ReferenceError: Invalid left-hand side in assignment
You have to use == to compare (or even ===, if you want to compare types). A single = is for assignment. if (one == ‘rock’ && two == ‘rock’) { console.log(‘Tie! Try again!’); }
logic
Visual Studio Project/Item Template Parameter Logic
This post is linked from the official Microsoft documentation for MSBuild Conditions as having examples of usage. The syntax for MSBuild conditions is not exactly equivalent to the way templating $if$ statements work but it’s a close approximation. However, it seems the examples here are now obsolete or were never completely accurate to begin with. … Read more
Fastest way to get sign in Java?
Any reasons why you don’t simply use: int sign = (int) Math.signum(a); //1 cast for floating-points, 2 for Integer types Additionally most Number implementations have a signum method taking a primitive of that type and returning an int, so you can avoid casting for extra performance. int sign1 = Integer.signum(12); //no casting int sign2 = … Read more
How does Djinn work?
Djinn is a theorem prover. It seems your question is: what does theorem proving have to do with programming? Strongly typed programming has a very close relationship to logic. In particular, traditional functional languages in the ML tradition are closely related to Intuitionist Propositional Logic. The slogan is “programs are proofs, the proposition that a … Read more
AND/OR in Python? [duplicate]
As Matt Ball’s answer explains, or is “and/or”. But or doesn’t work with in the way you use it above. You have to say if “a” in someList or “á” in someList or…. Or better yet, if any(c in someList for c in (“a”, “á”, “à”, “ã”, “â”)): … That’s the answer to your question … Read more
XOR of three values
For exactly three terms, you can use this expression: (a ^ b ^ c) && !(a && b && c) The first part is true iff one or three of the terms are true. The second part of the expression ensures that not all three are true. Note that the above expression does NOT generalize … Read more
Find the biggest interval that has all its members in list in O(n) [duplicate]
I know a solution based on hashing and dynamic programming. Let f(x) be the hash function. The trick is the hash-table value. Consider the longest interval contained in the list, which either starts or ends with x. Then h[f(x)] = y, where y is the other end of that interval. Note that length of that … Read more
Booleans have two possible values. Are there types that have three possible values? [duplicate]
In Python I’d do that with a wrapper object that holds one of those three values; I’d use True, False, and None. Since the implicit truthiness value of a Boolean-like object with three possible values is problematic, we’ll solve that by disallowing that entirely (raising an exception in __nonzero__(), or in Python 3, __bool__()), thus … Read more
Higher-order unification
State of the art — yes, so far as I know all algorithms more or less take the same shape as Huet’s (I follow theory of logic programming, although my expertise is tangential) provided you need full higher-order matching: subproblems such as higher-order matching (unification where one term is closed), and Dale Miller’s pattern calculus, … Read more
Why are default arguments evaluated at definition time? [duplicate]
The alternative would be quite heavyweight — storing “default argument values” in the function object as “thunks” of code to be executed over and over again every time the function is called without a specified value for that argument — and would make it much harder to get early binding (binding at def time), which … Read more