Moved SCL parser generator to platform repository.

[simantics/platform.git] / bundles / org.simantics.scl.compiler / src / org / simantics / scl / compiler / parser / generator / table / Item.java

diff --git a/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/parser/generator/table/Item.java b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/parser/generator/table/Item.java
new file mode 100644 (file)
index 0000000..33d9519
--- /dev/null
+++ b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/parser/generator/table/Item.java
@@ -0,0 +1,81 @@
+package org.simantics.scl.compiler.parser.generator.table;
+
+import org.simantics.scl.compiler.parser.generator.grammar.AnaGrammar;
+import org.simantics.scl.compiler.parser.generator.grammar.Prod;
+
+
+public class Item implements Comparable<Item> {
+    public final int production;
+    public final int position;
+    public int stackPos;
+    
+    public Item(int production, int position, int stackPos) {
+        this.production = production;
+        this.position = position;
+        this.stackPos = stackPos;
+    }
+
+    public int[] nextSymbols(AnaGrammar grammar) {
+        Prod prod = grammar.prods.get(production);
+        return prod.rhs.nextStates(position);
+    }
+
+    public int nextPosition(AnaGrammar grammar, int symbol) {
+        Prod prod = grammar.prods.get(production);
+        return prod.rhs.getTransition(position, symbol);
+    }
+    
+    @Override
+    public int hashCode() {
+        return (production * 31 + position) * 31 + stackPos;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null || getClass() != obj.getClass())
+            return false;
+        Item other = (Item) obj;
+        return production == other.production
+                && position == other.position
+                && stackPos == other.stackPos;
+    }
+
+    @Override
+    public int compareTo(Item o) {
+        if(production < o.production)
+            return -1;
+        if(production > o.production)
+            return 1;
+        if(position < o.position)
+            return -1;
+        if(position > o.position)
+            return 1;
+        return 0;        
+    }
+    
+    public String toString(AnaGrammar grammar) {
+        Prod prod = grammar.prods.get(production);
+        StringBuilder b = new StringBuilder();
+        b.append(grammar.nonterminalNames[prod.lhs]);
+        b.append(" ::= ");
+        /*prod.rhs.toRegexpTo(position).toString(b, grammar, 0);
+        b.append(" . ");
+        prod.rhs.toRegexpFrom(position).toString(b, grammar, 0);*/
+        prod.rhs.toPositionalRegexp(position).toString(b, grammar, 0);
+        if(stackPos >= 0)
+            b.append(" (stack ").append(stackPos).append(')');
+        /*for(int i=0;i<position;++i)
+            b.append(' ').append(grammar.getName(prod.rhs[i]));
+        b.append(" *");
+        for(int i=position;i<prod.rhs.length;++i)
+            b.append(' ').append(grammar.getName(prod.rhs[i]));*/
+        return b.toString();
+    }
+
+    public boolean isReducible(AnaGrammar grammar) {
+        return grammar.prods.get(production).rhs.getAccepts(position);
+    }
+
+}