Elona foobar has a string interpolation system to localize various text. Here is a complete syntax of the interpolation.
The syntax is writte in Extended Backus-Naur form (EBNF).
replacement ::= "{" exp "}"
exp ::= "nil"
| "false"
| "true"
| INT
| FLOAT
| STR
| IDENT "(" args ")"
| IDENT "." IDENT "(" args ")"
args ::= { exp separated by "," }
IDENT ::= /[A-Za-z_][A-Za-z_0-9]*/
INT ::= /[0-9]+/
FLOAT ::= /TBD/
STR ::= /TBD/