A Vortex variable is denoted by a dollar sign ($ ) immediately followed by a name. Variable names consist of alphanumerics, underscores, spaces or periods, and are case-sensitive (ie. $value and $Value are distinct variables). Except for local variables or function parameters, variables do not need to be explicitly declared. Nor does a variable always have to be a particular type; that is determined when it is assigned.

Assigning Values

Variables are automatically initialized from CGI form variables, environment variables, and cookies on script startup; there is no need to explicitly initialize them. A variable can be modified with an assignment statement:

  <$prefix = "re">

This assigns the string value "re" to the variable $prefix . Variables can also be set by some functions and statements, such as <SQL> .

Some variables are special and have reserved uses, such as $ret for the return value of functions, or $loop for the iteration count in looping statements.

Displaying

A variable is printed by simply giving its name with a dollar sign in the Vortex script. If the variable name contains spaces, or is adjacent to text not part of its name, it must be quoted to delimit it:

  The value of prefix is: $prefix
  I $'prefix'opened the case.
  The cost is $$100.

In the second line above, $prefix is adjacent to opened , so it is quoted to distinguish it from the erroneous variable $prefixopened . To print a literal dollar sign, it must be escaped with two dollar signs, as in the third line above.

As we've seen, variable values are automatically HTML-escaped when printed, if the MIME output type is HTML.

Math

SQL math can be used in variable assignments by enclosing the right side in parentheses. The right side can then be just about any valid SQL expression:

  <$x = ($x + 5)>               <!-- Add 5 to $x -->
  <$y = ( 'my ' + ' test' )>    <!-- Concatenate strings -->
  <$z = (counter)>              <!-- Make a new counter -->

Other assignment methods

Besides an assignment statement, variables can be set from the result rows of a <SQL> statement, as the return value of builtin/user functions (eg. $ret ), or as special variables in some circumstances.

Scope

All variables are global by default, meaning they are visible in every function. Local variables - only visible to a specific function or block - can be declared as well. The most common form of these are function parameters, which we'll explore later.