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package bjc.dicelang.v2;
import bjc.utils.funcdata.FunctionalList;
import bjc.utils.funcdata.FunctionalMap;
import bjc.utils.funcdata.IList;
import bjc.utils.funcdata.IMap;
import java.util.Deque;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Set;
import static bjc.dicelang.v2.Errors.ErrorKey.*;
import static bjc.dicelang.v2.Token.Type.*;
public class Shunter {
// The binary operators and their
// priorities
private IMap<Token.Type, Integer> ops;
// Unary operators that can only be
// applied to non-operator tokens and yield operator tokens
private Set<Token.Type> unaryAdjectives;
// Unary operators that can only be
// applied to operator tokens and yield operator tokens
private Set<Token.Type> unaryAdverbs;
// Unary operators that can only be
// applied to operator tokens and yield data tokens
private Set<Token.Type> unaryGerunds;
private final int MATH_PREC = 20;
private final int DICE_PREC = 10;
private final int EXPR_PREC = 0;
public Shunter() {
ops = new FunctionalMap<>();
unaryAdjectives = new HashSet<>();
unaryAdverbs = new HashSet<>();
unaryGerunds = new HashSet<>();
unaryAdjectives.add(COERCE);
ops.put(ADD, 0 + MATH_PREC);
ops.put(SUBTRACT, 0 + MATH_PREC);
ops.put(MULTIPLY, 1 + MATH_PREC);
ops.put(IDIVIDE, 1 + MATH_PREC);
ops.put(DIVIDE, 1 + MATH_PREC);
ops.put(DICEGROUP, 0 + DICE_PREC);
ops.put(DICECONCAT, 1 + DICE_PREC);
ops.put(DICELIST, 2 + DICE_PREC);
ops.put(LET, 0 + EXPR_PREC);
ops.put(BIND, 1 + EXPR_PREC);
}
private boolean isUnary(Token ty) {
switch(ty.type) {
default:
return false;
}
}
private boolean isOp(Token tk) {
Token.Type ty = tk.type;
if(ops.containsKey(ty)) return true;
if(unaryAdjectives.contains(ty)) return true;
if(unaryAdverbs.contains(ty)) return true;
if(unaryGerunds.contains(ty)) return true;
if(ty == TAGOPR) return true;
return false;
}
public boolean shuntTokens(IList<Token> tks, IList<Token> returned) {
Deque<Token> opStack = new LinkedList<>();
boolean unaryMode = false;
Deque<Token> unaryOps = new LinkedList<>();
Deque<Token> currReturned = new LinkedList<>();
for(Token tk : tks.toIterable()) {
Token.Type tkType = tk.type;
if(unaryMode) {
if(isUnary(tk)) {
unaryOps.add(tk);
continue;
}
Token unaryOp = unaryOps.pop();
Token.Type unaryType = unaryOp.type;
if(unaryAdjectives.contains(unaryType)) {
if(isOp(tk)) {
Errors.inst.printError(EK_SHUNT_NOTADV, unaryOp.toString(), tk.toString());
return false;
}
Token newTok = new Token(TAGOPR);
if(tk.type == TAGOP) {
newTok.tokenValues = tk.tokenValues;
} else {
newTok.tokenValues = new FunctionalList<>();
}
newTok.tokenValues.add(unaryOp);
opStack.push(newTok);
} else if(unaryAdverbs.contains(unaryType)) {
// @TODO finish implementing unary operators
// this will require adding a 'backfeed' to the shunter to catch
// tokens we missed while parsing unary operators
}
}
if(isUnary(tk)) {
unaryMode = true;
unaryOps.add(tk);
continue;
} else if(isOp(tk)) {
while(!opStack.isEmpty() && isHigherPrec(tk, opStack.peek())) {
currReturned.addLast(opStack.pop());
}
opStack.push(tk);
} else if(tk.type == OPAREN || tk.type == OBRACE) {
opStack.push(tk);
if(tk.type == OBRACE) currReturned.addLast(tk);
} else if(tk.type == CPAREN || tk.type == CBRACE) {
Token matching = null;
switch(tk.type) {
case CPAREN:
matching = new Token(OPAREN, tk.intValue);
break;
case CBRACE:
matching = new Token(OBRACE, tk.intValue);
break;
default:
break;
}
if(!opStack.contains(matching)) {
Errors.inst.printError(EK_SHUNT_NOGROUP, tk.toString(), matching.toString());
return false;
}
while(!opStack.peek().equals(matching)) {
currReturned.addLast(opStack.pop());
}
if(tk.type == CBRACE) {
currReturned.addLast(tk);
}
opStack.pop();
} else if(tk.type == GROUPSEP) {
IList<Token> group = new FunctionalList<>();
while(currReturned.size() != 0 && !currReturned.peek().isGrouper()) {
group.add(currReturned.pop());
}
while(opStack.size() != 0 && !opStack.peek().isGrouper()) {
group.add(opStack.pop());
}
if(currReturned.size() == 0) {
Errors.inst.printError(EK_SHUNT_INVSEP);
return false;
}
currReturned.addLast(new Token(TOKGROUP, group));
} else {
currReturned.addLast(tk);
}
}
// Flush leftover operators
while(!opStack.isEmpty()) {
currReturned.addLast(opStack.pop());
}
for(Token tk : currReturned) {
returned.add(tk);
}
return true;
}
private boolean isHigherPrec(Token lft, Token rght) {
Token.Type left = lft.type;
Token.Type right = rght.type;
boolean exists = ops.containsKey(right);
// If it doesn't, the left is higher precedence.
if (!exists) {
return false;
}
int rightPrecedence = ops.get(right);
int leftPrecedence = ops.get(left);
return rightPrecedence >= leftPrecedence;
}
}
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