strict

在看js代码时，有时会看到关于quirks mode(怪异模式)和strict mode(严格格式)的东西，一直也没深究怎么回事，只是零零碎碎的有些概念，最近终于受不了这种似懂非懂的感觉，决定好好学习总结一下。 1、quirks mode和strict mode是浏览器解析css的两种模式，或者可以称之为解析方法。目前正在使用的浏览器这两种模式都支持 。 2、历史原因。 当早期的浏览器Netscape 4和Explorer 4对css进行解析时，并未遵守W3C标准，这时的解析方式就被我们称之为quirks mode(怪异模式),但随着W3C的标准越来越重要，众多的浏览器开始依照W3C标准解析CSS，仿照W3C标准解析CSS的模式我们叫做strict mode(严格模式). 3、后来的浏览器虽然支持strict mode，但众多浏览器并未放弃支持quirks mode。 一个重要的原因就是为了之前大量在quirks mode下开发的网页能够得到正确的显示。所以，这些支持两种模式的浏览器当拿到一张网页时，所做的一个前期工作就是判断采取何种方式进行解析(判断条件后面会说)。注：Explorer 5仍然只支持quirks mode 4、浏览器如何判断何用哪种方式解析CSS？ 解决方案就是采用doctype声明，大多数浏览器采用下面的这些 判断规则 浏览器要使老旧的网页正常工作

Is there any recommend guidelines when to use strictness in Haskell ? For example, I was looking on the tagsoup library. They have one of their data structure defined like this: data Tag str = TagOpen str [Attribute str] | TagClose str | TagText str | TagComment str | TagWarning str | TagPosition !Row !Column type Row = Int type Column = Int So on what factor exactly do they decide that TagPosition should be strict ? Are there any recommend guidelines for this ? For simple, unstructured datatypes such as Int or Double , turning them into strict fields is often a good default. That makes their

Besides use strict , which other use directives are there? GitaarLAB Some more examples that can be in the “directive prologue” (a section potentially usable by JavaScript engines): 'use strict'; 'use asm'; Mozilla's asm.js is a subset of the language, geared towards crunching numbers. 'use stricter'; Google's SoundScript. For fast OOP Has also some modes like: 'use stricter+types'; http://www.2ality.com/2015/02/soundscript.html 'use babel'; Used in Atom.io . (Was previously: 'use 6to5'; ) A tweet by Jeremy Ashkenas suggests some further use of + and - prefixes in the same 'use ...'; string (

JavaScript doesn't care if your Strings are double-quoted "double" or single-quoted 'single' . Every example of ECMAScript 5's strict mode has it enabled by "use strict" in double-quotes. Can I do the following (single-quotes): alert(function(){ 'use strict'; return !this; }()); This will return true if Strict mode is enabled, and false if it is not. Felix Kling For you, without using a browser that supports strict mode : A Use Strict Directive is an ExpressionStatement in a Directive Prologue whose StringLiteral is either the exact character sequences "use strict" or 'use strict' . A Use

This FAQ says that The seq operator is seq :: a -> b -> b x seq y will evaluate x, enough to check that it is not bottom, then discard the result and evaluate y. This might not seem useful, but it means that x is guaranteed to be evaluated before y is considered. That's awfully nice of Haskell, but does it mean that in x `seq` f x the cost of evaluating x will be paid twice ("discard the result")? The seq function will discard the value of x , but since the value has been evaluated, all references to x are "updated" to no longer point to the unevaluated version of x , but to instead point to

This question already has an answer here: Recommended gcc warning options for C [closed] 15 answers What GCC options should be set to have GCC as strict as possible? (and I do mean as strict as possible) I'm writing in C89 and want my code to be ANSI/ISO compliant. Jonathan Leffler I'd recommend using: -Wall -Wextra -std=c89 -pedantic -Wmissing-prototypes -Wstrict-prototypes \ -Wold-style-definition You should compile with -O as well as -g as some warnings are only available when the optimizer is used (actually, I usually use -O3 for spotting the problems). You might prefer -std=gnu89 as that