5.4 KiB
php2go
Convert PHP source code to Go by AST walking.
The goal is to produce idiomatic, maintainable Go code as part of a one-off conversion. This is not generally possible for highly dynamic PHP code, that may require manual fixups.
Progress
Phase 1
[X] Convert some small programs
[X] Error handling
- [X] All functions return (type, error)
- [X] Convert throw to err return
- [X] Non-leaf function calls need to check + bubble errors
[X] Array handling
- [X] Infer whether to use slice/map for PHP array
[-] Namespaces
- [X] Basic support for namespace -> package name transformation
- [ ] Resolve namespace names in calls
- [ ] Resolve use statements
[X] if
[X] for/foreach
[X] switch
[ ] Generators
[ ] Goto
[X] null -> nil
[X] Consts and define()
- [X] Magic constants (__LINE__,__FILE__ etc)
[ ] isset/unset
[ ] instanceof
[X] die
[X] try/catch/finally
- [X] Implement using err checks, not panic/recover
- Any statements within the try block should capture the finally/catch to run within any interior err-check blocks
- [ ] finally
- Runs before any return statement inside the try block or catch block; also runs after the try block is complete
- Maybe finally would be more concisely implemented as defer inside an IIFE, but that is not idiomatic, maintainable Go code
[X] Abandon upon sight of highly dynamic constructs
- [X] eval
- [X] extract
- [ ] variable-variables
- [ ] Attempts to enable magic_quotes or register_globals
[X] Detect assignment expressions
- Go doesn't support assignment in rvalues, only as a statement
- When walking below stmt level, need to first fully walk and check for any function calls + assignments that may need hoisting (and we can probably only do that correctly if there is no short-circuiting)
- [X] Add subtree walk + catch error for this case
[X] Closures
- [ ] Handle value/reference captures
[X] Convert top-level calls to init()/main()
- [X] Wrap in function
- [X] Determine init/main based on package name
[ ] Class/object transformations
- [X] Convert new X constructor calls to NewX
- [X] Visibility
- [X] Apply PHP visibility modifiers as Go case change
- [ ] Call mangled function name at call sites
- PHP variable names are case-sensitive, function names are case-insensitive
- [X] Static methods
- [X] Inheritance partial
- [X] Interfaces
- [X] Class constants
- [X] super
- [X] Need to track current conversion state through into function generator, to select the concrete parent
- [X] parent::
- [X] self::
- [ ] static::
- [ ] Traits / use
- [ ] Abstract methods
[X] Track golang package imports
[X] Variadic function parameters
[X] Preserve comments
Productionize
[ ] Multi-file programs
- [ ] Include/Require
[ ] Infer whether to declare variable (var / :=) or reuse (=)
- [ ] Track current visibility scope
[ ] Comprehensive coverage of all AST node types
- [X] Create full-coverage interface to implement
- [ ] Node
- [ ] Stmt
- [ ] Expr
- [ ] Assign
- [X] Binary
- [X] Scalar
- [X] Heredocs/nowdocs
[ ] Numbered break/continue
[ ] Type inference
- [ ] Type declarations for literals (string, slice/map with constant initializer, etc)
- [ ] Convert known PHP typenames to Go equivalents
- [ ] Parse extra types from phpdoc blocks
[ ] Hoisting pass for rvalue expressions
- [ ] Behaviour of function calls in rvalue cases where err cannot be checked
- [ ] Assignment expressions
- [ ] Alternately - we can support the form if foo := bar(); foo {
- [ ] Ternarys
[ ] Simple standard library transformations
- [X] common string/array functions
- [ ] More string/array functions
- [ ] Top 100 from https://www.exakat.io/top-100-php-functions/
- [ ] substr -> slice index operator
- This has the same value semantics for string literals, but not variables
- [ ] error_reporting(E_ALL) --> just remove it
- [ ] ini_set('display_errors', 'On') --> remove it when the parameter is known
[ ] Elide error return for functions that cannot throw
- ?? Could be a standalone Go refactoring tool
Wishlist
[ ] Extended library/environment transformations
- [ ] Standard library transformations
- [X] Track golang package imports
- [ ] Handle conflicts between golang stdlib packages / local variable names
- [ ] uasort -> sort.Slice
- [ ] preg -> regexp
- [ ] json -> encoding/json
- [ ] Output buffering (ob_start / ob_get_clean)
- Can push/pop os.Stdout onto a private stack, then we can keep using fmt.Print
- [ ] PHP Superglobal transformations
- [ ] $_SERVER['argv'] to os.Args
- [ ] $_GET['name'] to r.FormValue('name')
- [ ] Common 3rd party package transformations to popular equivalents (optional)
- [ ] Guzzle
- [ ] AWS SDK
- [ ] PHPUnit -> Go Test
- [ ] Replace Composer/PSR-4 autoloading with Go imports
[ ] Preserve rough line spacing
[ ] Somehow detect whether map use should be order-preserving
[ ] Support scoped namespace (namespace { ... }) and multiple namespaces in file
[ ] Validation on imported comment formats
[ ] Convert wordpress / mediawiki / symfony
- [ ] Option to convert with preset=cli, preset=web, webroot path
- [ ] Option to generate built-in web server
[ ] Generate source maps
- The parser does have full positional information - exporting at the stmt level would be reasonable
- But the gofmt pass may lose this information
[ ] Command-line tool option to go run