Dexterity (Sans Script)
(Last updated: Jan 4th 2004)

Variables
Functions
Flow of Control
Other Items of Interest

Variables

• Delimited by optional single quotes
   
• Locals are prefixed (within quotes) with (L), e.g. '(L) Customer Name'
   
• Arrays are 1-based. Indexes are enclosed in square brackets outside the optional single quotes surrounding the variable name, for example '(L) myArray'[4]
   
• Data-types:
  • string is limited to 255 characters
  • text supports 32,000 characters
  • integer is a signed 16-bit   
  • long is a signed 32-bit
  • currency is to 5dp. variable currency is up to 15dp with a corresponding lost of pre-dp digits.
  • date is separate to time. datetime is for COM interoperability and isn't supported directly by any of the UI controls
     

Functions

• value() is the opposite of str()
   
• Casting is via the associated type function, for example:
  local long fred;

  fred = long(14.5);
  

  
  
• warning(), error() and ask() provide the MessageBox.Show functionality:

  local integer selection;

  selection = ask("How do you like them apples", "Not at all", "Somewhat", "Love 'em");
  

  (ask return value is the 1-based index of the selected button)
   
• UDF are declared in an unusual way. The procedure (or function) is named through the designed UI and there is no 'prototype' line declaring the parameters. Instead the procedure is selected from the a list (or a new one is created and named) and the parameter list defined as a set of in, out and inout statements prior to the first line of working code. For example, int Add2Numbers(int x, int y) would be defined as:
  function returns integer result;

  in integer x;

  in integer y;

  result = x + y;
  

  and called via
  local integer result;

  result = Add2Numbers(10, 20);

  
  while void AddXtoY(int x, ref y) would be defined as:
  in integer x;

  inout integer y;

  y = x + y;
  

  and called via
  local integer y;

  y = 20;

  call AddXtoY, 10, y;

  [I really don't like the way its the procedure that determines the by-reference or by-value status]
  
  Optional parameters can be specified using the optional keyword (optional in integer X) and detected using the missing() function. Optional parameters are not restricted to being the last items in the parameter list, but it is recommended. If the optional parameter is not specified by the caller and it is not the last parameter in the list a placeholder must be included by the called (e.g. call myfunc, x,,z;)

  If a parameter is passed as an out to procedure A then procedure A can only pass it to procedure B as an out. in and inout are not restricted in any way.
  

Flow of control

• if construct
  if 'X' > 100 then

      warning("X is bigger than 100!");

      warning("No block deliminators required for multiple statements");

  else

      warning("X is 100 or less!");

  end if;
  

  
  
• for construct
  for i = 1 to 10 do

      'X' = 'X" + i;

  end for;
  

   

  for i = 1 to 10 by 2 do

      'X' = 'X" + i;

  end for;

  
  
• while constructs
  local integer loop;

  'loop' = 0;

  while 'loop' < 10 do

      'loop' = 'loop' + 1;

  end while;

   

  repeat

      'loop' = 'loop' -1;

  until loop < 1;

  
  
• case construct
  case 'X'

      in [-10 to 10]

          warning ("X is between -10 and 10 inclusive");

      in [11 to 20]

          warning ("X is between 11 and 20 inclusive");

  else

      warning("default!");

  end case;
  

  (Note the lack of a colon at the end of the variable selection)
  
  
• case construct
   

Other Items of interest

• Comments are enclosed in curly braces
• No overflow protection. Numbers just wrap (e.g. myInteger = 450 * 75 = -31,786)
• Equality operator is single equals singe (e.g. if x=10)
• External dlls are called through a shim, XDLL32.DLL. The programmer then creates a 'placeholder' (my terminology) procedure named entryPoint@dll (e.g. MessageBoxA@user32.dll) to specify the parameters. Parameters are set up as if for a normal function except that the first parameter is always declared as out and represents the return result of the dll call. Use out long for VOID functions. Dll functions are then called using the syntax extern 'entryPoint@dll', outparameter, inparameter, ....
  
  Example of calling a DLL:
  'Beep@kernel32.dll' Procedure

  {

      // Beep prototype from user32.lib (but lives in kernel32.dll)

      BOOL Beep(DWORD dwFreq, DWORD dwDuration)

  }

  out integer result;

  in long dwFreq;

  in long dwDuration;
  

   
  'Play' function
  function returns integer result;

  in long frequency;

  in long duration;

   

  extern 'Beep@kernel32.dll', result, frequency, duration * 2;
  

   
  'PlayTune' function
  { Converted from some Pascal example I found on the internet - author unknown}

  { sixteenth,eighth,quarter,half,whole }

  local long s = 50; local long o = 100; local long q = 200;

  local long tq = 300; local long h = 400; local long th = 500;

  local long w = 800;

   

  local long lC = 262; local long lD = 294; local long lE = 330;

  local long lF = 350; local long lG = 392; local long lA = 440;

  local long lB = 494; local long lCs= 277; local long lDs= 311;

  local long lFs= 370; local long lGs= 415; local long lAs= 466;

   

  local long C = 523; local long D = 587; local long E = 659;

  local long F = 698; local long G = 784; local long A = 880;

  local long B = 988; local long Cs = 554; local long Ds = 622;

  local long Fs = 740; local long Gs = 830; local long As = 932;

   

  local long hC = 1046;

   

  Play (C,h); Play (G,h); Play (F,s); Play (E,s); Play (D,s);

  Play (hC,h); Play (G,h); Play (F,s); Play (E,s); Play (D,s);

  Play (hC,h); Play (G,h); Play (F,s); Play (E,s); Play (F,s);

  Play (D,h); Play (lG,s); Play (lG,s); Play (lG,s); Play (C,h);

  Play (G,h); Play (F,s); Play (E,s); Play (D,s); Play (hC,h);

  Play (G,h); Play (F,s); Play (E,s); Play (D,s); Play (hC,h);

  Play (G,h); Play (As,s); Play (A,s); Play (As,s); Play (G,h);

  Play (G,h); Play (lG,h); Play (lG,s); Play (lA,th);Play (lA,o);

  Play (F,o); Play (E,o); Play (D,o); Play (C,o); Play (C,s);

  Play (D,s); Play (E,s); Play (D,s); Play (lA,o); Play (lB,q);

  Play (lG,tq);Play (lG,s); Play (lA,th); Play (lA,o); Play (F,o);

  Play (E,o); Play (D,o); Play (C,o); Play (G,o); Play (D,th);

  Play (lG,tq);Play (lG,s); Play (lA,th); Play (lA,o); Play (F,o);

  Play (E,o); Play (D,o); Play (C,o); Play (C,s); Play (D,s);

  Play (E,s); Play (D,s); Play (lA,o); Play (lB,q); Play (G,tq);

  Play (G,s); Play (hC,tq);Play (As,s); Play (Gs,tq);Play (G,s);

  Play (F,tq); Play (Ds,s); Play (D,tq); Play (C,tq); Play (G,h);

  Play (G,tq); Play (G,s); Play (G,s); Play (G,s); Play (G,s);

  Play (hC,o); Play (C,s); Play (C,s); Play (C,s); Play (C,th);