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_archive/rhai_engine/rhaibook/ref/overload.md

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+Function Overloading
+====================
+
+{{#title Function Overloading}}
+
+[Functions](functions.md) defined in script can be _overloaded_ by _arity_ (i.e. they are resolved
+purely upon the function's _name_ and _number_ of parameters, but not parameter _types_ since all
+parameters are dynamic).
+
+New definitions _overwrite_ previous definitions of the same name and number of parameters.
+
+```js
+fn foo(x, y, z) {
+    print(`Three!!! ${x}, ${y}, ${z}`);
+}
+fn foo(x) {
+    print(`One! ${x}`);
+}
+fn foo(x, y) {
+    print(`Two! ${x}, ${y}`);
+}
+fn foo() {
+    print("None.");
+}
+fn foo(x) {     // <- overwrites previous definition
+    print(`HA! NEW ONE! ${x}`);
+}
+
+foo(1,2,3);     // prints "Three!!! 1,2,3"
+
+foo(42);        // prints "HA! NEW ONE! 42"
+
+foo(1,2);       // prints "Two!! 1,2"
+
+foo();          // prints "None."
+```