What are the methods for php syntax checking? (code example)

Grammar checking in php is very necessary. If the grammar is not checked, it will not work properly when an error occurs. If syntax checking is performed at the same time, the error may not occur. This article Let’s take a look at how to check PHP syntax.

We can use lint check

use lint static check.

Static is a method that only checks the syntax description method without executing the program.

Use the lint command at this time.

※php_check_syntax This syntax checking function has been abolished and cannot be used.

Then prepare the php file where the error actually occurs.

lint_test.php

<?php
echo "error"

It is just a code that displays error on the screen.

Move lint_test.php to a directory and issue the following command.

php -l lint_test.php

Execution result

PHP Parse error:  syntax error, unexpected end of file, expecting ',' or ';' in lint_test.php on line 2 Parse error: syntax error, unexpected end of file, expecting ',' or ';' in lint_test.php on line 2Errors parsing lint_test.php

syntax error=Output syntax error indication.

It also returns the error line number as line 2.

Because there is an unexpected end of file, the reason is that there is no ";" in the second line.

Then, modify lint_test.php and execute the lint command again.

<?php
echo "error";

The execution result is:

No syntax errors detected in lint_test.php

No syntax errors are displayed.

Use xdebug to dynamically check for syntax errors

First, enable xdebug.

① Download xdebug from the official site below, and note the path of the local environment where the downloaded .dll file is located.

https://xdebug.org/download.php

② Add the following content to php.ini.

zend_extension = ①中记录的路径

②Restart the Web server (Apache, etc.)

This completes the setting.

Use xdebug to check for errors

We run the lint_test.php used above.

lint_test.php

<?php
echo "error"

There is an error because there is no semicolon at the end.

The content is the same as when lint is executed, but with some decorations added for easier viewing.

The biggest difference with lint is the error that occurs after executing the code, so it can be said that the error occurs due to dynamic checking.

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