public static Node ParseFactor()
{
//Console.WriteLine("Parsing Factor");
//Factor rules
//1st -> num
//1st -> +
//1st -> -
//1st -> (
//+ -> factor
//- -> factor
//( -> expression
//expression -> )
//factor acts as num
Node root;
switch (tokens.actual.type)
{
case "INT":
root = new IntVal();
root.value = tokens.actual.value;
tokens.SelectNext();
return(root);
case "IDENTIFIER":
root = new Identifier((string)tokens.actual.value);
root.value = tokens.actual.value;
tokens.SelectNext();
return(root);
case "PLUS":
case "MINUS":
root = new UnOp();
root.value = tokens.actual.type == "PLUS" ? '+': '-';
tokens.SelectNext();
root.children[0] = ParseFactor();
return(root);
case "POPEN":
tokens.SelectNext();
root = ParseExpression();
if (tokens.actual.type != "PCLOSE")
{
throw new SystemException($"Missing closing parentesis (position {tokens.position}) [Line: {CurrentLine}]");
}
tokens.SelectNext();
return(root);
case "INPUT":
root = new UnOp();
root.value = "input";
tokens.SelectNext();
return(root);
}
//End of term reached, but exiting was not allowed
throw new SystemException($"Invalid expression format. Expression end was unexpected(position {tokens.position}) [Line: {CurrentLine}]");
}
public static Node ParseStatement()
{
//Console.WriteLine("parsing expression");
//Diagram rules
//1st - Identfier
//identifier - =
//= - expression
//1st - print
//print - expression
//1st - statements
Node root;
//TODO- condense this code by replacing similar code with some functions (expect line end for example)
switch (tokens.actual.type)
{
case "END":
return(new NoOp());
case "IDENTIFIER":
// IDENTIFIER - = - EXPRESSION
// get identifier
Identifier ident = new Identifier((string)tokens.actual.value);
tokens.SelectNext();
if (tokens.actual.type != "EQUAL") //expecting a EQUAL
{
throw new SystemException($"Identifier with no assignment ({tokens.actual.value}) (position {tokens.position}) [Line: {CurrentLine}]");
}
root = new BinOp(); //create the assign biop node
root.value = '=';
root.children[0] = ident; //left is the identfier
tokens.SelectNext();
root.children[1] = ParseExpression(); //right is a expression
if (tokens.actual.type != "LINEBREAK") //expect linebreak after the expression;
{
throw new SystemException($"No LINEBREAK after assignment (position {tokens.position}) [Line: {CurrentLine}]");
}
CurrentLine++;
tokens.SelectNext(); //go to next token after linebreak
return(root);
case "PRINT":
//print - expression
root = new UnOp();
root.value = "print";
tokens.SelectNext();
root.children[0] = ParseExpression();
if (tokens.actual.type != "LINEBREAK") //expect linebreak after the expression;
{
throw new SystemException($"No LINEBREAK after PRINT (position {tokens.position}) [Line: {CurrentLine}]");
}
CurrentLine++;
tokens.SelectNext(); //go to next token after linebreak
return(root);
case "WHILE":
root = new WhileNode();
tokens.SelectNext();
root.children[0] = ParseRelExpression();
if (tokens.actual.type != "LINEBREAK") //expect linebreak after the expression;
{
throw new SystemException($"No LINEBREAK after Relative Expression (position {tokens.position}) [Line: {CurrentLine}]");
}
CurrentLine++;
tokens.SelectNext(); //go to next token after linebreak
root.children[1] = ParseStatements(); //already goes to next line, no select next required
return(root);
case "IF":
root = new IfNode();
tokens.SelectNext();
root.children[0] = ParseRelExpression();
if (tokens.actual.type != "THEN") //expect THEN after the rel expression;
{
throw new SystemException($"THEN is required after an IF's Relative Expression (position {tokens.position}) [Line: {CurrentLine}]");
}
tokens.SelectNext();
if (tokens.actual.type != "LINEBREAK") //expect linebreak after THEN;
{
throw new SystemException($"No LINEBREAK after Relative Expression (position {tokens.position}) [Line: {CurrentLine}]");
}
CurrentLine++;
tokens.SelectNext(); //go to next token after linebreak
root.children[1] = ParseStatements(); //already goes to next line, no select next required
if (tokens.actual.type == "ELSE")
{
tokens.SelectNext();
if (tokens.actual.type != "LINEBREAK") //expect linebreak after ELSE;
{
throw new SystemException($"No LINEBREAK after ELSE (position {tokens.position}) [Line: {CurrentLine}]");
}
CurrentLine++;
tokens.SelectNext(); //go to next token after linebreak
root.children[2] = ParseStatements(); //left the token after the END, so it is probably on IF (END IF\n)
}
if (tokens.actual.type != "IF") //expect IF after the statements END for END IF\n construction;
{
throw new SystemException($"IF section end symbol not found, found END instead of END IF (position {tokens.position}) [Line: {CurrentLine}]");
}
tokens.SelectNext();
if (tokens.actual.type != "LINEBREAK") //expect linebreak after THEN;
{
throw new SystemException($"No LINEBREAK after Relative Expression (position {tokens.position}) [Line: {CurrentLine}]");
}
CurrentLine++;
tokens.SelectNext(); //go to next token after linebreak
return(root);
default:
return(new NoOp());
}
}
public static Node ParseStatement()
{
//Console.WriteLine("parsing expression");
//Diagram rules
//1st - Identfier
//identifier - =
//= - expression
//1st - print
//print - expression
//1st - statements
Node root;
switch (tokens.actual.type)
{
case "END":
return(new NoOp());
case "IDENTIFIER":
// IDENTIFIER - = - EXPRESSION
// get identifier
Identifier ident = new Identifier((string)tokens.actual.value);
tokens.SelectNext();
if (tokens.actual.type != "EQUAL") //expecting a EQUAL
{
throw new SystemException($"Identifier with no assignment ({tokens.actual.value}) (position {tokens.position}) [Line: {CurrentLine}]");
}
root = new BinOp(); //creat the assign biop node
root.value = '=';
root.children[0] = ident; //left is the identfier
tokens.SelectNext();
root.children[1] = ParseExpression(); //right is a expression
if (tokens.actual.type != "LINEBREAK") //expect linebreak after the expression;
{
throw new SystemException($"No LINEBREAK after assignment (position {tokens.position}) [Line: {CurrentLine}]");
}
CurrentLine++;
tokens.SelectNext(); //go to next token after linebreak
return(root);
case "PRINT":
//print - expression
root = new UnOp();
root.value = "print";
tokens.SelectNext();
root.children[0] = ParseExpression();
if (tokens.actual.type != "LINEBREAK") //expect linebreak after the expression;
{
throw new SystemException($"No LINEBREAK after PRINT (position {tokens.position}) [Line: {CurrentLine}]");
}
CurrentLine++;
tokens.SelectNext(); //go to next token after linebreak
return(root);
case "START":
return(ParseStatements());
default:
return(new NoOp());
}
}
public static Node ParseFactor()
{
//Console.WriteLine("Parsing Factor");
//Factor rules
//1st -> num
//1st -> +
//1st -> -
//1st -> not
//1st -> (
//+ -> factor
//- -> factor
//not -> factor
//( -> expression
//expression -> )
//identifier acts as num
//True | False acts as num
Node root;
switch (tokens.actual.type)
{
case "INT":
root = new IntVal();
root.value = tokens.actual.value;
tokens.SelectNext();
return(root);
case "IDENTIFIER":
root = new Identifier((string)tokens.actual.value);
root.value = tokens.actual.value;
tokens.SelectNext();
//check if this is a function
if (tokens.actual.type == "POPEN")
{
FuncCall call = new FuncCall();
call.value = root.value;
tokens.SelectNext();
if (tokens.actual.type != "PCLOSE")
{
do
{
if (tokens.actual.type == "COMMA")
{
tokens.SelectNext();
}
call.Add(ParseRelExpression());
} while(tokens.actual.type == "COMMA");
}
Expect("PCLOSE", true);
return(call);
}
return(root);
case "TRUE":
case "FALSE":
root = new UnOp();
root.value = tokens.actual.type == "TRUE" ? "true": "false";
tokens.SelectNext();
return(root);
case "PLUS":
case "MINUS":
root = new UnOp();
root.value = tokens.actual.type == "PLUS" ? '+': '-';
tokens.SelectNext();
root.children[0] = ParseFactor();
return(root);
case "NOT":
root = new UnOp();
root.value = "not";
tokens.SelectNext();
root.children[0] = ParseFactor();
return(root);
case "POPEN":
tokens.SelectNext();
root = ParseRelExpression();
if (tokens.actual.type != "PCLOSE")
{
throw new SystemException($"Missing closing parentesis (position {tokens.position}) [Line: {CurrentLine}]");
}
tokens.SelectNext();
return(root);
case "INPUT":
root = new UnOp();
root.value = "input";
tokens.SelectNext();
return(root);
}
//End of term reached, but exiting was not allowed
throw new SystemException($"Invalid expression format. Expression end was unexpected(position {tokens.position}) [Line: {CurrentLine}]");
}
public static Node ParseRelExpression()
{
//Console.WriteLine("parsing relative expression");
//Diagram rules
//1st - expression
//expression -> equal | higher | lower
//equal | higher| lower -> expression
//expression ->
Node root = ParseExpression();
//TODO make rel expressions
List <String> allowedTokens = new List <String>()
{
"IS", "EQUALS", "NOT"
};
if (allowedTokens.Contains(tokens.actual.type))
{
Node temp = root;
root = new BinOp();
root.children[0] = temp;
bool not = false;
if (tokens.actual.type == "IS")
{
tokens.SelectNext();
if (tokens.actual.type == "NOT")
{
//Node notChild= root;
//root = new UnOp();
//notNode.value = "not";
//root.children[1] = notNode;
not = true;
tokens.SelectNext();
}
switch (tokens.actual.type)
{
case "EQUAL":
tokens.SelectNext();
Expect("TO", true);
root.value = "==";
break;
case "HIGHER":
tokens.SelectNext();
Expect("THAN", true);
root.value = ">";
break;
case "LOWER":
tokens.SelectNext();
Expect("THAN", true);
root.value = "<";
break;
default:
root.value = "==";
break;
}
}
else if (tokens.actual.type == "EQUALS")
{
root.value = "==";
tokens.SelectNext();
}
else if (tokens.actual.type == "NOT")
{
tokens.SelectNext();
Expect("EQUALS", true);
root.value = "==";
}
root.children[1] = ParseExpression();
//apply not
if (not)
{
Node oldRoot = root;
root = new UnOp();
root.value = "not";
root.children[0] = oldRoot;
}
}
//if and or or, apply it to new relexp
if (tokens.actual.type == "AND")
{
tokens.SelectNext();
Node oldRoot = root;
root = new BinOp();
root.value = '&';
root.children[0] = oldRoot;
root.children[1] = ParseRelExpression();
}
if (tokens.actual.type == "OR")
{
tokens.SelectNext();
Node oldRoot = root;
root = new BinOp();
root.value = '|';
root.children[0] = oldRoot;
root.children[1] = ParseRelExpression();
}
return(root);
}
//public static Node ParseStatements(string poi){
// return ParseStatements("none");
// }
public static Node ParseStatement()
{
//Console.WriteLine("parsing expression");
Node root;
//TODO- condense this code by replacing similar code with some functions (expect line end for example)
switch (tokens.actual.type)
{
case "END":
return(new NoOp());
//assing, start wuth put
case "PUT":
root = new BinOp();
root.value = "=";
tokens.SelectNext();
root.children[1] = ParseRelExpression();
Expect("IN", true);
Expect("IDENTIFIER", false);
Identifier ident = new Identifier((string)tokens.actual.value);
root.children[0] = ident;
tokens.SelectNext();
return(root);
/*case "IDENTIFIER":
* // IDENTIFIER - = - EXPRESSION
* // get identifier
* Identifier ident = new Identifier((string)tokens.actual.value);
* tokens.SelectNext();
* if(tokens.actual.type != "EQUAL"){ //expecting a EQUAL
* throw new SystemException ($"Identifier with no assignment ({tokens.actual.value}) (position {tokens.position}) [Line: {CurrentLine}]");
* }
* root = new BinOp(); //create the assign biop node
* root.value = '=';
* root.children[0] = ident; //left is the identfier
* tokens.SelectNext();
* root.children[1] = ParseRelExpression(); //right is a relative expression
*
* if(tokens.actual.type != "LINEBREAK"){ //expect linebreak after the expression;
* throw new SystemException ($"No LINEBREAK after assignment (position {tokens.position}) [Line: {CurrentLine}]");
* }
* CurrentLine++;
* tokens.SelectNext(); //go to next token after linebreak
* return root;*/
case "DO":
tokens.SelectNext();
Expect("IDENTIFIER", false);
FuncCall call = new FuncCall();
call.value = (string)tokens.actual.value;
tokens.SelectNext();
if (tokens.actual.type == "WITH")
{
tokens.SelectNext();
do
{
if (tokens.actual.type == "COMMA")
{
tokens.SelectNext();
}
call.Add(ParseRelExpression());
}while (tokens.actual.type == "COMMA");
}
return(call);
case "TO":
tokens.SelectNext();
return(ParseFunction());
/*
* case "CALL":
* tokens.SelectNext();
* Expect("IDENTIFIER",false);
*
* FuncCall call = new FuncCall();
* call.value = (string)tokens.actual.value;
*
* tokens.SelectNext();
* Expect("POPEN",true);
* if(tokens.actual.type != "PCLOSE"){
* do{
* if(tokens.actual.type == "COMMA"){
* tokens.SelectNext();
* }
* call.Add(ParseRelExpression());
* }while (tokens.actual.type == "COMMA");
* }
* Expect("PCLOSE",true);
* return call;
*/
case "PRINT":
//print - expression
root = new UnOp();
root.value = "print";
tokens.SelectNext();
root.children[0] = ParseRelExpression();
return(root); //cl change
/*
* if(tokens.actual.type != "LINEBREAK"){ //expect linebreak after the expression;
* throw new SystemException ($"No LINEBREAK after PRINT (position {tokens.position}) [Line: {CurrentLine}]");
* }
* CurrentLine++;
* tokens.SelectNext(); //go to next token after linebreak
* return root;
*/
case "WHILE":
root = new WhileNode();
tokens.SelectNext();
root.children[0] = ParseRelExpression();
Expect("DO", true);
root.children[1] = ParseStatements("while");
Expect("PERIOD", true);
return(root);
/*
* root = new WhileNode();
* tokens.SelectNext();
* root.children[0] = ParseRelExpression();
* if(tokens.actual.type != "LINEBREAK"){ //expect linebreak after the expression;
* throw new SystemException ($"No LINEBREAK after Relative Expression (position {tokens.position}) [Line: {CurrentLine}]");
* }
* CurrentLine++;
* tokens.SelectNext(); //go to next token after linebreak
* root.children[1] = ParseStatements("while"); //already goes to next line, no select next required
* return root;
*/
/*
* case "DIM":
* root = new BinOp();
* root.value = "vardec";
* tokens.SelectNext();
*
* if(tokens.actual.type != "IDENTIFIER"){
* throw new SystemException ($"IDENTIFIER is required after an variable declaration declaration (position {tokens.position}) [Line: {CurrentLine}]");
* }
* root.children[0] = new NoOp();
* root.children[0].value = (string)tokens.actual.value;
* tokens.SelectNext();
*
* if(tokens.actual.type != "AS"){
* throw new SystemException ($"'As' is required in an variable declaration (position {tokens.position}) [Line: {CurrentLine}]");
* }
* tokens.SelectNext();
*
* root.children[1] = parseType();
*
* if(tokens.actual.type != "LINEBREAK"){ //expect linebreak after the expression;
* throw new SystemException ($"No LINEBREAK after Variable declaration(position {tokens.position}) [Line: {CurrentLine}]");
* }
* CurrentLine++;
* tokens.SelectNext(); //go to next token after linebreak
*
* return root;
*/
case "IF":
root = new IfNode();
tokens.SelectNext();
root.children[0] = ParseRelExpression();
Expect("DO", true);
root.children[1] = ParseStatements("if");
Expect("PERIOD", true);
if (tokens.actual.type == "ELSE")
{
tokens.SelectNext();
root.children[2] = ParseStatements("else");
}
return(root);
/*
* if(tokens.actual.type != "THEN"){ //expect THEN after the rel expression;
* throw new SystemException ($"THEN is required after an IF's Relative Expression (position {tokens.position}) [Line: {CurrentLine}]");
* }
* tokens.SelectNext();
*
* if(tokens.actual.type != "LINEBREAK"){ //expect linebreak after THEN;
* throw new SystemException ($"No LINEBREAK after Relative Expression (position {tokens.position}) [Line: {CurrentLine}]");
* }
* CurrentLine++;
* tokens.SelectNext(); //go to next token after linebreak
*
* root.children[1] = ParseStatements("if"); //already goes to next line, no select next required
*
* if(tokens.actual.type == "ELSE"){
* tokens.SelectNext();
* if(tokens.actual.type != "LINEBREAK"){ //expect linebreak after ELSE;
* throw new SystemException ($"No LINEBREAK after ELSE (position {tokens.position}) [Line: {CurrentLine}]");
* }
* CurrentLine++;
* tokens.SelectNext(); //go to next token after linebreak
* root.children[2] = ParseStatements("else"); //left the token after the END, so it is probably on IF (END IF\n)
* }
*
* if(tokens.actual.type != "IF"){ //expect IF after the statements END for END IF\n construction;
* throw new SystemException ($"IF section end symbol not found, found END instead of END IF (position {tokens.position}) [Line: {CurrentLine}]");
* }
* tokens.SelectNext();
*
* if(tokens.actual.type != "LINEBREAK"){ //expect linebreak after THEN;
* throw new SystemException ($"No LINEBREAK after Relative Expression (position {tokens.position}) [Line: {CurrentLine}]");
* }
* CurrentLine++;
* tokens.SelectNext(); //go to next token after linebreak
*
* return root; */
default:
return(new NoOp());
}
}
