crow

crow transpiles Crystal source code to valid Flow/ES2015/JavaScript).

Code that is transpiled to valid Flow syntax may be transpiled to valid ES2015, which may be transpiled to Javascript (via Babel).

Warning: Experimental

This project is in alpha stage and should be considered highly experimental.

Installation

Via Homebrew:

brew install geppetto-apps/bin/crow

Via npm:

npm install crow-cli -g

Usage

# Compiles and outputs to foo.js.flow
$ crow foo.cr

# Same as above
$ cat foo.cr | crow > foo.js.flow

# Compile to JavaScript (via Babel)
$ npm install babel-preset-es2015 babel-plugin-transform-flow-strip-types
$ cat foo.cr | crow | babel --plugins transform-flow-strip-types --presets es2015

You can also use Docker:

$ cat foo.cr | docker run -i geppetto-apps/crow > foo.js.flow

Development

You need to have a copy of the Crystal source code sitting in a directory next to crow.

Supported AST nodes

Extracted from [Crystal's compiler][cr-parser].

• [x] Expressions
• [x] NilLiteral
• [x] BoolLiteral
• [x] NumberLiteral
• [x] CharLiteral
• [x] StringLiteral
• [x] StringInterpolation
• [x] SymbolLiteral
• [x] ArrayLiteral
• [x] HashLiteral
• [x] NamedTupleLiteral
• [ ] ProcLiteral
• [ ] RangeLiteral
• [ ] RegexLiteral
• [ ] TupleLiteral
• [x] Var
• [x] Block
• [x] Call
• [ ] NamedArgument
• [x] If
• [x] Unless
• [ ] IfDef
• [x] Assign
• [ ] MultiAssign
• [x] InstanceVar
• [ ] ReadInstanceVar
• [ ] ClassVar
• [x] Global
• [ ] BinaryOp
• [ ] Arg
• [x] ProcNotation
• [x] Def
• [ ] Macro
• [ ] UnaryExpression
• [ ] VisibilityModifier
• [x] IsA
• [ ] RespondsTo
• [ ] Require
• [x] When
• [x] Case
• [ ] ImplicitObj
• [ ] Path
• [ ] While
• [ ] Until
• [ ] Generic
• [ ] TypeDeclaration
• [ ] UninitializedVar
• [x] Rescue
• [x] ExceptionHandler
• [ ] ProcPointer
• [ ] Union
• [x] Self
• [ ] ControlExpression
• [ ] Yield
• [ ] Include
• [ ] Extend
• [ ] EnumDef
• [x] ClassDef
• [ ] ModuleDef
• [ ] LibDef
• [ ] FunDef
• [ ] TypeDef
• [ ] CStructOrUnionDef
• [ ] ExternalVar
• [x] Alias
• [ ] Metaclass
• [ ] Cast
• [ ] NilableCast
• [ ] TypeOf
• [ ] Attribute
• [ ] MacroExpression
• [ ] MacroIf
• [ ] MacroFor
• [ ] MacroVar
• [ ] MacroLiteral
• [ ] Underscore
• [ ] MagicConstant
• [ ] Asm
• [ ] AsmOperand

Contributing

1. Fork it ( https://github.com/geppetto-apps/crow/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• theodorton Theodor Tonum - creator, maintainer