Difference between revisions of "If"
imported>Gblues (Moving the comparison operator list from the "commands" topic.) |
imported>Gblues (Added overview, else/elseif/endif information) |
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The <tt>if</tt> statement allows you to execute (or not execute) a block of script commands based on one or more comparisons that you specify. Oblivion's <tt>if</tt> command is very powerful and comparable to "real" programming languages. | The <tt>if</tt> statement allows you to execute (or not execute) a block of script commands based on one or more comparisons that you specify. Oblivion's <tt>if</tt> command is very powerful and comparable to "real" programming languages. | ||
== Overview == | |||
An if statement uses the following syntax: | |||
<pre> | |||
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 | |||
</pre> | |||
The <tt>else</tt> and <tt>elseif</tt> statements are optional. | |||
== Comparison Operators == | == Comparison Operators == | ||
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IF a * ( 5 + c ) - 14 == b | IF a * ( 5 + c ) - 14 == b | ||
IF 2*(a*(5+c)-14)==b - -b | IF 2*(a*(5+c)-14)==b - -b | ||
[[Category:Commands]] | [[Category:Commands]] |
Revision as of 01:06, 15 April 2006
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. |
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 or logical 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