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].

• Expressions
• NilLiteral
• BoolLiteral
• NumberLiteral
• CharLiteral
• StringLiteral
• StringInterpolation
• SymbolLiteral
• ArrayLiteral
• HashLiteral
• NamedTupleLiteral
• ProcLiteral
• RangeLiteral
• RegexLiteral
• TupleLiteral
• Var
• Block
• Call
• NamedArgument
• If
• Unless
• IfDef
• Assign
• MultiAssign
• InstanceVar
• ReadInstanceVar
• ClassVar
• Global
• BinaryOp
• Arg
• ProcNotation
• Def
• Macro
• UnaryExpression
• VisibilityModifier
• IsA
• RespondsTo
• Require
• When
• Case
• ImplicitObj
• Path
• While
• Until
• Generic
• TypeDeclaration
• UninitializedVar
• Rescue
• ExceptionHandler
• ProcPointer
• Union
• Self
• ControlExpression
• Yield
• Include
• Extend
• EnumDef
• ClassDef
• ModuleDef
• LibDef
• FunDef
• TypeDef
• CStructOrUnionDef
• ExternalVar
• 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