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1 files changed, 380 insertions, 0 deletions

diff --git a/base/src/bjc/dicelang/Shunter.java b/base/src/bjc/dicelang/Shunter.java
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+++ b/base/src/bjc/dicelang/Shunter.java
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+package bjc.dicelang;
+
+import java.util.Deque;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.Set;
+
+import bjc.utils.funcdata.FunctionalList;
+import bjc.utils.funcdata.FunctionalMap;
+import bjc.utils.funcdata.IList;
+import bjc.utils.funcdata.IMap;
+
+import static bjc.dicelang.Errors.ErrorKey.EK_SHUNT_INVSEP;
+import static bjc.dicelang.Errors.ErrorKey.EK_SHUNT_NOGROUP;
+import static bjc.dicelang.Errors.ErrorKey.EK_SHUNT_NOTADJ;
+import static bjc.dicelang.Errors.ErrorKey.EK_SHUNT_NOTADV;
+import static bjc.dicelang.Errors.ErrorKey.EK_SHUNT_NOTASSOC;
+import static bjc.dicelang.Token.Type.*;
+
+/**
+ * Shunt a set of infix tokens to postfix tokens.
+ *
+ * @author EVE
+ *
+ */
+public class Shunter {
+	/* The binary operators and their priorities. */
+	IMap<Token.Type, Integer> ops;
+
+	/* Operators that are right-associative */
+	Set<Token.Type> rightAssoc;
+
+	/* Operators that aren't associative */
+	Set<Token.Type> notAssoc;
+
+	/*
+	 * Unary operators that can only be applied to non-operator tokens and
+	 * yield operator tokens.
+	 */
+	Set<Token.Type> unaryAdjectives;
+
+	/*
+	 * Unary operators that can only be applied to operator tokens and yield
+	 * operator tokens.
+	 */
+	Set<Token.Type> unaryAdverbs;
+
+	/*
+	 * Unary operators that can only be applied to operator tokens and yield
+	 * data tokens
+	 */
+	Set<Token.Type> unaryGerunds;
+
+	/** Precedence for math operators. */
+	public final int MATH_PREC = 30;
+	/** Precedence for dice operators. */
+	public final int DICE_PREC = 20;
+	/** Precedence for string operators. */
+	public final int STR_PREC  = 10;
+	/** Precedence for expression operators. */
+	public final int EXPR_PREC = 0;
+
+	/** Create a new shunter. */
+	public Shunter() {
+		/* Create op map. */
+		ops = new FunctionalMap<>();
+
+		/* Create association maps. */
+		rightAssoc = new HashSet<>();
+		notAssoc   = new HashSet<>();
+
+		/* Create unary maps. */
+		unaryAdjectives = new HashSet<>();
+		unaryAdverbs    = new HashSet<>();
+		unaryGerunds    = new HashSet<>();
+
+		/* Set up unary adverbs. */
+		unaryAdverbs.add(COERCE);
+
+		/* Setup operators. */
+		/* Math operators. */
+		ops.put(ADD,      0 + MATH_PREC);
+		ops.put(SUBTRACT, 0 + MATH_PREC);
+
+		ops.put(MULTIPLY, 1 + MATH_PREC);
+		ops.put(IDIVIDE,  1 + MATH_PREC);
+		ops.put(DIVIDE,   1 + MATH_PREC);
+
+		/* Dice operators. */
+		ops.put(DICEGROUP, 0 + DICE_PREC);
+
+		ops.put(DICECONCAT, 1 + DICE_PREC);
+
+		ops.put(DICELIST, 2 + DICE_PREC);
+
+		/* String operators. */
+		ops.put(STRCAT, 0 + STR_PREC);
+
+		ops.put(STRREP, 1 + STR_PREC);
+
+		/* Expression operators. */
+		ops.put(LET, 0 + EXPR_PREC);
+
+		ops.put(BIND, 1 + EXPR_PREC);
+	}
+
+	/**
+	 * Shunt a set of tokens from infix to postfix.
+	 *
+	 * @param tks
+	 *                The tokens to input.
+	 *
+	 * @param returned
+	 *                The postfix tokens.
+	 *
+	 * @return Whether or not the shunt succeeded.
+	 */
+	public boolean shuntTokens(final IList<Token> tks, final IList<Token> returned) {
+		/* Operator stack for normal and unary operators. */
+		final Deque<Token> opStack  = new LinkedList<>();
+		final Deque<Token> unaryOps = new LinkedList<>();
+
+		/* Currently returned lists. */
+		final Deque<Token> currReturned = new LinkedList<>();
+
+		/* Tokens to feed ahead of the current one. */
+		final Deque<Token> feed = new LinkedList<>();
+
+		for (final Token tk : tks.toIterable()) {
+			boolean succ;
+
+			/* Drain the feed queue. */
+			while (feed.size() != 0) {
+				succ = shuntToken(feed.poll(), opStack, unaryOps, currReturned, feed);
+
+				if (!succ) {
+					return false;
+				}
+			}
+
+			succ = shuntToken(tk, opStack, unaryOps, currReturned, feed);
+
+			if (!succ) {
+				return false;
+			}
+		}
+
+		/* Flush leftover operators. */
+		while (!opStack.isEmpty()) {
+			currReturned.addLast(opStack.pop());
+		}
+
+		/* Add the tokens to the returned list. */
+		for (final Token tk : currReturned) {
+			returned.add(tk);
+		}
+
+		return true;
+	}
+
+	/* Shunt a token. */
+	private boolean shuntToken(final Token tk, final Deque<Token> opStack,
+	                           final Deque<Token> unaryStack,
+	                           final Deque<Token> currReturned, final Deque<Token> feed) {
+		/* Handle unary operators. */
+		if (unaryStack.size() != 0) {
+			if (isUnary(tk)) {
+				unaryStack.add(tk);
+				return true;
+			}
+
+			final Token unaryOp = unaryStack.pop();
+
+			final Token.Type unaryType = unaryOp.type;
+
+			if (unaryAdjectives.contains(unaryType)) {
+				/* 
+				 * Handle unary adjectives that take a
+				 * non-operator. 
+				 */
+				if (isOp(tk)) {
+					Errors.inst.printError(EK_SHUNT_NOTADV, unaryOp.toString(), tk.toString());
+					return false;
+				}
+
+				final Token newTok = new Token(TAGOPR);
+
+				if (tk.type == TAGOP) {
+					newTok.tokenValues = tk.tokenValues;
+				} else {
+					newTok.tokenValues = new FunctionalList<>(tk);
+				}
+
+				newTok.tokenValues.add(unaryOp);
+				opStack.push(newTok);
+
+				return true;
+			} else if (unaryAdverbs.contains(unaryType)) {
+				/* Handle unary adverbs that take an operator. */
+				if (!isOp(tk)) {
+					Errors.inst.printError(EK_SHUNT_NOTADJ, unaryOp.toString(), tk.toString());
+					return false;
+				}
+
+				final Token newTok = new Token(TAGOPR);
+
+				if (tk.type == TAGOP) {
+					newTok.tokenValues = tk.tokenValues;
+				} else {
+					newTok.tokenValues = new FunctionalList<>(tk);
+				}
+
+				newTok.tokenValues.add(unaryOp);
+				opStack.push(newTok);
+
+				return true;
+			}
+		}
+
+		if (isUnary(tk)) {
+			unaryStack.add(tk);
+			return true;
+		} else if (isOp(tk)) {
+			/* Drain higher precedence operators. */
+			while (!opStack.isEmpty() && isHigherPrec(tk, opStack.peek())) {
+				final Token newOp = opStack.pop();
+
+				if (tk.type == newOp.type && notAssoc.contains(tk.type)) {
+					Errors.inst.printError(EK_SHUNT_NOTASSOC, tk.type.toString());
+				}
+
+				currReturned.addLast(newOp);
+			}
+
+			opStack.push(tk);
+		} else if (tk.type == OPAREN || tk.type == OBRACE) {
+			opStack.push(tk);
+
+			if (tk.type == OBRACE) {
+				currReturned.addLast(tk);
+			}
+		} else if (tk.type == CPAREN || tk.type == CBRACE) {
+			/* Handle closing delimiter. */
+			Token matching = null;
+
+			switch (tk.type) {
+			case CPAREN:
+				matching = new Token(OPAREN, tk.intValue);
+				break;
+			case CBRACE:
+				matching = new Token(OBRACE, tk.intValue);
+				break;
+			default:
+				Errors.inst.printError(EK_SHUNT_NOGROUP);
+				return false;
+			}
+
+			if (!opStack.contains(matching)) {
+				Errors.inst.printError(EK_SHUNT_NOGROUP, tk.toString(), matching.toString());
+				return false;
+			}
+
+			while (!opStack.peek().equals(matching)) {
+				currReturned.addLast(opStack.pop());
+			}
+
+			if (tk.type == CBRACE) {
+				currReturned.addLast(tk);
+			}
+
+			opStack.pop();
+		} else if (tk.type == GROUPSEP) {
+			/* Add a grouped token. */
+			final IList<Token> group = new FunctionalList<>();
+
+			while (currReturned.size() != 0 && !currReturned.peek().isGrouper()) {
+				group.add(currReturned.pop());
+			}
+
+			while (opStack.size() != 0 && !opStack.peek().isGrouper()) {
+				group.add(opStack.pop());
+			}
+
+			if (currReturned.size() == 0) {
+				Errors.inst.printError(EK_SHUNT_INVSEP);
+				return false;
+			}
+
+			currReturned.addLast(new Token(TOKGROUP, group));
+		} else {
+			currReturned.addLast(tk);
+		}
+
+		return true;
+	}
+
+	/* Check if an operator has higher precedence. */
+	private boolean isHigherPrec(final Token lft, final Token rght) {
+		final Token.Type left  = lft.type;
+		final Token.Type right = rght.type;
+
+		boolean exists = ops.containsKey(right);
+
+		if (rght.type == TAGOPR) {
+			exists = true;
+		}
+
+		/* If it doesn't, the left is higher precedence. */
+		if (!exists) {
+			return false;
+		}
+
+		int rightPrecedence;
+		int leftPrecedence;
+
+		if (rght.type == TAGOPR) {
+			rightPrecedence = (int) rght.intValue;
+		} else {
+			rightPrecedence = ops.get(right);
+		}
+
+		if (lft.type == TAGOPR) {
+			leftPrecedence = (int) lft.intValue;
+		} else {
+			leftPrecedence = ops.get(left);
+		}
+
+		if (rightAssoc.contains(left)) {
+			return rightPrecedence > leftPrecedence;
+		}
+
+		return rightPrecedence >= leftPrecedence;
+	}
+
+	/* Check if something is an operator. */
+	private boolean isOp(final Token tk) {
+		final Token.Type ty = tk.type;
+
+		if (ops.containsKey(ty)) {
+			return true;
+		}
+
+		if (unaryAdjectives.contains(ty)) {
+			return true;
+		}
+
+		if (unaryAdverbs.contains(ty)) {
+			return true;
+		}
+
+		if (unaryGerunds.contains(ty)) {
+			return true;
+		}
+
+		if (ty == TAGOPR) {
+			return true;
+		}
+
+		return false;
+	}
+
+	/* Check if something is a unary operator. */
+	private boolean isUnary(final Token tk) {
+		final Token.Type ty = tk.type;
+
+		if (unaryAdjectives.contains(ty)) {
+			return true;
+		}
+
+		if (unaryAdverbs.contains(ty)) {
+			return true;
+		}
+
+		if (unaryGerunds.contains(ty)) {
+			return true;
+		}
+
+		return false;
+	}
+}