Option Menu Syntax

Standard (ISO Full BASIC)
  denies implicit array declaration.
  The default option base is 1.
Compel All Variables Declared
  All variables in Full BASIC can be declared using DECLARE-NUMERIC and DECLARE-STRING.
  When this option is enabled, compiling stops if any non-declared variable or function is found.
  This feature is effective to avoid a bug caused by a typo.
Minimal BASIC Compatible
  allows implicit array declaration.
  The default option base is 0.
Microsoft BASIC Compatible
  allows implicit array declaration.
  The default option base is 0.
  allows LET to be omitted and accepts multi-statements.
  Acceptable Microsoft jargons are about those shown on the Auto-correct menu.
  However, LET can not be omitted if the identifier is a keyword of this BASIC.
  Types of numeric variables are ignored.
  The result of a comparison or a logical operation AND, OR or NOT is a number 0 or -1, though any comparison of strings can not be written as an item in a PRINT statement or else.
  Logical operators XOR, IMP and EQV are not acceptable.
  invalidates the supplied function PI in order to enable PI to be used as a variable.
  validates MOD-operator and \-operator.
  validates INPUT statements in the form of 'INPUT "A=";A' .
  validates LPRINT.
  introduces the pixel-wise coordinate system of the origin left-top.
  validate the following graphics commands, where lower case characters are numeric expressions.
  SCREEN n
    n is one of 2,3,11,12 or 87.
    2 640×400 0 white, 1 black
    3 640×400 0 black, 1 blue, 2 red, …, 7 white(foreground)
    11 640×480 0 white, 1 black
    12 640×480 0 black, 1 blue, 2 green, …, 7 white(foreground)
    87 640×400 0 black, 1 blue, 2 green, …, 7 white(foreground)
    Any other value shall be ignored.
  CLS n
    do CLEAR regardless of the value of n.
  WINDOW (x1,y2)-(x2,y1)
  COLOR c
  COLOR ,,,c
  PSET (a,b)
  PSET (a,b),c
  LINE -(x,y)
  LINE (x1,y1)-(x2,y2)
  LINE (x1,y1)-(x2,y2),c,B
  LINE (x1,y1)-(x2,y2),c,BF
  PAINT (x,y),c,d
  CIRCLE (x,y),r,c,,,s
  CIRCLE (x,y),r,c,,,s,F,t
  starting angle and finishing angle can not be written.
  The other statements obeys the standard in principle.
  This BASIC has least compatibility on string or file manipulation with Microsoft BASIC.
  [Memo]
  Do SCREEN 12 to make the graphics compatible with Microsoft Quick BASIC.