Section 16 of 102
15. Lexical Structure
Stable section ID: S05-CON-007-SECTION-16 · 37 content blocks
The lexical structure defines the valid character, token, literal, comment, and identifier forms used by BDL text.
BDL text shall support Unicode while requiring normalized encoding for deterministic comparison.
Identifiers shall:
begin with a letter or permitted underscore;
contain letters, numbers, and permitted separators;
remain case-sensitive;
exclude whitespace;
avoid reserved keywords.
Examples:
- Column_C01
- node_n01
- Kitchen_Service_Cartridge
These identifiers are distinct:
- Node_N01
- node_n01
Strings shall use quoted form:
name: "Kitchen Service Cartridge";
Numeric literals may include:
- 120
- 120.5
- -18
- 1.2e3
Engineering quantities shall combine a value and unit:
length: 2400 mm;
load: 12.5 kN;
temperature: 21 °C;
slope: 2 percent;
Comments may use:
- // Single-line comment
- /*
- Multi-line comment
- */
- Comments shall not alter the semantic meaning of the document.
Reserved words shall include language terms such as:
- building, component, cartridge, interface, connect,
- require, prohibit, prefer, import, namespace, type,
- profile, evidence, unknown, null, true, false