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---
menuTitle: Variables
title: "Adding Variables"
weight: 3
---
In [the previous step](/learn/start), we introduced player choices. Dynamic
content is here, but it is not going far without variables.
Fate is a strongly typed language, meaning that variables **must** be assigned
a precise type and cannot deviate from it.
Variables have to be declared before being used. Let us keep things simple for
now, and declare variables using the `local` instruction. The alternative is
`global`. The difference between the two being about access from other
contexts, something that is introduced in the next chapter.
We are trying to add a variable that corresponds to money. An `int` is thus
appropriate.
**main.fate:**
{{< fatecode >}}(fate_version 1)
(local int hero_money)
(local int price_of_booze 12)
(set! hero_money 42)
Once upon a time, starting a story with these words wasn't considered a cliche.
Starting in a tavern might also not be seen as very original. Having the main
character be an street orphan, raised by some mysterious sage all to end up as
a mercenary with an uncommonly strong sense of honor probably isn't going to
lead to any praises for novelty either. Maybe you should drink to that.
(newline)
Or maybe you shouldn't. This isn't your first mug. Not your second either.
Drinking to forget that you are a stereotypical hero isn't going to solve
anything. Worse, the alcoholic trait is part of the image.
(newline)
As you contemplate your own pointless description, your gaze leaves what turns
out to be an already empty glass in your hand and finds the barman.
(player_choice!
(option ( Ask the barman for a refill )
Staring straight at the barman, you raise your glass and proclaim:
(newline)
"This soon-to-be world savior needs more booze!"
(newline)
The barman's lack of reaction is disappointing, but seeing the beer being
poured does improve your mood.
(newline)
Satisfied, you hand the barman (var price_of_booze) copper coins.
(set! hero_money (- hero_money price_of_booze))
)
(option ( Fall asleep )
Deciding to break away from the expected storyline, you promptly fall
asleep.
(newline)
...
(newline)
Upon waking up, your hard-trained reflexes inform you that someone stole
all your money.
(set! hero_money 0)
)
)
(end!)
{{< /fatecode >}}
* `(local int hero_money)` declares an `int` variable with the name
`hero_money`. This variable takes the default value for its type.
* `(local int price_of_booze 12)` declares an `int` variable with the name
`price_of_booze`. This variable takes the value `12`.
* `(set! hero_money 42)` sets the value of the `hero_money` variable to 42.
* `(var price_of_booze)` returns the current value of the `price_of_booze`
variable.
* `(- hero_money price_of_booze)` returns the result of subtracting
the value of `price_of_booze` to the value of `hero_money`. All operators
use a prefixed form. Because there is no ambiguity about `hero_money` and
`price_of_booze` being strings, it is not necessary to write
`(- (var hero_money) (var price_of_booze))`.
`local`, `set!`, `player_choice!`, and `end!`, are instructions. Instructions do
not return any value. Thus, they do not add to the printed text.
Having to continue the story from within the `player_choice` structure is going
to get tedious very fast. Let's [introduce sequences](/learn/sequences).
|
