Interface of interactive compiler to a client such as an IDE The model the presentation compiler consists of the following parts:

unitOfFile: The map from sourcefiles to loaded units. A sourcefile/unit is loaded if it occurs in that map.

manipulated by: removeUnitOf, reloadSources.

A call to reloadSources will add the given sources to the loaded units, and start a new background compiler pass to compile all loaded units (with the indicated sources first). Each background compiler pass has its own typer run. The background compiler thread can be interrupted each time an AST node is completely typechecked in the following ways:

1. by a new call to reloadSources. This starts a new background compiler pass with a new typer run. 2. by a call to askTypeTree. This starts a new typer run if the forceReload parameter = true 3. by a call to askTypeAt, askTypeCompletion, askScopeCompletion, askToDoFirst, askLinkPos, askLastType. 4. by raising an exception in the scheduler. 5. by passing a high-priority action wrapped in ask { ... }.

Actions under 1-3 can themselves be interrupted if they involve typechecking AST nodes. High-priority actions under 5 cannot; they always run to completion. So these high-priority actions should to be short.

Normally, an interrupted action continues after the interrupting action is finished. However, if the interrupting action created a new typer run, the interrupted action is aborted. If there's an outstanding response, it will be set to a Right value with a FreshRunReq exception.

Signals a request for a fresh background compiler run. Note: The object has to stay top-level so that the PresentationCompilerThread may access it.

A simple lexer for tokens as they are used in JSON, plus parens (, ) Tokens understood are:

(, ), [, ], {, }, :, ,, true, false, null, strings (syntax as in JSON), integer numbers (syntax as in JSON: -?(0|\d+) floating point numbers (syntax as in JSON: -?(0|\d+)(\.\d+)?((e|E)(+|-)?\d+)?) The end of input is represented as its own token, EOF. Lexers can keep one token lookahead

An abstract class for writing and reading Scala objects to and from a legible representation. The representation follows the following grammar:

Pickled = `true` | `false` | `null` | NumericLit | StringLit |
          Labelled | Pickled `,` Pickled
Labelled = StringLit `(` Pickled? `)`

All ...Lit classes are as in JSON. @see scala.tools.nsc.io.Lexer

Subclasses of Pickler each can write and read individual classes of values.

A presentation compiler thread. This is a lightweight class, delegating most of its functionality to the compiler instance.

Typical interaction, given a predicate <user-input>, a function <display>, and an exception handler <handle>:

val TIMEOUT = 100 // (milliseconds) or something like that val r = new Response() while (!r.isComplete && !r.isCancelled) { if (<user-input>) r.cancel() else r.get(TIMEOUT) match { case Some(Left(data)) => <display>(data) case Some(Right(exc)) => <handle>(exc) case None => } }