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Added function to the argument validator and refactored some code

This commit is contained in:
Mike Cifelli 2016-12-22 16:55:25 -05:00
parent 9bea0e6533
commit 7de7996a27
17 changed files with 187 additions and 120 deletions
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87
src/function/ArgumentValidator.java
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@ -8,20 +8,31 @@ import sexpression.*;
public class ArgumentValidator {
private Class<? extends SExpression> argumentType;
private Class<? extends SExpression> firstArgumentType;
private Class<? extends SExpression> trailingArgumentType;
private String functionName;
private Integer maximumNumberOfArguments;
private Integer minimumNumberOfArguments;
public ArgumentValidator(String functionName) {
this.argumentType = SExpression.class;
this.firstArgumentType = SExpression.class;
this.trailingArgumentType = SExpression.class;
this.functionName = functionName;
this.minimumNumberOfArguments = null;
this.maximumNumberOfArguments = null;
}
public void setArgumentType(Class<? extends SExpression> argumentType) {
this.argumentType = argumentType;
public void setFirstArgumentExpectedType(Class<? extends SExpression> argumentType) {
this.firstArgumentType = argumentType;
}
public void setTrailingArgumentExpectedType(Class<? extends SExpression> argumentType) {
this.trailingArgumentType = argumentType;
}
public void setEveryArgumentExpectedType(Class<? extends SExpression> argumentType) {
this.firstArgumentType = argumentType;
this.trailingArgumentType = argumentType;
}
public void setMaximumNumberOfArguments(int maximumNumberOfArguments) {
@ -38,12 +49,27 @@ public class ArgumentValidator {
}
public void validate(Cons argumentList) {
validateListNotDotted(argumentList);
if (containsTooFewArguments(argumentList))
throw new TooFewArgumentsException(functionName, argumentList);
else if (containsTooManyArguments(argumentList))
throw new TooManyArgumentsException(functionName, argumentList);
else if (!isExpectedArgumentType(argumentList.getCar()))
throw new BadArgumentTypeException(functionName, argumentList.getCar());
validateArgumentTypes(argumentList);
}
private void validateListNotDotted(Cons argumentList) {
Cons currentCons = argumentList;
SExpression nextCons = argumentList.getCdr();
while (!nextCons.nullp()) {
if (!nextCons.consp())
throw new DottedArgumentListException(functionName, argumentList);
currentCons = (Cons) nextCons;
nextCons = currentCons.getCdr();
}
}
private boolean containsTooFewArguments(Cons argumentList) {
@ -54,8 +80,25 @@ public class ArgumentValidator {
return (maximumNumberOfArguments != null) && (LENGTH.getLength(argumentList) > maximumNumberOfArguments);
}
private boolean isExpectedArgumentType(SExpression firstArgument) {
return argumentType.isInstance(firstArgument);
private void validateArgumentTypes(Cons argumentList) {
if (!isExpectedFirstArgumentType(argumentList.getCar()))
throw new BadArgumentTypeException(functionName, argumentList.getCar(), firstArgumentType);
validateRemainingArguments(argumentList);
}
private boolean isExpectedFirstArgumentType(SExpression firstArgument) {
return firstArgumentType.isInstance(firstArgument);
}
private void validateRemainingArguments(Cons cons) {
for (cons = (Cons) cons.getCdr(); !cons.nullp(); cons = (Cons) cons.getCdr())
if (!isExpectedRemainingArgumentType(cons.getCar()))
throw new BadArgumentTypeException(functionName, cons.getCar(), trailingArgumentType);
}
private boolean isExpectedRemainingArgumentType(SExpression remainingArgument) {
return trailingArgumentType.isInstance(remainingArgument);
}
public static class TooFewArgumentsException extends LispException {
@ -92,20 +135,44 @@ public class ArgumentValidator {
}
}
public static class DottedArgumentListException extends LispException {
private static final long serialVersionUID = 1L;
private String functionName;
private Cons originalSExpression;
public DottedArgumentListException(String functionName, Cons argumentList) {
this.functionName = functionName;
this.originalSExpression = new Cons(new Symbol(this.functionName), argumentList);
}
@Override
public String getMessage() {
return MessageFormat.format("dotted argument list given to {0}: {1}", functionName, originalSExpression);
}
}
public static class BadArgumentTypeException extends LispException {
private static final long serialVersionUID = 1L;
private String functionName;
private String argument;
private Class<? extends SExpression> expected;
public BadArgumentTypeException(String functionName, SExpression argument) {
public BadArgumentTypeException(String functionName, SExpression argument,
Class<? extends SExpression> expected) {
this.functionName = functionName;
this.argument = argument.toString();
this.expected = expected;
}
@Override
public String getMessage() {
return MessageFormat.format("{0}: {1} is not the expected type", functionName, argument);
DisplayName displayName = expected.getAnnotation(DisplayName.class);
String expectedType = (displayName == null) ? "unknown" : displayName.value();
return MessageFormat.format("{0}: {1} is not the expected type of ''{2}''", functionName, argument,
expectedType);
}
}

16
src/function/UserDefinedFunction.java
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@ -8,32 +8,20 @@ import table.SymbolTable;
public class UserDefinedFunction extends LispFunction {
private ArgumentValidator argumentValidator;
private String name;
private Cons body;
private Cons lambdaExpression;
private SymbolTable environment;
private ArrayList<String> formalParameters;
private ArgumentValidator argumentValidator;
/**
* Create a new user-defined function with the specified name, lambda list and body.
*
* @param name
* the name of this user-defined function
* @param lambdaList
* a list of the formal parameters of this user-defined function (MUST BE A PROPER
* LIST)
* @param body
* the body of this user-defined function (MUST BE A PROPER LIST)
*/
public UserDefinedFunction(String name, Cons lambdaList, Cons body) {
this.name = name;
this.body = body;
this.lambdaExpression = new Cons(new Symbol(name), new Cons(lambdaList, body));
this.environment = SETF.getEnvironment();
this.formalParameters = new ArrayList<String>();
for (; lambdaList.consp(); lambdaList = (Cons) lambdaList.getCdr())
for (this.formalParameters = new ArrayList<>(); lambdaList.consp(); lambdaList = (Cons) lambdaList.getCdr())
this.formalParameters.add(lambdaList.getCar().toString());
this.argumentValidator = new ArgumentValidator(this.name);

25
src/function/builtin/APPLY.java
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@ -5,7 +5,6 @@ import sexpression.*;
public class APPLY extends LispFunction {
private static final int NUMBER_OF_ARGUMENTS = 2;
private ArgumentValidator argumentValidator;
public static SExpression apply(Cons argList) {
@ -14,7 +13,8 @@ public class APPLY extends LispFunction {
public APPLY() {
this.argumentValidator = new ArgumentValidator("APPLY");
this.argumentValidator.setExactNumberOfArguments(NUMBER_OF_ARGUMENTS);
this.argumentValidator.setExactNumberOfArguments(2);
this.argumentValidator.setTrailingArgumentExpectedType(Cons.class);
}
public SExpression call(Cons argList) {
@ -23,26 +23,9 @@ public class APPLY extends LispFunction {
Cons cdr = (Cons) argList.getCdr();
SExpression functionName = argList.getCar();
SExpression argumentList = cdr.getCar();
LispFunction function = EVAL.lookupFunctionOrLambda(functionName);
if (argumentList.listp()) {
LispFunction function = EVAL.lookupFunction(functionName.toString());
if (function == null) {
if (functionName.functionp()) {
function = ((LambdaExpression) functionName).getFunction();
} else if (LAMBDA.isLambdaExpression(functionName)) {
Cons lexpr = (Cons) functionName;
function = LAMBDA.createFunction(lexpr);
} else {
throw new RuntimeException("undefined function " + functionName);
}
}
return function.call((Cons) argumentList);
}
throw new RuntimeException("APPLY: " + argumentList + " is not a list");
return function.call((Cons) argumentList);
}
}

3
src/function/builtin/ATOM.java
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@ -5,12 +5,11 @@ import sexpression.*;
public class ATOM extends LispFunction {
private static final int NUMBER_OF_ARGUMENTS = 1;
private ArgumentValidator argumentValidator;
public ATOM() {
this.argumentValidator = new ArgumentValidator("ATOM");
this.argumentValidator.setExactNumberOfArguments(NUMBER_OF_ARGUMENTS);
this.argumentValidator.setExactNumberOfArguments(1);
}
public SExpression call(Cons argumentList) {

85
src/function/builtin/EVAL.java
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@ -2,19 +2,14 @@ package function.builtin;
import java.util.HashMap;
import function.*;
import function.LispFunction;
import sexpression.*;
/**
* <code>EVAL</code> represents the EVAL function in Lisp.
*/
public class EVAL extends LispFunction {
// A table to contain all the built-in and user-defined Lisp functions.
private static HashMap<String, LispFunction> functionTable = new HashMap<String, LispFunction>();
static {
// place all of the built-in functions into the function table
functionTable.put("*", new MULTIPLY());
functionTable.put("+", new PLUS());
functionTable.put("-", new MINUS());
@ -50,33 +45,32 @@ public class EVAL extends LispFunction {
functionTable.put("SYMBOL-FUNCTION", new SYMBOL_FUNCTION());
}
/**
* Retrieve the function table.
*
* @return the function table
*/
public static HashMap<String, LispFunction> getFunctionTable() {
return functionTable;
}
/**
* Look up a function by its name.
*
* @param functionName
* the name of the function to look up
* @return the function with the name <code>functionName</code> if it exists; null otherwise
*/
public static LispFunction lookupFunction(String functionName) {
return functionTable.get(functionName);
}
/**
* Look up a symbol's value using its name.
*
* @param symbolName
* the name of the symbol to look up (must not be null)
* @return the value of <code>symbolName</code> if it has one; null otherwise
*/
public static LispFunction lookupFunctionOrLambda(SExpression functionExpression) {
LispFunction function = lookupFunction(functionExpression.toString());
if (function == null)
function = createLambdaFunction(functionExpression);
return function;
}
private static LispFunction createLambdaFunction(SExpression lambdaExpression) {
if (lambdaExpression.functionp())
return ((LambdaExpression) lambdaExpression).getFunction();
else if (LAMBDA.isLambdaExpression(lambdaExpression))
return LAMBDA.createFunction((Cons) lambdaExpression);
else
throw new RuntimeException("undefined function " + lambdaExpression);
}
public static SExpression lookupSymbol(String symbolName) {
if (symbolName.equals("NIL")) {
return Nil.getUniqueInstance();
@ -89,13 +83,6 @@ public class EVAL extends LispFunction {
return SETF.lookup(symbolName);
}
/**
* Determine if the given list is dotted.
*
* @param list
* the list to be tested (must not be null)
* @return <code>true</code> if <code>list</code> is dotted; <code>false</code> otherwise
*/
public static boolean isDotted(Cons list) {
if (list.nullp()) {
return false;
@ -111,13 +98,6 @@ public class EVAL extends LispFunction {
return true;
}
/**
* Evaluate the given S-expression.
*
* @param sexpr
* the S-expression to evaluate
* @return the value of <code>sexpr</code>
*/
public static SExpression eval(SExpression sexpr) {
Cons expList = LIST.makeList(sexpr);
EVAL evalFunction = new EVAL();
@ -125,7 +105,6 @@ public class EVAL extends LispFunction {
return evalFunction.call(expList);
}
// The number of arguments that EVAL takes.
private static final int NUM_ARGS = 1;
public SExpression call(Cons argList) {
@ -164,29 +143,11 @@ public class EVAL extends LispFunction {
return arg; // 'arg' is a NUMBER or a STRING
}
// Evaluate the specified list.
//
// Parameters: list - the list to evaluate
// Returns: the value of 'list'
// Precondition: 'list' must not be null.
private SExpression evaluateList(Cons list) {
SExpression car = list.getCar();
SExpression cdr = list.getCdr();
LispFunction function = lookupFunction(car.toString());
if (function == null) {
// check if the car of the list is a lambda expression
if (car.functionp()) {
function = ((LambdaExpression) car).getFunction();
} else if (LAMBDA.isLambdaExpression(car)) {
Cons lexpr = (Cons) car;
function = LAMBDA.createFunction(lexpr);
} else {
throw new RuntimeException("undefined function " + car);
}
}
LispFunction function = lookupFunctionOrLambda(car);
// make sure the list of arguments for 'function' is a list
if (cdr.listp()) {
@ -210,12 +171,6 @@ public class EVAL extends LispFunction {
throw new RuntimeException("argument list given to " + car + " is dotted: " + list);
}
// Evaluate a list of arguments for a function.
//
// Parameters: arguments - a list of arguments for a function
// Returns: a list consisting of the values of the S-expressions found in
// 'arguments'
// Precondition: 'arguments' must not be null.
private Cons evaluateArgList(Cons arguments) {
if (arguments.nullp()) {
return Nil.getUniqueInstance();

6
src/function/builtin/PLUS.java
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@ -3,9 +3,6 @@ package function.builtin;
import function.LispFunction;
import sexpression.*;
/**
* <code>PLUS</code> represents the '+' function in Lisp.
*/
public class PLUS extends LispFunction {
public LispNumber call(Cons argList) {
@ -13,6 +10,9 @@ public class PLUS extends LispFunction {
return new LispNumber(0);
}
if (!argList.getCdr().listp())
throw new RuntimeException("+: " + argList + " is dotted");
SExpression argFirst = argList.getCar();
Cons argRest = (Cons) argList.getCdr();

1
src/sexpression/Atom.java
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@ -1,5 +1,6 @@
package sexpression;
@DisplayName("atom")
public abstract class Atom extends SExpression {
private String text;

1
src/sexpression/Cons.java
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@ -1,5 +1,6 @@
package sexpression;
@DisplayName("list")
public class Cons extends SExpression {
private SExpression car;

11
src/sexpression/DisplayName.java Normal file
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@ -0,0 +1,11 @@
package sexpression;
import java.lang.annotation.*;
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
public @interface DisplayName {
String value();
}

1
src/sexpression/LambdaExpression.java
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@ -2,6 +2,7 @@ package sexpression;
import function.UserDefinedFunction;
@DisplayName("lambda-expression")
public class LambdaExpression extends SExpression {
private Cons lambdaExpression;

1
src/sexpression/LispNumber.java
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@ -4,6 +4,7 @@ import java.text.MessageFormat;
import error.LispException;
@DisplayName("number")
public class LispNumber extends Atom {
private int value;

1
src/sexpression/LispString.java
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@ -1,5 +1,6 @@
package sexpression;
@DisplayName("string")
public class LispString extends Atom {
public LispString(String text) {

1
src/sexpression/Nil.java
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@ -1,5 +1,6 @@
package sexpression;
@DisplayName("nil")
public class Nil extends Cons {
private static Nil uniqueInstance = new Nil();

1
src/sexpression/SExpression.java
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@ -1,5 +1,6 @@
package sexpression;
@DisplayName("s-expression")
public abstract class SExpression {
public boolean nullp() {

1
src/sexpression/Symbol.java
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@ -1,5 +1,6 @@
package sexpression;
@DisplayName("symbol")
public class Symbol extends Atom {
public static final Symbol T = new Symbol("T");

64
test/function/ArgumentValidatorTester.java
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@ -103,14 +103,14 @@ public class ArgumentValidatorTester {
@Test
public void BadArgumentTypeException_HasCorrectSeverity() {
BadArgumentTypeException e = new BadArgumentTypeException("TEST", Nil.getUniqueInstance());
BadArgumentTypeException e = new BadArgumentTypeException("TEST", Nil.getUniqueInstance(), SExpression.class);
assertTrue(e.getSeverity() < ErrorManager.CRITICAL_LEVEL);
}
@Test
public void BadArgumentTypeException_HasMessageText() {
BadArgumentTypeException e = new BadArgumentTypeException("TEST", Nil.getUniqueInstance());
BadArgumentTypeException e = new BadArgumentTypeException("TEST", Nil.getUniqueInstance(), SExpression.class);
assertNotNull(e.getMessage());
assertTrue(e.getMessage().length() > 0);
@ -118,14 +118,70 @@ public class ArgumentValidatorTester {
@Test
public void correctArgumentType_DoesNotThrowException() {
validator.setArgumentType(Nil.class);
validator.setEveryArgumentExpectedType(Nil.class);
validator.validate(makeArgumentListOfSize(1));
}
@Test(expected = BadArgumentTypeException.class)
public void badArgumentType_ThrowsException() {
validator.setArgumentType(LispString.class);
validator.setEveryArgumentExpectedType(LispString.class);
validator.validate(makeArgumentListOfSize(1));
}
@Test
public void correctFirstAndRestArgumentTypes_DoesNotThrowException() {
Cons argumentList = new Cons(Symbol.T, new Cons(Nil.getUniqueInstance(), Nil.getUniqueInstance()));
validator.setFirstArgumentExpectedType(Symbol.class);
validator.setTrailingArgumentExpectedType(Cons.class);
validator.validate(argumentList);
}
@Test(expected = BadArgumentTypeException.class)
public void badFirstArgumentType_ThrowsException() {
Cons argumentList = new Cons(Symbol.T, new Cons(Nil.getUniqueInstance(), Nil.getUniqueInstance()));
validator.setFirstArgumentExpectedType(Cons.class);
validator.setTrailingArgumentExpectedType(Cons.class);
validator.validate(argumentList);
}
@Test(expected = BadArgumentTypeException.class)
public void badTrailingArgumentType_ThrowsException() {
Cons argumentList = new Cons(Symbol.T, new Cons(Nil.getUniqueInstance(), Nil.getUniqueInstance()));
validator.setFirstArgumentExpectedType(Symbol.class);
validator.setTrailingArgumentExpectedType(Symbol.class);
validator.validate(argumentList);
}
@Test
public void expectedTypeWithNoDisplayName_DoesNotCauseNPE() {
Cons argumentList = new Cons(Symbol.T, new Cons(Nil.getUniqueInstance(), Nil.getUniqueInstance()));
SExpression withoutDisplayName = new SExpression() {};
validator.setEveryArgumentExpectedType(withoutDisplayName.getClass());
try {
validator.validate(argumentList);
} catch (BadArgumentTypeException e) {
e.getMessage();
}
}
@Test(expected = DottedArgumentListException.class)
public void givenDottedArgumentList_ThrowsException() {
Cons argumentList = new Cons(Symbol.T, Symbol.T);
validator.validate(argumentList);
}
@Test
public void dottedArgumentListException_HasMessageText() {
DottedArgumentListException e = new DottedArgumentListException("TEST", Nil.getUniqueInstance());
assertNotNull(e.getMessage());
assertTrue(e.getMessage().length() > 0);
}
}

2
test/function/builtin/APPLYTester.java
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@ -43,7 +43,7 @@ public class APPLYTester {
evaluateString("(apply 'f '(1 2 3))");
}
@Test(expected = RuntimeException.class)
@Test(expected = BadArgumentTypeException.class)
public void testApplyWithNonListSecondArgument() {
evaluateString("(apply '+ '2)");
}