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package bjc.dicelang;
import static bjc.dicelang.Errors.ErrorKey.EK_PARSE_BINARY;
import static bjc.dicelang.Errors.ErrorKey.EK_PARSE_INVTOKEN;
import static bjc.dicelang.Errors.ErrorKey.EK_PARSE_NOCLOSE;
import static bjc.dicelang.Errors.ErrorKey.EK_PARSE_UNCLOSE;
import static bjc.dicelang.Errors.ErrorKey.EK_PARSE_UNOPERAND;
import static bjc.dicelang.Node.Type.BINOP;
import static bjc.dicelang.Node.Type.GROUP;
import static bjc.dicelang.Node.Type.OGROUP;
import static bjc.dicelang.Node.Type.TOKREF;
import static bjc.dicelang.Node.Type.UNARYOP;
import static bjc.dicelang.tokens.Token.Type.CBRACE;
import static bjc.dicelang.tokens.Token.Type.CBRACKET;
import java.util.Deque;
import java.util.LinkedList;
import bjc.dicelang.tokens.Token;
import bjc.data.Tree;
import bjc.data.SimpleTree;
import bjc.funcdata.ListEx;
/**
* Parse a series of tree into tokens.
*
* @author EVE
*
*/
public class Parser {
/** Create a new parser. */
public Parser() {
}
/**
* Parse a series of tokens to a forest of ASTs.
*
* @param tokens
* The list of tokens to parse.
*
* @param results
* The place to set results.
*
* @return Whether or not the parse was successful.
*/
public static boolean parseTokens(final ListEx<Token> tokens, final ListEx<Tree<Node>> results) {
final Deque<Tree<Node>> working = new LinkedList<>();
for(final Token tk : tokens) {
switch(tk.type) {
case OBRACKET:
case OBRACE:
/* Parse opening delims. */
working.push(new SimpleTree<>(new Node(OGROUP, tk)));
break;
case CBRACKET:
case CBRACE:
/* Parse closing delims. */
final boolean sc = parseClosingGrouper(working, tk);
if(!sc) {
return false;
}
break;
case MULTIPLY:
case DIVIDE:
case IDIVIDE:
case DICEGROUP:
case DICECONCAT:
case DICELIST:
case STRCAT:
case STRREP:
case LET:
case BIND:
/* Parse binary operator. */
if(working.size() < 2) {
Errors.inst.printError(EK_PARSE_BINARY);
return false;
}
handleBinaryNode(working, tk);
break;
case ADD:
case SUBTRACT:
/* Handle binary/unary operators. */
if(working.size() == 0) {
Errors.inst.printError(EK_PARSE_UNOPERAND, tk.toString());
return false;
} else if(working.size() == 1) {
final Tree<Node> operand = working.pop();
final Tree<Node> opNode = new SimpleTree<>(new Node(UNARYOP, tk.type));
opNode.addChild(operand);
working.push(opNode);
} else {
handleBinaryNode(working, tk);
}
break;
case COERCE:
case DICESCALAR:
case DICEFUDGE:
/* Handle unary operators. */
if(working.size() == 0) {
Errors.inst.printError(EK_PARSE_UNOPERAND, tk.toString());
} else {
final Tree<Node> operand = working.pop();
final Tree<Node> opNode = new SimpleTree<>(new Node(UNARYOP, tk.type));
opNode.addChild(operand);
working.push(opNode);
}
break;
case INT_LIT:
case DEC_LIT:
case FLOAT_LIT:
case STRING_LIT:
case VREF:
case DICE_LIT:
/* Handle literals. */
working.push(new SimpleTree<>(new Node(TOKREF, tk)));
break;
default:
Errors.inst.printError(EK_PARSE_INVTOKEN, tk.type.toString());
return false;
}
}
/*
* Collect the remaining nodes as the roots of the trees in the
* AST forest.
*/
for(final Tree<Node> ast : working) {
/* Make sure that the tree are well-formed */
if(ast.containsMatching((val) -> {
switch(val.type) {
case OGROUP:
return true;
default:
return false;
}
})) {
System.out.printf("\tERROR: Malformed tree:\n%s\n", ast);
return false;
} else {
results.add(ast);
}
}
return true;
}
/* Handle a binary operator. */
private static void handleBinaryNode(final Deque<Tree<Node>> working, final Token tk) {
final Tree<Node> right = working.pop();
final Tree<Node> left = working.pop();
final Tree<Node> opNode = new SimpleTree<>(new Node(BINOP, tk.type));
opNode.addChild(left);
opNode.addChild(right);
working.push(opNode);
}
/* Parse a closing delimiter. */
private static boolean parseClosingGrouper(final Deque<Tree<Node>> working, final Token tk) {
if(working.size() == 0) {
Errors.inst.printError(EK_PARSE_NOCLOSE);
return false;
}
Tree<Node> groupNode = null;
switch(tk.type) {
case CBRACE:
groupNode = new SimpleTree<>(new Node(GROUP, Node.GroupType.CODE));
break;
case CBRACKET:
groupNode = new SimpleTree<>(new Node(GROUP, Node.GroupType.ARRAY));
break;
default:
Errors.inst.printError(EK_PARSE_UNCLOSE, tk.type.toString());
return false;
}
Token matching = null;
if(tk.type == CBRACKET) {
matching = new Token(Token.Type.OBRACKET, tk.intValue);
} else if(tk.type == CBRACE) {
matching = new Token(Token.Type.OBRACE, tk.intValue);
}
final Tree<Node> matchNode = new SimpleTree<>(new Node(OGROUP, matching));
if(!working.contains(matchNode)) {
Errors.inst.printError(EK_PARSE_UNCLOSE, tk.toString(), matchNode.toString());
System.out.println("\tCurrent forest is: ");
int treeNo = 1;
for(final Tree<Node> ast : working) {
System.out.println("Tree " + treeNo++ + ": " + ast.toString());
}
return false;
}
final Deque<Tree<Node>> childs = new LinkedList<>();
while(!working.peek().equals(matchNode)) {
childs.push(working.pop());
}
/* Discard opener */
working.pop();
for(final Tree<Node> child : childs) {
groupNode.addChild(child);
}
working.push(groupNode);
return true;
}
}
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