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package bjc.dicelang.v1.examples;
import java.util.Deque;
import java.util.LinkedList;
import bjc.utils.data.IPair;
import bjc.utils.data.Pair;
import bjc.utils.funcdata.FunctionalStringTokenizer;
import bjc.utils.funcdata.IList;
import bjc.utils.funcutils.ListUtils;
import bjc.utils.parserutils.ShuntingYard;
/**
* Prepare a dice expression to be parsed
*
* @author ben
*
*/
public class DiceExpressionPreparer {
/**
* The yard to use for shunting expressions
*/
private static ShuntingYard<String> yard;
private static final int MATH_PREC = 20;
private static final int DICE_PREC = 10;
private static final int EXPR_PREC = 0;
// Do initialization for all parsers
static {
// The shunter we're going to use
yard = new ShuntingYard<>(false);
// Configure the shunters operators
// Basic mathematical operators
yard.addOp("+", 0 + MATH_PREC);
yard.addOp("-", 0 + MATH_PREC);
yard.addOp("*", 1 + MATH_PREC);
yard.addOp("/", 1 + MATH_PREC);
yard.addOp("d", 0 + DICE_PREC); // dice operator: use for
// creating
// variable size dice groups
yard.addOp("c", 1 + DICE_PREC); // compound operator: use for
// creating compound dice from expressions
yard.addOp("=>", 0 + EXPR_PREC); // let operator: evaluate an
// expression in the context of another
yard.addOp(":=", 1 + EXPR_PREC); // binding operator: Bind a
// name
// to a variable expression
}
/**
* Prepare a command, turning raw tokens into input for the tree builder
*
* @param currentLine
* The command to prepare
* @return A stream of tokens representing the command
*/
public static IList<String> prepareCommand(String currentLine) {
// Split the command into tokens
IList<String> tokens = FunctionalStringTokenizer.fromString(currentLine).toList();
// The linked list to use for handling tokens
Deque<IPair<String, String>> ops = new LinkedList<>();
// Prepare the list for operator expansion
ops.add(new Pair<>("+", "\\+"));
ops.add(new Pair<>("-", "-"));
ops.add(new Pair<>("*", "\\*"));
ops.add(new Pair<>("/", "/"));
ops.add(new Pair<>(":=", ":="));
ops.add(new Pair<>("=>", "=>"));
// Expand infix single tokens to multiple infix tokens
IList<String> semiExpandedTokens = ListUtils.splitTokens(tokens, ops);
// Reinitialize the list
ops = new LinkedList<>();
// Prepare the list for deaffixation
ops.add(new Pair<>("(", "\\("));
ops.add(new Pair<>(")", "\\)"));
ops.add(new Pair<>("[", "\\["));
ops.add(new Pair<>("]", "\\]"));
// Deaffix ('s and ['s from tokens
IList<String> fullyExpandedTokens = ListUtils.deAffixTokens(semiExpandedTokens, ops);
// Remove blank tokens
fullyExpandedTokens.removeIf((strang) -> strang.equals(""));
// Shunt the tokens, and hand them back
return yard.postfix(fullyExpandedTokens, (token) -> token);
}
}
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