corvus-ecma-regex

name

corvus-ecma-regex

description

Translate ECMAScript 262 /u mode regular expressions to .NET regex patterns. Covers semantic differences between ECMAScript and .NET regex engines, supplementary code point handling via surrogate pairs, Unicode property escapes, backreference conditionals, character class strategies, and strict /u mode validation. USE FOR: understanding regex translation in generated validation code, debugging pattern matching issues in JSON Schema pattern/patternProperties, extending regex support for new Unicode properties or constructs. DO NOT USE FOR: general .NET regex usage, writing custom regex patterns.

ECMAScript Regex Translation

Entry Point API

The translator is in src/Corvus.Text.Json.CodeGeneration/EcmaRegexTranslator.cs:

// Translate an ECMAScript /u mode pattern to .NET
string dotnetPattern = EcmaRegexTranslator.Translate(@"\d+\.\d+");

// Non-throwing variant with span output
OperationStatus status = EcmaRegexTranslator.TryTranslate(
    ecmaPattern, buffer, out int charsWritten);

// Safe fallback — returns original pattern if translation fails
string pattern = EcmaRegexTranslator.TranslateOrFallback(ecmaPattern);

Translation Examples

ECMAScript Pattern	.NET Translation	Reason
.	[^\n\r\u2028\u2029]	Dot excludes specific line terminators
\d	[0-9]	ASCII digits only