private Syntax.Statement ParseStmt()
{
Syntax.Statement node = null;
const string NOT_CYCLE = "оператор можно использовать только внутри цикла";
switch (scan.Peek().type)
{
case Token.Type.KW_WHILE:
this.parse_cycle = true;
try
{
scan.Read();
CheckToken(scan.Peek(), Token.Type.LPAREN, true);
Syntax.Expression cond = ParseExpression();
node = new Syntax.WHILE(cond);
CheckToken(scan.Peek(), Token.Type.RPAREN, true);
((Syntax.WHILE)node).SetCycleStatement(ParseStmt());
}
catch (Exception e)
{
this.parse_cycle = false;
throw e;
}
break;
case Token.Type.KW_DO:
this.parse_cycle = true;
try
{
scan.Read();
node = new Syntax.DO(ParseStmt());
CheckToken(scan.Peek(), Token.Type.KW_WHILE, true);
CheckToken(scan.Peek(), Token.Type.LPAREN, true);
((Syntax.DO)node).SetCondition(ParseExpression());
CheckToken(scan.Peek(), Token.Type.RPAREN, true);
CheckToken(scan.Peek(), Token.Type.SEMICOLON, true);
}
catch (Exception e)
{
this.parse_cycle = false;
throw e;
}
break;
case Token.Type.KW_FOR:
this.parse_cycle = true;
try
{
scan.Read();
CheckToken(scan.Peek(), Token.Type.LPAREN, true);
node = new Syntax.FOR();
((Syntax.FOR)node).SetCounter(
((Syntax.StatementExpression)ParseStmExpression()).GetExpression()
);
((Syntax.FOR)node).SetCondition(
((Syntax.StatementExpression)ParseStmExpression()).GetExpression()
);
if (scan.Peek().type != Token.Type.RPAREN)
{
((Syntax.FOR)node).SetIncriment(ParseExpression());
}
CheckToken(scan.Peek(), Token.Type.RPAREN, true);
((Syntax.FOR)node).SetCycleStatement(ParseStmt());
}
catch (Exception e)
{
this.parse_cycle = false;
throw e;
}
break;
case Token.Type.KW_IF:
scan.Read();
CheckToken(scan.Peek(), Token.Type.LPAREN, true);
node = new Syntax.IF(ParseExpression());
CheckToken(scan.Peek(), Token.Type.RPAREN, true);
((Syntax.IF)node).SetBranchTrue(ParseStmt());
if (scan.Peek().type == Token.Type.KW_ELSE)
{
scan.Read();
((Syntax.IF)node).SetBranchFalse(ParseStmt());
}
break;
case Token.Type.LBRACE:
node = ParseCompound();
break;
case Token.Type.KW_RETURN:
scan.Read();
if (scan.Peek().type != Token.Type.SEMICOLON)
{
node = new Syntax.RETURN(this.ret_func_type);
((Syntax.RETURN)node).SetValue(ParseExpression());
}
else
{
node = new Syntax.RETURN(this.ret_func_type);
((Syntax.RETURN)node).SetValue(new Syntax.EmptyExpression());
}
CheckToken(scan.Peek(), Token.Type.SEMICOLON, true);
break;
case Token.Type.KW_BREAK:
if (!this.parse_cycle)
{
this.logger.Add(new Syntax.Exception(NOT_CYCLE, scan.GetPos(), scan.GetLine()));
}
try
{
scan.Read();
node = new Syntax.BREAK();
CheckToken(scan.Peek(), Token.Type.SEMICOLON, true);
}
catch (Exception e)
{
if (this.parse_cycle)
{
throw e;
}
}
break;
case Token.Type.KW_CONTINUE:
if (!this.parse_cycle)
{
this.logger.Add(new Syntax.Exception(NOT_CYCLE, scan.GetPos(), scan.GetLine()));
}
try
{
scan.Read();
node = new Syntax.CONTINUE();
CheckToken(scan.Peek(), Token.Type.SEMICOLON, true);
}
catch (Exception e)
{
if (this.parse_cycle)
{
throw e;
}
}
break;
default:
node = ParseStmExpression();
break;
}
return node;
}
private Syntax.Statement ParseStmt()
{
Syntax.Statement node = null;
const string NOT_CYCLE = "оператор можно использовать только внутри цикла";
switch (scan.Peek().type)
{
case Token.Type.KW_WHILE:
this.parse_cycle = true;
try
{
scan.Read();
CheckToken(scan.Peek(), Token.Type.LPAREN, true);
Syntax.Expression cond = ParseExpression();
node = new Syntax.WHILE(cond);
CheckToken(scan.Peek(), Token.Type.RPAREN, true);
((Syntax.WHILE)node).SetCycleStatement(ParseStmt());
}
catch (Exception e)
{
this.parse_cycle = false;
throw e;
}
break;
case Token.Type.KW_DO:
this.parse_cycle = true;
try
{
scan.Read();
node = new Syntax.DO(ParseStmt());
CheckToken(scan.Peek(), Token.Type.KW_WHILE, true);
CheckToken(scan.Peek(), Token.Type.LPAREN, true);
((Syntax.DO)node).SetCondition(ParseExpression());
CheckToken(scan.Peek(), Token.Type.RPAREN, true);
CheckToken(scan.Peek(), Token.Type.SEMICOLON, true);
}
catch (Exception e)
{
this.parse_cycle = false;
throw e;
}
break;
case Token.Type.KW_FOR:
this.parse_cycle = true;
try
{
scan.Read();
CheckToken(scan.Peek(), Token.Type.LPAREN, true);
node = new Syntax.FOR();
((Syntax.FOR)node).SetCounter(
((Syntax.StatementExpression)ParseStmExpression()).GetExpression()
);
((Syntax.FOR)node).SetCondition(
((Syntax.StatementExpression)ParseStmExpression()).GetExpression()
);
if (scan.Peek().type != Token.Type.RPAREN)
{
((Syntax.FOR)node).SetIncriment(ParseExpression());
}
CheckToken(scan.Peek(), Token.Type.RPAREN, true);
((Syntax.FOR)node).SetCycleStatement(ParseStmt());
}
catch (Exception e)
{
this.parse_cycle = false;
throw e;
}
break;
case Token.Type.KW_IF:
scan.Read();
CheckToken(scan.Peek(), Token.Type.LPAREN, true);
node = new Syntax.IF(ParseExpression());
CheckToken(scan.Peek(), Token.Type.RPAREN, true);
((Syntax.IF)node).SetBranchTrue(ParseStmt());
if (scan.Peek().type == Token.Type.KW_ELSE)
{
scan.Read();
((Syntax.IF)node).SetBranchFalse(ParseStmt());
}
break;
case Token.Type.LBRACE:
node = ParseCompound();
break;
case Token.Type.KW_RETURN:
scan.Read();
if (scan.Peek().type != Token.Type.SEMICOLON)
{
node = new Syntax.RETURN(this.ret_func_type);
((Syntax.RETURN)node).SetValue(ParseExpression());
}
else
{
node = new Syntax.RETURN(this.ret_func_type);
((Syntax.RETURN)node).SetValue(new Syntax.EmptyExpression());
}
CheckToken(scan.Peek(), Token.Type.SEMICOLON, true);
break;
case Token.Type.KW_BREAK:
if (!this.parse_cycle)
{
this.logger.Add(new Syntax.Exception(NOT_CYCLE, scan.GetPos(), scan.GetLine()));
}
try
{
scan.Read();
node = new Syntax.BREAK();
CheckToken(scan.Peek(), Token.Type.SEMICOLON, true);
}
catch (Exception e)
{
if (this.parse_cycle)
{
throw e;
}
}
break;
case Token.Type.KW_CONTINUE:
if (!this.parse_cycle)
{
this.logger.Add(new Syntax.Exception(NOT_CYCLE, scan.GetPos(), scan.GetLine()));
}
try
{
scan.Read();
node = new Syntax.CONTINUE();
CheckToken(scan.Peek(), Token.Type.SEMICOLON, true);
}
catch (Exception e)
{
if (this.parse_cycle)
{
throw e;
}
}
break;
default:
node = ParseStmExpression();
break;
}
return(node);
}
