Table of Contents | Heidi: our first adv3Lite game > Adding the Tree and the Branch
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Adding the Tree and the Branch

The description of the clearing mentions a tall sycamore tree standing at its centre. We’d better define it next. A first attempt based on what we’ve done so far is:

    + tree: Thing 'tall sycamore tree;;stout proud'     
        "Standing proud in the middle of the clearing, the stout tree looks easy to
        climb."
    ;

Add this to your file just after the definition of the nest (in the clearing). Because both the nest and the tree have a single + sign, both will be located in the clearing (tree won’t be in the nest!). If you now compile the game and try running it, you’ll find it works — but only after a fashion. When the player character travels to the clearing the tree is now mentioned twice in the room description. Even worse, Heidi can pick up the tree and carry it around with her!

In front of a Cottage
You stand outside a cottage. The forest stretches east. 

>e

Deep in the forest
Through the dense foliage, you glimpse a building to the west. A track heads to the northeast. 

You can see a baby bird here.

>ne

A forest clearing
A tall sycamore stands in the middle of this clearing. The path winds southwest through the trees. 

You can see a bird’s nest and a tall sycamore tree here.

>x tree
Standing proud in the middle of the clearing, the stout tree looks easy to climb.

>take tree
Taken. 

>i
You are carrying a tall sycamore tree.

We should fix this at once. We can do so by adding isFixed = true to the definition of the tree.

     
    + tree: Thing 'tall sycamore tree;;stout proud'     
        "Standing proud in the middle of the clearing, the stout tree looks easy to
        climb."
        
        isFixed = true
    ;

If you try compiling and running the game again, you should find it now works rather better: the tree isn’t listed twice in the clearing and Heidi can’t pick it up. The first thing defining isFixed = true does is to make the tree non-portable so it can’t be picked up and carried around. More often than not non-portable items like the tree have already been mentioned in the main body of the room description, so we normally don’t want to see them listed among the miscellaneous portable items that happen to be in the location like the nest. For that reason Thing is set up so that when isFixed is true, isListed is nil (i.e. false) so that fixed items aren’t listed separately (though note that if you want to, you can override isListed separately from isFixed, as we’ll go on to illustrate next).

Finally, we’ll add a branch at the top of the tree. Once again this needs to be fixed in place, so we’ll define isFixed = true. This time, though, just to show that it can be done (and because we haven’t mentioned the branch yet in the room description of topOfTree) we’ll also define isListed = true, so that the branch is still listed as a separate object. Finally, we want Heidi to be able to put things (such as the bird and the nest) on the branch, so we’ll define contType = On (meaning that things can now be placed on the branch, and that anything located ‘in’ the branch (via the + syntax or one of its equivalents) is to be considered as resting on top of it.

The definition of the branch object should come directly after the definition for topOfTree, and should look like this:

    + branch: Thing 'wide firm bough; flat; branch'
        "It's flat enough to support a small object. "
        
        isFixed = true
        isListed = true
        contType = On
    ;

Once you’ve made all the appropriate changes, try compiling and running the game again and see what you can now do in it.

adv3Lite Library Tutorial
Table of Contents | Heidi: our first adv3Lite game > Adding the Tree and the Branch
Prev: Adding the Bird and the Nest     Next: Finishing Touches