Learn X in Y minutes

REM This is a comment
' and this is also a comment

REM print text
print "hello"
? "? is short for PRINT"

REM Control structures
FOR index = 0 TO 10 STEP 2
  ? "This is line number "; index
NEXT
J=0
REPEAT
 J++
UNTIL J=10
WHILE J>0
 J--
WEND

REM Select case statement
Select Case "Cool"
 Case "null", 1,2,3,4,5,6,7,8,"Cool","blah"
 Case "Not cool"
   PRINT "Epic fail"
 Case Else
   PRINT "Fail"
End Select

REM catching errors with TRY/CATCH
Try
  fn = Freefile
  Open filename For Input As #fn
Catch err
  Print "failed to open"
End Try

REM User defined subs and functions
func add2(x,y)
  ' variables may be declared as local within the scope of a SUB or FUNC
  local K
  k = "k will cease to exist when this FUNC returns"
  add2=x+y
end
Print add2(5,5)
sub print_it(it)
  print it
end
print_it "IT...."

REM Display lines and pixels
At 0,ymax/2+txth("Q")
Color 1: ? "sin(x)":
Color 8: ? "cos(x)":
Color 12: ? "tan(x)"
Line 0,ymax/2,xmax,ymax/2
For i=0 to xmax
  Pset i,ymax/2-sin(i*2*pi/ymax)*ymax/4 color 1
  Pset i,ymax/2-cos(i*2*pi/ymax)*ymax/4 color 8
  Pset i,ymax/2-tan(i*2*pi/ymax)*ymax/4 color 12
Next
showpage

REM SmallBASIC is great for experimenting with fractals and other interesting effects
Delay 3000
Randomize
ff = 440.03
For j = 0 to 20
  r = rnd * 1000 % 255
  b = rnd * 1000 % 255
  g = rnd * 1000 % 255
  c = rgb(r,b,g)
  ff += 9.444
  for i=0 to 25000
    f += ff
    x = min(xmax, -x + cos(f*i))
    y = min(ymax, -y + sin(f*i))
    pset x, y color c
    if (i%1000==0) then
      showpage
    fi
  next
Next j

REM For computer historians, SmallBASIC can run programs
REM found in early computer books and magazines, for example:
10 LET A=9
20 LET B=7
30 PRINT A*B
40 PRINT A/B

REM SmallBASIC also has support for a few modern concepts such as JSON
aa = array("{\"cat\":{\"name\":\"harry\"},\"pet\":\"true\"}")
If (ismap(aa) == false) Then
  throw "not an map"
End If
Print aa

PAUSE