org.hecl

Class Interp

java.lang.Object

java.lang.Thread

org.hecl.Interp

All Implemented Interfaces:

java.lang.Runnable

public class Interp
extends java.lang.Thread

Interp is the Hecl interpreter, the class responsible for knowing what variables and commands are available.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

java.lang.Thread.State, java.lang.Thread.UncaughtExceptionHandler

Field Summary

Fields

Modifier and Type	Field and Description
static int	ALL_EVENTS
static java.lang.String	ASYNCPREFIX Some string constants used to generate names for internal events.
long	cacheversion
Thing	currentFile
static int	DONT_WAIT Flags for the event loop.
static char[]	eol eol is the end-of-line character or characters.
static java.lang.String	fileseparator fileseparator is the file separator, such as "/".
static int	IDLE_EVENTS
static java.lang.String	IDLEPREFIX
static java.lang.String	MODULE_CLASS_PACKAGE Package name prefix of the module classes.
java.lang.String	PROMPT The prompt for the readEvalPrint loop.
java.lang.String	PROMPT2 The prompt for continued lines in the readEvalPrint loop.
static int	TIMER_EVENTS
static java.lang.String	TIMERPREFIX

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor and Description
Interp() Creates a new Interp instance, initializing command and variable hashtables, a stack, and an error stack.

Method Summary

Modifier and Type	Method and Description
void	addClassCmd(java.lang.Class clazz, ClassCommand cmd) Add a new class command to an Interp.
java.lang.String	addCommand(java.lang.String name, Command c) Add a new command to an Interp.
void	addError(Thing err) addError adds a Thing as an error message.
HeclTask	addTimer(Thing timerThing, int millisecs)
void	backgroundError(java.lang.String errorMessage) The backgroundError method can be called to dispatch a bgerror command.
void	cancelAsync(java.lang.String name)
void	cancelIdle(HeclTask idletask)
void	cancelIdle(java.lang.String name)
void	cancelTimer(java.lang.String name)
static void	checkArgCount(Thing[] argv, int minargs, int maxargs) checkArgCount checks to see whether the command actually has the required number of arguments.
void	clearError() clearError clears the error stack.
void	cmdAlias(java.lang.String oldname, java.lang.String newname)
void	cmdRename(java.lang.String oldname, java.lang.String newname) The cmdRename method renames a command, or throws an error if the original command didn't exist.
boolean	commandExists(java.lang.String name) The commandExists method returns true if a command exists, otherwise false.
boolean	doOneEvent(int flags)
Thing	eval(Thing in) The eval method evaluates some Hecl code passed to it.
Thing	eval(Thing in, int level) This version of eval takes a 'level' argument that tells Hecl what level to run the code at.
HeclTask	evalAsync(Thing asyncThing)
Thing	evalAsyncAndWait(Thing in)
HeclTask	evalIdle(Thing idleThing)
boolean	existsVar(java.lang.String varname) existsVar returns true if the given variable exists in the current variable stack frame, false if it does not.
boolean	existsVar(java.lang.String varname, int level) existsVar returns true if the given variable exists in the variable stack frame given by level, false if it does not.
boolean	existsVar(Thing varname) existsVar returns true if the given variable exists in the current variable stack frame, false if it does not.
java.util.Vector	getAllEvents()
java.lang.Object	getAuxData(java.lang.String key) Retrieve auxiliary data from an Interp.
HeclTask	getEvent(java.lang.String name)
Thing	getVar(java.lang.String varname) getVar returns the value of a variable given its name.
Thing	getVar(java.lang.String varname, int level) getVar returns the value of a variable given its name and level.
Thing	getVar(Thing varname) getVar returns the value of a variable given its name.
boolean	hasIdleTasks()
void	notifyToken(java.lang.String tokenname)
void	removeAuxData(java.lang.String key) Remove auxiliary data from an Interp.
void	removeClassCmd(java.lang.Class clazz) Remove a command for a specific class from an Interp.
void	removeCommand(java.lang.String name) Remove a command from an Interp.
void	run()
void	setAuxData(java.lang.String key, java.lang.Object value) Attach auxiliary data to an Interp.
void	setVar(java.lang.String varname, Thing value) setVar sets a variable in the innermost variable stack frame to a value.
void	setVar(java.lang.String varname, Thing value, int level) setVar sets a variable to a value in the variable stack frame specified by level.
void	setVar(Thing varname, Thing value) setVar sets a variable in the innermost variable stack frame to a value.
java.util.Hashtable	stackDecr() stackDecr pops the stack frame, returning it so that commands like upeval can save it.
void	stackIncr() The stackIncr method creates a new stack frame.
void	stackPush(java.util.Hashtable vars) stackDecr pushes a new variable hashtable (probably saved via upeval) onto the stack frame.
void	terminate() The terminate method terminates the Hecl interpreter thread in a graceful manner.
void	unSetVar(java.lang.String varname)
void	unSetVar(java.lang.String varname, int level)
void	unSetVar(Thing varname) unSetVar unsets a variable in the current stack frame.
void	waitForToken(java.lang.String tokenname)

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

MODULE_CLASS_PACKAGE

public static final java.lang.String MODULE_CLASS_PACKAGE

Package name prefix of the module classes.

See Also:

Constant Field Values

DONT_WAIT

public static final int DONT_WAIT

Flags for the event loop.

See Also:

Constant Field Values

IDLE_EVENTS

public static final int IDLE_EVENTS

See Also:

Constant Field Values

TIMER_EVENTS

public static final int TIMER_EVENTS

See Also:

Constant Field Values

ALL_EVENTS

public static final int ALL_EVENTS

See Also:

Constant Field Values

ASYNCPREFIX

public static final java.lang.String ASYNCPREFIX

Some string constants used to generate names for internal events.

See Also:

Constant Field Values

IDLEPREFIX

public static final java.lang.String IDLEPREFIX

See Also:

Constant Field Values

TIMERPREFIX

public static final java.lang.String TIMERPREFIX

See Also:

Constant Field Values

PROMPT

public final java.lang.String PROMPT

The prompt for the readEvalPrint loop.

See Also:

Constant Field Values

PROMPT2

public final java.lang.String PROMPT2

The prompt for continued lines in the readEvalPrint loop.

See Also:

Constant Field Values

cacheversion

public long cacheversion

eol

public static final char[] eol

eol is the end-of-line character or characters.

fileseparator

public static final java.lang.String fileseparator

fileseparator is the file separator, such as "/".

currentFile

public Thing currentFile

Constructor Detail

Interp

public Interp()
       throws HeclException

Creates a new Interp instance, initializing command and variable hashtables, a stack, and an error stack.

Throws:

HeclException - if an error occurs

Method Detail

addClassCmd

public void addClassCmd(java.lang.Class clazz,
                        ClassCommand cmd)

Add a new class command to an Interp.

Parameters:

clazz - The Java class the command should operate on.

cmd - The command to add. When this paramter is null, an existing command is removed.

removeClassCmd

public void removeClassCmd(java.lang.Class clazz)

Remove a command for a specific class from an Interp.

Parameters:

clazz - The class to remove the command for.

addCommand

public java.lang.String addCommand(java.lang.String name,
                                   Command c)

Add a new command to an Interp.

Parameters:

name - the name of the command to add.

c - the command to add.

removeCommand

public void removeCommand(java.lang.String name)

Remove a command from an Interp.

Parameters:

name - the name of the command to add.

commandExists

public boolean commandExists(java.lang.String name)

The commandExists method returns true if a command exists, otherwise false.

Parameters:

name - a String value

Returns:

a boolean value

setAuxData

public void setAuxData(java.lang.String key,
                       java.lang.Object value)

Attach auxiliary data to an Interp.

getAuxData

public java.lang.Object getAuxData(java.lang.String key)

Retrieve auxiliary data from an Interp.

Returns:

a Object value or null when no auxiliary data under the given key is attached to the interpreter.

removeAuxData

public void removeAuxData(java.lang.String key)

Remove auxiliary data from an Interp.

eval

public Thing eval(Thing in)
           throws HeclException

The eval method evaluates some Hecl code passed to it.

Returns:

a Thing value - the result of the evaluation.

Throws:

HeclException - if an error occurs.

evalIdle

public HeclTask evalIdle(Thing idleThing)

evalAsync

public HeclTask evalAsync(Thing asyncThing)

evalAsyncAndWait

public Thing evalAsyncAndWait(Thing in)
                       throws HeclException

Throws:

HeclException

eval

public Thing eval(Thing in,
                  int level)
           throws HeclException

This version of eval takes a 'level' argument that tells Hecl what level to run the code at. Level 0 means global, negative numbers indicate relative levels down from the current stackframe, and positive numbers mean absolute stack frames counting up from 0.

Parameters:

in - a Thing value

level - an int value

Returns:

a Thing value

Throws:

HeclException - if an error occurs

hasIdleTasks

public boolean hasIdleTasks()

getEvent

public HeclTask getEvent(java.lang.String name)

getAllEvents

public java.util.Vector getAllEvents()

addTimer

public HeclTask addTimer(Thing timerThing,
                         int millisecs)

cancelTimer

public void cancelTimer(java.lang.String name)

cancelIdle

public void cancelIdle(java.lang.String name)

cancelAsync

public void cancelAsync(java.lang.String name)

cancelIdle

public void cancelIdle(HeclTask idletask)

doOneEvent

public boolean doOneEvent(int flags)

waitForToken

public void waitForToken(java.lang.String tokenname)
                  throws HeclException

Throws:

HeclException

notifyToken

public void notifyToken(java.lang.String tokenname)
                 throws HeclException

Throws:

HeclException

terminate

public void terminate()

The terminate method terminates the Hecl interpreter thread in a graceful manner. The thread will eventually finish its run-method.

run

public void run()

Specified by:

run in interface java.lang.Runnable

Overrides:

run in class java.lang.Thread

cmdRename

public void cmdRename(java.lang.String oldname,
                      java.lang.String newname)
               throws HeclException

The cmdRename method renames a command, or throws an error if the original command didn't exist.

Parameters:

oldname - a String value

newname - a String value

Throws:

HeclException - if an error occurs

cmdAlias

public void cmdAlias(java.lang.String oldname,
                     java.lang.String newname)
              throws HeclException

Throws:

HeclException

stackIncr

public void stackIncr()

The stackIncr method creates a new stack frame. Used in the Proc class.

stackDecr

public java.util.Hashtable stackDecr()

stackDecr pops the stack frame, returning it so that commands like upeval can save it. If it's not saved, it's gone.

stackPush

public void stackPush(java.util.Hashtable vars)

stackDecr pushes a new variable hashtable (probably saved via upeval) onto the stack frame.

getVar

public Thing getVar(Thing varname)
             throws HeclException

getVar returns the value of a variable given its name.

Parameters:

varname - a Thing value

Returns:

a Thing value

Throws:

HeclException - if an error occurs

getVar

public Thing getVar(java.lang.String varname)
             throws HeclException

getVar returns the value of a variable given its name.

Parameters:

varname - a String value

Returns:

a Thing value

Throws:

HeclException - if an error occurs

getVar

public Thing getVar(java.lang.String varname,
                    int level)
             throws HeclException

getVar returns the value of a variable given its name and level.

Parameters:

varname - a String value

level - an int value

Returns:

a Thing value

Throws:

HeclException - if an error occurs

setVar

public void setVar(Thing varname,
                   Thing value)
            throws HeclException

setVar sets a variable in the innermost variable stack frame to a value.

Parameters:

varname - a Thing value

value - a Thing value

Throws:

HeclException

setVar

public void setVar(java.lang.String varname,
                   Thing value)

setVar sets a variable in the innermost variable stack frame to a value.

Parameters:

varname - a String value

value - a Thing value

setVar

public void setVar(java.lang.String varname,
                   Thing value,
                   int level)

setVar sets a variable to a value in the variable stack frame specified by level.

Parameters:

varname - a String value

value - a Thing value

level - an int value

unSetVar

public void unSetVar(Thing varname)
              throws HeclException

unSetVar unsets a variable in the current stack frame.

Parameters:

varname - a Thing value

Throws:

HeclException

unSetVar

public void unSetVar(java.lang.String varname)
              throws HeclException

Throws:

HeclException

unSetVar

public void unSetVar(java.lang.String varname,
                     int level)
              throws HeclException

Throws:

HeclException

existsVar

public boolean existsVar(Thing varname)
                  throws HeclException

existsVar returns true if the given variable exists in the current variable stack frame, false if it does not.

Parameters:

varname - a Thing value

Returns:

a boolean value

Throws:

HeclException

existsVar

public boolean existsVar(java.lang.String varname)

existsVar returns true if the given variable exists in the current variable stack frame, false if it does not.

Parameters:

varname - a String value

Returns:

a boolean value

existsVar

public boolean existsVar(java.lang.String varname,
                         int level)

existsVar returns true if the given variable exists in the variable stack frame given by level, false if it does not.

Parameters:

varname - a String value

level - an int value

Returns:

a boolean value

addError

public void addError(Thing err)

addError adds a Thing as an error message.

Parameters:

err - a Thing value

clearError

public void clearError()

clearError clears the error stack.

checkArgCount

public static void checkArgCount(Thing[] argv,
                                 int minargs,
                                 int maxargs)
                          throws HeclException

checkArgCount checks to see whether the command actually has the required number of arguments. The first element of the parameter array argv is not counted as argument!

Parameters:

argv - A Thing[] parameter array.

minargs - The minimal number of arguments or -1 if no check is required.

maxargs - The maximal number of arguments or -1 if no check is required.

Throws:

HeclException - if an error occurs

backgroundError

public void backgroundError(java.lang.String errorMessage)

The backgroundError method can be called to dispatch a bgerror command.

Parameters:

errorMessage - a String value