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Techniques for Tracing Constraints
Here's the scenario: I've written some code with a type signature and GHC complains could not deduce x ~ y for some x and y . You can usually throw GHC a bone and simply add the isomorphism to the function constraints, but this is a bad idea for several reasons:
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How can I verify if one list is a subset of another?
I need to verify if a list is a subset of another - a boolean return is all I seek.
15 Answers
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Scala: Abstract types vs generics
I was reading A Tour of Scala: Abstract Types . When is it better to use abstract types?
4 Answers
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Sorting an array of objects by property values
I've got the following objects using AJAX and stored them in an array:
30 Answers
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What does the `forall` keyword in Haskell/GHC do?
I'm beginning to understand how the forall keyword is used in so-called "existential types" like this:
8 Answers
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What is the difference between a deep copy and a shallow copy?
What is the difference between a deep copy and a shallow copy?
31 Answers
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Does Java support default parameter values?
I came across some Java code that had the following structure:
24 Answers
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Split delimited strings in a column and insert as new rows [duplicate]
I have a data frame as follow:
6 Answers
6
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Is double square brackets [[ ]] preferable over single square brackets [ ] in Bash?
A co-worker claimed recently in a code review that the [[ ]] construct is to be preferred over [ ] in constructs like
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Multiple variables in a 'with' statement?
Is it possible to declare more than one variable using a with statement in Python?
6 Answers
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