Assignment copies the value in Mojo

Mojo structs are values, so assigning one makes an independent copy, not an alias.

@fieldwise_init
struct Score(ImplicitlyCopyable, Movable):
    var points: Int
    var label: String


def main():
    var original = Score(10, "first")
    var duplicate = original
    duplicate.points = 99
    duplicate.label = "second"
    print(original.points, original.label)
    print(duplicate.points, duplicate.label)

How it works

ImplicitlyCopyable is what lets a plain = duplicate the struct.
duplicate gets its own points and label to overwrite.
original prints unchanged, proving the two never shared storage.

Keywords and builtins used here

Int
Movable
String
def
main
print
struct
var

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Characters to type: 294
Tokens: 66
Three-star pace: 80 tpm

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Type this snippet

Step 1 of 5 in Value semantics, step 6 of 22 in Structs & traits.

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