docs: add more info about sets and for-in loop

doc/pascalprogramming.md

@@ -20,7 +20,38 @@ Note that the **char** type is a 32-bit type, and strings contain bytes. Non-ASC
 When indexing a string, the result is a **char** type with bits 31 to 8 set to zero. When assigning a **char** to an indexed string element, the destination byte is set to bits 7 to 0 from the **char** variable. Bits 31 to 8 are ignored.
 
 ## For-in Loop
-The for-in-loop which allows iterating over a string or a linear array of scalar variables is supported. It is more efficient than using a for loop for indexing a string or an array, because no bounds checks are needed.
+The for-in-loop is supported, which allows iterating over a string or a linear array of scalar variables. It is more efficient than using a for loop for indexing a string or an array, because no bounds checks are needed on each iteration.
+
+String Example:
+```
+var s:string;
+    c:char;
+
+	...
+
+	s := 'Test';
+
+	for c in s do
+		writeln(ord(c));
+
+	...
+```
+
+Array Example:
+```
+var a:array [1..3] of integer;
+    i:integer;
+
+	...
+
+	a[1] := 3; a[3] := 2; a[5] := 1; 
+
+	for i in a do
+		writeln(i);
+
+	...
+
+```
 
 ## Sets
 The maximum number of elements in a set is 32. This makes a SET OF CHAR impossible.
@@ -39,9 +70,32 @@ The _in_ operator also works for linear arrays, so the _if_ statement will have
 
 Note that the array _in_ operator will be more inefficient for larger ranges (i.e. `'A'..'z'`), but more efficient for sparse sets (i.e. `'A','z'`).
 
+A set literal can only appear on the right side of an assignment to a set variable, or when passing an argument of a set type to a procedure/function.
+
+Example:
+```
+program settest;
+type weekday = (Mon,Tue,Wed,Thu,Fri,Sat,Sun);
+     days = set of weekday;
+
+var s:days;
+    d:weekday;
+
+begin
+	s := [Sat,Sun]; (* set literal  *)
+
+	d := Sun;
+	if d in [Sat,Sun] then (* array literal, IN operator for arrays *)
+		writeln('weekend');
+
+	if d in s then   (* IN operator for sets *)
+		writeln('also weekend');
+end.
+```
+
 ## Break and Continue Statements
 
-Wirth Pascal has no statement to exit a loop. Other Pascal dialects have the _break_ and _continue_ statements to exit the loop or skip to the next iteration.
+Wirth Pascal has no statement to exit a loop other than the loop condition. Other Pascal dialects have the _break_ and _continue_ statements to exit the loop or skip to the next iteration.
 
 Tridora-Pascal only supports the _break_ statement at the moment.
 

doc/vga.md

@@ -39,7 +39,7 @@ Video memory uses a linear layout, with words using an address increment of one.
 The first word (horizontal pixel coordinates 0-3) is at address 0, the second (coordinates 4-7) at address 1 etc.
 The first line starts at address 0, the second at address 80 etc.
 
-To access video memory, the corresponding video memory address must be written to a latch register, then pixel data can be read or written by the I/O register. Reading and writing uses separate latch registers (the "Read Adress" and "Write Address" registers. To read the same word and write it back, both addresses need to be set.
+To access video memory, the corresponding video memory address must be written to a latch register, then pixel data can be read or written by the I/O register. Reading and writing uses separate latch registers (the "Read Adress" and "Write Address" registers, _FB_RA_ and _FB_WA_). To read the same word and write it back, both addresses need to be set.
 Both registers have an auto-increment function. After reading the I/O register, the FB_RA register is ingremented by one. After writing to the I/O register, the FB_WA register is incremented by one.
 
 ## Palette Data