currencies in client never drifts from the server from now on

common/proto/table_definition.proto

@@ -743,4 +743,8 @@ message ListColumnTypesResponse {
 
   // Every column type, declarable or not, ordered by name.
   repeated ColumnType column_types = 1;
+
+  // Every canonical ISO-4217 code accepted by currency-bearing columns and
+  // profile accounting settings, ordered alphabetically.
+  repeated string currency_codes = 2;
 }

common/src/money.rs

@@ -18,6 +18,24 @@ pub fn require_iso_currency_code(currency_code: &str) -> Result<&'static iso::Cu
     iso::find(currency_code).ok_or_else(|| format!("Unknown ISO-4217 currency: {currency_code}"))
 }
 
+/// Returns every currency accepted by [`require_iso_currency_code`], ordered by
+/// its canonical alphabetic code.
+pub fn iso_currency_codes() -> Vec<&'static str> {
+    let mut currencies = Vec::new();
+    for first in b'A'..=b'Z' {
+        for second in b'A'..=b'Z' {
+            for third in b'A'..=b'Z' {
+                let bytes = [first, second, third];
+                let code = std::str::from_utf8(&bytes).expect("uppercase ASCII currency code");
+                if let Some(currency) = iso::find(code) {
+                    currencies.push(currency.iso_alpha_code);
+                }
+            }
+        }
+    }
+    currencies
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

common/src/proto/komp_ac.table_definition.rs

@@ -734,6 +734,10 @@ pub struct ListColumnTypesResponse {
     /// Every column type, declarable or not, ordered by name.
     #[prost(message, repeated, tag = "1")]
     pub column_types: ::prost::alloc::vec::Vec<list_column_types_response::ColumnType>,
+    /// Every canonical ISO-4217 code accepted by currency-bearing columns and
+    /// profile accounting settings, ordered alphabetically.
+    #[prost(string, repeated, tag = "2")]
+    pub currency_codes: ::prost::alloc::vec::Vec<::prost::alloc::string::String>,
 }
 /// Nested message and enum types in `ListColumnTypesResponse`.
 pub mod list_column_types_response {