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It seems that this is a huge source of confusion for beginners writing regular expressions, can cause hidden performance problems, and it would seem that a typical use case would be non-greedy.
Is this just for legacy reasons (it was how it was first done, and every implementation copies that), or is there a reason for it?
Hysterical Raisens
Part of the answer may involve the origins of REs in practical computing. They were originally a theoretical concept from automata theory and formal language theory until Ken Thompson himself wrote a real implementation and used them in qed and ed(1).
The original version had only the greedy syntax and so there wasn’t a decision to even make.