Currencies are a bit strange; the layout of currency data in the CLDR is
not particularly compatible with what ECMA-402 expects. For example, the
currency format in the "en" and "ar" locales for the Latin script are:
en: "¤#,##0.00"
ar: "¤\u00A0#,##0.00"
Note how the "ar" locale has a non-breaking space after the currency
symbol (¤), but "en" does not. This does not mean that this space will
appear in the "ar"-formatted string, nor does it mean that a space won't
appear in the "en"-formatted string. This is a runtime decision based on
the currency display chosen by the user ("$" vs. "USD" vs. "US dollar")
and other rules in the Unicode TR-35 spec.
ECMA-402 shies away from the nuances here with "implementation-defined"
steps. LibUnicode will store the data parsed from the CLDR however it is
presented; making decisions about spacing, etc. will occur at runtime
based on user input.
For example, there isn't a unique set of data for the en-US locale;
rather, it defaults to the data for the en locale. See this commit for
much more detail: 357c97dfa8
These are used when formatting a number as currency with a display
option of "name" (e.g. for USD, the name is "US Dollars" in en-US).
These patterns appear in the CLDR in a different manner than other
number formats that are pluralized. They are of the form "{0} {1}",
therefore do not undergo subpattern replacements.
