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# Syntax and Vocabulary

The syntax of Gentle is defined in the Extended Backus Naur Formalism which uses the following conventions: `X|Y` denotes `X` or `Y`, `[X]` denotes `X` or empty, `{X}` denotes a possibly empty sequence of `X`'s, and `(X)` denotes `X`.

Terminal symbols are enclosed in quotes. In addition, Ident denotes a sequence composed of letters, digits, and underscores and starting with a letter. IdentLC is an Ident that starts with a lower-case letter, IdentUC is an Ident that starts with an upper-case letter. Number denotes a sequence of decimal digits. String denotes a possibly empty sequence of characters enclosed in quotes (``"`'). Inside a String, the sequence `\t' represents a tabulator, `\n' represents a new-line character, `\\' stands for `\', and `\"' stands for `"'.

Blanks, newlines, tabulators, and comments may be inserted between symbols. A comment is a sequence of characters starting with ``-`' and ending at the end of the line, or a sequence of characters enclosed in ``/*`' and ``*/`' (comments of this style may be nested).