“贪婪令牌解析”在PHP [英] 'Greedy Token Parsing' in PHP

问题描述

PHP中的Greedy token parsing是什么？
我在Codeigniter指南中发现了这一点：

总是使用单引号字符串，除非你需要变量解析，如果你需要变量解析，使用大括号

我的字符串{$ foo}

解决方案

贪心标记解析指的是这样的：

  $ fruit =apple 
 $ amount = 3; 
 $ string =我有$ amount $ fruits; 
  

可能的预期输出：我有3个苹果

实际输出：我有3

当然，这是一个初学者的错误，但即使专家有时也犯错误！

就个人而言，我不喜欢内插变量的所有，大括号或不。我发现我的代码更容易阅读，像这样：

  $ string =I have。$ amount。。 。s; 
  

请注意，代码编辑器可以更方便地对此行进行颜色编码，如Notepad ++中所示： / p>

再次，有些人可能更喜欢让引擎做内插：

  $ string = sprintf ％d％ss，$ amount，$ fruit）; 
  

这完全取决于个人喜好，但你引用的指南中的要点是小心您正在写的内容。

What is 'Greedy token parsing' in PHP ? I found this in Codeigniter guideline:

"Always use single quoted strings unless you need variables parsed, and in cases where you do need variables parsed, use braces to prevent greedy token parsing."

"My string {$foo}"

An answer with good explanation will help.

Thanks !!

解决方案

Greedy token parsing refers to something like this:

$fruit = "apple";
$amount = 3;
$string = "I have $amount $fruits";

Possible expected output: "I have 3 apples"
Actual output: "I have 3 "

Of course, this is a beginner mistake, but even experts make mistakes sometimes!

Personally, I don't like to interpolate variables at all, braces or not. I find my code much more readable like this:

$string = "I have ".$amount." ".$fruit."s";

Note that code editors have an easier job colour-coding this line, as shown here in Notepad++:

Then again, some people might prefer letting the engine do the interpolation:

$string = sprintf("I have %d %ss",$amount,$fruit);

It's all up to personal preference really, but the point made in the guideline you quoted is to be careful of what you are writing.

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