num/num_intl_format_extensions library

Locale-aware number formatting via intl's CLDR data — an opt-in module that pulls the intl dependency, mirroring date_time_intl_display_extensions.dart.

The rest of lib/num/ formats numbers manually (see num_locale_utils.dart's formatNumberLocale, which inserts caller-supplied separator strings every three digits with NO locale data). These extensions exist because a manual separator-insertion cannot know that fr_FR groups with U+202F (a NARROW no-break space), that de_DE swaps ./,, or that en_IN groups in a ##,##,##0 (2-2-3) pattern. intl carries the CLDR tables that encode all of that, and accepts arbitrary ICU number patterns the manual helper cannot express. None of the logic is domain-specific; it operates on any num.

Extensions

NumIntlFormatExtensions on num
Locale-aware number formatting backed by intl's CLDR number-symbol data.