# 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
	- [ ] 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
	- [ ] Expr
	- [X] Binary
	- [ ] Scalar
	- [ ] ...
	- [ ] Convert instanceof for Exception types to Go1.13 `errors.Is`
[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
[ ] Namespaces
[ ] Generators
[ ] Numbered break/continue
[ ] Goto
[ ] Closures
	- [ ] Handle value/reference captures
[ ] Sort callbacks
	- [ ] Transparent conversion to sort.Slice
[X] Convert top-level calls to `init()`/`main()`
	- *Currently always `init`*
[ ] Class/object transformations
	- [X] Convert `new X` constructor calls to `NewX`
	- [X] Static methods
	- [X] Inheritance *partial*
	- [ ] Interfaces
	- [ ] super
		- [ ] Need to track current conversion state through into function generator, to select the concrete parent
	- [ ] parent::
	- [ ] static, self
	- [ ] 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
		- [ ] Track golang package imports
		- [ ] Handle conflicts between golang stdlib packages / local variable names
	- [ ] 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
[ ] 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
[ ] Command-line tool option to `go run`