Alan Gauld wrote:
Can I ask what the objection to lambda is? 1) Is it the syntax?
2) Is it the limitation to a single expression?
3) Is it the word itself?
I can sympathise with 1 and 2 but the 3rd seems strange since a lambda is a well defined name for an anonymous function used in several programming languages and originating in lambda calculus in math. Lambda therefore seems like a pefectly good name to choose.
I think that the real objection is a little bit of 1), and something that's kinda close to 2), but has nothing to do with 3).
The issue isn't that lambdas are bad because they're limited to a single expression. The issue is that they're an awkward special case of a function, which was added to the language to mollify functional-programming advocates but which GvR never felt really "fit" into Python. Other, more pythonic functional-programming features have since been added (like list comprehensions and iterators).
It seems to me that in other, less-dynamic languages, lambdas are significantly different from functions in that lambdas can be created at runtime. In Python, *all* functions are created at runtime, and new ones can be defined at any point in execution, so lambdas don't get that advantage. Thus, their advantages are limited to the fact that they're anonymous (but names are treated differently in Python than in most other languages, so this is of marginal utility), and that they can be created inline. This last bit makes them suitable for creating quick closures (wrapping a function and tweaking its parameters/return values) and for creating a delayed-execution object (e.g. callbacks), so there's a lot of pressure to keep them, but they're still a special case, and "special cases aren't special enough to break the rules".
Jeff Shannon Technician/Programmer Credit International
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