If
The if statement allows you to execute (or not execute) a block of script commands based on one or more comparisons that you specify. Oblivion's if command is very powerful and comparable to "real" programming languages.
Overview
An if statement uses the following syntax:
if expressionA [comparison] expressionB ; test "expressionA [comparison] expressionB" passed elseif expressionB [comparison] expressionC ; test "expressionB [comparison] expressionC" passed else ; none of the above tests passed endif
The else and elseif statements are optional.
Comparison Operators
An if statement may contain one or more comparison operators. Below is a table of valid comparison operators:
| Operator | Description |
|---|---|
| == | Exactly equal to |
| != | Not equal to |
| > | Greater than |
| >= | Greater than or equal to |
| < | Less than |
| <= | Less than or equal to |
It is important to note that there are no bitwise comparisons available in Oblivion's scripting language.
Combining Comparisons
Comparisons can be linked together using the following logical operators:
| Operator | Description | Example |
|---|---|---|
| && | Logical AND | if x == 1 && y == 1 ; considered true only if both x and y equal 1. |
| || | Logical OR | if x == 1 || y == 1 ; considered true unless both x and y equal 0. |
Note that "||" is evaluated before "&&", just like "*" is evaluated before "+" in normal algebra.
If you want the && to be evaluated first, you have to include that part in parentheses. For example:
if myVar1 == 1 && myVar2 == 1 || myVar2 == 5
This is true when MyVar1 = 1 AND myVar2 is either 1 or 5.
if (myVar1 == 1 && myVar2 == 1) || myVar2 == 5
This is true when either myVar2 is 5 OR both, myVar1 and myVar2 are 1
Comparisons and Expressions
The comparison operators can be used with any expression that can be evaluated into a number. Assuming "a = 17", "b = 20" and "c = a - b", all of the following expressions work as expected. Parentheses are only needed when they're necessary for mathematical reasons.
IF c == -3 && b == 20 IF c == -3 && b == 20 && a == 17 IF c - 1 == -4 && b == 20 && a == 17 IF a - 20 == 17 - b IF a - 20 == 17 - b && c + 3 == 0 IF a + 3 == b IF a - b == c IF a *4 - b * 4 == c * 4 IF a * ( 5 + c ) - 14 == b IF 2*(a*(5+c)-14)==b - -b
If a variable or the result of a function returns 1 or 0, or you're just interested in whether the result is 0 or not you don't need to test on "== 1" or "!=0"
IF Done IF Getisid MyNPC IF Getitemcount Lockpick IF IsActor && Flag
Do the same as
IF Done != 0 IF Getisid MyNPC != 0 IF Getitemcount Lockpick != 0 IF IsActor != 0 && Flag != 0
Notes
Keep in mind that the script parser doesn't accept one-lined statments. While
if condition==1 set varname to 1 else set varname to 2
works in other programming languages, you need to split this up for Oblivion.
if condition==1 set varname to 1 else set varname to 2 endif
(it's more readable too...)
After the condition or the "else" statement the rest of the line is ignored. There aren't any error messages to warn you, so (since the line appears to be correct) you might spend a lot of time locating the source of the problem.
The whole if test is evaluated as a whole. Even if a sub-test returns false, the rest is still evaluated. Make sure your reference functions in the test are ALWAYS called on valid references or unexpected things might happen.