Operator precedence is defined in the appropriate standard. The standards for C and C++ are the One True Definition of what exactly C and C++ are. So if you look closely, the details are there. In fact, the details are in the grammar of the language. For example, take a look at the grammar production … Read more
The order of evaluation of expressions in the select is undefined. For the most part, you only notice this when you have variables, because the errors result in erroneous information. Why? The SQL standard does not require the order of evaluation, so each database is free to decide how to evaluate the expressions. Typically such … Read more
An AwaitExpression is a UnaryExpression and has the same precedence as delete, void, typeof, +, -, ~, and !, binding stronger than any binary operator. This is unlike yield which has a precedence lower than anything else except the comma operator. This design decision was made because both yield a+b and await a + await … Read more
All the answers explaining why you get 2 and not 1 are actually wrong. According to the PHP documentation, mixing + and ++ in this manner is undefined behavior, so you could get either 1 or 2. Switching to a different version of PHP may change the result you get, and it would be just … Read more
The first one is equivalent to: (true ? (++x, ++y) : (–x)), –y; The second one is equivalent to: (false ? (++x, ++y) : (–x)), –y; Thus the –y is always executed. In the first line, the increments are executed first so x = 1, y = 0 is expected. In the second line, the … Read more
This happens because: gmodels imports gdata gdata creates a new method for reorder.factor Start a clean session. Then: methods(“reorder”) [1] reorder.default* reorder.dendrogram* Now load gdata (or load gmodels, which has the same effect): library(gdata) methods(“reorder”) [1] reorder.default* reorder.dendrogram* reorder.factor Notice there is no masking, since reorder.factor doesn’t exist in base Recreate the problem, but this … Read more
Yes, it’s guaranteed, otherwise such operators would lose much of their usefulness. Important notice: this is valid only for the builtin && and ||; if some criminal overloads them, they are treated as “regular” overloaded binary operators, so in this case both operands are always evaluated, and in unspecified order as usual. For this reason, … Read more
Because the operator : has precedence over + so 1+1:3 is really 1+(1:3) (i. e. 2:4) and not 2:3. Thus, to change the order of execution as defined operator precedence, use parentheses () You can see the order of precedence of operators in the help file ?Syntax. Here is the relevant part: The following unary … Read more
The short answer is that right-associativity can improve readability by making what the programmer type consistent with what the program actually does. So, if you type ‘1 :: 2 :: 3‘, you get a List(1, 2, 3) back, instead of getting a List back in a completely different order. That would be because ‘1 :: … Read more
Explanation Prec. denotes operator precedence, where group 1 has the highest precedence and group 17 the lowest. Assoc. denotes operator associativity, where such is applicable. Associativity can be either left-to-right or right-to-left. Sources My ambition with this post is to provide a operator precedence table on-site at Stack Overflow, which is correct and canonical. This … Read more