Original article, welcome to reprint. Please indicate: Guan Dongsheng's blog
Code layout includes : blank lines, spaces, line breaks, and indentation. The content of the code typesetting is more and the workload is a lot, but it is very important.
Blank line
Blank lines separate logically related sections of code to improve readability. Blank lines should always be added when:
- before the type declaration.
- Before and after the import statement.
- between two methods or functions.
- before block or single-line comments.
- Between two logical sections within a method or function to improve readability.
- between two fragments of a source file. space
Spaces are required in some positions in the code, and this workload is also very large. The following are the specifications for using spaces:
1. There is a space before and after the assignment symbol " = ". There is a space between var or let and the identifier. All binary operators should be separated from their operands by a space. Spaces should not be added between unary operators and operands, such as: ++ , -- etc. Examples are as follows.
var a = 10 var c = 10 a += c + d
2. There should be no space after the small left parenthesis " ( " and before the small right parenthesis " ) ". Examples are as follows.
a = (a + b) / (c * d)
3. There is a space before the opening brace " { ". Examples are as follows.
while a == d {
n++
}
4. There is a space before the method or function parameter, and there is a space between the parameter colon and the data type.
Recommended Use:
func tableView(tableView: UITableView,didSelectRowAtIndexPath indexPath: NSIndexPath) {
...
}
Deprecated:
func tableView(tableView: UITableView,didSelectRowAtIndexPath indexPath: NSIndexPath) {
...
}
Decisive action
Try to avoid the length of a line of code exceeding 80 characters. In order to check whether a line of code exceeds 80 characters, many IDE development tools can display 80 vertical lines in the editing window. The setup process in Xcode is to open the menu Xcode→Preferences , select the Text Editing tab, and select Show→Page guide at column .
Since some codes are relatively long and need to be broken, they can be broken according to the following general specifications:
<!--[if !supportLists]--> l <!--[endif]--> Break after a comma.
<!--[if !supportLists]--> l <!--[endif]--> Break in front of an operator, to choose higher-level operator break, not lower-level operator break .
<!--[if !supportLists]--> l <!--[endif]--> The new line should be indented two levels ( 8 spaces) from the previous line
indentation
4 spaces are often used as a unit of indentation typesetting. Tabs are used for indentation during development. Although a tab is equal to 8 spaces by default, a tab may be set in different IDE tools. The corresponding number of characters and spaces will be different. In Xcode , a tab corresponds to 4 spaces by default. We can open the menu Xcode→Preferences in Xcode , select the Text Editing→Indentation label, and set the Tab width .
Indentation can be based on the following general specifications:
<!--[if !supportLists]-->l <!--[endif]-->在函数、方法、闭包、控制语句、计算属性等包含大括号“{}”代码块中，代码块中的内容与首行缩进一个级（4个空格）。
<!--[if !supportLists]-->l <!--[endif]-->如果是if语句中条件表达式的断行，那么新的一行应该与上一行缩进两个级别（8个空格），再往后的断行要与第一次的断行对齐。