Parsing & formatting

Accepted syntax

• Optional leading sign: + or -
• Digits with optional single .
• No exponent form (e / E)

Examples: - 0 - -0.1 - 123.0004

Formatting

• uint128/int128: minimal digits, no leading zeros.
• Numeric128<P,S>: prints exactly S digits after . when S>0.
• Numeric: prints according to current scale() (no trimming beyond internal normalization).