Ask HN: What is the meaning of "Python’s broken notion of lambda"*?

1 points by mechnik ↗ HN
* Hal Abelson in http://www.codequarterly.com/2011/hal-abelson/

3 comments

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He may be referring to the fact that lambda expressions in Python are limited to a single statement. If you want anything more complex than that, you have to define a function elsewhere and pass it by name.
Two possible issues. As tmhedberg says (more or less), they're second-class citizens: they may contain one expression, and cannot contain any statements (e.g., 'print').

A more important issue: in LISP, ML, and other languages with a "proper" lambda, the value of a lambda expression is a lexical closure. Python's lambdas are dynamically scoped, which certainly qualifies as broken.

See, e.g., http://math.andrej.com/2009/04/09/pythons-lambda-is-broken/

Thank you for explaining this.