Starting with Version 1.69, literal number values have been replaced by an expression evaluator.  Put simply, anywhere you can type in a number, you can also type in a math expression like (5 * 2 / 6.554).  Most importantly, you can use variable names in the expressions, too.  All variable names are case-sensitive.

For example, these are all valid mission scripting commands:

    <set_variable name="ds38ZVAL" value="93000"/>

    <set_variable name="ds38ZVAL" value="9300*20 / 2"/>

    <set_variable name="ds38ZVAL" value="targetRange * (3000/2.55)"/>

You can use four usual - + * / operators, as well as ( ) parentheses. You cannot use ^, % or other operators.

Take note that variable names can consist of only numbers, and will be parsed before literals are.

Therefore, the following code will set the variable "var1" to 3, not the expected 125:

    <set_variable name="123" value="1"/>

    <set_variable name="var1" value="123+2"/>

However, even though variable names can also consist of only numbers and operators, such names will not be parsed before literals.

Therefore, the following code will set the variable "var1" to 4, not 9:

    <set_variable name="100/50" value="7"/>

    <set_variable name="var1" value="100/50+2"/>

Prior to Version 2.5.102, all scripting variables were integers, and assigning any floating point value would result in truncation to the next lowest integer.

Starting with Version 2.5.102, all scripting variables are instead assumed to be floating point unless expressly set. For example:

   <set_variable name="var10" value="2.55"/>

   <set_variable name="intstep" value="0" integer="yes"/>

Also starting with Version 2.5.102, all text in scripts comes with built-in variable formatting.  Any place in a script, like:

   <log text="This is text." />

can now have formatted variables placed inside them, using the 'escape' character, which is '|' in Version 2.5.104 and later (not '^' as mission-file-docs.txt claims, which was used prior to Version 2.5.104).  For example:

   <log text="This is text.  Variable Bob = |Bob|" />