POS Script Variables

Script variables consist of an internal polymorphic value. This means that a variable can be declared in one form, but change to other forms as required. There are a number of internal data types, which define the way variables are stored internally, and there is also a range of commands to create variables of certain types.

Visual Basic Users will find that script variables behave like Variant datatypes in many respects. While they are not simply variants in the VB sense, they have similar morphic abilities.

Variable Creation

Variables are created by using the set command, in the form:

    set var = expression

Where expression can be taken from the table below.

Internal Data Types

• Number Signed 64 bit number.
  
• Float A floating point number able to hold numbers to 6 decimal places
  
• String Text String. Length limited by machine memory
  
• Money Holds currency amounts
• Date An absolute date and time
• Time A time value
• TimeSpan A time interval, such as 3 hours 42 minutes
• Null An internal representation. Does not represent SQL null value
• Special A range of special purpose value representations. For example the is(odd) condition is held in a special variable class
• Boolean A Yes/No or True/False value.
• AlixData A stream of data, such as a file or a SQL cursor, supplied using Alix Protocols
• Array An array of other datatypes, such as an array of strings.
• Chart A linked variable that generates chart/graphs in JPEG format for display.

Datatypes can be converted from one type to another using the convert command.

Money DataType

    money(amount-text)

An alternative form using the price() keyword, which is a direct synonym. The amount-text string can be any valid price string, valid for the current country configuration.

Example:

    set s = money(2.34)

This results in the variable s, having the value: $ 2-34

String DataType

    string(text)

String variables can contain up to 16,000 characters.

An alternative form using the string() keyword is to use quoted strings. When using quoted strings, the POS detects if the first character is quotation marks ("), and if so, removes the trailing quotation mark also if present. Using this technique, it is not necessary to double-quote in strings themselves to obtain quote marks.

Example:

    set s = "Hello, "Mum", How are you?

This results in the variable s, having the value: Hello, "Mum", How are you?

Date DataType

    date(keyword)

When keywords are used, the POS first removes any whitespace and converts them to lowercase. This means that Start OF MONTH is equivalent to startofmonth

Examples:

     set now = date(now)
     set yesterday = date(yesterday)
     set lastclosedshift = date(shift-1)

     set now = date(now)
     set adjust = timespan(15,0,0,0)
     set day17ago = now - adjust

TimeSpan DataType

    timespan(days , hours , minutes , seconds)

days

The whole number of days to include in this span. Should be 0 or greater to create an absolute timespan, that is a fixed period of time. A negative value in the days argument is used to create relative timespans.

hours

The whole number of hours, between 0 and 23 inclusive.

minutes

The whole number of minutes, between 0 and 59 inclusive.

seconds

The whole number of seconds, between 0 and 59 inclusive.

If the days argument has a value of -1, (minus one), then the timespan created is equal to the period of time (days only) since the beginning of the month. For example, on the 20th of the month, the value of timespan(-1,2,3,4) will be 19 days, 2 hours 3 minutes and 4 seconds. This timespan can be useful when analysing data and working out statistics.

If the days argument has a value of -2, (minus two), then the timespan created is equal to the period of time (days only) since the beginning of the week, where Sunday is day number 1. For example, on tuesday, value of timespan(-2,3,4,5) will be 2 days, 3 hours, 4 minutes and 5 seconds. The same variable on thursday will be 4 days, 3 hours, 4 minutes and 5 seconds. This ability can be useful when writing reports which need to run from the start of the week or some other aribitary date position. By adding or subtracting these timespan values from the date(now) variable, you can achieve any date. eg:

     set now = date(now)
     set days = timespan(-2,0,0,0)
     set startofweek = now - days

Total Expression

     set x = total(pid(16))
     set y = total(pid(20,22,27))

:event(number(1025) index(0))
    set x = total(pid(300))
	set y = total(pid(408))
	if x > y
	then
		message(99,1,You cannot sell more X than Y. [X=%x%, Y=%y%])
		return 0
	endif
	return 1

button
define
	at(10,205,197,245) brgb(223,253,179) label(Eftpos) keys(+Ee) legend(label(E) at(5,5) font(arial,16)) font(arial,22)
	if(cond(total(pid(300)) > total(pid(400))) then(position(disable) rgb(255,255,255) brgb(98,99,92))) hook(20200) 
execute
	eftpos(go)
end

Saleline Expression

     set x = saleline(-1,piditem)
     set y = saleline(-1,quantity)

Object DataType

    object(object-type(arguments))

Object Types can be any of the following, each of which has it's own list of creation arguments:

When an object variable is on the left side of an assignment operator, the action depends on the object.

Object Type: _file

This object allows access to Windows files. Files can open created or existing files opened. Files can be read, write or appended.

     set x = object(_file(filename(test.log) flags(append)))
     set x = "Hello There"
     set x = %013%
     destroy x

This examples writes the string Hello There, followed by a newline into the file test.log. Note the use of destroy x to close the file.

Tax Operator

    tax(Type , input-value)

The value of type can be taken from the following table:

Symbol Operator

    symbol(name)

Example:

     set x = 3
     set answer = symbol(abc.%x%.def)

This script results in the variable answer being set to the value of the symbol abc.3.def

Function Operator

    function(var , method)

Example:

     set x = float(0.6666666)
     convert money x
     set answer = function(x,financialround)
     message(99,3,Money 0.6666666 financial rounds too %x%)

This script results in the variable answer being set to the value of the money value of 67 cents (in 2 decimal point countries).

Right Operator

    right(var , length)

Example:

     set x = "abcdef"
     set answer = right(x,2)

This script results in the variable answer being set to the value "ef".

Left Operator

    left(var , length)

Example:

     set x = "abcdef"
     set answer = left(x,2)

This script results in the variable answer being set to the value "ab".

Mid Operator

    left(var , position, length)

Example:

     set x = "abcdef"
     set answer = mid(x,2,2)

This script results in the variable answer being set to the value "cd".

Length Operator

    length(var)

When using the length operator, the variable name should not be enclosed in % subsitution characters, otherwise the length of the substituted result will be returned, not the variable itself.

Example:

     set x = "abcdef"
     set answer = length(x)

This script results in the variable answer being set to the value 6.

Config Operator

    config(tablefield(table, field))
    config(function(name))
    config(file(filename))

tablefield(table, field) provides quick check to see if the field exists on a table.

function(name) checks to see if specific POS functionality has been enabled.

file(filename) scans for the given name and returns true if it is present. The check is based on the current working directory.

Example:

     set x = float(function(stickyprintformat))

This script results in the variable answer being set true or false depending on whether the current system has stickyprintformats configured.