Data Type [[data_type: SyntaxConcept]]SyntaxConcept

• dependsField

Description [[description: text]]text💡

QMD.md supports these primitive data types: string, number, boolean, null. Type auto-detection rules determine how field values are parsed.

Syntax [[syntax: text]]text💡

Type auto-detection rules (applied to field values):

1. true | false → Boolean (lowercase only)
2. null or empty value after colon → Null
3. Integer or decimal → Number (-?\d+(\.\d+)?, magnitude from 1e-4 to 2^53-1)
4. Everything else → String

NOT supported: yes, no, True, FALSE (for unambiguity)

Nor are these numeric forms — each is a String and raises unsupported_number_format, because each one only ever worked in whichever host language happened to accept it: 1e5, 1.5e-3, 2E3 (exponents), .5 and 5. (a bare leading or trailing dot), +1 (unary plus), 1_000 (digit separators), 0x10 and 0o17 (other bases). The authored text is kept as the value, so nothing is lost — the error exists so the spelling is refused out loud rather than silently reinterpreted.

A bare ~ is likewise a String, not null — that spelling belongs to YAML — but it raises no error, because it is not a number anyone mis-spelled. Infinity and NaN are plain Strings for the same reason.

Forcing string type: use quotes "123" to prevent number parsing.

Empty string requires quotes: - field: "" (without quotes, empty value = null).

Primitives [[primitives: text]]text💡

• String: text values. Quotes optional for simple strings. Required in YAML arrays for values with spaces/commas.
• Number: an integer or a decimal, optionally negative — exactly -?\d+(\.\d+)?, with a magnitude between 1e-4 and 9007199254740991 (2^53-1). No exponents, no bare leading or trailing dot, no unary plus, no digit separators, no alternative bases. A literal outside the range keeps its authored text as a String and raises unsupported_number_format, so digits are never silently rounded (9223372036854775807 stays text) and nothing is written back in a spelling the format cannot read (0.00001 would need an exponent). Within the range a decimal carries IEEE-754 double semantics, so authored precision beyond a double's is not preserved (0.1234567890123456789 reads back shorter).
• Boolean: true or false only (lowercase). True, FALSE, yes, no are strings.
• Null: keyword null or empty value after colon (- field:).
• Array: ordered list of primitives or objects. Two syntaxes: YAML notation and Markdown lists.
• Object: nested structure with fields. Created via subheadings — result is a separate object + reference in parent. Everything is flat: array of objects + [[#id]] references.
• Map: flat string dictionary (str→str). Defined via [[field: map]]. No type auto-detection — all values stored as strings.

Map Type [[map_type: text]]text💡

The map type is a flat dictionary str→str. Defined via [[field: map]] heading syntax. Type auto-detection is NOT applied: all values are stored as strings. true, false, null, numbers — everything remains a string.

### env [[env: map]]
- port: 8080
- debug: true
- count: null
- description:

Result: {"port": "8080", "debug": "true", "count": "null", "description": ""}.

Map supports multiline values via YAML pipe syntax |.

Rules [[rules: text]]text💡

• Type detection is case-sensitive: only lowercase true, false, null are recognized
• Quoted values are always strings regardless of content
• Empty value after colon = null; empty string requires quotes
• Map fields accept only bullet lists with - key: value pairs
• Invalid map entries generate invalid_map_entry error
• Non-bullet content in map fields generates invalid_map_content error