---
menuTitle: Structures
title: "Structuring the Data"
weight: 7
---
In [the previous step](/learn/pointers), we added pointers, which made it
possible to change data from other contexts/sequences. As we add more and more
data, it becomes clear that some structuring is needed.

Structures are types. Types must be declared before being used. This also
prevents recursive types.

The fields of a structure are initialized at the same time as the structure.

Fields of a structure can be accessed in two ways: using the
`struct_var.field_name` notation, or the `(field struct_var field_name)` one.
If `struct_ptr` is a pointer to a structure, `struct_ptr.field_name` will also
work.

To set the value of a structure's fields, one can use the `set` instruction or,
to set multiple fields at once, the `set_fields!` one. Note that omitting the
`!` at the end of `set_fields` is also valid Fate, but performs a computation
instead of a instruction: the structure is not modified, but a copy with the
modifications performed is returned.

**data.fate:**

         (fate_version 1)

         (declare_structure weapon
            (text name)
            (int attack)
            (int precision)
         )

         (declare_structure armor
            (text name)
            (int defense)
         )

         (declare_structure character
            (string name)
            (int money)
            (weapon weapon)
            (armor armor)
         )

         (global character hero)

         (set_fields! hero.weapon
            (name (text "Legendary" sword))
            (attack 3)
            (precision 50)
         )

         (set_fields! hero.armor
            (name (text "Refined" attire))
            (defense 1)
         )

         (set hero.money 42)

* `(text "Refined" attire)` generates a `text` value containing a textual
  representation of the values passed as parameter. `"Refined" attire` is, by
  itself, a `string`, and thus incompatible with the `text` field without a
  conversion taking place.
* Because `hero_money` and `hero_name` have been removed in favor of a
  structure, they should be replaced in the other files by `hero.money` and
  `hero.name`.

With this, it is time for our hero to get some proper gear, [let's see what
collection is available at the smithy](/learn/collections).

----

## (Mostly) Unchanged Files

**get_a_refill.fate:**

         (fate_version 1)

         (require data.fate)
         (require actions.fate)

         (define_sequence lower_price_of_booze
            (
               ((ptr int) price_pointer)
               (int decrease)
            )
            Great! The price of booze just lowered from (at price_pointer)
            (set (at price_pointer)
               (-
                  (at price_pointer)
                  (var decrease)
               )
            )
            to (at price_pointer)!
         )

         (define_sequence get_a_refill ()
            (local int price_of_booze)

            (set price_of_booze 12)

            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 help improve the mood.
            (newline)
            Satisfied, you hand the barman (var price_of_booze) copper coins.
            (visit pay (var price_of_booze))
            (newline)
            The barman sighs, then asks:
            (prompt_string (ptr hero.name) 2 64 What is your name, then, hero?)
            (var hero.name)?
            (newline)
            The barman looks surprised.
            (newline)
            (visit lower_price_of_booze (ptr price_of_booze) 4)
            (newline)
            "I have heard of you, (var hero.name)," the barman exclaims, "I have
            a quest for you!"
            (newline)
            It's your turn to sigh.
            (newline)
            The barman hands you a bag, and says:
            (newline)
            "Take this pre-payment and head to the smithy."
            (newline)
         )

**actions.fate:**

         (fate_version 1)

         (require data.fate)

         (define_sequence pay ( (int cost) )
            (set hero_money
               (- (var hero.money) (var cost))
            )
         )

**falling_asleep.fate:**

         (fate_version 1)

         (require data.fate)

         (define_sequence 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)
            (newline)
            This set-back was more than you could take. You give up on this
            barely coherent story.
            (end)
         )

**main.fate:**

         (fate_version 1)

         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
            (
               ( Ask the barman for a refill )
               (visit get_a_refill)
            )
            (
               ( Fall asleep )
               (jump_to fall_asleep)
            )
         )

         (require get_a_refill.fate)
         (require falling_asleep.fate)

         (end)