Compile a script file into a pod and return the first public type declared in the script file. If the file has been previously compiled and hasn't changed, then a cached type is returned. If the script contains errors then the first CompilerErr found is thrown. The options available:

logLevel: the default LogLevel to use for logging the compilation process and errors
log: the https://fantom.org/doc/compiler/CompilerLog to use for logging the compilation process and errors
logOut: an output stream to capture logging
force: pass true to not use caching, always forces a recompile

compileScriptToJs

virtual Str compileScriptToJs(File f, [Str:Obj]? options)

Compile a script file into a pod and return the JS source code of resulting pod. If the script contains errors then the first CompilerErr found is thrown. The options available:

podName: the name of pod created for script
logLevel: the default LogLevel to use for logging the compilation process and errors
log: the https://fantom.org/doc/compiler/CompilerLog to use for logging the compilation process and errors
logOut: an output stream to capture logging
output: The output format of the compile javascript. Use "legacy" for old js format, "js" for CommonJs and "esm" for ES module. The default is "js" if not specified.

config

virtual Str? config(Pod pod, Str key, Str? def)

Lookup a configuration property for given pod/key pair. If not found then return def. Default implementation routes to props using max age of one minute:

props(pod, `config.props`, 1min).get(key, def)

Also see Pod.config and Env.

cur

static Env cur()

Get the current runtime environment

diagnostics

virtual Str:Obj diagnostics()

Poll for a platform dependent map of diagnostics name/value pairs for the current state of the VM. Java platforms return key values from the java.lang.management interface. Default implementation delegates to parent.

err

virtual OutStream err()

Standard error output stream. Default implementation delegates to parent.

exit

virtual Void exit(Int status)

Terminate the current virtual machine. Default implementation delegates to parent.

findAllFiles

virtual File[] findAllFiles(Uri uri)

Find all the files in the environment which match a relative path such as "etc/foo/config.props". It is possible to have multiple matches if the environment uses a search path model. If the list contains more than one item, then the first file has the highest priority and the last item has the lowest priority. If the URI is not relative then throw ArgErr. Return empty list if the file is not found in environment. Default implementation delegates to parent.

findAllPodNames

virtual Str[] findAllPodNames()

Return the list of pod names for all the pods currently installed in this environemnt. This method is used by Pod.list and for constructing the type database. Each of these names must be resolvable by findPodFile. The default implementation routes to findFile to look in the "lib/fan" directory and assumes a naming convention of "{name}.pod".

findFile

virtual File? findFile(Uri uri, Bool checked)

Find a file in the environment using a relative path such as "etc/foo/config.props". If the URI is not relative then throw ArgErr. If the file is not found in the environment then throw UnresolvedErr or return null based on checked flag. If findAllFiles would return multiple matches, then this method should always return the file with the highest priority. Default implementation delegates to parent.

findPodFile

virtual File? findPodFile(Str podName)

Resolve the pod file for the given pod name. If the name cannot be resolved to a pod, return null. The default implementation routes to findFile to look in "lib/fan" directory.

virtual Void gc()

Run the garbage collector. No guarantee is made to what the VM will actually do. Default implementation delegates to parent.

homeDir

virtual File homeDir()

Get the home directory of Fantom installation. Default implementation delegates to parent.

host

virtual Str host()

Get the local host name of the machine running the virtual machine process. Default implementation delegates to parent.

idHash

Int idHash(Obj? obj)

Return the default hash code of Obj.hash for the specified object regardless of whether the object has overridden the hash method. If null then return 0.

virtual InStream in()

Standard input stream. Default implementation delegates to parent.

index

virtual Str[] index(Str key)

Lookup all the matching values for a pod indexed key. If no matches are found return the empty list. Indexed props are declared in your pod's build script, and coalesced into a master index by the current environment. See docLang for details.

indexByPodName

virtual Str:Str[] indexByPodName(Str key)

Get the values for this key organized by each pod that defines the key. The keys of the map are the pod names, and the values of the map are the key values defined by that pod.

indexKeys

virtual Str[] indexKeys()

Get listing of all keys mapped by indexed props. The values of each key may be resolved by the fan.sys method. See docLang for details. NOTE: Java runtime only

indexPodNames

virtual Str[] indexPodNames(Str key)

Return list of all pod names that define the given key.

isBrowser

Bool isBrowser()

Returns true if the runtime is js and execution environment is a web browser.

javaVersion

Int javaVersion()

Get the Java VM Version as a single integer (8, 9, etc.). If the runtime is not java, return 0.

locale

virtual Str? locale(Pod pod, Str key, Str? def, Locale locale)

Lookup a localized property for the specified pod/key pair. The following rules are used for resolution:

props(pod, `locale/{locale}.props`)
props(pod, `locale/{lang}.props`)
props(pod, `locale/en.props`)
Fallback to pod::key unless def specified

Where {locale} is Locale.toStr and {lang} is Locale.lang. The maxAge parameter is set to Duration.maxVal (cached for life of the VM).

Also see Pod.locale and Localization.

mainMethod

virtual Method? mainMethod()

Get the main method which was used to run this Fantom VM. Return null if VM was booted outside of a Fantom main method. Default implementation delegates to parent.

make

new make(Env parent)

Subclasses are constructed from a parent environment.

Str os()

Operating system name as one of the following constants:

"win32"
"macosx"
"linux"
"aix"
"solaris"
"hpux"
"qnx"

out

virtual OutStream out()

Standard output stream. Default implementation delegates to parent.

parent

Env? parent()

Get the parent environment or null if this is the bootstrap environment. Many virtual methods delegate to their parent by default.

path

virtual File[] path()

Path used by findFile if this is a PathEnv.

platform

Str platform()

Name of the host platform as a string formatted as "<os>-<arch>". See os and arch.

prompt

virtual Str? prompt(Str msg)

Prompt the user to enter a command line from standard input. This method routes to Console.prompt.

promptPassword

virtual Str? promptPassword(Str msg)

Prompt the user to enter a password from standard input with echo disabled. This method routes to Console.promptPassword.

props

virtual Str:Str props(Pod pod, Uri uri, Duration maxAge)

Return a merged key/value map of all the prop files found using the following resolution rules:

Env.findAllFiles: "etc/{pod}/{uri}"
Pods indexed with sys.envProps: "/{pod}/uri"
Pod.files: "/{uri}"

The uri must be relative. Note that props such as locale files can be bundled into a pod for deployment and searched by adding an indexed prop with the key "sys.envProps" and the pod name as the value. This feature does not support "config.props".

The files are parsed using InStream.readProps and merged according to their priority order. If the file is defined as a resource in the pod itself, then it is treated as lowest priority. The first file returned by findAllFiles is treated as highest priority and overwrites any key-value pairs defined at a lower priority.

The map is cached so that subsequent calls for the same path don't require accessing the file system again. The maxAge parameter specifies the tolerance accepted before a cache refresh is performed to check if any of the files have been modified.

Also see Pod.props and Env.

removeShutdownHook

virtual Bool removeShutdownHook(|->Void| hook)

Remove a shutdown hook function which was added by addShutdownHook. Remove true if hook had been previously added and was unregistered, false otherwise. Default implementation delegates to parent.

runtime

Str runtime()

Virtual machine runtime as one of the following constants:

"java"
"dotnet"
"js"

tempDir

virtual File tempDir()

Get the temp directory to use for scratch files. Default implementation delegates to parent.

user

virtual Str user()

Get the user name of the user account used to run the virtual machine process. Default implementation delegates to parent.

vars

virtual Str:Str vars()

Get the environment variables as a case insensitive, immutable map of Str name/value pairs. The environment map is initialized from the following sources from lowest priority to highest priority:

shell environment variables
Java system properties (Java VM only obviously)

Default implementation delegates to parent.

workDir

virtual File workDir()

Get the working directory to use for saving compiled pods and configuration information. Default implementation delegates to parent.

Haxall 4.0.5 ∙ 24-Feb-2026 14:33 EST