ruby ignore return value

Rather than assigning an empty string to a variable, we can create an empty string … But: if the timeout is detected it is extremely useful to indicate that fact via the return value. JavaScript passes a value from a function back to the code that called it by using the return statement. cv.wait sec This is a method which destructively slices its receiver, and returns what was sliced. They do not speed things up by themselves. In Ruby, blocks are snippets of code that can be created to be executed later. Here in the example above, the return value of discarded_method is not used; thus it is marked as "DISCARDED". For example: def say_hello(name) “Hello, ” + name end. end. This method is different from casecmp! When waiting upon a Condition, a "spurious wakeup" is permitted to occur, in general, as a concession to Ruby 1.8.7 p248 and p249 have marshalling bugs that crash Rails. new { puts "What's the big deal"} . When cv#signal was not only fired but also timeout occur, some OS return timeout occur and other return … We’ll occasionally send you account related emails. They become instant garbage unless referenced elsewhere; which is of course a waste of both time and space. In the usual case you certainly need to check your condition. Same for core methods like String#slice! This rule requires return statements to either always or never specify values. defineclass: pass VM_FRAME_FLAGS_DISCAEDED, vm_call_iseq_setup_noramal: pass VM_FRAME_FLAG_DISCARDED, vm_call_cfunc_with_frame: pass calling->flags, vm_invoke_iseq_block: pass calling->flags, rb_whether_the_return_value_is_used_p: added, StringScanner#scan: skip allocating return values, _mjit_compile_send: eliminate uninitialized bits, TestGc#test_stat: ensure cache population, https://bugs.ruby-lang.org/issues/17004#note-5. However when you take a closer look, for instance String#slice! In order not to break existing codes, methods must be allowed to return values even if they are discarded. However, for new ones, let us make room for optimisations. In the last form, an array of the given size is created. The class must provide a method each, which yields successive members of the collection. does improve considerably. 3- The svn:global-ignores property. Optimisation of this situation is beyond this proposal. You must change the existing code in this line in order to create a valid suggestion. Suggestions cannot be applied on multi-line comments. I consider this an API bug: when invoked with a timeout value the caller cannot distinguish from the return value whether the condition has been signaled or the time has run out. To make it possible, a return value of a method is not forced to be used: every method can (and does) return possibly multiple values, while its callers are free to ignore them. When cv#signal was not only fired but also timeout occur, some OS return timeout occur and Then we could remove the loop altogether yet retain the time limitation. You signed in with another tab or window. Secondly, it takes a whole different approach to annotating programs: ideally, you can leave your .rb files entirely unchanged. Because looking at the current frame's flag by calling another method is kind of suboptimal, we also provide a new VM instruction opt_RubyVM_return_value_is_used_ which transparently does the same thing without modifying the execution context at all. This record sale is a testament to the growing ruby market and the high value that rubies can collect on the secondhand market. To remedy, we introduce a new method calling convention that allows methods to return arbitrary return values when not used. Suggestions cannot be applied while the pull request is closed. Likewise, if the value isn't literally "false" but evaluates as false, we call it "falsey." Noppakun is a Tokyo-based full-stack software engineer with extensive experience using Vue.js and Ruby on Rails. And then, no timeout doesn't mean the condition become true and an API user always have to ignore the return value and check then, you must not trust the return value. Ruby do not force you a style of writing. It has been committed to the trunk so anyone who is interested can install Ruby 2.7.0-dev and check it out. It tells the interpreter: load the value for the global variable “foo”, then call it without arguments, then throw away the return value. Ruby Bridges, the “youngest foot soldier” of the Civil Rights movement, delivered the Presidential Colloquium to a crowd of over 2,000 people at Smith College on Friday, Feb. 2. Though, Java threads also have a dark chapter in the history: http://docs.oracle.com/javase/1.5.0/docs/guide/misc/threadPrimitiveDeprecation.html, rklemme (Robert Klemme), 09/30/2012 12:14 AM, http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/locks/Condition.html#awaitUntil(java.util.Date), Program which tests a few alternative timeout implementations. The masgn case ('1.times {|i| x, y = self, i }') could be done transparently by the VM without exposing any predicate. Covering Method Names, Return Values, Scope, Overriding, Arguments, Default Values, Array Decomposition, Array/Hash Argument, Keyword Arguments, Block Argument, Exception Handling. Go to the editor Sample Output: 12 110 0 Click me to see the solution. Here, the leave instruction (almost) resembles ruby's return statement, and the pop instruction (almost) resembles ruby's ';' delimiter. By taking such 2-grams of the entire execution of a Ruby program, we can see the ratio of the operation we are talking about. And Ruby has real true and false values too . You can also do this in cucumber.yml. END.This is an odd Ruby quirk as other engines use (?m) for the "^ and $ match on every line" mode. You might not know that Perl has something similar - the poorly named wantarray function. Is there a good example for this predicate in user code? ruby-warning adds custom processing for warnings, including the ability to ignore specific warning messages, ignore warnings in specific files/directories, include backtraces with warnings, treat warnings as errors, deduplicate warnings, and add custom handling for all warnings in specific files/directories. until condition Reposting some of https://bugs.ruby-lang.org/issues/17004#note-5 here: Do you have measurements on real applications, not just micro-benchmarks? A substring is a smaller part of a string, it’s useful if you only want that specific part, like the beginning, middle, or end. The closest equivalent to variables is its ancillary stacks. So frex [nil, false].any? We can protect against … Sure: https://bugs.ruby-lang.org/issues/17004. :-). We certainly need to give a bit more thought to this. Having only thought about this for about half and hour I am concerned with this feature. ... (rb_class_path(under)); / copy the return value / 222 rb_str_cat2(str, “:: ... therefore we can ignore it. But I think nevertheless that the Java way is not crazy. target = Time.now + timeout, lock.synchronize do This is considered to be a good thing. sec = target - Time.now def two_plus_two return 2 + 2 1 + 1 # this expression is never evaluated end. This operator compares two Ruby objects and returns -1 if the object on the left is smaller, 0 if the objects are the same, and 1 if the object on the left is bigger. … As you can see, although we assign a new value to x in #plus, the original argument, a, is left unchanged. Applying suggestions on deleted lines is not supported. There is some truth in what you write. ; Holding down the Shift key and then using the Up and Down cursor keys to increase or decrease the range of items selected. end. We add a flag called VM_FRAME_FLAG_DISCARDED which denotes that the return value is not used. Ruby Methods: A method in Ruby is a set of expressions that returns a value. We provide Ruby level API RubyVM.return_value_is_used? (e.g., with an internal predicate). pthread_cond_wait does not return such as information. The usage pattern would look like this: def do_whatever(timeout) As only ` VALUE `s can be put in the instance variable table, the `ID` is converted to `Symbol` using `ID2SYM()`. learnpython.org is a free interactive Python tutorial for people who want to learn Python, fast. We are only providing APIs in this pull request. We do not force them to eliminate unused return values. No side-effects: when passed a given value, a function must always return the same result. To disclose this kind of information to the Ruby level is just too much. As you said ("Otherwise the idiom shown above would become more complex"), there is a trivial workaround. Here is my example using Array A I need to remove the value 3 from my array. How to add additional code to be run at application start time. return :fail if sec <= 0 other return cv#signal received. If the value isn't literally "true" but evaluates as true, we call it "truthy." This suggestion is invalid because no changes were made to the code. In Ruby many statements are implemented in a way that they are either expressions or at least behave in such a way. This is not a bug. Keyboard users can select multiple contiguous items by: Focusing on the