1 Null coalescing operators return the right hand side of an expression of 2 the left hand side is null. 3 4 5 1. The `??` operator returns the right hand side of the expression if the 6 left hand side evaluates to `null`. 7 8 -- Expect stdout -- 9 is null 10 false 11 0 12 -- End -- 13 14 -- Testcase -- 15 {% 16 x = null; 17 y = false; 18 z = 0; 19 20 print(x ?? "is null", "\n"); 21 print(y ?? "is null", "\n"); 22 print(z ?? "is null", "\n"); 23 %} 24 -- End -- 25 26 27 2. The `??=` nullish assignment operator sets the left hand side variable 28 or value to the right hand side expression if the existing value is null. 29 30 -- Expect stdout -- 31 is null 32 false 33 0 34 -- End -- 35 36 -- Testcase -- 37 {% 38 x = null; 39 y = false; 40 z = 0; 41 42 x ??= "is null"; 43 y ??= "is null"; 44 z ??= "is null"; 45 46 print(x, "\n"); 47 print(y, "\n"); 48 print(z, "\n"); 49 %} 50 -- End --
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