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

[X] Convert some small programs [X] Error handling - [X] All functions return (type, error) - [X] Convert throw to err return - [ ] Elide error return for functions that cannot throw - ?? Could be a standalone Go refactoring tool - [X] Non-leaf function calls need to check + bubble errors - [ ] Behaviour of function calls in rvalue cases where err cannot be checked [ ] Comprehensive coverage of all AST node types - [ ] Node - [ ] Stmt - [ ] Expr - [X] Binary - [ ] Scalar [X] Array handling - [X] Infer whether to use slice/map for PHP array - [ ] Infer whether map use should be order-preserving [ ] Multi-file programs - [ ] Include/Require [X] Namespaces - [X] Basic support for namespace -> package name transformation - [ ] Namespace resolution in calls - [ ] use - [ ] Support scoped namespace (namespace { ... }) and multiple namespaces in file [ ] Generators [ ] Numbered break/continue [ ] Goto [ ] Comma operator [ ] null -> nil [X] Consts and define() [ ] 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 [ ] Abandon upon sight of eval / extract / ... [ ] 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 - [ ] Add hoisting pass [ ] Closures - [ ] Handle value/reference captures [X] Convert top-level calls to init()/main() - Currently always init [ ] 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 [ ] Type inference - [ ] Convert known PHP typenames to Go equivalents - [ ] Parse extra types from phpdoc blocks [ ] Infer whether to declare variable (var / :=) or reuse (=) - [ ] Track current visibility scope [ ] Library/environment transformations - [ ] Standard library transformations - [X] Track golang package imports - [ ] Handle conflicts between golang stdlib packages / local variable names - [ ] uasort -> sort.Slice - [ ] 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 [X] Variadic function parameters [X] Preserve comments [ ] Preserve rough line spacing [ ] 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