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Implement the negation operator.

This commit is contained in:
Danila Fedorin 2017-08-02 11:26:59 -07:00
parent 9713f24ed2
commit d964fbfb6f
3 changed files with 30 additions and 6 deletions
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2
src/main/java/org/nwapw/abacus/function/OperatorType.java
View File

@ -4,5 +4,5 @@ package org.nwapw.abacus.function;
* The type of an operator, describing how it should behave.
*/
public enum OperatorType {
BINARY_INFIX, UNARY_POSTFIX
BINARY_INFIX, UNARY_POSTFIX, UNARY_PREFIX
}

17
src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java
View File

@ -55,9 +55,12 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
public List<Match<TokenType>> intoPostfix(List<Match<TokenType>> from) {
ArrayList<Match<TokenType>> output = new ArrayList<>();
Stack<Match<TokenType>> tokenStack = new Stack<>();
TokenType previousType;
TokenType matchType = null;
while (!from.isEmpty()) {
Match<TokenType> match = from.remove(0);
TokenType matchType = match.getType();
previousType = matchType;
matchType = match.getType();
if (matchType == TokenType.NUM) {
output.add(match);
} else if (matchType == TokenType.FUNCTION) {
@ -74,7 +77,13 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
continue;
}
while (!tokenStack.empty()) {
if(tokenString.equals("-") && (previousType == null || previousType == TokenType.OP ||
previousType == TokenType.OPEN_PARENTH)){
from.add(0, new Match<>("`", TokenType.OP));
continue;
}
while (!tokenStack.empty() && type == OperatorType.BINARY_INFIX) {
Match<TokenType> otherMatch = tokenStack.peek();
TokenType otherMatchType = otherMatch.getType();
if (!(otherMatchType == TokenType.OP || otherMatchType == TokenType.FUNCTION)) break;
@ -103,8 +112,8 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
}
while (!tokenStack.empty()) {
Match<TokenType> match = tokenStack.peek();
TokenType matchType = match.getType();
if (!(matchType == TokenType.OP || matchType == TokenType.FUNCTION)) return null;
TokenType newMatchType = match.getType();
if (!(newMatchType == TokenType.OP || newMatchType == TokenType.FUNCTION)) return null;
output.add(tokenStack.pop());
}
return output;

17
src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
View File

@ -52,6 +52,20 @@ public class StandardPlugin extends Plugin {
return params[0].subtract(params[1]);
}
});
/**
* The negation operator, -
*/
public static final Operator OP_NEGATE = new Operator(OperatorAssociativity.LEFT, OperatorType.UNARY_PREFIX, 0, new Function() {
@Override
protected boolean matchesParams(NumberInterface[] params) {
return params.length == 1;
}
@Override
protected NumberInterface applyInternal(NumberInterface[] params) {
return params[0].negate();
}
});
/**
* The multiplication operator, *
*/
@ -317,6 +331,7 @@ public class StandardPlugin extends Plugin {
registerOperator("+", OP_ADD);
registerOperator("-", OP_SUBTRACT);
registerOperator("`", OP_NEGATE);
registerOperator("*", OP_MULTIPLY);
registerOperator("/", OP_DIVIDE);
registerOperator("^", OP_CARET);
@ -335,7 +350,7 @@ public class StandardPlugin extends Plugin {
public static NumberInterface factorial(Class<? extends NumberInterface> numberClass, int n){
if(!factorialLists.containsKey(numberClass)){
factorialLists.put(numberClass, new ArrayList<NumberInterface>());
factorialLists.put(numberClass, new ArrayList<>());
factorialLists.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
factorialLists.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
}