closures

问题 I want to create a vector of functions let all_rerankers = vec![ match_full , match_partial , match_regex , match_camel_case ]; However, match_camel_case needs one more parameter than other functions, so I though I could define a closure for match_camel_case // 3 is the extra parameter needed by match_camel_case let close_camel_case = |str: &str, keyword: &str| { match_camel_case(str, keyword, 3) }; and then specify the type of my vector: let all_rerankers: Vec<|str: &str, kwd: &str| ->

问题 I want to create a vector of functions let all_rerankers = vec![ match_full , match_partial , match_regex , match_camel_case ]; However, match_camel_case needs one more parameter than other functions, so I though I could define a closure for match_camel_case // 3 is the extra parameter needed by match_camel_case let close_camel_case = |str: &str, keyword: &str| { match_camel_case(str, keyword, 3) }; and then specify the type of my vector: let all_rerankers: Vec<|str: &str, kwd: &str| ->

问题 I want to create a vector of functions let all_rerankers = vec![ match_full , match_partial , match_regex , match_camel_case ]; However, match_camel_case needs one more parameter than other functions, so I though I could define a closure for match_camel_case // 3 is the extra parameter needed by match_camel_case let close_camel_case = |str: &str, keyword: &str| { match_camel_case(str, keyword, 3) }; and then specify the type of my vector: let all_rerankers: Vec<|str: &str, kwd: &str| ->

问题 final Object o; List l = new ArrayList(){{ // closure over o, in lexical scope this.add(o); }}; why must o be declared final? why don't other JVM languages with mutable vars have this requirement? 回答1: This is not JVM-deep, it all happens at syntactic-sugar level. The reason is that exporting a non-final var via a closure makes it vulnerable to datarace issues and, since Java was designed to be a "blue-collar" language, such a surprising change in the behavior of an otherwise tame and safe

问题 I have an array sorting function as follows: public function sortAscending($accounts) { function ascending($accountA, $accountB) { if ($accountA['AmountUntilNextTarget'] == $accountB['AmountUntilNextTarget']) { return 0; } return ($accountA['AmountUntilNextTarget'] < $accountB['AmountUntilNextTarget']) ? -1 : 1; } usort($accounts, $ascending); return $accounts; } Clearly this is not ideal as it is hard-coding the key to search for. I thought I would make this generic by passing the key as a

问题 I have a javascript function which contains another javascript function inside (closure) function function1() { $("button").bind("click", function () { function2(); }); function function2() { // code }; }; My question: When i call function1() for many times, does the function2() gets created each time (and saved in memory)? or it is shared? function1 is not used as a constructor, so i don't think i should use prototype 回答1: Yes, function2 would be created each time function1 is executed,

问题 I have two javascript closures and I'm trying to understand why one will accept and input with a particular syntax and the other will reject. function multiply(factor) { var ace = (function(number) { return number*factor; }); return ace; } var yup = multiply(4); console.log(yup(5)); This outputs 20 to the console as it should. The second Closure I have is var k = 3; var add = (function () { console.log(k); var counter = k; return function (j) {counter += 1; return counter*j} })(k); add();

问题 I see in the docs and in Closure.java references to "directive" with no explanation of whgat it is or what it is for, public static final int DONE = 1, SKIP = 2; private int directive; /** * @return Returns the directive. */ public int getDirective() { return directive; } /** * @param directive The directive to set. */ public void setDirective(int directive) { this.directive = directive; } I also googled it but I found not a single reference to it, except from some tests where it appears

问题 I see in the docs and in Closure.java references to "directive" with no explanation of whgat it is or what it is for, public static final int DONE = 1, SKIP = 2; private int directive; /** * @return Returns the directive. */ public int getDirective() { return directive; } /** * @param directive The directive to set. */ public void setDirective(int directive) { this.directive = directive; } I also googled it but I found not a single reference to it, except from some tests where it appears

问题 I see in the docs and in Closure.java references to "directive" with no explanation of whgat it is or what it is for, public static final int DONE = 1, SKIP = 2; private int directive; /** * @return Returns the directive. */ public int getDirective() { return directive; } /** * @param directive The directive to set. */ public void setDirective(int directive) { this.directive = directive; } I also googled it but I found not a single reference to it, except from some tests where it appears