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Re: [scala] Scala plugin BETA

by David Pollak :: Rate this Message:

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Sean,

At some point I will start testing the plugin, but there's an absolute
requirement for any plugin: it absolutely has to let me choose the
version of Scala it works with, just like the Java mode in Eclipse
allows for the choice of JDKs.

Each version of Scala has minor (and sometimes major) byte-code
incompatibilities such that code compiled with one version will not work
with any runtime but the runtime that the code way compiled against (as
compared to Javac byte code which has always been forward compatible.)

Having the compiler version baked into the plugin (especially when the
version is often a development version a week or two off from the actual
releases) means that the code generated by the plugin cannot be used
from the command line unless the exact same version of the runtime is
the version invoked with "scala".

I'm looking forward to being able to use the new plugin with the same
version of Scala as I have running from the command line.

Thanks,

David

sean mcdirmid wrote:

> Hi,
>
> As some of you might know, I've been working on a new Scala plugin for
> the past year and a half with the intention of replacing the current
> plugin, which I hacked together in the course of a couple of months.
> Our goals with the new plugin are pretty ambitious and have required
> exploring lots of new technology (incremental parsing, type checking)
> as well as obtaining a better understanding of Eclipse. I'm happy to
> announce that it is kind of done and I'd like to start BETA testing in
> the community. The update site for the new plugin BETA is at
> http://lamp.epfl.ch/~mcdirmid/scala.update 
> (http://lamp.epfl.ch/~mcdirmid/scala.update/site.jar if you prefer an
> archive install). Notable features:
>
> * Truly incremental syntax/type checking and semantic highlighting (no
> more ctrl-shift-z!), works fast even in very large files.
>
> * Code completion (content assist) that works reliably and responsively
>
> * Almost 100% semantic highlighting coverage (better for search and
> refactoring later...)
>
> * Better integration with Java. Java-doc comments from Java source now
> show in hover help (if the Java-doc attachment is set) and can
> hyperlink to Java definitions (if the Java source attachment is set).
>
> * The incremental builder now knows about changes to classfiles in
> other Scala and Java projects, and will rebuild accordingly
> (hopefully, still needs more testing). The Scala editor also knows
> about classfile changes.
>
> * Can now set breakpoints in Scala-derived classfiles. When the
> debugger triggers a break point in a Scala-derived classfile, the
> debugger opens the breakpoint in a Scala editor and not a Java editor
> as before. Also, when Scala-derived classfiles are opened up through
> the Project Explorer (but unfortunately, not the Package Explorer),
> they will open up in a Scala editor rather than a Java editor as before.
>
> * Position/highlighting information is saved so Scala-derived
> classfiles can be opened very quickly (assuming the Scala source
> attachment is set).
>
> * Folding and Scala-centric auto indenting!
>
> * Better editor preferences dialogue.
>
> * For keyboard junkies, goto declaration has been implemented (using
> the JDT configured key binding, by default F3).
>
> Because the technology used in the plugin is very new and untested, I
> initially expect that there will be ALOT of bugs. I'm continuously
> afraid whenever I'm editing in the new plugin that any keystroke will
> cause a crash :) I really need the community's help if the plugin is
> going to become stable. Please keep your error log view open while
> using the plugin, as this could fill up pretty quickly and you'll only
> be notified of the first crash. We'll use trac to manage bug reports,
> but check the open bug reports to avoid wasting time on duplicate
> reports. Also, I've checked in the source if you want to hack on it or
> add features. In particular, Documentation would be greatly
> appreciated. I haven't documented the code yet, and we don't have a
> DOM, so if you want to implement a feature that requires compiler
> information, please talk to me.
>
> On a personal note, I'm leaving EPFL (and the western hemisphere) at
> the end of October, and we don't know who will take this over yet. I'm
> still going to try and fix bugs and keep releases going, but for this
> to work we really need to open it up and attract community
> contributions. Suggestions on how to do this would be greatly
> appreciated.
>
> Please read the following release notes if you want to use the new
> plugin (also included in the plugin documentation):
>
> * The plugin is currently based on (and comes with) the unfinished
> 2.6.1 Scala release. No feature for 2.6.1 has yet been set in stone
> and 2.6.1 probably contains some new bugs not in 2.6.0.
>
> * The plugin currently relies heavily on "IDE" files. Please
> clean-rebuild your existing projects in the new plugin before opening
> up files in the editor.
>
> * Existing .project files must be updated in the following way:
> ch.epfl.lamp.sdt.core.scalabuilder becomes scala.plugin.scalabuilder
> and ch.epfl.lamp.sdt.core.scalanature becomes
> scala.plugin.scalanature. Thankfully, .classpath files don't need to
> be migrated.
>
> * Existing application and Scala breakpoint profiles cannot be
> migrated. Please remove them from your workspace before installing the
> new plugin.
>
> * Its probably not a good idea to have both the old and new plugin
> installed on the same Eclipse installation. Please uninstall or
> disable the old plugin before installing the new one, or use a
> different configuration profile.
>
> * The IDE file is used to ensure that the file is opened quickly, but
> parsing and type checking will not occur until the first edit
> ("breaking the ice"). This means that there will be a lag on the first
> edit of a large file (due to parsing, which occurs in the UI thread)
> and then later when type checking completes (as the type checking
> results are integrated into the UI). While type checking is occurring,
> no type-dependent services will work (e.g., hover help, code
> completion). Type checking for most edits is incremental and so
> completes fast enough that this is not an issue. The biggest type
> checking times occur when (a) modifying a top-level import in a large
> file or (b) when you start editing a large file. As an example,
> Typers.scala, which is around 3300 lines of DENSE Scala code, takes
> around 8 seconds to type check initially in the editor. This will
> balloon to 20 or so seconds if you edit a top-level import. Import
> statements are currently a big problem given the way they are
> represented in the compiler, we still don't have a fix in mind for this.
>
> * You are free to change the parse tree while type checking occurs in
> the background, it shouldn't crash the compiler :) All changed parse
> nodes are scheduled for type checking in the background.
>
> * Parsing and type checking will not occur if braces (including
> comments and double quotes) in the file are unbalanced. For this
> reason, brace completion (as implemented in the IDE) is essential to
> keep things lively and is definitely not a save-on-typing convenience.
> If you type over any closing brace, a new closing brace won't be
> inserted. Braces can go unbalanced (e.g., if you block paste in some
> code with unbalanced braces), but many IDE features will not work
> during this time.  There are a few more features that aid in keeping
> braces balanced: deleting an opening brace will delete its matched
> closing brace; typing a closing brace will move out or in an existing
> closing brace in certain contexts; and you can select a block of text
> and type ",`,(,{,[,/ to enclose the block in double quotes, back
> quotes, parentheses, curly braces, brackets, or a multi-line comment,
> respectively.
>
> * There is currently no XML support. Support is planned, but not right
> now.
>
> *  The content outliner, interpreter, and test pad views are not yet
> implemented for the new plugin.
>
> * There is still no support for refactoring or search.
>
> * The Project Explorer replaces the Package Explorer as the preferred
> navigation view of Scala projects (the Package Explorer will still
> work). However, I've noticed some conflicts with the JDT "Java
> Element" content view, you'll probably have to disable it (click the
> down white triangle in the project explorer view, select the
> "Customize View" menu, select the "Content" tab, uncheck "Java
> Elements").
>
> * For some strange reason, no default highlighting colors are
> configured when the plugin is first installed. Go to
> Preferences/Scala/Scala Editor Preferences, hit "Restore Defaults",
> "Ok" then colors will be enabled. I know the default color scheme is
> atrocious, but you can also customize Scala highlighting colors.
>
> * Scala classpath entries do not make use of Java-doc attachments (all
> scala-doc entries are extracted from source attachments) while Java
> requires these attachments even if source is available. Make sure your
> Java-doc/source code attachments are configured correctly for your
> JRE_CONTAINER. Source attachments are included for the embedded Scala
> library.
>

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