Rule explicit_string_variable¶
Converts implicit variables into explicit ones in double-quoted strings or heredoc syntax.
Description¶
The reasoning behind this rule is the following:
- When there are two valid ways of doing the same thing, using both is
confusing, there should be a coding standard to follow.
- PHP manual marks "$var" syntax as implicit and "${var}" syntax as
explicit: explicit code should always be preferred.
- Explicit syntax allows word concatenation inside strings, e.g.
"${var}IsAVar", implicit doesn’t.
- Explicit syntax is easier to detect for IDE/editors and therefore has
colors/highlight with higher contrast, which is easier to read.
Backtick operator is skipped because it is harder to handle; you can use
backtick_to_shell_exec fixer to normalize backticks to strings.
Examples¶
Example #1¶
--- Original
+++ New
<?php
-$a = "My name is $name !";
-$b = "I live in $state->country !";
-$c = "I have $farm[0] chickens !";
+$a = "My name is {$name} !";
+$b = "I live in {$state->country} !";
+$c = "I have {$farm[0]} chickens !";
Rule sets¶
The rule is part of the following rule set:
References¶
Fixer class: PhpCsFixer\Fixer\StringNotation\ExplicitStringVariableFixer
Test class: PhpCsFixer\Tests\Fixer\StringNotation\ExplicitStringVariableFixerTest
The test class defines officially supported behaviour. Each test case is a part of our backward compatibility promise.