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Parser.cs
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Parser.cs
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/*=======================================================================
Wyvern compiler: Version 0.4
Copyright (C) 2019 Carlos Rivero A01371368, ITESM CEM
========================================================================*/
using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
namespace Wyvern {
class Parser{
static readonly ISet<TokenCategory> firstOfExprPrimary = new HashSet<TokenCategory>(){
TokenCategory.IDENTIFIER,
TokenCategory.SQUARE_OPEN,
TokenCategory.STRING_LITERAL,
TokenCategory.CHAR_LITERAL,
TokenCategory.INT_LITERAL,
TokenCategory.PARENTHESIS_OPEN
};
static readonly ISet<TokenCategory> firstOfStmt = new HashSet<TokenCategory>(){
TokenCategory.IDENTIFIER,
TokenCategory.IF,
TokenCategory.WHILE,
TokenCategory.BREAK,
TokenCategory.RETURN,
TokenCategory.SEMICOLON
};
static readonly ISet<TokenCategory> firstOfExprMul = new HashSet<TokenCategory>(){
TokenCategory.MUL,
TokenCategory.MOD,
TokenCategory.DIV
};
static readonly ISet<TokenCategory> firstOfExprUnary = new HashSet<TokenCategory>(){
TokenCategory.PLUS,
TokenCategory.NEG,
TokenCategory.NOT
};
static readonly ISet<TokenCategory> firstOfExprRel = new HashSet<TokenCategory>(){
TokenCategory.LESS,
TokenCategory.LESS_EQUAL,
TokenCategory.GREATER,
TokenCategory.GREATER_EQUAL
};
IEnumerator<Token> tokenStream;
public Parser(IEnumerator<Token> tokenStream) {
this.tokenStream = tokenStream;
this.tokenStream.MoveNext();
}
public TokenCategory CurrentToken {
get { return tokenStream.Current.Category; }
}
public Token Expect(TokenCategory category) {
if (CurrentToken == category) {
Token current = tokenStream.Current;
tokenStream.MoveNext();
return current;
}
else {
throw new SyntaxError(category, tokenStream.Current);
}
}
public Node Program(){
var node = new ProgramNode();
while(CurrentToken != TokenCategory.EOF){
if(CurrentToken == TokenCategory.VAR){
node.Add(VarDef());
}
else{
node.Add(FunDef());
}
}
Expect(TokenCategory.EOF);
return node;
}
public Node Return(){
var node = new ReturnNode() {
AnchorToken = Expect(TokenCategory.RETURN)
};
node.Add(Expr());
Expect(TokenCategory.SEMICOLON);
return node;
}
public Node FunDef(){
var node = new FunDefNode(){
AnchorToken = Expect(TokenCategory.IDENTIFIER)
};
Expect(TokenCategory.PARENTHESIS_OPEN);
node.Add(IdList());
Expect(TokenCategory.PARENTHESIS_CLOSE);
Expect(TokenCategory.LLAVE_OPEN);
node.Add(VarDefList());
node.Add(StmtList());
Expect(TokenCategory.LLAVE_CLOSE);
return node;
}
public Node VarDefList(){
var node = new VarDefListNode();
while(CurrentToken == TokenCategory.VAR){
node.Add(VarDef());
}
return node;
}
public Node VarDef(){
var node = new VarDefNode(){
AnchorToken = Expect(TokenCategory.VAR)
};
node.Add(IdList());
Expect(TokenCategory.SEMICOLON);
return node;
}
public Node IdList(){
var node = new IdListNode();
if(CurrentToken == TokenCategory.PARENTHESIS_CLOSE){
return node;
}
node.Add(new IdentifierNode(){
AnchorToken = Expect(TokenCategory.IDENTIFIER)
});
while(CurrentToken == TokenCategory.COMMA){
Expect(TokenCategory.COMMA);
node.Add(new IdentifierNode(){
AnchorToken = Expect(TokenCategory.IDENTIFIER)
});
}
return node;
}
public Node StmtList(){
var node = new StmtListNode();
if(CurrentToken == TokenCategory.LLAVE_CLOSE){
return node;
}
while (firstOfStmt.Contains(CurrentToken)){
node.Add(Stmt());
}
return node;
}
public Node While(){
var node = new WhileNode(){
AnchorToken = Expect(TokenCategory.WHILE)
};
Expect(TokenCategory.PARENTHESIS_OPEN);
node.Add(Expr());
Expect(TokenCategory.PARENTHESIS_CLOSE);
Expect(TokenCategory.LLAVE_OPEN);
if(CurrentToken != TokenCategory.LLAVE_CLOSE){
node.Add(StmtList());
}
Expect(TokenCategory.LLAVE_CLOSE);
return node;
}
public Node If(){
var node = new IfNode();
Expect(TokenCategory.IF);
Expect(TokenCategory.PARENTHESIS_OPEN);
node.Add(Expr());
Expect(TokenCategory.PARENTHESIS_CLOSE);
Expect(TokenCategory.LLAVE_OPEN);
node.Add(StmtList());
Expect(TokenCategory.LLAVE_CLOSE);
node.Add(ElseIf());
node.Add(Else());
return node;
}
public Node ElseIf(){
var node = new ElseIfListNode();
while (CurrentToken == TokenCategory.ELSEIF){
var node1 = new ElseIfNode();
Expect(TokenCategory.ELSEIF);
Expect(TokenCategory.PARENTHESIS_OPEN);
node1.Add(Expr());
Expect(TokenCategory.PARENTHESIS_CLOSE);
Expect(TokenCategory.LLAVE_OPEN);
node1.Add(StmtList());
Expect(TokenCategory.LLAVE_CLOSE);
node.Add(node1);
}
return node;
}
public Node Else(){
var node = new ElseNode();
if (CurrentToken == TokenCategory.ELSE){
Expect(TokenCategory.ELSE);
Expect(TokenCategory.LLAVE_OPEN);
if(CurrentToken != TokenCategory.LLAVE_CLOSE){
node.Add(StmtList());
}
Expect(TokenCategory.LLAVE_CLOSE);
}
return node;
}
public Node Stmt(){
switch (CurrentToken){
case TokenCategory.IDENTIFIER:
var idToken = Expect(TokenCategory.IDENTIFIER);
switch (CurrentToken){
case TokenCategory.ASSIGN:
Expect(TokenCategory.ASSIGN);
var ass = new AssignmentNode(){
AnchorToken = idToken
};
ass.Add(Expr());
Expect(TokenCategory.SEMICOLON);
return ass;
case TokenCategory.INCREMENT:
Expect(TokenCategory.INCREMENT);
var inc = new IncrementNode(){
AnchorToken = idToken
};
Expect(TokenCategory.SEMICOLON);
return inc;
case TokenCategory.DECREMENT:
Expect(TokenCategory.DECREMENT);
var dec = new DecrementNode(){
AnchorToken = idToken
};
Expect(TokenCategory.SEMICOLON);
return dec;
case TokenCategory.PARENTHESIS_OPEN:
Expect(TokenCategory.PARENTHESIS_OPEN);
var fun = new FunCallNode(){
AnchorToken = idToken
};
fun.Add(ExprList());
Expect(TokenCategory.PARENTHESIS_CLOSE);
Expect(TokenCategory.SEMICOLON);
return fun;
}
break;
case TokenCategory.IF:
return If();
case TokenCategory.WHILE:
return While();
case TokenCategory.BREAK:
var bre = new StmtNode(){
AnchorToken = Expect(TokenCategory.BREAK)
};
Expect(TokenCategory.SEMICOLON);
return bre;
case TokenCategory.RETURN:
return Return();
case TokenCategory.SEMICOLON:
return new StmtNode(){
AnchorToken = Expect(TokenCategory.SEMICOLON)
};
default:
throw new SyntaxError(firstOfStmt,tokenStream.Current);
}
throw new SyntaxError(firstOfStmt,tokenStream.Current);
}
public Node Expr(){
var node = ExprAnd();
while(CurrentToken == TokenCategory.OR){
var node1 = new ExprOrNode(){
AnchorToken = Expect(TokenCategory.OR)
};
node1.Add(node);
node1.Add(ExprAnd());
node = node1;
}
return node;
}
public Node ExprAnd(){
var node1 = ExprComp();
while(CurrentToken == TokenCategory.AND){
var node2 = new ExprAndNode(){
AnchorToken = Expect(TokenCategory.AND)
};
node2.Add(node1);
node2.Add(ExprComp());
node1 = node2;
}
return node1;
}
public Node ExprComp(){
var node1 = ExprRel();
while(CurrentToken == TokenCategory.EQUAL || CurrentToken == TokenCategory.NOTEQUAL){
var node2 = new ExprCompNode();
if(CurrentToken == TokenCategory.EQUAL){
node2.AnchorToken = Expect(TokenCategory.EQUAL);
}
else{
node2.AnchorToken = Expect(TokenCategory.NOTEQUAL);
}
node2.Add(node1);
node2.Add(ExprRel());
node1 = node2;
}
return node1;
}
public Node ExprList(){
var node = new ExprListNode();
if(CurrentToken == TokenCategory.PARENTHESIS_CLOSE || CurrentToken == TokenCategory.SQUARE_CLOSE){
return node;
}
node.Add(Expr());
while (CurrentToken == TokenCategory.COMMA){
Expect(TokenCategory.COMMA);
node.Add(Expr());
}
return node;
}
public Node ExprRel(){
var node1 = ExprAdd();
while (firstOfExprRel.Contains(CurrentToken)){
var node2 = new ExprRelNode();
switch (CurrentToken){
case TokenCategory.LESS:
node2.AnchorToken = Expect(TokenCategory.LESS);
break;
case TokenCategory.LESS_EQUAL:
node2.AnchorToken = Expect(TokenCategory.LESS_EQUAL);
break;
case TokenCategory.GREATER:
node2.AnchorToken = Expect(TokenCategory.GREATER);
break;
case TokenCategory.GREATER_EQUAL:
node2.AnchorToken = Expect(TokenCategory.GREATER_EQUAL);
break;
default:
throw new SyntaxError(firstOfExprRel,tokenStream.Current);
}
node2.Add(node1);
node2.Add(ExprAdd());
node1 = node2;
}
return node1;
}
public Node ExprAdd(){
var node1 = ExprMul();
while (CurrentToken == TokenCategory.PLUS || CurrentToken == TokenCategory.NEG){
var node2 = new ExprAddNode();
if(CurrentToken == TokenCategory.NEG){
node2.AnchorToken = Expect(TokenCategory.NEG);
}
else{
node2.AnchorToken = Expect(TokenCategory.PLUS);
}
node2.Add(node1);
node2.Add(ExprMul());
node1 = node2;
}
return node1;
}
public Node ExprUnary(){
var top = new ExprUnaryNode();
var temp = top;
if (firstOfExprUnary.Contains(CurrentToken)){
while (firstOfExprUnary.Contains(CurrentToken)){
switch (CurrentToken){
case TokenCategory.PLUS:
temp.AnchorToken = Expect(TokenCategory.PLUS);
break;
case TokenCategory.NEG:
temp.AnchorToken = Expect(TokenCategory.NEG);
break;
case TokenCategory.NOT:
temp.AnchorToken = Expect(TokenCategory.NOT);
break;
default:
throw new SyntaxError(firstOfExprUnary,tokenStream.Current);
}
if (!firstOfExprUnary.Contains(CurrentToken)){
temp.Add(ExprPrimary());
}
else{
var newNode = new ExprUnaryNode();
temp.Add(newNode);
temp = newNode;
}
}
}
else{
return ExprPrimary();
}
return top;
}
public Node ExprPrimary(){
switch (CurrentToken){
case TokenCategory.IDENTIFIER:
var idToken = Expect(TokenCategory.IDENTIFIER);
if (CurrentToken == TokenCategory.PARENTHESIS_OPEN){
Expect(TokenCategory.PARENTHESIS_OPEN);
var fun = new FunCallNode(){
AnchorToken = idToken
};
fun.Add(ExprList());
Expect(TokenCategory.PARENTHESIS_CLOSE);
return fun;
}
else{
var id = new IdentifierNode(){
AnchorToken = idToken
};
return id;
}
case TokenCategory.SQUARE_OPEN:
return Arr();
case TokenCategory.PARENTHESIS_OPEN:
Expect(TokenCategory.PARENTHESIS_OPEN);
var node = Expr();
Expect(TokenCategory.PARENTHESIS_CLOSE);
return node;
case TokenCategory.STRING_LITERAL:
return new StrNode(){
AnchorToken = Expect(TokenCategory.STRING_LITERAL)
};
case TokenCategory.CHAR_LITERAL:
return new CharNode(){
AnchorToken = Expect(TokenCategory.CHAR_LITERAL)
};
case TokenCategory.INT_LITERAL:
return new IntLiteralNode(){
AnchorToken = Expect(TokenCategory.INT_LITERAL)
};
case TokenCategory.TRUE:
return new TrueNode(){
AnchorToken = Expect(TokenCategory.TRUE)
};
case TokenCategory.FALSE:
return new IntLiteralNode(){
AnchorToken = Expect(TokenCategory.FALSE)
};
default:
throw new SyntaxError(firstOfExprPrimary,tokenStream.Current);
}
}
public Node ExprMul(){
var node1 = ExprUnary();
while (firstOfExprMul.Contains(CurrentToken)){
var node2 = new ExprMulNode();
switch (CurrentToken){
case TokenCategory.MUL:
node2.AnchorToken = Expect(TokenCategory.MUL);
break;
case TokenCategory.MOD:
node2.AnchorToken = Expect(TokenCategory.MOD);
break;
case TokenCategory.DIV:
node2.AnchorToken = Expect(TokenCategory.DIV);
break;
default:
throw new SyntaxError(firstOfExprMul,tokenStream.Current);
}
node2.Add(node1);
node2.Add(ExprUnary());
node1 = node2;
}
return node1;
}
public Node Arr(){
var node = new ArrNode();
Expect(TokenCategory.SQUARE_OPEN);
node.Add(ExprList());
Expect(TokenCategory.SQUARE_CLOSE);
return node;
}
}
}