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What is 'Pattern Matching' in functional languages?
...e functional languages allow you define simple data types called "disjoint unions" or "algebraic data types". These data structures are simple containers, and can be recursively defined. For example:
type 'a list =
| Nil
| Cons of 'a * 'a list
defines a stack-like data structure. Think of...
__attribute__ - C/C++ - 清泛网 - 专注C/C++及内核技术
...nocommon，deprecated，mode，section，shared， tls_model，transparent_union，unused，vector_size，weak，dllimport，dlexport等，
详细信息可参考：
http://gcc.gnu.org/onlinedocs/gcc-4.0.0/gcc/Variable-Attributes.html#Variable-Attributes
类型属性（Type Attribute）
关键...
C/C++ Struct vs Class
...long ago, back when C++ was still known as "C with Classes."
Note that C unions work with C++, but not the other way around. For example
union WorksWithCppOnly{
WorksWithCppOnly():a(0){}
friend class FloatAccessor;
int a;
private:
float b;
};
And likewise
typedef union friend{...
How to prevent ifelse() from turning Date objects into numeric objects
... My vote would be for a factor return object that had levels that were the union of the levels of true's and false's levels.
– IRTFM
Aug 28 '16 at 20:05
3
...
How to use NULL or empty string in SQL
...ERE SomeCol = '' OR SomeCol IS NULL;
SELECT *
FROM #T
WHERE SomeCol = ''
UNION ALL
SELECT *
FROM #T
WHERE SomeCol IS NULL;
SELECT *
FROM #T
WHERE EXISTS ((SELECT NULL UNION SELECT '') INTERSECT SELECT SomeCol);
And some non-sargable ones...
SELECT *
FROM #T
WHERE IIF(SomeCol <> '',0,1) ...
String.Join method that ignores empty strings?
...earchTerm1, N'') AS RPT_SearchTerm, 1 AS RPT_Sort
UNION ALL SELECT NULLIF(@in_SearchTerm2, N'') AS RPT_SearchTerm, 2 AS RPT_Sort
UNION ALL SELECT NULLIF(@in_SearchTerm3, N'') AS RPT_SearchTerm, 3 AS RPT_Sort
UNION ALL SELECT...
Is there any difference between GROUP BY and DISTINCT
... 12 there do appear to be cases where DISTINCT, getting distinct values by UNION, and GROUP BY work differently. I just had a case earlier today where DISTINCT and distinct by UNION cause an oracle error, but GROUP BY worked; I was selecting only 1 column from a view and not using any aggregation; I...
Enforcing the type of the indexed members of a Typescript object?
... a similar syntax to enforce that an object has a key for every entry in a union type:
type DayOfTheWeek = "sunday" | "monday" | "tuesday" | "wednesday" | "thursday" | "friday" | "saturday";
type ChoresMap = { [day in DayOfTheWeek]: string };
const chores: ChoresMap = { // ERROR! Property 'saturd...
What is the most ridiculous pessimization you've seen? [closed]
...'s "too big".
Create an archive table for retired records, but continue to UNION it with the production table.
Duplicate entire databases by (division/customer/product/etc.)
Resist adding columns to an index because it makes it too big.
Create lots of summary tables because recalculating from raw da...
How to allocate aligned memory only using the standard library?
...better idea, please say so...
[Added:
The 'standard' trick is to create a union of 'likely to be maximally aligned types' to determine the requisite alignment. The maximally aligned types are likely to be (in C99) 'long long', 'long double', 'void *', or 'void (*)(void)'; if you include <stdint...