2$, a [link](https://geml-spec.github.io/geml/),
an auto-reference to [[#revenue]], and a footnote.[^refs]

=== note {.tip}
A `note` is a callout with full inline markup. It can point at other blocks —
see the [[#revenue]] table and the [[#roadmap]] below. Finer intent goes on a
class, e.g. `=== note {.warning}` or `{.aside}`.
===

## Roadmap {#roadmap}

Task lists render as checkboxes; lists nest by indentation:

- [x] Ship the 1.0 spec
- [x] Publish the reference parser and CLI
- [ ] Recruit a second implementation
  - [ ] Python
  - [ ] Rust

Release steps, in order:

1. Tag the release
2. Publish to npm
3. Announce

## Numbers {#numbers}

A `table` in data form with a **computed column** and a **summary row** — the
`FY` column and the `Total` row are computed at build time:

=== table {#revenue caption="Revenue by segment" format=csv header=1 compute="FY [%.0f] = Q1 + Q2 + Q3 + Q4" summary="Segment = 'Total'; FY [%.0f] = sum(FY)"}
Segment, Q1, Q2, Q3, Q4
Cloud,    8, 10, 12, 14
Platform, 5,  6,  7,  9
Services, 3,  4,  4,  5
===

A `geml-chart` charts that table **by reference** — one source of truth, the
column names checked at build time, no data copied:

=== diagram {#chart format=geml-chart data=#revenue type=bar x=Segment y=FY caption="FY by segment"}
===

## Code, math, diagrams {#more}

A `code` block keeps its body verbatim:

=== code {#hello lang=python}
def greet(name):
    return f"hi {name}"
===

A `math` block, rendered with KaTeX:

=== math {#pythagoras caption="Pythagoras"}
c^2 = a^2 + b^2
===

A `diagram` hosts an external DSL — GEML never interprets the body, a renderer
does. This one is Mermaid, and renders below:

=== diagram {#flow format=mermaid caption="Review flow"}
graph LR
  A[Draft] --> B{Review} --> C[Publish]
===

`geml-code-graph` is different: GEML *does* interpret it. It points at a
codemap — a call graph stored as checked GEML documents. The one below is
**this repository's own source** — the reference parser and the viewer that
is rendering this page — generated by `geml codemap build` (SCIP). The
two clusters meet only at the package boundary: the viewer calls the parser's
built API, not its internals. **Click a module to open its rendered page**:

=== diagram {#modmap format=geml-code-graph src=codemap/index.geml caption="geml-parser + geml-viewer — module overview (their own codemap)"}
===

And one container from the same codemap at method level, rooted at
`renderHtml` — **click a node for its callee chain; the ⊕ on an entry node
expands the complete caller chain up to the app entry**, and the breadcrumb
(`modules / container`) walks back up without leaving the page. Dashed red =
recursion back-edge, dotted = dispatch candidate, dimmed = leaf helper:

=== diagram {#callmap format=geml-code-graph src=codemap/geml-parser--render.ts.geml caption="geml-parser/src/render.ts — layered method flow (interactive)"}
===

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

[^refs]: Every reference — `[[#id]]`, `[text](#id)`, `[^footnote]`, a chart's `data=#id` — is checked at build time. Break one and the build fails.