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package bjc.utils.examples.parsing;
import java.util.Deque;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.function.Function;
import java.util.function.Predicate;
import bjc.utils.data.IPair;
import bjc.utils.data.Pair;
import bjc.utils.funcdata.FunctionalMap;
import bjc.utils.funcdata.FunctionalStringTokenizer;
import bjc.utils.funcdata.IList;
import bjc.utils.funcdata.IMap;
import bjc.utils.funcdata.ITree;
import bjc.utils.funcdata.Tree;
import bjc.utils.funcutils.ListUtils;
import bjc.utils.funcutils.StringUtils;
import bjc.utils.parserutils.ShuntingYard;
import bjc.utils.parserutils.TreeConstructor;
/**
* Test of tree constructor
*
* @author ben
*
*/
public class TreeConstructTest {
private static final class OperatorPicker
implements Predicate<String> {
@Override
public boolean test(String token) {
if (StringUtils.containsOnly(token, "\\[")) {
return true;
} else if (StringUtils.containsOnly(token, "\\]")) {
return true;
}
switch (token) {
case "+":
case "-":
case "*":
case "/":
return true;
default:
return false;
}
}
}
/**
* Main method
*
* @param args
* Unused CLI args
*/
@SuppressWarnings("resource")
public static void main(String[] args) {
Scanner inputSource = new Scanner(System.in);
System.out.print("Enter a expression to parse: ");
String line = inputSource.nextLine();
IList<String> tokens = new FunctionalStringTokenizer(
line).toList();
ShuntingYard<String> yard = new ShuntingYard<>(true);
Deque<IPair<String, String>> ops = new LinkedList<>();
ops.add(new Pair<>("+", "\\+"));
ops.add(new Pair<>("-", "-"));
ops.add(new Pair<>("*", "\\*"));
ops.add(new Pair<>("/", "/"));
ops.add(new Pair<>(":=", ":="));
ops.add(new Pair<>("=>", "=>"));
IList<String> semiExpandedTokens = ListUtils
.splitTokens(tokens, ops);
ops = new LinkedList<>();
ops.add(new Pair<>("(", "\\("));
ops.add(new Pair<>(")", "\\)"));
ops.add(new Pair<>("[", "\\["));
ops.add(new Pair<>("]", "\\]"));
IList<String> fullyExpandedTokens = ListUtils
.deAffixTokens(semiExpandedTokens, ops);
fullyExpandedTokens.removeIf((strang) -> strang.equals(""));
IList<String> shuntedTokens = yard
.postfix(fullyExpandedTokens, (token) -> token);
System.out.println("Shunted: " + shuntedTokens.toString());
Predicate<String> specialPicker = (operator) -> {
if (StringUtils.containsOnly(operator, "\\[")) {
return true;
} else if (StringUtils.containsOnly(operator, "\\]")) {
return true;
}
return false;
};
IMap<String, Function<Deque<ITree<String>>, ITree<String>>> operators = new FunctionalMap<>();
operators.put("[", (queuedTrees) -> {
return null;
});
operators.put("[", (queuedTrees) -> {
Tree<String> openTree = new Tree<>("[");
queuedTrees.push(openTree);
return openTree;
});
operators.put("]", (queuedTrees) -> {
ITree<String> arrayTree = new Tree<>("[]");
while (!queuedTrees.peek().getHead().equals("[")) {
arrayTree.addChild(queuedTrees.pop());
}
queuedTrees.push(arrayTree);
return arrayTree;
});
ITree<String> constructedTree = TreeConstructor.constructTree(
shuntedTokens, new OperatorPicker(), specialPicker,
operators::get);
System.out.println("AST: " + constructedTree.toString());
inputSource.close();
}
}
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