Feature: Support regex flags in tags.Pattern (for Unicode property escapes) #1699
Description
Feature Request
Problem
The tags.Pattern type does not support regex flags. This prevents using Unicode property escapes (\p{ID_Start}, \p{ID_Continue}) which require the u flag.
Use Case
Validating ECMAScript identifiers per UAX #31 requires Unicode property escapes:
// Standard JavaScript approach
const pattern = /^[\p{ID_Start}_$][\p{ID_Continue}_$]*$/u;
// With typia - no way to specify the 'u' flag
type Identifier = string & tags.Pattern<"^[\\p{ID_Start}_$][\\p{ID_Continue}_$]*$">;Current Workaround
Manually expand all Unicode character ranges from DerivedCoreProperties.txt:
const ID_Start = [
"\\u0041-\\u005A", // Latin uppercase
"\\u0061-\\u007A", // Latin lowercase
"\\u00C0-\\u00D6", // Latin Extended
// ... 448 ranges total for full BMP coverage
].join("");
type Identifier = string & tags.Pattern<`^[_$${typeof ID_Start}][_$0-9${typeof ID_Start}]*$`>;This workaround:
- Produces unreadable generated code
- Cannot cover astral planes (characters > U+FFFF)
- Requires manual updates when Unicode standard changes