Added tagged union examples (#277)

docs/examples/tagged-union-example-1.zig

@@ -0,0 +1,13 @@
+const std = @import("std");
+
+pub const Number = union(enum) {
+    integer: i32,
+    big_integer: i64,
+    decimal: f64,
+    complex: std.math.complex.Complex(f64),
+};
+
+pub const a: Number = .{ .integer = 123 };
+pub const b: Number = .{ .big_integer = 1234567890 };
+pub const c: Number = .{ .decimal = 0.12345 };
+pub const d: Number = .{ .complex = .{ .re = 1, .im = 2 } };

docs/examples/tagged-union-example-1a.js

@@ -0,0 +1,6 @@
+import { a, b, c, d } from './tagged-union-example-1.zig';
+
+console.log(a.integer);
+console.log(b.big_integer);
+console.log(c.decimal);
+console.log(d.complex.valueOf());

docs/examples/tagged-union-example-1a.txt

@@ -0,0 +1,4 @@
+123
+1234567890n
+0.12345
+{ re: 1, im: 2 }

docs/examples/tagged-union-example-1b.js

@@ -0,0 +1,6 @@
+import { b, c } from './tagged-union-example-1.zig';
+
+console.log(b.big_integer);
+console.log(b.integer);
+
+console.log(c.integer ?? c.big_integer ?? c.decimal);

docs/examples/tagged-union-example-1b.txt

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+1234567890n
+null
+0.12345

docs/examples/tagged-union-example-1c.js

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+import { c } from './tagged-union-example-1.zig';
+
+for (const [ tag, value ] of c) {
+    console.log(`${tag} => ${value}`);
+}

docs/examples/tagged-union-example-1c.txt

@@ -0,0 +1 @@
+decimal => 0.12345

docs/examples/tagged-union-example-1d.js

@@ -0,0 +1,21 @@
+import { a, b, c, d } from './tagged-union-example-1.zig';
+
+for (const number of [a, b, c, d ]) {
+    for (const [ tag, value ] of number) {        
+        switch (tag) {
+            case 'integer':
+                console.log('Do something with integer');
+                break
+            case 'big_integer':
+                console.log('Do something with big integer');
+                break;
+            case 'decimal':
+                console.log('Do something with decimal number');
+                break;
+            case 'complex': 
+                console.log('Do something with complex number');
+                break;
+        }
+    }   
+}
+

docs/examples/tagged-union-example-1d.txt

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+Do something with integer
+Do something with big integer
+Do something with decimal number
+Do something with complex number

docs/examples/tagged-union-example-1e.js

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+import { a, Number } from './tagged-union-example-1.zig';
+
+console.log(`${Number.tag(a)}`);

docs/examples/tagged-union-example-1e.txt

@@ -0,0 +1 @@
+integer