On several occasions in this documentation, we'll be using a formalism to explain XLIA syntax and grammar. This formalism is inspired by the BNF i.e. Backus-Naur Form.
Symbols for the grammar meta-language are in orange :
Terminal symbols i.e. language keywords, are in red, and non-terminals in green.
In black are variable names and standard non-terminals (e.g. statement, expression) that will not be recalled in this document.