Patrisika [Revented]

An library converts orthogonal AST into SpiderMonkey AST.

Semantics

AST for Patrisika is provided as JavaScript arraies. The following forms represents a node:

'identifier'

Represents a variable.

['.quote', value]

Represents a literal value.

['.unit']

Represents undefined value.

['.thisp']

Represents this reference.

['.argsp']

Represents argument list passed into the current function.

['.lambda', [...params], body]

Defines an anonymous function.

['.list', ...items]

Represents an array.

['.hash', ...['propName', propValue]]

Represents an object.

['.', base, member]

Represents a membering operation, i.e. base[member].

['.if', condition, consequent, alternate?]

Represents a conditional evaluation.

['.while', condition, body]

Represents a while loop evaluation. It returns the value of body in the last evaluation.

['.begin', ...items]

Represents a sequencial evaluation. Returns the last item evaluated.

['.return', value]

Return a value. Similar to JavaScript return statement.

['.try', block, [param], handler]

Represents a exception handling expression. Returns the value of block normally, or the value of handler1 when a exception is thrown during evaluating block.

['.throw', value]

Throws value as an exception.

['.set', left, right]

Assign right to variable or property node left.

[fn, ...args]

Once fn is a valid node, it means a common function invocation.

['.new', callee, ...args]

Initiates an instance of constructor callee, with args as arguments.

['.yield', value]

Represents a ES6 yield expression. Any functions directly containing such node will become a generator function described in ES6 specification.

['.beta', [...params], body, ...args]

Represents a beta redex which is similar to [['.lambda', [...params], body], ...args], used to implement semantics of let in scheme.

Operators

• Unary operator
  • ['.typeof', x] : typeof
  • ['!', x] : !
  • ['+', x] : +
  • ['-', x] : -
• Binary and Logical operator
  • ['+', x, y] : + (both numeric and string)
  • ['-', x, y] : -
  • ['*', x, y] : *
  • ['/', x, y] : /
  • ['%', x, y] : %
  • ['<', x, y] : <
  • ['>', x, y] : >
  • ['<=', x, y] : <=
  • ['>=', x, y] : >=
  • ['===', x, y] : ===
  • ['!==', x, y] : !==
  • ['=~', x, y] : ==
  • ['!~', x, y] : !=
  • ['.is', x, y] : instanceof
  • ['&&', x, y] : &&
  • ['||', x, y] : ||

Usage

Using Patrisika is pretty simple and straight forward:

// Note : global scopes must be provided. Undeclared variables in Patrisika
//        are treated as local variables, instead of global.
var globalScope = new Patrisika.DefaultExterns;
globalScope.declare("globalVariable");
patrisika.compile(ast, globals);