package ir

  1. Public
  2. All

Type Members

  1. sealed abstract class ClassKind extends AnyRef

  2. final case class Position(source: SourceFile, line: Int, column: Int) extends Product with Serializable

  3. class SourceMapWriter extends AnyRef

Value Members

  1. object ClassKind

  2. object Definitions

  3. object InfoSerializers

  4. object Infos

  5. object JSDesugaring

    Desugaring of the IR (herein called Extended-JS) to regular ES5 JavaScript

    Desugaring of the IR (herein called Extended-JS) to regular ES5 JavaScript

    Extended-JS is a non-existent language that is a superset of JavaScript with Scala-esque constructs. Most notably, most constructs can be used in expression position. Extended-JS also features ES6-like classes.

    GenJSCode emits Extended-JS because it is *much* easier not to deal with the expression position issue in there. But of course, in the end, we need to output genuine JavaScript code.

    JSDesugaring desugars a statement of Extended-JS into genuine ES5 JavaScript code.

    The general idea is two-folded: 1) Unnest complex constructs in "argument position": When a complex construct is used in a non-rhs expression position (argument to a function, operand, condition of an if, etc.), that we call "argument position", declare a variable before the statement, assign the complex construct to it and then use that variable in the argument position instead. 2) Push LHS's inside complex RHS's: When an rhs is a complex construct, push the lhs inside the complex construct. Are considered lhs: * Assign, i.e., x = * VarDef, i.e., var x = * Return, i.e., return * (EmptyTree is also used as a trick for code reuse) In fact, think that, in this context, LHS means: what to do with the result of evaluating the RHS.

    Typical example, consider the method call:

    obj.meth({ var x = foo(42); x*x });

    According to rule 1), the block that is passed as a parameter to obj.meth is first extracted in a synthetic var:

    var x$1 = { var x = foo(42); x*x } obj.meth(x$1);

    Then, according to rule 2), the lhs var x$1 = is pushed inside the block:

    { var x = foo(42); var x$1 = x*x; } obj.meth(x$1);

    Because bare blocks are non-significant in JS, this is equivalent to

    var x = foo(42); var x$1 = x*x; obj.meth(x$1);

    JSDesugaring does all this in a single pass, but it helps to think that: * Rule 1) is implemented by unnest(), and used most notably in * transformStat() for statement-only constructs * pushLhsInto() for statement-or-expression constructs * Rule 2) is implemented by pushLhsInto() * Emitting the class structure is delegated to ScalaJSClassEmitter.

  6. object Position extends Serializable

  7. object Printers

  8. object ScalaJSClassEmitter

    Defines methods to emit Scala.

    Defines methods to emit Scala.js classes to JavaScript code. The results are not desugared. Only the class *structure* is decomposed to a lower representation in the IR. The output of all these methods should be further desugared before being emitted as JavaScript code.

  9. object ScalaJSVersions

  10. object Serializers

  11. object SourceMapWriter

  12. object Transformers

  13. object Trees

  14. object Types

  15. object Utils