Preface

In daily development, we often use JSON、XML、HTML、SQL、Regex Wait for the string to copy and paste into our code , These strings often contain a lot of quotation marks ", We have to add escape characters to all quotation marks one by one \ Transference . This is very troublesome , And easy to make mistakes , And when we need to replace these strings , The re pasted text still needs to be escaped again , It's just breaking down .

In my work, I often encounter such a scene , For a core business approach , Before business execution, log output parameter objects are generally used (Json Format ), In this way, the parameter value at that time can be traced in case of business failure , It is conducive to afterwards compensation or recurrence bug etc. .
Suppose a fault occurs , I got the parameter value from the log. The content is as follows

{
    "kpzdbs": "YJ2",
    "jqbh": "499098528334",
    "fplxdm": "026",
    "fpqqlsh": "ZJBX965525",
    "kplx": 0,
    "tspz": "00"
}

To reproduce the problem , In console or unit tests , Define this parameter , And call MyLogic Method ,

You can see that the error string is copied directly from the log json Pasted in , Need for all " Transference , This is a very painful problem , Sometimes you may need to paste many objects in the log to test , Insert escape symbols after pasting each time

Now we don't need to do this .

Original string of new features

Original string text   Is a new format for string text . The original string text can contain any text , Including Spaces 、 New line 、 Embed quotation marks and other special characters , Without an escape sequence . The original string text starts with at least three double quotes , (""") Characters . It ends with the same number of double quote characters . Usually , The original string text uses three double quotes on a single line to start the string , Three double quotes on the other line end the string . The closing quotation mark and the line break before the closing quotation mark are not included in the final content . Refer to here for details

Use cases

I use this new feature to modify the code in the above scenario as follows , You can see ,json The string can be pasted directly without any escape .

Another example is that I need to paste a paragraph html, Without this new feature , Escape so many quotes , You may be crazy ！！

The use of the original string should pay attention to

• Use at least three double quotes ( """...""") The beginning and the end , Any number of double quotation marks less than the number of open original string text is considered content .

• The closing quotation mark and the line break before the closing quotation mark are not included in the final content .

• The original string text usually uses three double quotes on a single line to start the string , Three double quotes on the other line end the string .

• You can talk to $( There can be multiple ) Use with interpolated strings , Prefix $ The number of is the number of curly braces required to indicate nested code expressions . If the original string text starts with $$ The prefix , A single brace is treated as the content , And you need two curly braces to indicate nested code . It's like using quotation marks , You can add more $ To allow more braces to be treated as content .

When more than three double quotes are needed

When the content of the string contains at least three " Come together , Your continuous presence " Add the number of 1( At least three ), Namely Original string Use... At the beginning and end " The number of , So it's not fixed three "
Be careful ： Before the string in the figure | Not the character you entered , Is the alignment prompt of the compiler .

Output

The closing quotation mark and the line break before the closing quotation mark are not included in the final content

As follows , The compiler automatically ends with """" The front shows a vertical line for the boundary , The space to the left of the vertical line is not counted as content .

The three quotation marks at the end can't start another line

Put the ending character after the content , The compiler will prompt you to put it on your own line

This can be interpreted as , In this case, it may cause ambiguity , The compiler is not sure which of the following three is your original string .

 you """ good """ ah 

or （ There's a space in front ）

 you """ good """ ah 

or （ Line break + There's a space in front ）

 you """ good """ ah 

If so , There will be no ambiguity , Bounded by the vertical line pointed by the arrow , The space on the left does not count as content , The space on the right is counted as the content

If it's all in one line , Because there will be no ambiguity .

Use with interpolated characters

This is more difficult to understand ,$ The number of symbols is also not fixed , Depending on how many curly braces you need to use in succession as the original character
When the content you want to output has no parentheses , It belongs to the general usage , There's nothing to say .

If you want to output the following

{ Zhang San }

Tips for meeting this problem

The simple understanding is , You need to treat a brace as content , Two are needed $ As a prefix , You need to n Parentheses are for the content , Need n + 1 individual $ Prefix , Similarly, the interpolation of strings also requires the consumption of $ The same number of braces .
Because you want to treat a brace as content , So we need to 1 + 1 = 2 individual $, Again , Interpolated variables also need to follow $ A consistent number of parentheses wrap , So the modified code is as follows .

If what you want to output is

{
    {
    {
    { Zhang San 

You need to treat the four parentheses as content ,n = 4, $ The number of  4 + 1 = 5, Interpolated variables also need 5 And bracket wrapping .

summary

When we paste quoted text into the compiler, we need to do a lot of escape operations , Original string The feature can solve this problem well , Let's have fun pasting these strings , But when used with interpolated strings , In particular, multiple brace scenes are still difficult to understand , Fortunately, the compiler will prompt how to do , And those scenes are extremely uncommon .