NAME

scalac – Compiler for the Scala 2 language

SYNOPSIS

scalac [ <options> ] <source files>

PARAMETERS

<options>

Command line options. See OPTIONS below.

<source files>

One or more source files to be compiled (such as MyClass.scala).

DESCRIPTION

The scalac tool reads class and object definitions, written in the Scala programming language, and compiles them into bytecode class files.

By default, the compiler puts each class file in the same directory as its source file. You can specify a separate destination directory with -d (see OPTIONS, below).

OPTIONS

The compiler has a set of standard options that are supported on the current development environment and will be supported in future releases. An additional set of non-standard options are specific to the current virtual machine implementation and are subject to change in the future. Non-standard options begin with -X.

Standard Options

–Dproperty=value

Pass –Dproperty=value directly to the runtime system.

–J<flag>

Pass <flag> directly to the runtime system.

–P:<plugin:opt>

Pass an option to a plugin

–X

Print a synopsis of advanced options.

–bootclasspath <path>

Override location of bootstrap class files (where to find the standard built-in classes, such as "scala.List").

–classpath <path>

Specify where to find user class files (on Unix-based systems a colon-separated list of paths, on Windows-based systems, a semicolon-separate list of paths). This does not override the built-in ("boot") search path.

The default class path is the current directory. Setting the CLASSPATH variable or using the -classpath command-line option overrides that default, so if you want to include the current directory in the search path, you must include "." in the new settings.

–d <directory|jar>

Specify where to place generated class files.

–deprecation

Emit warning and location for usages of deprecated APIs.

Available since Scala version 2.2.1

–encoding <encoding>

Specify character encoding used by source files.

The default value is platform-specific (Linux: "UTF8", Windows: "Cp1252"). Executing the following code in the Scala interpreter will return the default value on your system:

scala> new java.io.InputStreamReader(System.in).getEncoding

–explaintypes

Explain type errors in more detail.

–extdirs <dirs>

Override location of installed extensions.

–feature

Emit warning and location for usages of features that should be imported explicitly.

–g:{none,source,line,vars,notailcalls}

"none" generates no debugging info,

"source" generates only the source file attribute,

"line" generates source and line number information,

"vars" generates source, line number and local variable information,

"notailcalls" generates all of the above and will not perform tail call optimization.

–help

Print a synopsis of standard options.

–javabootclasspath <path>

Override Java boot classpath.

–javaextdirs <path>

Override Java extdirs classpath.

–language:<feature>

Enable one or more language features.

–no-specialization

Ignore @specialize annotations.

–nobootcp

Do not use the boot classpath for the Scala jar files.

–nowarn

Generate no warnings

–optimise

Generates faster bytecode by applying optimisations to the program.

–print

Print program with all Scala-specific features removed.

–sourcepath <path>

Specify location(s) of source files.

–target:{jvm-1.5,jvm-1.6,jvm-1.7,jvm-1.8}

"jvm-1.5" target JVM 1.5 (deprecated),

"jvm-1.6" target JVM 1.6 (default),

"jvm-1.7" target JVM 1.7,

"jvm-1.8" target JVM 1.8,

–toolcp <path>

Add to the runner classpath.

–unchecked

Enable detailed unchecked (erasure) warnings

Non variable type-arguments in type patterns are unchecked since they are eliminated by erasure

Available since Scala version 2.3.0

–uniqid

Uniquely tag all identifiers in debugging output.

–usejavacp

Utilize the java.class.path in classpath resolution.

–usemanifestcp

Utilize the manifest in classpath resolution.

–verbose

Output messages about what the compiler is doing

–version

Print product version and exit.

@<file>

A text file containing compiler arguments (options and source files)

Advanced Options

–Xcheckinit

Wrap field accessors to throw an exception on uninitialized access.

–Xdev

Enable warnings for developers working on the Scala compiler

–Xdisable-assertions

Generate no assertions and assumptions

–Xelide-below <n>

Calls to @elidable methods are omitted if method priority is lower than argument.

–Xexperimental

Enable experimental extensions

–Xfatal-warnings

Fail the compilation if there are any warnings.

–Xfull-lubs

Retain pre 2.10 behavior of less aggressive truncation of least upper bounds.

–Xfuture

Turn on future language features.

–Xgenerate-phase-graph <file>

Generate the phase graphs (outputs .dot files) to fileX.dot.

–Xlint

Enable recommended additional warnings.

–Xlog-free-terms

Print a message when reification creates a free term.

–Xlog-free-types

Print a message when reification resorts to generating a free type.

–Xlog-implicit-conversions

Print a message whenever an implicit conversion is inserted.

–Xlog-implicits

Show more detail on why some implicits are not applicable.

–Xlog-reflective-calls

Print a message when a reflective method call is generated.

–Xmacro-settings:<option>

Custom settings for macros.

–Xmain-class <path>

Class for manifest's Main-Class entry (only useful with -d <jar>).

–Xmax-classfile-name <n>

Maximum filename length for generated classes.

–Xmigration:<version>

Warn about constructs whose behavior may have changed since<version>.

–Xno-forwarders

Do not generate static forwarders in mirror classes.

–Xno-patmat-analysis

Don't perform exhaustivity/unreachability analysis. Also, ignore @switch annotation.

–Xno-uescape

Disable handling of \u unicode escapes

–Xnojline

Do not use JLine for editing.

–Xplugin:<paths>

Load a plugin from each classpath.

–Xplugin-disable:<plugin>

Disable plugins by name.

–Xplugin-list

Print a synopsis of loaded plugins.

–Xplugin-require:<plugin>

Abort if a named plugin is not loaded.

–Xpluginsdir <path>

Path to search for plugin archives.

–Xprint:<phases>

Print out program after <phases> (see below).

–Xprint-icode[:<phases>]

Log internal icode to *.icode files after<phases> (default: icode).

–Xprint-pos

Print tree positions, as offsets.

–Xprint-types

Print tree types (debugging option).

–Xprompt

Display a prompt after each error (debugging option).

–Xresident

Compiler stays resident, files to compile are read from standard input.

–Xscript <object>

Treat the source file as a script and wrap it in a main method.

–Xshow-class <class>

Show internal representation of class.

–Xshow-object <object>

Show internal representation of object.

–Xshow-phases

Print a synopsis of compiler phases.

–Xsource:<version>

Treat compiler input as Scala source for the specified version, see SI-8126.

–Xsource-reader <classname>

Specify a custom method for reading source files.

–Xstrict-inference

Don't infer known-unsound types.

–Xverify

Verify generic signatures in generated bytecode (asm backend only).

–Y

Print a synopsis of private options.

Compilation Phases

parser

parse source into ASTs, perform simple desugaring

namer

resolve names, attach symbols to named trees

packageobjects

load package objects

typer

the meat and potatoes: type the trees

patmat

translate match expressions

superaccessors

add super accessors in traits and nested classes

extmethods

add extension methods for inline classes

pickler

serialize symbol tables

refchecks

reference/override checking, translate nested objects

selectiveanf

ANF pre-transform for @cps (CPS plugin)

selectivecps

@cps-driven transform of selectiveanf assignments (CPS plugin)

uncurry

uncurry, translate function values to anonymous classes

tailcalls

replace tail calls by jumps

specialize

@specialized-driven class and method specialization

explicitouter

this refs to outer pointers, translate patterns

erasure

erase types, add interfaces for traits

posterasure

clean up erased inline classes

lazyvals

allocate bitmaps, translate lazy vals into lazified defs

lambdalift

move nested functions to top level

constructors

move field definitions into constructors

flatten

eliminate inner classes

mixin

mixin composition

cleanup

platform-specific cleanups, generate reflective calls

delambdafy

remove lambdas

icode

generate portable intermediate code

inliner

optimization: do inlining

inlineHandlers

optimization: inline exception handlers

closelim

optimization: eliminate uncalled closures

constopt

optimization: optimize null and other constants

dce

optimization: eliminate dead code

jvm

generate JVM bytecode

terminal

the last phase in the compiler chain

all

matches all phases

ENVIRONMENT

JAVACMD

Specify the java command to be used for running the Scala code. Arguments may be specified as part of the environment variable; spaces, quotation marks, etc., will be passed directly to the shell for expansion.

JAVA_HOME

Specify JDK/JRE home directory. This directory is used to locate the java command unless JAVACMD variable set.

JAVA_OPTS

Specify the options to be passed to the java command defined by JAVACMD.

With Java 1.5 (or newer) one may for example configure the memory usage of the JVM as follows: JAVA_OPTS="-Xmx512M -Xms16M -Xss16M"

With GNU Java one may configure the memory usage of the GIJ as follows: JAVA_OPTS="--mx512m --ms16m"

EXAMPLES

Compile a Scala program to the current directory

scalac HelloWorld

Compile a Scala program to the destination directory classes

scalac –d classes HelloWorld.scala

Compile a Scala program using a user-defined java command

env JAVACMD=/usr/local/bin/cacao scalac –d classes HelloWorld.scala

Compile all Scala files found in the source directory src to the destination directory classes

scalac –d classes src/*.scala

EXIT STATUS

scalac returns a zero exist status if it succeeds to compile the specified input files. Non zero is returned in case of failure.

AUTHOR

Written by Martin Odersky and other members of the Scala team.

REPORTING BUGS

Report bugs to https://issues.scala-lang.org/.

COPYRIGHT

This is open-source software, available to you under a BSD-like license. See accompanying "copyright" or "LICENSE" file for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

fsc(1), scala(1), scaladoc(1), scalap(1)