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- Subject: Syntactic sugar idea: Safe use of nil
- From: Mark Hamburg <mhamburg@...>
- Date: Sun, 27 Jun 2004 23:42:14 -0700
Would it be useful to define syntactic sugar that would allow nils to turn
into no-ops? For example, what if:
x = expr?.field
Were sugar for:
local var = expr;
x = expr and expr.field
In other words, ?. applied to nil yields nil. Similarly for ?.
func?() could result in a call to a function returning nothing if func was
nil. (I leave it as an open point of discussion whether any arguments get
evaluated. They probably do.)
obj?:message() would be like a call to a function returning nothing if obj
was nil. Similarly, for obj:message?() if obj fails to support message. If
both are optional, then one writes: obj?:message?().
I find myself writing a fair amount of code that avoids going down a path
when something is nil and if this is a common pattern for other people it
might be useful to encode it in some form of syntactic sugar.