Basic Question: How do I use if's? (ALREADY FIXED IT)

Question

I'm trying to make it where if the player has seen a knife in one of the rooms, then when they go to the attic it will add additional text saying "You see another knife from the left room."

Answer 1

The following attempts to clarify the answer given by @Seyru.

You can use a story variable to track is the player has seen a knife in another room.

1. Initialise your story variable within your project's startup tagged special passage.

If you don't have such a passage yet then add a new Passage to your project, you can assign it any name you like because the name isn't important but I name mine Startup, and then assign this new passage a Passage Tag of startup (all lower-case letters). Place the following code within this passage's body...

(set: $seenKnife to false)

2. Set the story variable to true when the player first sees a knife within the other passages.

(set: $seenKnife to true)

3. Check the current value of the story variable in your attic passage.

You see {(if: $seenKnife)[another](else:)[a]} knife from the left room.

 

Comments

Thank you both for these answers, but I have fixed the problem. I watched a video about this problem and learned about sets and ifs. I now have set it up.

Answer 2

Hello there, 

Maybe you could do something like this : 

(set: $seenKnife to true) 

You see {(if: $seenKnife)[another] (else:)[a]} knife from the left room. 

(set: $seenKnife to false) 

You see {(if: $seenKnife)[another] (else:)[a]} knife from the left room. 

Here, when $seenKnife is true (the knife has been seen), it writes "another". If $seenKnife is false (the knife has not been seen), it writes "a" instead. 
 

If there are plenty of knives to be seen, you could also do it like this :

 

(set: $seenKnife to 0) 

You saw {(if: $seenKnife is 0)[no knives yet.] (else-if: $seenKnife is 1)[one knife ! Great.] (else-if: $seenKnife is 2)[two knives. You're a knife finder. That's a gift. Really.](else-if: $seenKnife is 3)[three knives. I'm amazed. There were only two knives in the game.]} 

(set: $seenKnife to 1) 

You saw {(if: $seenKnife is 0)[no knives yet.] (else-if: $seenKnife is 1)[one knife ! Great.] (else-if: $seenKnife is 2)[two knives. You're a knife finder. That's a gift. Really.](else-if: $seenKnife is 3)[three knives. I'm amazed. There were only two knives in the game.]} 

(set: $seenKnife to 2) 

You saw {(if: $seenKnife is 0)[no knives yet.] (else-if: $seenKnife is 1)[one knife ! Great.] (else-if: $seenKnife is 2)[two knives. You're a knife finder. That's a gift. Really.](else-if: $seenKnife is 3)[three knives. I'm amazed. There were only two knives in the game.]} 

(set: $seenKnife to 3) 

You saw {(if: $seenKnife is 0)[no knives yet.] (else-if: $seenKnife is 1)[one knife ! Great.] (else-if: $seenKnife is 2)[two knives. You're a knife finder. That's a gift. Really.](else-if: $seenKnife is 3)[three knives. I'm amazed. There were only two knives in the game.]} 

 

Here, the game checks how many knives you saw, and acts accordingly

Comments

I tried to set up $seenKnife in another passage, and it worked well for me. So I don't really understand what's going wrong. Check if the setting up is correct !

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What did you do to set it up? I am still new with variables and stuff, so I probably didn't properly set it up correct

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(set: $seenKnife to true)
Should be good.
Then in another passage, $seenKnife will still be set to true. It will be set to true as long as you do not change it within the story.

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The issue is caused because you aren't initialising your story varaibles before you reference then within the conditional expresson you are passing to your (if:) macros, and Harlowe automatically initialises such variables to a default value of zero (0).

eg. Lets assume you have a Passage containing the following two conditional expressions, the first of which is testing to see if $seenKnife is equal to Boolean true...

<!-- You haven't assign $seenKnife a default value yet. -->

(if: $seenKnife)[show an error about zero not being a Boolean]

<!-- Harlowe assigned zero (0) to $seenKnife in previous conditional expression. -->

(if: $seenKnife is 0)[The variable is zero now]

...and if you haven't previously assigned $seenKnife a value then Harlowe will automactically initialise the variable to zero (0) before testing it's value. This is why the second conditional expression will evaulate to true, because $seenKnife now does contain a value of zero.

It is a good idea to always initialise your story variables sometime before you first reference them in either a conditional expression or before you output their current value to the page.
The best place to do such initialisation is within your project's startup tagged special passage like so...

(set: $seenKnife to false)

Now if we visit the previous Passage with the conditional expressions again...
(note: I have added a third to show how to test for Boolean false)

<!-- You have initialised $seenKnife to a default value. -->

(if: $seenKnife)[nothing displayed because value is false]

(if: $seenKnife is 0)[nothing displayed because value is false]

(if: not $seenKnife)[displayed because value is false]

... the will notice that the error message has gone away.

 

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You do it the same way you would in science/grammer...

If this happens, then this will happen