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package bjc.dicelang.ast;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.lang3.StringUtils;
import bjc.dicelang.ComplexDice;
import bjc.dicelang.CompoundDice;
import bjc.dicelang.IDiceExpression;
import bjc.utils.data.Pair;
import bjc.utils.parserutils.AST;
/**
* An implementation of {@link IDiceExpression} backed by an AST of
* {@link IDiceASTNode}s
*
* @author ben
*
*/
public class DiceASTExpression implements IDiceExpression {
/**
* Build the map of operations to use when collapsing the AST
*
* @param enviroment
* The enviroment to evaluate bindings and such against
* @return The operations to use when collapsing the AST
*/
private static Map<IDiceASTNode, IOperatorCollapser>
buildOperations(Map<String, DiceASTExpression> enviroment) {
Map<IDiceASTNode, IOperatorCollapser> operatorCollapsers =
new HashMap<>();
operatorCollapsers.put(OperatorDiceNode.ADD,
(leftNode, rightNode) -> {
return leftNode.merge((leftValue, leftAST) -> {
return rightNode.merge((rightValue, rightAST) -> {
return new Pair<>(leftValue + rightValue,
new AST<>(OperatorDiceNode.ADD,
leftAST, rightAST));
});
});
});
operatorCollapsers.put(OperatorDiceNode.SUBTRACT,
(left, right) -> {
return left.merge(
(lval, last) -> right.merge((rval, rast) -> {
return new Pair<>(lval - rval,
new AST<>(
OperatorDiceNode.SUBTRACT,
last, rast));
}));
});
operatorCollapsers.put(OperatorDiceNode.MULTIPLY,
(left, right) -> {
return left.merge(
(lval, last) -> right.merge((rval, rast) -> {
return new Pair<>(lval * rval,
new AST<>(
OperatorDiceNode.MULTIPLY,
last, rast));
}));
});
operatorCollapsers.put(OperatorDiceNode.DIVIDE, (left, right) -> {
return left.merge((lval, last) -> right.merge((rval, rast) -> {
return new Pair<>(lval / rval,
new AST<>(OperatorDiceNode.DIVIDE, last, rast));
}));
});
operatorCollapsers.put(OperatorDiceNode.ASSIGN, (left, right) -> {
return left.merge((lval, last) -> right.merge((rval, rast) -> {
String nam = last.collapse((nod) -> {
return ((VariableDiceNode) nod).getVariable();
}, (v) -> (lv, rv) -> null, (r) -> r);
enviroment.put(nam,
new DiceASTExpression(rast, enviroment));
return new Pair<>(rval,
new AST<>(OperatorDiceNode.ASSIGN, last, rast));
}));
});
operatorCollapsers.put(OperatorDiceNode.COMPOUND,
(left, right) -> {
return left.merge(
(lval, last) -> right.merge((rval, rast) -> {
int ival = Integer
.parseInt(Integer.toString(lval)
+ Integer.toString(rval));
return new Pair<>(ival,
new AST<>(
OperatorDiceNode.COMPOUND,
last, rast));
}));
});
operatorCollapsers.put(OperatorDiceNode.GROUP, (left, right) -> {
return left.merge((lval, last) -> right.merge((rval, rast) -> {
return new Pair<>(new ComplexDice(lval, rval).roll(),
new AST<>(OperatorDiceNode.GROUP, last, rast));
}));
});
return operatorCollapsers;
}
/**
* The AST this expression will evaluate
*/
private AST<IDiceASTNode> ast;
/**
* The enviroment to evaluate bindings and such against
*/
private Map<String, DiceASTExpression> env;
/**
* Create a new dice expression backed by an AST
*
* @param ast
* The AST backing this expression
* @param env
* The enviroment to evaluate bindings against
*/
public DiceASTExpression(AST<IDiceASTNode> ast,
Map<String, DiceASTExpression> env) {
this.ast = ast;
this.env = env;
}
/**
* Expand a leaf AST token into a pair for evaluation
*
* @param tokn
* The token to evaluate
* @return A pair consisting of the token's value and the AST it
* represents
*/
private Pair<Integer, AST<IDiceASTNode>> evalLeaf(IDiceASTNode tokn) {
if (tokn instanceof VariableDiceNode) {
String varName = ((VariableDiceNode) tokn).getVariable();
if (env.containsKey(varName)) {
return new Pair<>(env.get(varName).roll(),
new AST<>(tokn));
} else {
// Handle special case for defining variables
return new Pair<>(0, new AST<>(tokn));
}
} else {
LiteralDiceNode lnod = (LiteralDiceNode) tokn;
String dat = lnod.getData();
if (StringUtils.countMatches(dat, 'c') == 1
&& !dat.equalsIgnoreCase("c")) {
String[] strangs = dat.split("c");
return new Pair<>(new CompoundDice(strangs).roll(),
new AST<>(tokn));
} else if (StringUtils.countMatches(dat, 'd') == 1
&& !dat.equalsIgnoreCase("d")) {
/*
* Handle dice groups
*/
return new Pair<>(ComplexDice.fromString(dat).roll(),
new AST<>(tokn));
} else {
return new Pair<>(Integer.parseInt(dat), new AST<>(tokn));
}
}
}
/**
* Get the AST bound to this expression
*
* @return the ast
*/
public AST<IDiceASTNode> getAst() {
return ast;
}
/*
* (non-Javadoc)
*
* @see bjc.utils.dice.IDiceExpression#roll()
*/
@Override
public int roll() {
Map<IDiceASTNode, IOperatorCollapser> operations =
buildOperations(env);
return ast.collapse(this::evalLeaf, operations::get,
(r) -> r.merge((left, right) -> left));
}
/*
* (non-Javadoc)
*
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return ast.toString();
}
}
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