Merge branch 'dev' into parser

src/doc/syntax.md

@@ -1,19 +1,26 @@
 # Syntax
 
 ```
-point(3 | 4) -> A
-point(6 | 7) -> B
+[point(3, 4) -> A]
+point(6, 7) -> B
 
-line(A, B) -> AB
-line(0 | 0, 100 | 100)
+line[color=red, weight=4](A, B) -> AB
+line(point(0, 0), point(100, 100))
 
 circle(A, len(AB))
 ```
 
-## Primitives
-* `Point point(x, y)` is a 2D point. It returns an element of type `Point`
-* `Line line(Point from, Point to)` is a straight line. It returns an element of type `Line`.
-* `Circle circle(Point center, radius)` draws a circle at `center` and `radius`
+## Behaviour
+Every line is one instruction. It is possible to assign instructions names to re-use them later.
+These variables are immutable. Objects do not exist in this script, in fact, variables are more similar to C-style macros than actual variables.
+
+Lines in brackets `[]` are "hidden". They are parsed, but will not be rendered.
+
+It is possible to add an optional set of parameters in front of each parameter list, in order to specify the appearance of the element.
+
+## Primitives vs Functions
+Primitives (e.g. `point`, `line`) and Functions (e.g. `len`, `intersection`) are syntactically indistinguishable.
+Both can be used as parameters or instructions and can be assigned to variables. The only difference is that Primitives generate a visual output (unless they are surrounded by square brackets)
 
 ## Grammar
 ```
@@ -21,4 +28,4 @@ instruction ::= identifier({parameter, }) [-> identifer]
 parameter ::= instruction | identifier | number
 identifier ::= (A-Za-z)
 number ::= (0-9)[.(0-9)]
-```
+```