(*:maxLineLen=78:*)
theory Scala
imports Base
begin
chapter \<open>Isabelle/Scala development tools\<close>
text \<open>
Isabelle/ML and Isabelle/Scala are the two main language environments for
Isabelle tool implementations. There are some basic command-line tools to
work with the underlying Java Virtual Machine, the Scala toplevel and
compiler. Note that Isabelle/jEdit @{cite "isabelle-jedit"} provides a Scala
Console for interactive experimentation within the running application.
\<close>
section \<open>Java Runtime Environment within Isabelle \label{sec:tool-java}\<close>
text \<open>
The @{tool_def java} tool is a direct wrapper for the Java Runtime
Environment, within the regular Isabelle settings environment
(\secref{sec:settings}). The command line arguments are that of the
underlying Java version. It is run in \<^verbatim>\<open>-server\<close> mode if possible, to
improve performance (at the cost of extra startup time).
The \<^verbatim>\<open>java\<close> executable is the one within @{setting ISABELLE_JDK_HOME},
according to the standard directory layout for official JDK distributions.
The class loader is augmented such that the name space of
\<^verbatim>\<open>Isabelle/Pure.jar\<close> is available, which is the main Isabelle/Scala module.
\<close>
section \<open>Scala toplevel \label{sec:tool-scala}\<close>
text \<open>
The @{tool_def scala} tool is a direct wrapper for the Scala toplevel; see
also @{tool java} above. The command line arguments are that of the
underlying Scala version.
This allows to interact with Isabelle/Scala in TTY mode like this:
@{verbatim [display]
\<open>isabelle scala
scala> isabelle.Isabelle_System.getenv("ISABELLE_HOME")
scala> val options = isabelle.Options.init()
scala> options.bool("browser_info")
scala> options.string("document")\<close>}
\<close>
section \<open>Scala compiler \label{sec:tool-scalac}\<close>
text \<open>
The @{tool_def scalac} tool is a direct wrapper for the Scala compiler; see
also @{tool scala} above. The command line arguments are that of the
underlying Scala version.
This allows to compile further Scala modules, depending on existing
Isabelle/Scala functionality. The resulting class or jar files can be added
to the Java classpath using the \<^verbatim>\<open>classpath\<close> Bash function that is provided
by the Isabelle process environment. Thus add-on components can register
themselves in a modular manner, see also \secref{sec:components}.
Note that jEdit @{cite "isabelle-jedit"} has its own mechanisms for adding
plugin components, which needs special attention since it overrides the
standard Java class loader.
\<close>
section \<open>Scala script wrapper\<close>
text \<open>
The executable @{executable "$ISABELLE_HOME/bin/isabelle_scala_script"}
allows to run Isabelle/Scala source files stand-alone programs, by using a
suitable ``hash-bang'' line and executable file permissions. For example:
@{verbatim [display]
\<open>#!/usr/bin/env isabelle_scala_script
val options = isabelle.Options.init()
Console.println("browser_info = " + options.bool("browser_info"))
Console.println("document = " + options.string("document"))\<close>}
This assumes that the executable may be found via the @{setting PATH} from
the process environment: this is the case when Isabelle settings are active,
e.g.\ in the context of the main Isabelle tool wrapper
\secref{sec:isabelle-tool}. Alternatively, the full
\<^file>\<open>$ISABELLE_HOME/bin/isabelle_scala_script\<close> may be specified in expanded
form.
\<close>
section \<open>Project setup for common Scala IDEs\<close>
text \<open>
The @{tool_def scala_project} tool creates a project configuration for
Isabelle/Scala/jEdit:
@{verbatim [display]
\<open>Usage: isabelle scala_project [OPTIONS] PROJECT_DIR
Options are:
-L make symlinks to original scala files
Setup Gradle project for Isabelle/Scala/jEdit --- to support Scala IDEs
such as IntelliJ IDEA.\<close>}
The generated configuration is for Gradle\<^footnote>\<open>\<^url>\<open>https://gradle.org\<close>\<close>, but the
main purpose is to import it into common Scala IDEs, such as IntelliJ
IDEA\<^footnote>\<open>\<^url>\<open>https://www.jetbrains.com/idea\<close>\<close>. This allows to explore the
sources with static analysis and other hints in real-time.
The specified project directory must not exist yet. The generated files
refer to physical file-system locations, using the path notation of the
underlying OS platform. Thus the project needs to be recreated whenever the
Isabelle installation is changed or moved.
\<^medskip> By default, Scala sources are \<^emph>\<open>copied\<close> from the Isabelle distribution and
editing them within the IDE has no permanent effect.
Option \<^verbatim>\<open>-L\<close> produces \<^emph>\<open>symlinks\<close> to the original files: this allows to
develop Isabelle/Scala/jEdit within an external Scala IDE. Note that
building the result always requires \<^verbatim>\<open>isabelle jedit -b\<close> on the
command-line.
\<close>
end