d) Comments
***********
You can add comments in the functions you write up, in the "New function..." or "Function editor..." windows ; do not put comments in the console, as these will be lost and serve no purpose. The program ignores these comments. There are two types of comments : line comments and section comments

Line comments allow comments on one line only. The comments start out with a double slash ( // ). For example, the following instructions:

forward(10);
// right(90);
forward(20);

is equivalent to:

forward(30);

because the instruction right(90); is bypassed.

Section comments allow putting in a complete paragraph as an explanation or comment on certain instructions. They start out with slash asterisk ( /* ) and end with asterisk slash ( */ ). For example, the following instructions :

forward(10);
/* right(90);
forward();
this is also a comment !
*/
forward(20);

is equivalent to:

forward(30);

Note: You can also nest the two types of comments. For example :

/* this is a comment
// this is also a comment
this is still a comment !
*/
forward(20);


Ending comments
**************
To stop the execution of a function, you can hit simultaneously command and period ( . ) at any time.

Don't mix the term " variable " and the term " function ". For example, if you carry out pen color(blue); , then the turtle becomes blue. However, if you carry out instead pen color=blue;, then a new variable will be created. Its name is " pen color " and its value is blue. This second instruction will
not change the color of the turtle to blue.

Mask() and unmask(); accelerate by up to 50 % elaborate functions, but slow down shorter ones.

Logo is not, in this version 1.0 of Learn and Play , a complex language. For example, one cannot write :

variable = (12+8)*6;

instead, one must write :

variable = 12+8
variable = variable *6;

Accordingly, one cannot write :

if ((12==3) and (13==9))
{
//instructions
}

but rather :

if (12==3)
{
if (13==9)
{
//instructions
}
}