Final answer:
Languages disallow casting and coercion to maintain type safety and predictability, sacrificing some flexibility. Comprehensions in Haskell and Python provide a concise and readable way to create and transform data structures from iterables.
Step-by-step explanation:
The reasoning behind disallowing casting and coercion in some programming languages is to maintain type safety and avoid errors that can result from unintended type conversions. These languages often prioritize ensuring that operations are performed on compatible data types, thus preventing runtime errors and leading to more predictable and reliable code. When a language disallows both casting and coercion, what is lost is some flexibility in handling different data types, which can lead to a need for more explicit and sometimes verbose code to manage type conversions manually.
A comprehension is a concise way to create a list, set, dictionary, or other data structure from existing iterables in programming languages like Haskell and Python. It usually involves iterating over a sequence, applying a condition or filter, and then transforming the elements that meet the condition. Comprehensions provide a more readable and expressive syntax for these operations compared to using loops and conditional statements.