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## 1 Basics

### 1.1 General Syntax

Eukleides source files should be ISO 8859-1 encoded text files. Line breaks can be either in DOS, Mac OS or Unix format.

Eukleides code consists in directives, statements and comments.

Directives are one-line special instructions starting with either the number sign (`#`) or the at sign (@).

Statements end in a semi-colon or a line break. Runs of white space are ignored. A statement may be written on more than one line using a backslash (\) as line continuation character. Statements are either assignments or commands. Command parameters require no parentheses, which differs from the syntax of the first version of the language.

Comments start with a percent sign (`%`) and run to the end of the line.

Identifiers are case sensitive. Valid symbols in identifiers are letters, underscore (`_`), ISO 8859-1 accented letters (`0xC0` to `0xFF`, except `0xD7` and `0xF7`) and (except for the first character) digits and single quote (`'`).

Default keywords are taken from the English vocabulary, hence contain only unaccented letters, but localized keywords may contain accented letters as well.

A variable may contain any type of data: number, string, point, vector, set, line, circle or conic. Assignments to single variables are made using the equal sign (`=`). A variable in use may be unset using the `clear` command.

Angular parameters may be given either in degrees or radians. An angle measure consists in a number followed by either the `deg` keyword or a colon (`:`) or a degree sign (°) for degrees or by the `rad` keyword for radians. Usage of colons is deprecated.

In this manual, optional parameters are enclosed in braces.

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