90 lines
1.8 KiB
Markdown
90 lines
1.8 KiB
Markdown
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# Function definition
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Functions are defined with `fun` followed by the name of the function,
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the parameters, the return type, `=` and an expression.
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## Function with no parameters
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To declare a function with no parameters include `()`, and call it with `()`.
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```misti
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fun getName() =
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// code...
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val name = getName()
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```
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## Function that returns void/nothing
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In Misti we return `Unit` instead of `void`, `null`, `undefined` or others.
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So a function that doesn't return anything, would return `Unit`.
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```misti
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// This function just prints Hello and returns
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fun printHello() -> Unit =
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print("Hello")
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```
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This type, `Unit`, is treated like `void`, so it is ignored.
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If a function doesn't return anything, `Unit` can be omitted.
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```misti
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// This first declaration
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fun doSomething() -> Unit =
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something()
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// is equivalent to this one
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fun doSomething() =
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something()
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```
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## Function with return
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First, the return type must be defined in the declaration.
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Let's say that a function `getLuckyNumber` returns a Float, then it
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would be declared like this:
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```misti
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fun getLuckyNumber() -> Float =
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// Body of the function
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```
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And finally, the return value is the last expression in the function.
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The following function will return 7.
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```misti
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fun getLuckyNumber() -> Float =
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// This '7' is the last expression, so it will be returned
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7
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val number = getLuckyNumber() // number = 7
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```
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## Return multiple values
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We can use a tuple if we need to return multiple values.
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```misti
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fun getPerson() -> #(Str, Int) =
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// Logic...
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#("Kim", 33)
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fun tupleContains(#(Str, Int) data, Str key) -> #(Bool, Int) =
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val #(currentKey, value) = data
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if currentKey == key do
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#(true, value)
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else
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#(false, 0)
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tupleContains(#("Test", 200), "Test")
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```
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