mdz_helpers.ts

Check if position in text is the start of an absolute path (starts with /). Must be preceded by whitespace or be at the start of the string. Rejects // (comments/protocol-relative) and / (bare slash).

Check if position in text is the start of a relative path (./ or ../). Must be preceded by whitespace or be at the start of the string. Requires at least one path character after the prefix.

Check if character code is a letter (A-Z, a-z).

Check if character code is valid for tag name (letter, number, hyphen, underscore).

Check if character code is valid in URI path per RFC 3986. Validates against the pchar production plus path/query/fragment separators.

Valid characters: - unreserved: A-Z a-z 0-9 - . _ ~ - sub-delims: ! $ & ' ( ) * + , ; = - path allowed: : @ - separators: / ? # - percent-encoding: %

Check if character is part of a word for word boundary detection. Used to prevent intraword emphasis with _ and ~ delimiters.

Formatting delimiters (*, _, ~) are NOT word characters - they're transparent. Only alphanumeric characters (A-Z, a-z, 0-9) are considered word characters.

This prevents false positives with snake_case identifiers while allowing adjacent formatting like **bold**_italic_.

Trim trailing punctuation from URL/path per RFC 3986 and GFM rules. - Trims simple trailing: .,;:!?] - Balanced logic for () only (valid in path components) - Invalid chars like [] {} are already stopped by whitelist, but ] trimmed as fallback

Optimized to avoid O(n²) string slicing - tracks end index and slices once at the end.