Reference list of syntax elements
=================================

Space and new line characters (actually all characters identified as white
spaces by isspace()) are lexical separators.

+----------+-----------+---------+---------------------------------------------+
| Element  | Usage     | Returns | Meaning                                     |
+----------+-----------+---------+---------------------------------------------+
| a        | a         | a       | Variable a. the regular expression          |
|          |           |         | [a-zA-Z_][a-zA-Z0-9_]* applies to names.    |
+----------+-----------+---------+---------------------------------------------+
| v        | v         | v       | Temporary object of value v. It is unnamed  |
|          |           |         | and exists only within the expression,      |
|          |           |         | which is ended by ), ], , ; or ,.           |
|          |           |         | Values can be integers ([0-9]+), rationals  |
|          |           |         | (([0-9]+\.[0-9]*|[0-9]*\.[0-9]+)), or       |
|          |           |         | matrices, described with operator [].       |
|          |           |         | Values can be used wherever a variable is   |
|          |           |         | used except as the lvalue of an assignment. |
|          |           |         | A value is considered to exist when used.   |
+----------+-----------+---------+---------------------------------------------+
| =        | a = b     | a       | Store the value of b in a. b must exist. a  |
|          |           |         | is created if it didn't exist.              |
+----------+-----------+---------+---------------------------------------------+
| +        | a + b     | a + b   | Create a temporary object of value a + b. a |
| -        | a + b     | a - b   | and b must exist. The same applies to       |
|          |           |         | a - b. If both a and b are integers, the    |
|          |           |         | result is an integer. If one of them is an  |
|          |           |         | integer or a rational and the other is a    |
|          |           |         |  rational, the result is a rational. If one |
|          |           |         | of them is a matrix, the result is a        |
|          |           |         | matrix.                                     |
+----------+-----------+---------+---------------------------------------------+
| +        | +a        | a       | Create a temporary object of value a or -a. |
| -        | -a        | -a      | a must exist.                               |
+----------+-----------+---------+---------------------------------------------+
| *        | a * b     | a * b   | Create a temporary object of value a * b. a |
|          |           |         | and b must exist. The same rules as for the |
|          |           |         | + and - operators apply concerning the type |
|          |           |         | of the result.                              |
+----------+-----------+---------+---------------------------------------------+
| /        | a / b     | a / b   | Create a temporary object of value a / b. a |
|          |           |         | and b must exist. If a and b are integers   |
|          |           |         | or rationals (possibly mixing the two       |
|          |           |         | types), the result is a rational. If a is a |
|          |           |         | matrix, the result is a matrix. It is not   |
|          |           |         | possible to divide by a matrix.             |
+----------+-----------+---------+---------------------------------------------+
| +=       | a += b    | a       | a = a + b                                   |
| -=       | a -= b    | a       | a = a - b                                   |
| *=       | a *= b    | a       | a = a * b                                   |
| /=       | a /= b    | a       | a = a / b                                   |
|          |           |         | All comments concerning operators =, +, -,  |
|          |           |         | * and / apply.                              |
+----------+-----------+---------+---------------------------------------------+
| ()       | f(args)   | f(args) | Call builtin function f with args. The      |
|          |           |         | result is a temporary object. Function      |
|          |           |         | names follow the same restrictions as       |
|          |           |         | variable names. Parameters are separated    |
|          |           |         | by commas.                                  |
+----------+-----------+---------+---------------------------------------------+
| ()       | (expr)    | expr    | Evaluate an expression and return the value |
|          |           |         | of the expression, which may be a temporary |
|          |           |         | object or a variable.                       |
+----------+-----------+---------+---------------------------------------------+
| []       | [vals]    | [vals]  | Create a temporary matrix object. Rows are  |
|          |           |         | separated by ; whereas values are separated |
|          |           |         | by ,. Values can only be rationals. Integer |
|          |           |         | values will be converted automatically.     |
|          |           |         | Example : a = [1, 2; 3, 4] creates a 2x2    |
|          |           |         | square matrix of value                      |
|          |           |         |  (1 2)                                      |
|          |           |         |  (3 4)                                      |
+----------+-----------+---------+---------------------------------------------+
| ,        | expr,     | N/A     | When not used as parameter separator or     |
| ;        | expr;     | N/A     | value/row separator, these operators        |
|          |           |         | are expression separators. ; prevents       |
|          |           |         | result to be displayed.                     |
+----------+-----------+---------+---------------------------------------------+