private Stmt ParseStmt()
{
Stmt result;
if (index == tokens.Count)
{
throw new System.Exception("expected statement, got EOF");
}
// print
if (tokens[index] == Tokens.Print)
{
MoveNext();
Print print = new Print();
print.Expr = ParseExpr();
result = print;
}
// printline
else if (tokens[index] == Tokens.PrintLine)
{
MoveNext();
PrintLine printLine = new PrintLine();
printLine.Expr = ParseExpr();
result = printLine;
}
// clear
else if (tokens[index] == Tokens.Clear)
{
Clear clearStmt = new Clear();
MoveNext();
clearStmt.Tag = "_Clear_"; // for debug
result = clearStmt;
}
// var
else if (tokens[index] == Tokens.Var)
{
MoveNext();
DeclareVar declareVar = new DeclareVar();
if (index < tokens.Count &&
tokens[index] is IdentifierToken)
{
declareVar.Ident = ((IdentifierToken)tokens[index]).Name;
}
else
{
throw new System.Exception("expected variable name after 'var'");
}
MoveNext();
if (index == tokens.Count ||
tokens[index] != Tokens.Assignment)
{
throw new System.Exception("expected = after 'var ident'");
}
MoveNext();
declareVar.Expr = ParseExpr();
result = declareVar;
}
// readvar
else if (tokens[index] == Tokens.ReadVar)
{
ReadVar readVar = new ReadVar();
Expr expr;
Variable var;
MoveNext();
Eat(Tokens.LeftCurlyBracket);
while ((tokens[index] != Tokens.RightCurlyBracket) &&
(index < tokens.Count))
{
var = new Variable();
expr = ParseExpr();
Eat(Tokens.Colon);
var.Ident = ((IdentifierToken)tokens[index]).Name;
MoveNext();
readVar.Vars.Add(var, expr);
if (tokens[index] == Tokens.Comma)
{
MoveNext(); // Skip comma
}
else if (tokens[index] == Tokens.RightCurlyBracket)
{
break;
}
else
{
throw new System.Exception("unexpected character in arg list");
}
}
if (index == tokens.Count ||
tokens[index] != Tokens.RightCurlyBracket)
{
throw new System.Exception("expect close curly bracket after open bracket/args");
}
result = readVar;
// Skip RightCurlyBracket
Eat(Tokens.RightCurlyBracket);
}
// for
else if (tokens[index] == Tokens.For)
{
ForLoop forLoop = new ForLoop();
MoveNext();
if (index < tokens.Count &&
tokens[index] is IdentifierToken)
{
forLoop.Ident = ((IdentifierToken)tokens[index]).Name;
}
else
{
throw new System.Exception("expected identifier after 'for'");
}
MoveNext();
if (index == tokens.Count ||
tokens[index] != Tokens.Assignment)
{
throw new System.Exception("for missing '='");
}
MoveNext();
forLoop.From = ParseExpr();
if (index == tokens.Count ||
tokens[index] != Tokens.To)
{
throw new System.Exception("expected 'to' after for");
}
MoveNext();
forLoop.To = ParseExpr();
// Body for loop
forLoop.Body = ParseStmt();
result = forLoop;
// end for
if (index == tokens.Count ||
tokens[index] != Tokens.EndSequence)
{
throw new System.Exception("unterminated 'end for' loop body");
}
MoveNext();
if (!MaybeEat(Tokens.For))
{
throw new System.Exception("unterminated 'for' body");
}
}
// foreach
else if (tokens[index] == Tokens.ForEach)
{
ForEachLoop forEachLoop = new ForEachLoop();
MoveNext();
if (index < tokens.Count &&
tokens[index] is IdentifierToken)
{
forEachLoop.Ident = ((IdentifierToken)tokens[index]).Name;
}
else
{
throw new System.Exception("expected identifier after 'for'");
}
MoveNext();
if (index == tokens.Count ||
tokens[index] != Tokens.In)
{
throw new System.Exception("foreach missing 'in '");
}
MoveNext();
forEachLoop.Colec = ParseExpr();
// Body for loop
forEachLoop.Body = ParseStmt();
result = forEachLoop;
// end for
if (index == tokens.Count ||
tokens[index] != Tokens.EndSequence)
{
throw new System.Exception("unterminated 'end foreach' loop body");
}
MoveNext();
if (!MaybeEat(Tokens.ForEach))
{
throw new System.Exception("unterminated 'for' body");
}
}
// if
else if (tokens[index] == Tokens.If)
{
IfStmt ifStmt = new IfStmt();
MoveNext();
ifStmt.TestExpr = ParseExpr();
if (index == tokens.Count ||
tokens[index] != Tokens.Then)
{
throw new System.Exception("expected 'then' after if");
}
MoveNext();
ifStmt.BodyIf = ParseStmt();
// Does else
ifStmt.DoElse = MaybeEat(Tokens.Else);
if (ifStmt.DoElse)
{
ifStmt.BodyElse = ParseStmt();
}
result = ifStmt;
if (index == tokens.Count ||
tokens[index] != Tokens.EndSequence)
{
throw new System.Exception("unterminated 'end if' body");
}
MoveNext();
if (!MaybeEat(Tokens.If))
{
throw new System.Exception("unterminated 'if' body");
}
}
// while
else if (tokens[index] == Tokens.While)
{
WhileStmt whileStmt = new WhileStmt();
MoveNext();
whileStmt.TestExpr = ParseExpr();
whileStmt.Body = ParseStmt();
result = whileStmt;
if (index == tokens.Count ||
tokens[index] != Tokens.EndSequence)
{
throw new System.Exception("unterminated 'end while' body");
}
MoveNext();
if (!MaybeEat(Tokens.While))
{
throw new System.Exception("unterminated 'while' body");
}
}
// break
else if (tokens[index] == Tokens.Break)
{
BreakStmt breakStmt = new BreakStmt();
MoveNext();
breakStmt.Tag = "_Break_"; // for debug
result = breakStmt;
}
// assignment or funcionStmt
else if (tokens[index] is IdentifierToken)
{
string ident = ((IdentifierToken)tokens[index]).Name;
MoveNext();
if (MaybeEat(Tokens.Assignment))
{
Assign assign = new Assign();
assign.Ident = ident;
assign.Expr = ParseExpr();
result = assign;
}
else if (MaybeEat(Tokens.LeftBracket))
{
FunctionStmt functionStmt = new FunctionStmt();
functionStmt.Function = ParseFunction(ident);
result = functionStmt;
}
else
{
throw new System.Exception("expected assing or function call");
}
}
else
{
throw new System.Exception("parse error at token " + index + ": " + tokens[index].Name);
}
if ((index < tokens.Count && tokens[index] == Tokens.Semi))
{
MoveNext();
if ((index < tokens.Count && tokens[index] != Tokens.EndSequence) &&
tokens[index] != Tokens.Else)
{
Sequence sequence = new Sequence();
sequence.First = result;
sequence.Second = ParseStmt();
result = sequence;
}
}
return(result);
}
private void RunStmt(Stmt stmt)
{
if (flagBreak)
{
return;
}
//Application.DoEvents();
#region Sequence
if (stmt is Sequence)
{
Sequence seq = (Sequence)stmt;
RunStmt(seq.First);
RunStmt(seq.Second);
}
#endregion
#region DeclareVar
else if (stmt is DeclareVar)
{
// declare
DeclareVar declare = (DeclareVar)stmt;
CodeDeclareSymbol(declare);
//TODO: (Z) Sustituir lo anterior por esto cuando se
// arregle el código de asignación + declaración.
//Assign assign = new Assign();
//assign.Ident = declare.Ident;
//assign.Expr = declare.Expr;
//RunStmt(assign);
}
#endregion
#region Assign
else if (stmt is Assign)
{
Assign assign = (Assign)stmt;
CodeStoreSymbol(assign);
}
#endregion
#region Print / PrintLine / Clear
else if (stmt is Print)
{
Print print = (Print)stmt;
CodeExecutePrint(print);
}
else if (stmt is PrintLine)
{
PrintLine printLine = (PrintLine)stmt;
CodeExecutePrintLine(printLine);
}
else if (stmt is Clear)
{
CodeExecuteClear();
}
#endregion
#region FunctionStmt
else if (stmt is FunctionStmt)
{
FunctionStmt fun = (FunctionStmt)stmt;
CodeExecuteFunction(fun.Function);
}
#endregion
#region ReadVar
else if (stmt is ReadVar)
{
ReadVar read = (ReadVar)stmt;
ReadVarItem readVarItem;
Assign assign;
List <ReadVarItem> readVarItmes = new List <ReadVarItem>();
foreach (var pair in read.Vars)
{
readVarItem = new ReadVarItem();
readVarItem.VarIdent = pair.Key.Ident;
readVarItem.VarValue = CodeReadSymbol(pair.Key);
readVarItem.Label = GenExpr(pair.Value);
readVarItmes.Add(readVarItem);
}
if (CodeExecuteReadVars(readVarItmes))
{
foreach (ReadVarItem vi in readVarItmes)
{
assign = new Assign();
//assign.Ident = vi.Var.Ident;
assign.Ident = vi.VarIdent;
assign.Expr = ValueToExpr(vi.VarValue.GetType(), vi.VarNewValueText);
RunStmt(assign);
}
}
}
#endregion
#region BreakStmt
else if (stmt is BreakStmt)
{
flagBreak = true;
return;
}
#endregion
#region FoorLoop
else if (stmt is ForLoop)
{
// example:
// for x = 0 to 100
// print "hello";
// end for;
ForLoop forLoop = (ForLoop)stmt;
IntVal numFrom = new IntVal();
IntVal numTo = new IntVal();
Assign assignFrom = new Assign();
assignFrom.Ident = forLoop.Ident;
assignFrom.Expr = forLoop.From;
RunStmt(assignFrom);
numFrom.Value = Convert.ToInt32(GenExpr(forLoop.From));
numTo.Value = Convert.ToInt32(GenExpr(forLoop.To));
while (numFrom.Value <= numTo.Value)
{
if (flagBreak)
{
break;
}
RunStmt(forLoop.Body);
numFrom.Value++;
assignFrom.Expr = numFrom;
RunStmt(assignFrom);
}
if (flagBreak)
{
flagBreak = false;
}
}
#endregion
#region FoorEachLoop
else if (stmt is ForEachLoop)
{
// example:
// foreach x in myColec
// print "hello";
// print x.MyProp;
// end foreach;
ForEachLoop forEachLoop = (ForEachLoop)stmt;
object colec = GenExpr(forEachLoop.Colec);
foreach (object o in (IEnumerable <object>)colec)
{
if (flagBreak)
{
break;
}
// TODO: Pending susutiruir CodeSpecialStoreObject by CodeStoreSymbol
// In the future, CodeStoreSymbol should store the variable
// if it had not previously been declared.
CodeSpecialStoreObject(forEachLoop.Ident, o);
// CodeStoreSymbol(forEachLoop.Ident, o);
RunStmt(forEachLoop.Body);
}
if (flagBreak)
{
flagBreak = false;
}
}
#endregion
#region IfStmt
else if (stmt is IfStmt)
{
// example:
// if a == 10 then
// print "hello";
// else
// print "bye";
// end if;
IfStmt ifStmt = (IfStmt)stmt;
IntVal ifExp = new IntVal();
ifExp.Value = Convert.ToInt32(GenExpr(ifStmt.TestExpr));
if (ifExp.Value != 0)
{
RunStmt(ifStmt.BodyIf);
}
else
{
if (ifStmt.DoElse)
{
RunStmt(ifStmt.BodyElse);
}
}
}
#endregion
#region WhileStmt
else if (stmt is WhileStmt)
{
// example:
// while a <= 10
// print "hello";
// a = a + 1;
// end while;
WhileStmt whileStmt = (WhileStmt)stmt;
IntVal whileExp = new IntVal();
while (true)
{
if (flagBreak)
{
break;
}
whileExp.Value = Convert.ToInt32(GenExpr(whileStmt.TestExpr));
if (whileExp.Value == 0)
{
break;
}
RunStmt(whileStmt.Body);
}
if (flagBreak)
{
flagBreak = false;
}
}
#endregion
else
{
throw new System.Exception("don't know how to gen a " + stmt.GetType().Name);
}
}
