jonathrg/repl-breakpoint

Inject a REPL anywhere in your PHP script

v1.0 2017-06-20 18:18 UTC

Requires

• php: ^5.6

MIT

• Jonathan Reichelt Gjertsen

README

ReplBreakpoint lets you start a REPL at any point in a PHP script and gives you access to the state of execution at that point.

Install

composer require jonathrg/repl-breakpoint

Usage

Here we define a variable and a function, and then call repl(get_defined_vars()).

// File: examples/simple_example.php
<?php
require_once __DIR__.'/../vendor/autoload.php';
use function ReplBreakpoint\repl;

$a = 2;
function sq($x) { return $x * $x; }

repl(get_defined_vars());

Execute the script with PHP, and a REPL will be started on line 8. It has access to the variables we defined in the parent script:

$ php examples/simple_example.php
REPL launched
To exit, write "exit" or press Ctrl+C.
> $a
2
> [$a, $a+2]
[2, 4]
> sq($a)
4

A variable called $_ANS always keeps track of the last result:

> $_ANS
4

Multiline code

Multiline code is fine: input is automatically buffered if the parentheses are unbalanced...

> function cube($x) {
    return sq($x)*$x;
    }

> cube($_ANS)
64

... or whenever you end a line with \ or /.

> $_ANS \

> -2
62

Options

Printer

You can swap out the function ReplBreakpoint uses to print results. Just add it as an option in your code:

// File: examples/simple_example.php
...
repl(get_defined_vars(), ['printer' => 'print_r']);

Results are now printed with print_r.

$ php examples/simple_example.php
REPL launched
To exit, write "exit" or press Ctrl+C.
> $a
2
> [$a, $a+2]
Array
(
    [0] => 2
    [1] => 4
)

Any function which takes one parameter (the value to be printed) is OK.

Function name, file name and line number

Provide repl() with a file and a line number to have it printed at the start of the session:

// File: examples/simple_example.php
...
repl(get_defined_vars(), ['file' => __FILE__, 'line' => __LINE__, 'function' => __FUNCTION__]);

Run it (we called repl() outside of a function context, so no function is shown):

$ php examples/simple_example.php
REPL launched in file path\to\examples\simple_example.php on line 8
To exit, write "exit" or press Ctrl+C.
> 

Or just set the 'quiet' flag to skip the info altogether:

// File: examples/simple_example.php
...
repl(get_defined_vars(), ['quiet' => true]);

Run it:

$ php examples/simple_example.php
>

Error handler and shutdown function

By default, repl() will try to just echo the error and carry on. You can override this behaviour by providing your own callbacks as 'error_handler' and 'shutdown_function' options. The callback must be compatible with set_error_handler and register_shutdown_function, respectively.