private void Solve()
{
int N = ReadInt;
int odd = 0, even = 0;
for (int i = 0; i < N; i++)
{
if (ReadInt.IsEven())
{
even++;
}
else
{
odd++;
}
}
if (odd.IsEven())
{
Console.WriteLine("YES");
}
else
{
Console.WriteLine("NO");
}
#if DEBUG
Solve();
#endif
}
static void WorkflowSample()
{
// Declaring a set of tokens that can be used to refer to a particular unit of compensable work
Variable <CompensationToken> tokenA = new Variable <CompensationToken>
{
Name = "Token A",
};
Variable <CompensationToken> tokenB = new Variable <CompensationToken>
{
Name = "Token B",
};
Variable <CompensationToken> tokenC = new Variable <CompensationToken>
{
Name = "Token C",
};
Activity task_a1 = new RSCustomActivity("a1");
Activity task_b1 = new RSCustomActivity("b1");
Activity task_b2 = new RSCustomActivity("b2");
Activity task_c1 = new RSCustomActivity("c1");
Activity task_c2 = new RSCustomActivity("c2");
Activity task_c3 = new RSCustomActivity("c3");
Activity task_d1 = new RSCustomActivity("d1");
Activity task_d2 = new RSCustomActivity("d2");
Activity task_d3 = new RSCustomActivity("d3");
Activity task_e1 = new RSCustomActivity("e1");
Activity taskX = new ReadInt();
// System.Activities.Statements.Assign.Equals()
Activity A = new Parallel
{
DisplayName = "Task A",
CompletionCondition = true,
Branches = { task_a1 }
};
Activity B = new Parallel
{
DisplayName = "Task B",
CompletionCondition = true,
Branches = { task_b1, task_b2 }
};
Activity C = new Parallel
{
DisplayName = "Task C",
CompletionCondition = true,
Branches = { task_c1, task_c2, task_c3 }
};
Activity D = new Parallel
{
DisplayName = "Task D",
CompletionCondition = true,
Branches = { task_d1, task_d2, task_d3 }
};
Activity E = new Parallel
{
DisplayName = "Task E",
CompletionCondition = true,
Branches = { task_e1 }
};
Activity Root = new Parallel
{
DisplayName = "Task Root",
CompletionCondition = true,
Branches = { B, A, B, C, D, E }
};
WorkflowInvoker.Invoke(Root);
WorkflowInvoker.Invoke(Root);
}
private Stmt ParseStmt()
{
Stmt result = null;
if (this.index == this.tokens.Count)
{
throw new System.Exception("expected statement, got EOF");
}
// <stmt> := print <expr>
// <expr> := <string>
// | <int>
// | <arith_expr>
// | <ident>
if (this.tokens[this.index].Equals(languageSetting["End"]))
{
this.index++;
}
else if (this.tokens[this.index].Equals(languageSetting["Start"]))
{
this.index++;
return(ParseStmt());
}
else if (this.tokens[this.index].Equals(languageSetting["Print"]))
{
this.index++;
Print print = new Print();
print.Expr = this.ParseExpr();
result = print;
}
else if (this.tokens[this.index] == Scanner.Call)
{
VoidMethodCall vmc = new VoidMethodCall();
vmc.Expr = this.ParseExpr();
result = vmc;
}
else if (this.tokens[this.index].Equals(languageSetting["VariableDeclaration"]))
{
this.index++;
DeclareVar declareVar = new DeclareVar();
if (this.index < this.tokens.Count &&
this.tokens[this.index] is string)
{
declareVar.Ident = (string)this.tokens[this.index];
}
else
{
throw new System.Exception("expected variable name after 'var'");
}
this.index++;
if (this.index == this.tokens.Count ||
this.tokens[this.index] != Scanner.Equal)
{
throw new System.Exception("expected = after 'var ident'");
}
this.index++;
declareVar.Expr = this.ParseExpr();
result = declareVar;
}
else if (this.tokens[this.index].Equals(languageSetting["if"]))
{
this.index++;
IfCondition ifCon = new IfCondition();
ifCon.BooleanExp = this.ParseExpr();
if (!this.tokens[++this.index].Equals(languageSetting["Start"]))
{
throw new System.Exception("Start Expected");
}
ifCon.Body = this.ParseStmt();
if (!this.tokens[this.index++].Equals(languageSetting["End"]))
{
throw new System.Exception("End Expected");
}
result = ifCon;
}
else if (this.tokens[this.index].Equals(languageSetting["while"]))
{
this.index++;
WhileLoop whileLoop = new WhileLoop();
whileLoop.BooleanExp = this.ParseExpr();
if (!this.tokens[++this.index].Equals(languageSetting["Start"]))
{
throw new System.Exception("Start Expected");
}
whileLoop.Body = this.ParseStmt();
if (!this.tokens[this.index++].Equals(languageSetting["End"]))
{
throw new System.Exception("End Expected");
}
result = whileLoop;
}
else if (this.tokens[this.index].Equals("read_int"))
{
this.index++;
ReadInt readInt = new ReadInt();
if (this.index < this.tokens.Count &&
this.tokens[this.index] is string)
{
readInt.Ident = (string)this.tokens[this.index++];
result = readInt;
}
else
{
throw new System.Exception("expected variable name after 'read_int'");
}
}
else if (this.tokens[this.index].Equals("for"))
{
this.index++;
ForLoop forLoop = new ForLoop();
if (this.index < this.tokens.Count &&
this.tokens[this.index] is string)
{
forLoop.Ident = (string)this.tokens[this.index];
}
else
{
throw new System.Exception("expected identifier after 'for'");
}
this.index++;
if (this.index == this.tokens.Count ||
this.tokens[this.index] != Scanner.Equal)
{
throw new System.Exception("for missing '='");
}
this.index++;
forLoop.From = this.ParseSingleExpression();
if (this.index == this.tokens.Count ||
!this.tokens[this.index].Equals("to"))
{
throw new System.Exception("expected 'to' after for");
}
this.index++;
forLoop.To = this.ParseSingleExpression();
if (this.index == this.tokens.Count ||
!this.tokens[this.index].Equals("do"))
{
throw new System.Exception("expected 'do' after from expression in for loop");
}
this.index++;
forLoop.Body = this.ParseStmt();
result = forLoop;
if (this.index == this.tokens.Count ||
!this.tokens[this.index].Equals("end"))
{
throw new System.Exception("unterminated 'for' loop body");
}
this.index++;
}
else if (this.tokens[this.index] is string)
{
// assignment
Assign assign = new Assign();
assign.Ident = (string)this.tokens[this.index++];
if (this.index == this.tokens.Count ||
this.tokens[this.index] != Scanner.Equal)
{
throw new System.Exception("expected '='");
}
this.index++;
assign.Expr = this.ParseExpr();
result = assign;
}
else
{
throw new System.Exception("parse error at token " + this.index + ": " + this.tokens[this.index]);
}
if (this.index < this.tokens.Count && this.tokens[this.index] == Scanner.Semi)
{
this.index++;
if (this.index < this.tokens.Count &&
!this.tokens[this.index].Equals(languageSetting["End"]))
{
Sequence sequence = new Sequence();
sequence.First = result;
sequence.Second = this.ParseStmt();
result = sequence;
}
}
return(result);
}
private Stmt ParseStmt()
{
Stmt resultado;
if (this.indice == this.tokens.Count)
{
throw new System.Exception("se esperaban sentencias, se llego al final del archivo");
}
// <stmt> := print <expr>
// <expr> := <string>
// | <int>
// | <arith_expr>
// | <ident>
if (this.tokens[this.indice].Equals("print"))
{
this.indice++;
Print print = new Print();
print.Expr = this.ParseExpr();
resultado = print;
}
else if (this.tokens[this.indice].Equals("var"))
{
this.indice++;
DeclareVar declareVar = new DeclareVar();
if (this.indice < this.tokens.Count &&
this.tokens[this.indice] is string)
{
declareVar.Ident = (string)this.tokens[this.indice];
}
else
{
throw new System.Exception("Se esperaba nombre de variable despues de 'var'");
}
this.indice++;
if (this.indice == this.tokens.Count ||
this.tokens[this.indice] != Scanner.Igual)
{
throw new System.Exception("se esperaba = despues de 'var ident'");
}
this.indice++;
declareVar.Expr = this.ParseExpr();
resultado = declareVar;
}
else if (this.tokens[this.indice].Equals("read_int"))
{
this.indice++;
ReadInt readInt = new ReadInt();
if (this.indice < this.tokens.Count &&
this.tokens[this.indice] is string)
{
readInt.Ident = (string)this.tokens[this.indice++];
resultado = readInt;
}
else
{
throw new System.Exception("Se esperaba el nombre de la variable 'read_int'");
}
}
//*******************
else if (this.tokens[this.indice].Equals("if"))
{
this.indice++;
mcIf mcif = new mcIf();
Expr temp = ParseExpr();
if (this.tokens[this.indice] == Scanner.Eq || this.tokens[this.indice] == Scanner.Neq ||
this.tokens[this.indice] == Scanner.Gt || this.tokens[this.indice] == Scanner.Gte ||
this.tokens[this.indice] == Scanner.Lt || this.tokens[this.indice] == Scanner.Lte)
{
CompExpr compExpr = new CompExpr();
compExpr.Left = temp;
object op = this.tokens[this.indice++];
if (op == Scanner.Eq)
compExpr.Op = CompOp.Eq;
else if (op == Scanner.Neq)
compExpr.Op = CompOp.Neq;
else if (op == Scanner.Gt)
compExpr.Op = CompOp.Gt;
else if (op == Scanner.Gte)
compExpr.Op = CompOp.Gte;
else if (op == Scanner.Lt)
compExpr.Op = CompOp.Lt;
else if (op == Scanner.Lte)
compExpr.Op = CompOp.Lte;
compExpr.Rigth = ParseExpr();
temp = compExpr;
}
mcif.compExpr = temp;
if (this.indice == this.tokens.Count || !this.tokens[this.indice].Equals("then"))
{
throw new System.Exception("Se esperaba el identificador 'then' despues de 'if'");
}
this.indice++;
mcif.Then = ParseStmt();
if (this.tokens[this.indice].Equals("else"))
{
this.indice++;
mcif.Else = ParseStmt();
}
resultado = mcif;
if (this.indice == this.tokens.Count ||
!this.tokens[this.indice].Equals("end"))
{
throw new System.Exception("Sentencia if inconclusa");
}
this.indice++;
}
else if (this.tokens[this.indice].Equals("while"))
{
this.indice++;
WhileLoop whileLoop = new WhileLoop();
Expr temp = ParseExpr();
if (this.tokens[this.indice] == Scanner.Eq || this.tokens[this.indice] == Scanner.Neq ||
this.tokens[this.indice] == Scanner.Gt || this.tokens[this.indice] == Scanner.Gte ||
this.tokens[this.indice] == Scanner.Lt || this.tokens[this.indice] == Scanner.Lte)
{
CompExpr compExpr = new CompExpr();
compExpr.Left = temp;
object op = this.tokens[this.indice++];
if (op == Scanner.Eq)
compExpr.Op = CompOp.Eq;
else if (op == Scanner.Neq)
compExpr.Op = CompOp.Neq;
else if (op == Scanner.Gt)
compExpr.Op = CompOp.Gt;
else if (op == Scanner.Gte)
compExpr.Op = CompOp.Gte;
else if (op == Scanner.Lt)
compExpr.Op = CompOp.Lt;
else if (op == Scanner.Lte)
compExpr.Op = CompOp.Lte;
compExpr.Rigth = ParseExpr();
temp = compExpr;
}
whileLoop.Cond = temp;
if (this.indice == this.tokens.Count || !this.tokens[this.indice].Equals("do"))
{
throw new System.Exception("Se esperaba el identificador 'do' despues de 'while'");
}
this.indice++;
whileLoop.Body = ParseStmt();
resultado = whileLoop;
if (this.indice == this.tokens.Count ||
!this.tokens[this.indice].Equals("end"))
{
throw new System.Exception("sentencia while inconclusa");
}
this.indice++;
}
//*******************
else if (this.tokens[this.indice].Equals("for"))
{
this.indice++;
ForLoop forLoop = new ForLoop();
if (this.indice < this.tokens.Count &&
this.tokens[this.indice] is string)
{
forLoop.Ident = (string)this.tokens[this.indice];
}
else
{
throw new System.Exception("se esperaba un indentificador despues de 'for'");
}
this.indice++;
if (this.indice == this.tokens.Count ||
this.tokens[this.indice] != Scanner.Igual)
{
throw new System.Exception("no se encontro en la sentencia for '='");
}
this.indice++;
forLoop.From = this.ParseExpr();
if (this.indice == this.tokens.Count ||
!this.tokens[this.indice].Equals("to"))
{
throw new System.Exception("se epsaraba 'to' despues de for");
}
this.indice++;
forLoop.To = this.ParseExpr();
if (this.indice == this.tokens.Count ||
!this.tokens[this.indice].Equals("do"))
{
throw new System.Exception("se esperaba 'do' despues de la expresion en el ciclo for");
}
this.indice++;
forLoop.Body = this.ParseStmt();
resultado = forLoop;
if (this.indice == this.tokens.Count ||
!this.tokens[this.indice].Equals("end"))
{
throw new System.Exception("setencia for inconclusa");
}
this.indice++;
}
else if (this.tokens[this.indice] is string)
{
// assignment
Assign assign = new Assign();
assign.Ident = (string)this.tokens[this.indice++];
if (this.indice == this.tokens.Count ||
this.tokens[this.indice] != Scanner.Igual)
{
throw new System.Exception("se esperaba '='");
}
this.indice++;
assign.Expr = this.ParseExpr();
resultado = assign;
}
else
{
throw new System.Exception("Error en el token " + this.indice + ": " + this.tokens[this.indice]);
}
if (this.indice < this.tokens.Count && this.tokens[this.indice] == Scanner.PyC)
{
this.indice++;
if (this.indice < this.tokens.Count &&
!this.tokens[this.indice].Equals("end") && !this.tokens[this.indice].Equals("else"))
{
Sequence sequence = new Sequence();
sequence.First = resultado;
sequence.Second = this.ParseStmt();
resultado = sequence;
}
}
return resultado;
}
private Stmt ParseStmt()
{
Stmt result;
if (this.index == this.tokens.Count)
{
throw new System.Exception("expected statement, got EOF");
}
// <stmt> := print <expr>
// <expr> := <string>
// | <int>
// | <arith_expr>
// | <ident>
if (this.tokens[this.index].Equals("print"))
{
this.index++;
Print print = new Print();
print.Expr = this.ParseExpr();
result = print;
}
else if (this.tokens[this.index].Equals("var"))
{
this.index++;
DeclareVar declareVar = new DeclareVar();
if (this.index < this.tokens.Count &&
this.tokens[this.index] is string)
{
declareVar.Ident = (string)this.tokens[this.index];
}
else
{
throw new System.Exception("expected variable name after 'var'");
}
this.index++;
if (this.index == this.tokens.Count ||
this.tokens[this.index] != Scanner.Equal)
{
throw new System.Exception("expected = after 'var ident'");
}
this.index++;
declareVar.Expr = this.ParseExpr();
result = declareVar;
}
else if (this.tokens[this.index].Equals("read_int"))
{
this.index++;
ReadInt readInt = new ReadInt();
if (this.index < this.tokens.Count &&
this.tokens[this.index] is string)
{
readInt.Ident = (string)this.tokens[this.index++];
result = readInt;
}
else
{
throw new System.Exception("expected variable name after 'read_int'");
}
}
else if (this.tokens[this.index].Equals("for"))
{
this.index++;
ForLoop forLoop = new ForLoop();
if (this.index < this.tokens.Count &&
this.tokens[this.index] is string)
{
forLoop.Ident = (string)this.tokens[this.index];
}
else
{
throw new System.Exception("expected identifier after 'for'");
}
this.index++;
if (this.index == this.tokens.Count ||
this.tokens[this.index] != Scanner.Equal)
{
throw new System.Exception("for missing '='");
}
this.index++;
forLoop.From = this.ParseExpr();
if (this.index == this.tokens.Count ||
!this.tokens[this.index].Equals("to"))
{
throw new System.Exception("expected 'to' after for");
}
this.index++;
forLoop.To = this.ParseExpr();
if (this.index == this.tokens.Count ||
!this.tokens[this.index].Equals("do"))
{
throw new System.Exception("expected 'do' after from expression in for loop");
}
this.index++;
forLoop.Body = this.ParseStmt();
result = forLoop;
if (this.index == this.tokens.Count ||
!this.tokens[this.index].Equals("end"))
{
throw new System.Exception("unterminated 'for' loop body");
}
this.index++;
}
else if (this.tokens[this.index] is string)
{
// assignment
Assign assign = new Assign();
assign.Ident = (string)this.tokens[this.index++];
if (this.index == this.tokens.Count ||
this.tokens[this.index] != Scanner.Equal)
{
throw new System.Exception("expected '='");
}
this.index++;
assign.Expr = this.ParseExpr();
result = assign;
}
else
{
throw new System.Exception("parse error at token " + this.index + ": " + this.tokens[this.index]);
}
if (this.index < this.tokens.Count && this.tokens[this.index] == Scanner.Semi)
{
this.index++;
if (this.index < this.tokens.Count &&
!this.tokens[this.index].Equals("end"))
{
Sequence sequence = new Sequence();
sequence.First = result;
sequence.Second = this.ParseStmt();
result = sequence;
}
}
return(result);
}
private Stmt ParseStmt()
{
Stmt resultado;
if (this.indice == this.tokens.Count)
{
throw new System.Exception("se esperaban sentencias, se llego al final del archivo");
}
// <stmt> := print <expr>
// <expr> := <string>
// | <int>
// | <arith_expr>
// | <ident>
if (this.tokens[this.indice].Equals("print"))
{
this.indice++;
Print print = new Print();
print.Expr = this.ParseExpr();
resultado = print;
}
else if (this.tokens[this.indice].Equals("var"))
{
this.indice++;
DeclareVar declareVar = new DeclareVar();
if (this.indice < this.tokens.Count &&
this.tokens[this.indice] is string)
{
declareVar.Ident = (string)this.tokens[this.indice];
}
else
{
throw new System.Exception("Se esperaba nombre de variable despues de 'var'");
}
this.indice++;
if (this.indice == this.tokens.Count ||
this.tokens[this.indice] != Scanner.Igual)
{
throw new System.Exception("se esperaba = despues de 'var ident'");
}
this.indice++;
declareVar.Expr = this.ParseExpr();
resultado = declareVar;
}
else if (this.tokens[this.indice].Equals("read_int"))
{
this.indice++;
ReadInt readInt = new ReadInt();
if (this.indice < this.tokens.Count &&
this.tokens[this.indice] is string)
{
readInt.Ident = (string)this.tokens[this.indice++];
resultado = readInt;
}
else
{
throw new System.Exception("Se esperaba el nombre de la variable 'read_int'");
}
}
//*******************
else if (this.tokens[this.indice].Equals("if"))
{
this.indice++;
mcIf mcif = new mcIf();
Expr temp = ParseExpr();
if (this.tokens[this.indice] == Scanner.Eq || this.tokens[this.indice] == Scanner.Neq ||
this.tokens[this.indice] == Scanner.Gt || this.tokens[this.indice] == Scanner.Gte ||
this.tokens[this.indice] == Scanner.Lt || this.tokens[this.indice] == Scanner.Lte)
{
CompExpr compExpr = new CompExpr();
compExpr.Left = temp;
object op = this.tokens[this.indice++];
if (op == Scanner.Eq)
{
compExpr.Op = CompOp.Eq;
}
else if (op == Scanner.Neq)
{
compExpr.Op = CompOp.Neq;
}
else if (op == Scanner.Gt)
{
compExpr.Op = CompOp.Gt;
}
else if (op == Scanner.Gte)
{
compExpr.Op = CompOp.Gte;
}
else if (op == Scanner.Lt)
{
compExpr.Op = CompOp.Lt;
}
else if (op == Scanner.Lte)
{
compExpr.Op = CompOp.Lte;
}
compExpr.Rigth = ParseExpr();
temp = compExpr;
}
mcif.compExpr = temp;
if (this.indice == this.tokens.Count || !this.tokens[this.indice].Equals("then"))
{
throw new System.Exception("Se esperaba el identificador 'then' despues de 'if'");
}
this.indice++;
mcif.Then = ParseStmt();
if (this.tokens[this.indice].Equals("else"))
{
this.indice++;
mcif.Else = ParseStmt();
}
resultado = mcif;
if (this.indice == this.tokens.Count ||
!this.tokens[this.indice].Equals("end"))
{
throw new System.Exception("Sentencia if inconclusa");
}
this.indice++;
}
else if (this.tokens[this.indice].Equals("while"))
{
this.indice++;
WhileLoop whileLoop = new WhileLoop();
Expr temp = ParseExpr();
if (this.tokens[this.indice] == Scanner.Eq || this.tokens[this.indice] == Scanner.Neq ||
this.tokens[this.indice] == Scanner.Gt || this.tokens[this.indice] == Scanner.Gte ||
this.tokens[this.indice] == Scanner.Lt || this.tokens[this.indice] == Scanner.Lte)
{
CompExpr compExpr = new CompExpr();
compExpr.Left = temp;
object op = this.tokens[this.indice++];
if (op == Scanner.Eq)
{
compExpr.Op = CompOp.Eq;
}
else if (op == Scanner.Neq)
{
compExpr.Op = CompOp.Neq;
}
else if (op == Scanner.Gt)
{
compExpr.Op = CompOp.Gt;
}
else if (op == Scanner.Gte)
{
compExpr.Op = CompOp.Gte;
}
else if (op == Scanner.Lt)
{
compExpr.Op = CompOp.Lt;
}
else if (op == Scanner.Lte)
{
compExpr.Op = CompOp.Lte;
}
compExpr.Rigth = ParseExpr();
temp = compExpr;
}
whileLoop.Cond = temp;
if (this.indice == this.tokens.Count || !this.tokens[this.indice].Equals("do"))
{
throw new System.Exception("Se esperaba el identificador 'do' despues de 'while'");
}
this.indice++;
whileLoop.Body = ParseStmt();
resultado = whileLoop;
if (this.indice == this.tokens.Count ||
!this.tokens[this.indice].Equals("end"))
{
throw new System.Exception("sentencia while inconclusa");
}
this.indice++;
}
//*******************
else if (this.tokens[this.indice].Equals("for"))
{
this.indice++;
ForLoop forLoop = new ForLoop();
if (this.indice < this.tokens.Count &&
this.tokens[this.indice] is string)
{
forLoop.Ident = (string)this.tokens[this.indice];
}
else
{
throw new System.Exception("se esperaba un indentificador despues de 'for'");
}
this.indice++;
if (this.indice == this.tokens.Count ||
this.tokens[this.indice] != Scanner.Igual)
{
throw new System.Exception("no se encontro en la sentencia for '='");
}
this.indice++;
forLoop.From = this.ParseExpr();
if (this.indice == this.tokens.Count ||
!this.tokens[this.indice].Equals("to"))
{
throw new System.Exception("se epsaraba 'to' despues de for");
}
this.indice++;
forLoop.To = this.ParseExpr();
if (this.indice == this.tokens.Count ||
!this.tokens[this.indice].Equals("do"))
{
throw new System.Exception("se esperaba 'do' despues de la expresion en el ciclo for");
}
this.indice++;
forLoop.Body = this.ParseStmt();
resultado = forLoop;
if (this.indice == this.tokens.Count ||
!this.tokens[this.indice].Equals("end"))
{
throw new System.Exception("setencia for inconclusa");
}
this.indice++;
}
else if (this.tokens[this.indice] is string)
{
// assignment
Assign assign = new Assign();
assign.Ident = (string)this.tokens[this.indice++];
if (this.indice == this.tokens.Count ||
this.tokens[this.indice] != Scanner.Igual)
{
throw new System.Exception("se esperaba '='");
}
this.indice++;
assign.Expr = this.ParseExpr();
resultado = assign;
}
else
{
throw new System.Exception("Error en el token " + this.indice + ": " + this.tokens[this.indice]);
}
if (this.indice < this.tokens.Count && this.tokens[this.indice] == Scanner.PyC)
{
this.indice++;
if (this.indice < this.tokens.Count &&
!this.tokens[this.indice].Equals("end") && !this.tokens[this.indice].Equals("else"))
{
Sequence sequence = new Sequence();
sequence.First = resultado;
sequence.Second = this.ParseStmt();
resultado = sequence;
}
}
return(resultado);
}
private Stmt ParseStmt()
{
Stmt result;
if (this.index == this.tokens.Count)
{
throw new System.Exception("expected statement, got EOF");
}
// <stmt> := print <expr>
// <expr> := <string>
// | <int>
// | <arith_expr>
// | <ident>
if (this.tokens[this.index].Equals("print"))
{
this.index++;
Print print = new Print();
print.Expr = this.ParseExpr();
result = print;
}
else if (this.tokens[this.index].Equals("var"))
{
this.index++;
DeclareVar declareVar = new DeclareVar();
if (this.index < this.tokens.Count &&
this.tokens[this.index] is string)
{
declareVar.Ident = (string)this.tokens[this.index];
}
else
{
throw new System.Exception("expected variable name after 'var'");
}
this.index++;
if (this.index == this.tokens.Count ||
this.tokens[this.index] != Scanner.Equal)
{
throw new System.Exception("expected = after 'var ident'");
}
this.index++;
declareVar.Expr = this.ParseExpr();
result = declareVar;
}
else if (this.tokens[this.index].Equals("read_int"))
{
this.index++;
ReadInt readInt = new ReadInt();
if (this.index < this.tokens.Count &&
this.tokens[this.index] is string)
{
readInt.Ident = (string)this.tokens[this.index++];
result = readInt;
}
else
{
throw new System.Exception("expected variable name after 'read_int'");
}
}
else if (this.tokens[this.index].Equals("for"))
{
this.index++;
ForLoop forLoop = new ForLoop();
if (this.index < this.tokens.Count &&
this.tokens[this.index] is string)
{
forLoop.Ident = (string)this.tokens[this.index];
}
else
{
throw new System.Exception("expected identifier after 'for'");
}
this.index++;
if (this.index == this.tokens.Count ||
this.tokens[this.index] != Scanner.Equal)
{
throw new System.Exception("for missing '='");
}
this.index++;
forLoop.From = this.ParseExpr();
if (this.index == this.tokens.Count ||
!this.tokens[this.index].Equals("to"))
{
throw new System.Exception("expected 'to' after for");
}
this.index++;
forLoop.To = this.ParseExpr();
if (this.index == this.tokens.Count ||
!this.tokens[this.index].Equals("do"))
{
throw new System.Exception("expected 'do' after from expression in for loop");
}
this.index++;
forLoop.Body = this.ParseStmt();
result = forLoop;
if (this.index == this.tokens.Count ||
!this.tokens[this.index].Equals("end"))
{
throw new System.Exception("unterminated 'for' loop body");
}
this.index++;
}
else if (this.tokens[this.index] is string)
{
// assignment
Assign assign = new Assign();
assign.Ident = (string)this.tokens[this.index++];
if (this.index == this.tokens.Count ||
this.tokens[this.index] != Scanner.Equal)
{
throw new System.Exception("expected '='");
}
this.index++;
assign.Expr = this.ParseExpr();
result = assign;
}
else
{
throw new System.Exception("parse error at token " + this.index + ": " + this.tokens[this.index]);
}
if (this.index < this.tokens.Count && this.tokens[this.index] == Scanner.Semi)
{
this.index++;
if (this.index < this.tokens.Count &&
!this.tokens[this.index].Equals("end"))
{
Sequence sequence = new Sequence();
sequence.First = result;
sequence.Second = this.ParseStmt();
result = sequence;
}
}
return result;
}
