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package bjc.utils.dice.ast;
import java.util.HashMap;
import java.util.Map;
import java.util.function.BinaryOperator;
import org.apache.commons.lang3.StringUtils;
import bjc.utils.dice.BindingDiceExpression;
import bjc.utils.dice.ComplexDice;
import bjc.utils.dice.CompoundDice;
import bjc.utils.dice.CompoundDiceExpression;
import bjc.utils.dice.DiceExpressionType;
import bjc.utils.dice.IDiceExpression;
import bjc.utils.dice.ReferenceDiceExpression;
import bjc.utils.dice.ScalarDie;
import bjc.utils.parserutils.AST;
/**
* Flatten an {@link AST} of {@link IDiceASTNode} into a
* {@link IDiceExpression}
*
* @author ben
*
*/
public class DiceASTFlattener {
/**
* Build the operations to use for tree flattening
*
* @param env
* The enviroment the tree will be flattened against
* @return The operations needed for tree flattening
*/
private static Map<IDiceASTNode, BinaryOperator<IDiceExpression>>
buildOperations(Map<String, IDiceExpression> env) {
Map<IDiceASTNode, BinaryOperator<IDiceExpression>> opCollapsers =
new HashMap<>();
opCollapsers.put(OperatorDiceNode.ADD, (left, right) -> {
return new CompoundDiceExpression(right, left,
DiceExpressionType.ADD);
});
opCollapsers.put(OperatorDiceNode.SUBTRACT, (left, right) -> {
return new CompoundDiceExpression(right, left,
DiceExpressionType.SUBTRACT);
});
opCollapsers.put(OperatorDiceNode.MULTIPLY, (left, right) -> {
return new CompoundDiceExpression(right, left,
DiceExpressionType.MULTIPLY);
});
opCollapsers.put(OperatorDiceNode.DIVIDE, (left, right) -> {
return new CompoundDiceExpression(right, left,
DiceExpressionType.DIVIDE);
});
opCollapsers.put(OperatorDiceNode.ASSIGN, (left, right) -> {
return new BindingDiceExpression(left, right, env);
});
opCollapsers.put(OperatorDiceNode.COMPOUND, (left, right) -> {
return new CompoundDice(left, right);
});
opCollapsers.put(OperatorDiceNode.GROUP, (left, right) -> {
return new ComplexDice(left, right);
});
return opCollapsers;
}
/**
* Create a dice expression from a literal token
*
* @param tok
* The token to convert to an expression
* @return The dice expression represented by the token
*/
private static IDiceExpression expFromLiteral(LiteralDiceNode tok) {
String data = tok.getData();
if (StringUtils.countMatches(data, 'c') == 1
&& !data.equalsIgnoreCase("c")) {
String[] strangs = data.split("c");
return new CompoundDice(ComplexDice.fromString(strangs[0]),
ComplexDice.fromString(strangs[1]));
} else if (StringUtils.countMatches(data, 'd') == 1
&& !data.equalsIgnoreCase("d")) {
return ComplexDice.fromString(data);
} else {
return new ScalarDie(Integer.parseInt(data));
}
}
/**
* Flatten a AST into a dice expression
*
* @param ast
* The AST to flatten
* @param env
* The enviroment to flatten against
* @return The AST, flattened into a dice expression
*/
public static IDiceExpression flatten(AST<IDiceASTNode> ast,
Map<String, IDiceExpression> env) {
Map<IDiceASTNode, BinaryOperator<IDiceExpression>> opCollapsers =
buildOperations(env);
return ast.collapse((nod) -> {
if (nod instanceof LiteralDiceNode) {
return expFromLiteral((LiteralDiceNode) nod);
} else {
return new ReferenceDiceExpression(
((VariableDiceNode) nod).getVariable(), env);
}
} , opCollapsers::get, (r) -> r);
}
}
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