New expression repr.

1 files changed, 145 insertions, 0 deletions

diff --git a/dice-lang/src/bjc/dicelang/expr/Ezpr.java b/dice-lang/src/bjc/dicelang/expr/Ezpr.java
new file mode 100644
index 0000000..bc1d5d4
--- /dev/null
+++ b/dice-lang/src/bjc/dicelang/expr/Ezpr.java
@@ -0,0 +1,145 @@
+package bjc.dicelang.expr;
+
+import bjc.utils.data.ITree;
+
+import com.google.guava.collect.HashMultiset;
+import com.google.guava.collect.Multiset;
+
+import static bjc.dicelang.expr.EzprType;
+import static bjc.dicelang.expr.EzprType.SUM;
+import static bjc.dicelang.expr.EzprType.MUL;
+
+import static bjc.dicelang.expr.EzprNode;
+import static bjc.dicelnag.ezpr.EzprNode.EzprNodeType;
+import static bjc.dicelnag.ezpr.EzprNode.EzprNodeType.EZPR;
+import static bjc.dicelnag.ezpr.EzprNode.EzprNodeType.TOKEN;
+
+public class Ezpr {
+	public static enum EzprType {
+		SUM, MUL
+	}
+
+	public static class EzprNode {
+		public static enum EzprNodeType {
+			EZPR, TOKEN
+		}
+
+		public final EzprNodeType typ;
+
+		public final Ezpr ezp;
+		public final Token tok;
+
+		public EzprNode(Ezpr exp) {
+			typ = EZPR:
+
+			ezp = exp;
+			tok = null;
+		}
+
+		public EzprNode(Token tk) {
+			typ = TOKEN;
+
+			tok = tk;
+			ezp = null;
+		}
+
+		public String toString() {
+			if(typ == TOKEN) {
+				return tok.toString();
+			}
+			return ezp.toString();
+		}
+	}
+
+	private EzprType typ;
+
+	private Multiset<EzprNode> positive;
+	private Multiset<EzprNode> negative;
+
+	public Ezpr(EzprType type, Multiset<EzprNode> pos, Multiset<EzprNode> neg) {
+		typ = type;
+		
+		positive = pos;
+		negative = neg;
+	}
+
+	public Ezpr flatten() {
+		HashMultiset<EzprNode> newPositive = HashMultiset<>.create();
+		HashMultiset<EzprNode> newNegative = HashMultiset<>.create();
+
+		for(EzprNode nd : positive) {
+			/* Flatten enclosed ezprs of the same type. */
+			if(nd.typ == EZPR && (nd.ezp.typ == typ)) {
+				/* Recursively flatten kids. */
+				Ezpr kid = nd.ezp.flatten();
+
+				if(typ == SUM) {
+					/* Add sum parts to corresponding bags. */
+					for(EzprNode knd : kid.positive) {
+						newPositive.add(knd);
+					}
+					for(EzprNode knd : kid.negative) {
+						newNegative.add(knd);
+					}
+				} else {
+					/* @TODO ensure that this is correct. */
+					for(EzprNode knd : kid.positive) {
+						newPositive.add(knd);
+					}
+					for(EzprNode knd : kid.negative) {
+						newNegative.add(knd);
+					}
+				}
+			} else {
+				newPositive.add(nd);
+			}
+		}
+
+		for(EzprNode nd : negative) {
+			/* Flatten enclosed ezprs of the same type. */
+			if(nd.typ == EZPR && (nd.ezp.typ == typ)) {
+				/* Recursively flatten kids. */
+				Ezpr kid = nd.ezp.flatten();
+
+				/* @TODO ensure that this is correct. */
+				if(typ == SUM) {
+					for(EzprNode knd : kid.positive) {
+						newNegative.add(knd);
+					}
+					for(EzprNode knd : kid.negative) {
+						newPositive.add(knd);
+					}
+				} else {
+					for(EzprNode knd : kid.positive) {
+						newNegative.add(knd);
+					}
+					for(EzprNode knd : kid.negative) {
+						newPositive.add(knd);
+					}
+				}
+			} else {
+				newNegative.add(nd);
+			}
+		}
+	}
+
+	public String toString() {
+		StringBuilder sb = new StringBuilder(typ.toString());
+
+		sb.append(" [ ");
+		for(EzprNode nd : positive) {
+			sb.append(nd.toString());
+			sb.append(" ");
+		}
+
+		sb.append("# ");
+		for(EzprNode nd : negative) {
+			sb.append(nd.toString());
+			sb.append(" ");
+		}
+
+		sb.append("]");
+
+		return sb.toString();
+	}
+}