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Use Kotlin function reference in HOF example #11

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7 changes: 4 additions & 3 deletions code/hof-parameter.kt
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Original file line number Diff line number Diff line change
@@ -1,7 +1,8 @@
fun transform(initial: String, f: (String) -> String) = f(initial)
fun transform(initial: String, transformer: (String) -> String) = transformer(initial)
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@ttu ttu Oct 1, 2023

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Naming function with a single letter (f) is not the best practice. However, it was used to ensure the code would fit to a single view.


val result = transform("hello", { x -> x.toUpperCase() })
// Function reference
val result = transform("hello", String::uppercase)
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@ttu ttu Oct 1, 2023

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Perhaps, from the example's perspective, changing the functionality slightly, e.g. to { "PREFIX_${it.uppercase()}" }, would make more sense. The point is not to showcase the shortest example, but to demonstrate how functions are used. I can make the corresponding change to the C# example later to match with this modification.

// HELLO

// Trailing lambda can be placed outside the parentheses
val result2 = transform("hello") { x -> x.toUpperCase() }
val result2 = transform("hello") { it.uppercase() }
7 changes: 4 additions & 3 deletions index.html
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// MakeIncrementer can also be written in a shorter way:
Func<int, int> MakeIncrementer() => i => 1 + i;
</code></pre></div></div></div><div class="case"><div class="name">HOF - Function as Parameter</div><div class="pair"><div class="card"><div class="lang">Kotlin</div><pre class="code"><code>fun transform(initial: String, f: (String) -> String) = f(initial)
</code></pre></div></div></div><div class="case"><div class="name">HOF - Function as Parameter</div><div class="pair"><div class="card"><div class="lang">Kotlin</div><pre class="code"><code>fun transform(initial: String, transformer: (String) -> String) = transformer(initial)

val result = transform("hello", { x -> x.toUpperCase() })
// Function reference
val result = transform("hello", String::uppercase)
// HELLO

// Trailing lambda can be placed outside the parentheses
val result2 = transform("hello") { x -> x.toUpperCase() }</code></pre></div><div class="card"><div class="lang">C#</div><pre class="code"><code>string Transform(string initial, Func&lt;string, string> f) => f(initial);
val result2 = transform("hello") { it.uppercase() }</code></pre></div><div class="card"><div class="lang">C#</div><pre class="code"><code>string Transform(string initial, Func&lt;string, string> f) => f(initial);

var result = Transform("hello", x => x.ToUpper());
// HELLO</code></pre></div></div></div><div class="case"><div class="name">Tuple Return</div><div class="pair"><div class="card"><div class="lang">Kotlin</div><pre class="code"><code>// Kotlin doesn't have tuples, use data classes
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