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# Structs
In Tomo, you can define your own structs, which hold members with arbitrary
types that can be accessed by fields:
```tomo
struct Foo(name:Text, age:Int)
...
my_foo := Foo("Bob", age=10)
assert my_foo == Foo(name="Bob", age=10)
assert my_foo.name == "Bob"
```
Structs are value types and comparisons on them operate on the member values
one after the other.
## Namespaces
Structs can define their own methods that can be called with a `:` or different
values that are stored on the type itself.
```tomo
struct Foo(name:Text, age:Int)
oldest := Foo("Methuselah", 969)
func greet(f:Foo)
say("Hi my name is $f.name and I am $f.age years old!")
func get_older(f:@Foo)
f.age += 1
...
my_foo := @Foo("Alice", 28)
my_foo.greet()
my_foo.get_older()
```
Method calls work when the first argument is the struct type or a pointer to
the struct type.
## Secret Values
If you want to prevent accidental leaking of sensitive information, you can
create a struct with the `secret` flag turned on, which causes the struct to
be converted to text without showing any of its contents:
```tomo
struct Password(raw_password_text:Text; secret)
struct User(username:Text, password:Password)
...
user := User("Stanley", Password("Swordfish"))
assert user == User("Stanley", Password("Swordfish"))
assert "You are: $user" == 'You are: User(username="Stanley", password=Password(...))'
```
Designing APIs so they take secrecy-protected structs instead of raw data
values is a great way to prevent accidentally leaking sensitive information in
your logs! Secrecy-protected values still work the same as any other struct,
they just don't divulge their contents when converting to strings:
```tomo
assert user.password == Password("Swordfish")
```
You can also access the fields directly, but hopefully this extra amount of
friction reduces the chances of accidentally divulging sensitive content:
```tomo
assert user.password.raw_password_text == "Swordfish"
```
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