parentheses, more operators, some docs

docs/math.md

@@ -0,0 +1,56 @@
+# Operators
+
+## Precedence
+
+Same as in C++.
+
+|     Priority     | Operations                           |
+|:----------------:|--------------------------------------|
+| **Highest**<br>0 | power, not, calls, indexing, dot,... |
+|        1         | `%` `*` `/`                          |
+|        2         | `+` `-`                              |
+|        3         | bit shifts (NI)                      |
+|        4         | `<=>` (NI)                           |
+|        5         | `<=` `>=` `<` `>` (NI)               |
+|        6         | `==` `!=` (NI)                       |
+|        7         | `&` (NI)                             |
+|        9         | `\|` (NI)                            |
+|        10        | `&&`                                 |
+|  11<br/>lowest   | `\|\|`                               |
+
+- (NI) stands for not yet implemented.
+
+## Operators
+
+`+ - * / % `: if both operand is `Int`, calculates as int. Otherwise, as real.
+
+## Round and range
+
+The following functions return its argument if it is `Int`,
+or transformed `Real` otherwise.
+
+| name     | description                                            |
+|----------|--------------------------------------------------------|
+| floor(x) | Computes the largest integer value not greater than x  |
+| ceil(x)  | Computes the least integer value value not less than x |
+| round(x) | Rounds x                                               |
+|          |                                                        |
+|          |                                                        |
+
+## Scientific functions
+
+| name                | meaning |
+|---------------------|---------|
+| `sin(x:Real): Real` | sine    |
+|                     |         |
+|                     |         |
+|                     |         |
+
+## Scientific constant
+
+| name                 | meaning      |
+|----------------------|--------------|
+| `Math.PI: Real` or π | 3.1415926... |
+|                      |              |
+|                      |              |
+|                      |              |