jsint
Class Evaluator

java.lang.Object
  |
  +--jsint.Evaluator

All Implemented Interfaces:

SchemeEvaluator

public class Evaluator

extends java.lang.Object

implements SchemeEvaluator

This class represents a Scheme interpreter.

Author:

Peter Norvig, Copyright 1998, peter@norvig.com, license subsequently modified by Jscheme project members licensed under zlib licence (see license.txt)

Field Summary

java.io.PrintWriter	error
boolean	EXIT Should REP Loop exit?
DynamicEnvironment	INITIAL_ENVIRONMENT
InputPort	input
DynamicEnvironment	interactionEnvironment
boolean	INTERRUPTABLE Is execution interruptable.
static DynamicEnvironment	NULL_ENVIRONMENT
java.io.PrintWriter	output

Constructor Summary

Evaluator()

Evaluator(DynamicEnvironment env)

Method Summary

java.lang.Object	analyze(java.lang.Object x, DynamicEnvironment dynamicEnv, LexicalEnvironment lexenv) Analyze (or preprocess or precompile) an expression into "code".
java.lang.Boolean	environmentImport(java.lang.Object x, java.lang.Object prefix)
java.lang.Boolean	environmentImport(java.lang.Object x, java.lang.Object prefix, boolean macrosFlag, Symbol[] procnames)
java.lang.Object	eval(java.lang.Object x) Evaluate an s-expression in the global environment.
java.lang.Object	eval(java.lang.Object x, java.lang.Object env) Evaluate an s-expression in a lexical environment.
java.lang.Object	evalToplevel(java.lang.Object x, DynamicEnvironment env) evalToplevel evaluates each element of a BEGIN.
java.lang.Object	execute(java.lang.Object x, LexicalEnvironment lexenv) Evaluate analyzed code in a lexical environment.
DynamicEnvironment	getInitialEnvironment()
DynamicEnvironment	getInteractionEnvironment()
static DynamicEnvironment	getNullEnvironment()
void	interrupt(java.lang.Thread t) Interrupt execution on thread t.
void	interruptCheck() Maybe interrupt this thread of execution.
java.lang.Boolean	languageImport(java.lang.Object x)
java.lang.Object	load(InputPort in) Eval all the expressions coming from an InputPort, putting them in the interactionEnvironment.
java.lang.Object	load(java.lang.Object fileName) Eval all the expressions in a file.
DynamicEnvironment	loadEnvironment(java.lang.Object x) load the current object (file or class) into a new Evaluator and return the resulting Evaluator's DynamicEnvironment.
void	readEvalWriteLoop(java.lang.String prompt) Prompt, read, eval, and write the result.
void	runJscheme()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EXIT

public boolean EXIT

Should REP Loop exit?

input

public InputPort input

output

public java.io.PrintWriter output

error

public java.io.PrintWriter error

INTERRUPTABLE

public boolean INTERRUPTABLE

Is execution interruptable.

interactionEnvironment

public DynamicEnvironment interactionEnvironment

NULL_ENVIRONMENT

public static DynamicEnvironment NULL_ENVIRONMENT

INITIAL_ENVIRONMENT

public DynamicEnvironment INITIAL_ENVIRONMENT

Constructor Detail

Evaluator

public Evaluator()

Evaluator

public Evaluator(DynamicEnvironment env)

Method Detail

interrupt

public void interrupt(java.lang.Thread t)

Interrupt execution on thread t.

interruptCheck

public void interruptCheck()

Maybe interrupt this thread of execution.

getInteractionEnvironment

public DynamicEnvironment getInteractionEnvironment()

getNullEnvironment

public static DynamicEnvironment getNullEnvironment()

getInitialEnvironment

public DynamicEnvironment getInitialEnvironment()

runJscheme

public void runJscheme()

readEvalWriteLoop

public void readEvalWriteLoop(java.lang.String prompt)

Prompt, read, eval, and write the result. Also sets up a catch for any RuntimeExceptions encountered.

loadEnvironment

public DynamicEnvironment loadEnvironment(java.lang.Object x)

load the current object (file or class) into a new Evaluator and return the resulting Evaluator's DynamicEnvironment.

environmentImport

public java.lang.Boolean environmentImport(java.lang.Object x,
                                           java.lang.Object prefix)

environmentImport

public java.lang.Boolean environmentImport(java.lang.Object x,
                                           java.lang.Object prefix,
                                           boolean macrosFlag,
                                           Symbol[] procnames)

languageImport

public java.lang.Boolean languageImport(java.lang.Object x)

load

public java.lang.Object load(java.lang.Object fileName)

Eval all the expressions in a file. Calls load(InputPort).

load

public java.lang.Object load(InputPort in)

Eval all the expressions coming from an InputPort, putting them in the interactionEnvironment. The interactionEnvironment might have been rebound to a module environment, but we don't care about that.

evalToplevel

public java.lang.Object evalToplevel(java.lang.Object x,
                                     DynamicEnvironment env)

evalToplevel evaluates each element of a BEGIN. This is so macros can be defined and then used. Also toplevel macros can expand into begin.

eval

public java.lang.Object eval(java.lang.Object x)

Evaluate an s-expression in the global environment.

eval

public java.lang.Object eval(java.lang.Object x,
                             java.lang.Object env)

Evaluate an s-expression in a lexical environment. First analyze it.

analyze

public java.lang.Object analyze(java.lang.Object x,
                                DynamicEnvironment dynamicEnv,
                                LexicalEnvironment lexenv)

Analyze (or preprocess or precompile) an expression into "code". The code returned is either a Symbol, a LocalVariable, a Closure, or an array whose first element is either one of (quote if or begin set!) or is code evaluating to a procedure.

execute

public java.lang.Object execute(java.lang.Object x,
                                LexicalEnvironment lexenv)

Evaluate analyzed code in a lexical environment. Don't pass this a raw s-expression; you need to analyze the s-expression first.