phpinspect.el

PHPInspect is a minor mode that provides code intelligence for PHP in Emacs. At its core is a PHP parser implemented in Emacs Lisp. PHPInspect comes with backends for completion-at-point, company-mode and eldoc. A backend for xref (which provides go-to-definition functionality) is planned to be implemented at a later date. The main documentation of the mode is in the docstring of the mode itself (C-h f phpinspect-mode RET to view, or read it in the source code of phpinspect.el).

Projects and Finding Types

By default, phpinspect will recognize composer projects and read their composer.json files for autoload information which is used to find files in which the types/classes/functions you use in your code are defined. It is also possible to add an "include directory" of files that should always be read and indexed for a certain project. To do this, open a file in a project and run M-x phpinspect-project-add-include-dir. You can also edit the list of include directories via M-x customize-goup RET phpinspect RET.

Example Configuration

If you already have a completion UI setup that is able to use completion-at-point-functions as completion source, you can basically just enable phpinspect-mode and you'll be good to go. An example of a basic mode hook configuration to get the most out of phpinspect is the following:

(defun my-php-personal-hook ()
  ;; Shortcut to add use statements for classes you use.
  (define-key php-mode-map (kbd \"C-c u\") 'phpinspect-fix-imports)

  ;; Shortcuts to quickly search/open files of PHP classes.
  ;; You can make these local to php-mode, but making them global
  ;; like this makes them work in other modes/filetypes as well, which
  ;; can be handy when jumping between templates, config files and PHP code.
  (global-set-key (kbd \"C-c a\") 'phpinspect-find-class-file)
  (global-set-key (kbd \"C-c c\") 'phpinspect-find-own-class-file)

  ;; Enable phpinspect-mode
  (phpinspect-mode))

(add-hook 'php-mode-hook #'my-php-personal-hook)

Example config with company mode setup

;;;###autoload
(defun my-php-personal-hook ()
  ;; It is important to enable `company-mode' before setting
  ;; the variables below.
  (company-mode)
  (setq-local company-minimum-prefix-length 0)
  (setq-local company-tooltip-align-annotations t)
  (setq-local company-idle-delay 0.1)
  (setq-local company-backends '(phpinspect-company-backend))

  ;; Shortcut to add use statements for classes you use.
  (define-key php-mode-map (kbd "C-c u") 'phpinspect-fix-imports)

  ;; Shortcuts to quickly search/open files of PHP classes.
  (global-set-key (kbd "C-c a") 'phpinspect-find-class-file)
  (global-set-key (kbd "C-c c") 'phpinspect-find-own-class-file)

  (phpinspect-mode))

(add-hook 'php-mode-hook #'my-php-personal-hook)

Install from git

git clone https://git.snorba.art/hugo/phpinspect.el ~/projects/phpinspect.el
cd ~/projects/phpinspect.el
make

(add-to-list 'load-path "~/projects/phpinspect.el")
(require 'phpinspect)

Compilation

It is highly recommended to byte- or native compile phpinspect. Aside from the normal performance boost that this brings to most packages, it can reduce phpinspect's parsing time by up to 90%. It especially makes a difference when incrementally parsing edited buffers. For example:

benchmarks/parse-file.el uncompiled on Ryzen 5 3600 (time in seconds):

Incremental parse (warmup):
Elapsed time: 0.168390 (0.019751 in 1 GC’s)
Incremental parse:
Elapsed time: 0.143811 (0.000000 in 0 GC’s)
Incremental parse (no edits):
Elapsed time: 0.000284 (0.000000 in 0 GC’s)
Incremental parse repeat (no edits):
Elapsed time: 0.000241 (0.000000 in 0 GC’s)
Incremental parse after buffer edit:
Elapsed time: 0.012449 (0.000000 in 0 GC’s)
Incremental parse after 2 more edits:
Elapsed time: 0.015839 (0.000000 in 0 GC’s)
Bare (no token reuse) parse (warmup):
Elapsed time: 0.048996 (0.000000 in 0 GC’s)
Bare (no token reuse) parse:
Elapsed time: 0.052495 (0.000000 in 0 GC’s)

benchmarks/parse-file.el with native compilation on Ryzen 5 3600 (time in seconds):

Incremental parse (warmup):
Elapsed time: 0.023432 (0.000000 in 0 GC’s)
Incremental parse:
Elapsed time: 0.018350 (0.000000 in 0 GC’s)
Incremental parse (no edits):
Elapsed time: 0.000076 (0.000000 in 0 GC’s)
Incremental parse repeat (no edits):
Elapsed time: 0.000058 (0.000000 in 0 GC’s)
Incremental parse after buffer edit:
Elapsed time: 0.001212 (0.000000 in 0 GC’s)
Incremental parse after 2 more edits:
Elapsed time: 0.001381 (0.000000 in 0 GC’s)
Bare (no token reuse) parse (warmup):
Elapsed time: 0.013874 (0.000000 in 0 GC’s)
Bare (no token reuse) parse:
Elapsed time: 0.013878 (0.000000 in 0 GC’s)

Development

The codebase of phpinspect is relatively large. As a new contributor, you'll probably feel a bit lost in the many files, functions and datatypes of the package. Let me tell you a bit about phpinspect's architecture.

Domains

There are roughly four main domains under which code in phpinspect can fall: parsing, indexation, interpetation and user-facing functions. Below is a short explanation of each domain.

Parsing

The parser provides the underpinnings for almost all of phpinspect's functionalities. It is implemented with specialized macros and supports two main parsing modes: bare and incremental. The parser code is located in phpinspect-parser.el.

Bare Parsing

The parser produces a parse result in the form of a basic list, where each parsed token is a list itself. The car of each list contains a keyword, describing its meaning in the parsed code. Below is a lisp form and its resulting insertion to demonstrate the structure of a syntax tree produced by the bare parser.

(insert (pp-to-string (phpinspect-parse-string "function foo(Bar $bar) { return $bar->baz; }")))

(:root
 (:function
  (:declaration
   (:word "function")
   (:word "foo")
   (:list
    (:word "Bar")
    (:variable "bar")))
  (:block
   (:word "return")
   (:variable "bar")
   (:object-attrib
    (:word "baz"))
   (:terminator ";"))))

Incremental Parsing

Bare parsing is fast, because it makes use of simple lisp datastructures and keeps the parser logic simple. A downside of this parsing mode is that the result lacks any extra metadata about the tokens, like what their start- and endpoints are in a buffer. It also makes it hard to partially update the tree after a buffer has been edited. As both are essential for a program that needs to work efficiently in live-edited buffers, the incremental parser was implemented. When parsing incrementally, the parser still produces the same structure of nested lists as a result. But it also stores metadata about each parsed token in an n-ary tree of phpinspect-meta objects (see phpinspect-meta.el). The incremental parser is able to partially update an existing tree after code has been edited, making it efficient for live buffers.

Parsers Summarised

The incremental parsing is efficient for use with live edited buffers. Due to its higher complexity it is not as fast at parsing entire files as the bare parser. For this reason, both the bare and the incremental parser are used for what they are best at.

Indexation

Within phpinspect, indexation is referred to as the process of extracting information from parsed code and project configuration files.

Code Indexation

The code in phpinspect-index.el consumes bare syntax trees and extracts information about PHP functions and types from them. Code in phpinspect-buffer.el implements the same functionality, but for live buffers based on the data produced by the incremental parser.

Project Indexation

Code in phpinspect-autoload.el implements logic for psr-4, psr-0 and files autoload strategies. It is able to read a composer.json file and generate autoload information based on which a project's types and functions can be found.

Caching

Code in phpinspect-cache.el and phpinspect-class.el allows phpinspect to store the result of code indexations in memory, so that they can be accessed instantly when a user requests information about their code.

Threading

Indexation takes time. Because emacs is single-threaded, you might think that indexing a project would lock up your emacs for a while. Do not despair! phpinspect-worker.el contains code for a worker with a job queue that uses collaborative threads to do work when emacs is idle. When you start interacting with emacs, it will back off and let you do your thing! phpinspect-pipeline.el contains code for something similar to generators in PHP, combined with collaborative threading. Pipelines are used for more intense processes that should be completed with a bit more of a hurry. Emacs should remain responsive while a pipeline is running, but there may be a slightly noticeable sluggishness while they run. At the moment of writing, pipelines are mainly used to refresh a projects autoloader.

Interpretation

Having parsing, indexation and caching infrastructure is all well and good, but how to we determine what information is actually useful to show to a user? This is where code interpretation plays a big role. The main goal of interpretation in phpinspect is the determination of the PHP type to display information about. Determining this type is referred to as "resolving" in phpinspect's codebase. Resolving a type is built around the concept of a "resolvecontext". A resolvecontext is an object that contains information about a location in a buffer and its surroundings. Based on the informatoin in the resolvecontext, the type that a statement is expected to evaluate to can be determined. The code for resolving types is mostly contained in phpinspect-type.el, phpinspect-resolve.el and phpinspect-resolvecontext.el. The main entrypoints are the functions phpinspect-get-resolvecontext and phpinspect-resolve-type-from-context.

User-facing Functions

User-facing functions in phpinspect are mostly integrations with existing infrastructure within emacs. For completion there is completion-at-point-functions, for tooltips there is eldoc and for go-to-definition there is xref. Aside from these integrations, phpinspect aims to provide functionalities for code formatting.

Completion

Completion is implemented in phpinspect-completion.el as a strategy pattern. A completion strategy can be added by implementing the methods phpinspect-comp-strategy-supports and phpinspect-comp-strategy-execute. Completion strategies are high level abstractions that build on top of the type resolving code and the code in phpinspect-suggest.el.

Eldoc

Eldoc support is implemented in a strategy pattern similar to that of completion. An eldoc strategy can be added by implementing the methods phpinspect-eld-strategy-supports and phpinspect-eld-strategy-execute.

Code Formatting

phpinspect-fix-imports adds, removes and sorts use statements. At the time of writing, this is the only code formatting functionality that phpinspect provides. See phpinspect-imports.el for the implementation.

Really Want To But Not Implemented: Xref

A thing that would be possible to implement on top of phpinspect's infrastructure, but not much time has been spent on yet, is an integration with xref. Xref integration would enable functionalities like go-to-definition.

Building

make

Running tests

Tests are implemented using ert. You can run them in batch mode with the following command:

make test

# or:
emacs -L ./ -batch -l ert -l ./test/phpinspect-test.el -f ert-run-tests-batch-and-exit