GEML 块图解 · 简单四型

==== note {#outer}
Outer holds an inner block.
=== code {lang=sh}
echo hi
===
====                    %% 外长内短，嵌套安全

=== note {#labeled}
A long block closed by a labeled fence.
=== #labeled            %% 标签围栏：不用数长度

=== note {#early}
This body contains a bare run of the opening length:
===                     ← 等长裸围栏，块在这里就关了
which closed the block above at that line.
=== #early              ← 关的是已经关掉的块

warning: labeled fence for `#early` at line 22, but block `#early`
  was already closed by a bare fence at line 20 — body may be
  silently truncated (line 22)
0 error(s), 1 warning(s)

$ geml list p1-fences.geml
#outer               note           L7-12
=== code             code     anon  L9-11
#labeled             note           L14-16
#early               note           L18-20   ← 只到 L20
#fences-after-early  prose          L21-22   ← 掉出来的两行成了散文

=== embed src=#f          ← 属性没加 {}，整行是段落
This line follows a fence-like line that had no braces.

=== note {#open}
This block is never closed.  %% 文件到此为止

warning: line looks like an open fence for `embed` but is not one —
  attributes must be braced (`=== embed {…}`); the line reads as
  plain paragraph text (line 5)
error: unterminated `note` block (no matching === or `=== #open`) (line 8)
1 error(s), 1 warning(s)   exit 1

%% a top-level comment: kept in the file, never rendered

=== note {#hiddennote hidden}
Not rendered, but referenced: still checked.
===
=== note {#badattr foo=bar}
Unknown attribute on a known type.
===
=== fancy {#unknown}
An unknown type keeps its body raw: **not parsed**.
===
See [[#hiddennote]].

=== code {lang=ts}
export const x = 1;
%% this percent line is body text inside a raw block
===

=== meta
title = "Meta probe"
version = 3
draft = true
===
=== meta
title = "Second title"       ← 同键，后到者被忽略
owner = "docs"
===

# Interpolation {#interp}

Version {{version}}, owner {{owner}}, escaped \{{version}}, code `{{version}}`.

Unknown {{nope}} key.

=== note {#cap caption="{{title}}"}
Attribute values are not interpolated.
===

warning: meta key `title` already defined at line 1; later
  definition at line 6 is ignored (line 6)
error: unknown metadata reference `{{nope}}` (line 15)

$ geml get p2-meta.geml '#meta'      ← 合并后的命名空间
title = "Meta probe"
version = 3
draft = true
owner = "docs"

$ geml get p2-meta.geml '#meta["version"]'   GEP-0011
3

=== meta
title = "a"
===
=== meta
owner = "b"
===
=== note {#meta}          ← §4：两个以上 meta 时应为 reserved-id error
Declared #meta with two meta blocks.
===

error: `#meta` is reserved for this document's merged meta namespace, and this
  document has more than one `meta` block — give the block another id (line 7)

$ geml list p2b-reserved.geml
=== meta@61f06c79  meta  anon  L1-3
=== meta@0e8db6c1  meta  anon  L4-6
#meta              note        L7-9   ← 同一个地址，一个读者读到 note，处理器读到合并

$ geml check p2c-single.geml     单个 meta 自带 {#meta}：合法
ok: no diagnostics

=== math {#euler caption="Euler"}
e^{i\pi} + 1 = 0
===
Inline math $a^2+b^2=c^2$ stays inline; block math is the typed block.
Reference: [[#euler]].

==== note {#warn .warning caption="Careful"}
A callout with **inline** markup and a nested block:
=== code {lang=sh}
geml check doc.geml
===
==== #warn
Reference: [[#warn]].

=== text {#intro}
One paragraph of addressable prose.
===
=== text {#two}
First paragraph.

Second paragraph.
===
Projection of one paragraph: ![[#intro]]. Projection of two: ![[#two]].
Reference: [[#intro]].

error: `![[#two]]` projects inline content, but the target is not a
  single-paragraph `text` block; for block content use
  `=== embed {src=#two}` (line 28)