diff options
| -rw-r--r-- | src/main/java/io/github/moulberry/notenoughupdates/util/Calculator.java | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/src/main/java/io/github/moulberry/notenoughupdates/util/Calculator.java b/src/main/java/io/github/moulberry/notenoughupdates/util/Calculator.java index 54636791..4d57d92f 100644 --- a/src/main/java/io/github/moulberry/notenoughupdates/util/Calculator.java +++ b/src/main/java/io/github/moulberry/notenoughupdates/util/Calculator.java @@ -33,12 +33,10 @@ public class Calculator { source = source.toLowerCase(Locale.ROOT); return evaluate(shuntingYard(lex(source))); } - ///<editor-fold desc="Lexing Time"> public enum TokenType { - NUMBER, BINOP, LPAREN, RPAREN, POSTOP + NUMBER, BINOP, LPAREN, RPAREN, POSTOP, PREOP } - public static class Token { public TokenType type; String operatorValue; @@ -89,6 +87,7 @@ public class Calculator { public static List<Token> lex(String source) throws CalculatorException { List<Token> tokens = new ArrayList<>(); + boolean justParsedNumber = false; for (int i = 0; i < source.length(); ) { char c = source.charAt(i); if (Character.isWhitespace(c)) { @@ -97,7 +96,11 @@ public class Calculator { } Token token = new Token(); token.tokenStart = i; - if (binops.indexOf(c) != -1) { + if (!justParsedNumber && c == '-') { + token.tokenLength = 1; + token.type = TokenType.PREOP; + token.operatorValue = "-"; + } else if (binops.indexOf(c) != -1) { token.tokenLength = 1; token.type = TokenType.BINOP; token.operatorValue = c + ""; @@ -137,6 +140,7 @@ public class Calculator { } else { throw new CalculatorException("Unknown thing " + c, i, 1); } + justParsedNumber = token.type == TokenType.NUMBER; tokens.add(token); i += token.tokenLength; } @@ -188,6 +192,9 @@ public class Calculator { } op.push(currentlyShunting); break; + case PREOP: + op.push(currentlyShunting); + break; case LPAREN: op.push(currentlyShunting); break; @@ -223,12 +230,14 @@ public class Calculator { /// </editor-fold> ///<editor-fold desc="Evaluating Time"> - public static BigDecimal evaluate(List<Token> rpnTokens) throws CalculatorException { Deque<BigDecimal> values = new ArrayDeque<>(); try { for (Token command : rpnTokens) { switch (command.type) { + case PREOP: + values.push(values.pop().negate()); + break; case NUMBER: values.push(new BigDecimal(command.numericValue).scaleByPowerOfTen(command.exponent)); break; @@ -317,7 +326,5 @@ public class Calculator { throw new CalculatorException("Unfinished expression", 0, 0); } } - - ///</editor-fold> - + /// </editor-fold> } |