WML for Complete Beginners: Chapter 10 - Revision history

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2023-01-29T20:42:20Z

Use syntax highlighting

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2023-01-29T19:21:54Z

Nicer index and navigation

Sapient: /* Else */

2017-04-18T03:15:51Z

‎Else

Sapient: /* If This, Then That */

2017-04-18T03:15:22Z

‎If This, Then That

William: /* Chapter 10: Introduction to Logic */

2015-11-10T09:17:16Z

‎Chapter 10: Introduction to Logic

Implementor37: Added link to the next chapter of WML_for_Complete_Beginners (Chapter 11)

2015-03-17T16:59:04Z

Added link to the next chapter of WML_for_Complete_Beginners (Chapter 11)

Iceiceice at 21:20, 6 April 2014

2014-04-06T21:20:11Z

Artisticdude: Created page with '==Chapter 10: Introduction to Logic== ===If This, Then That=== Suppose you went to the grocery store to get some food. You park you car in the parking lot and begin to walk tow…'

2013-04-02T17:39:08Z

Created page with '==Chapter 10: Introduction to Logic== ===If This, Then That=== Suppose you went to the grocery store to get some food. You park you car in the parking lot and begin to walk tow…'

New page

==Chapter 10: Introduction to Logic==

===If This, Then That===

Suppose you went to the grocery store to get some food. You park you car in the parking lot and begin to walk towards the store, when suddenly you realize that you can't remember if you shut the car door or not after you got out. You turn around to see if the car door is open...

...and then what?

Well, if the car door is open, you know that you ''did'' forget to close it, so you go over and close it before you go into the grocery store. If the car door isn't open, there's no need for you to do anything, so you keep walking towards the store.

This kind of logic (called ''conditional'' logic) evaluates a condition and determines a reaction based on the state of that condition. In the example above, the condition is whether or not the car door is open. If it is open, then you go over and close it. If it isn't open, then you continue walking towards the store.

In WML you have a number of logical operations available to assess and react to conditions. The first one we will go over is the if/then operation. The syntax of this operations is:

[if]
(condition)
[then]
(do something)
[/then]
[/if]

===Else===

With the if clause, if the condition is true then we do something. But what if the condition isn't true? Well, in the examples above the WML engine doesn't have anything to do if the condition isn't true, so it just keeps running and doesn't do anything. However, it is possible to make the game perform a task if the condition isn't true, which is done by using the tagset [else]. The syntax is:

[if]
(condition]
[then]
(do something)
[/then]
[else]
(do something else)
[/else]
[/if]

Returning to the example of the car door, suppose that, before you turn around to check to see whether the door is open or not, you decide to go over and close the door if it is open, and if it isn't then you'll do a backflip to celebrate your genius before continuing your journey across the parking lot to the grocery store. In pseudocode:
[if]
the car door is open
[then]
go over and shut it
[/then]
[else]
do a backflip
[/else]
[/if]

@@ Line 14: / Line 14: @@
 In WML you have a number of logical operations available to assess and react to conditions. The first one we will go over is the if/then operation. The syntax of this operations is:
+<syntaxhighlight lang=wml>
- [if]
+[if]
-     # (condition)
+    # (condition)
-     [then]
+    [then]
-         # (do something)
+        # (do something)
-     [/then]
+    [/then]
- [/if]
+[/if]
 ===Else===
 With the if clause, if the condition is true then we do something. But what if the condition isn't true? Well, in the examples above the WML engine doesn't have anything to do if the condition isn't true, so it just keeps running and doesn't do anything. However, it is possible to make the game perform a task if the condition isn't true, which is done by using the tagset [else]. The syntax is:
+<syntaxhighlight lang=wml>
- [if]
+[if]
-     # (condition]
+    # (condition]
-     [then]
+    [then]
-         # (do something)
+        # (do something)
-     [/then]
+    [/then]
-     [else]
+    [else]
-         # (do something else)
+        # (do something else)
-     [/else]
+    [/else]
- [/if]
+[/if]
 Returning to the example of the car door, suppose that, before you turn around to check to see whether the door is open or not, you decide to go over and close the door if it is open, and if it isn't then you'll do a backflip to celebrate your genius before continuing your journey across the parking lot to the grocery store. In pseudocode:
- [if]
+<syntaxhighlight lang=wml>
-     # the car door is open
+[if]
-     [then]
+    # the car door is open
-         # go over and shut it
+    [then]
-     [/then]
+        # go over and shut it
-     [else]
+    [/then]
-         # do a backflip
+    [else]
-     [/else]
+        # do a backflip
- [/if]
+    [/else]
 {{Navigation|[[WML for Complete Beginners: Chapter 9|'''Chapter 9'''<br>Macros]]|[[WML for Complete Beginners: Chapter 11|'''Chapter 11'''<br>More Logic]]}}
 [[Category:WML_for_Complete_Beginners]]

@@ Line 1: / Line 1: @@
 ==Chapter 10: Introduction to Logic==
@@ Line 45: / Line 47: @@
   [/if]
-Next Chapter:
+{{Navigation|[[WML for Complete Beginners: Chapter 9|'''Chapter 9'''<br>Macros]]|[[WML for Complete Beginners: Chapter 11|'''Chapter 11'''<br>More Logic]]}}
 [[Category:WML_for_Complete_Beginners]]

@@ Line 45: / Line 45: @@
   [/if]
 [[WML for Complete Beginners: Chapter 11]]
 [[Category:WML_for_Complete_Beginners]]

@@ Line 44: / Line 44: @@
       [/else]
   [/if]
 [[Category:WML_for_Complete_Beginners]]

← Older revision		Revision as of 21:20, 6 April 2014
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		+
		+	[[Category:WML_for_Complete_Beginners]]