Original article, welcome to reprint. Please indicate: Guan Dongsheng's blog
Before the advent of the Swift language, the development of iOS or OS X applications mainly used the Objective-C language, in addition to the C and C++ languages, but the UI part can only use the Objective-C language.
Choose a language
After the Swift language appeared, Apple gave programmers more options to allow the two languages to coexist. Since it is coexistence, we have 4 ways to choose:
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Adopt a pure Swift reformist approach;
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A conservative approach in pure Objective-C ;
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The left-leaning reformist way of calling Objective-C using Swift ;
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A right-leaning reformist way of calling Swift in Objective-C .
file extension
When developing iOS or OS X applications in Xcode and other tools , various forms of source files can be written. Originally, Objective-C , C and C++ languages can be used. After the appearance of Swift language, source files have more diverse forms. Description of possible file extensions:
