private Statements ParseStatements()
{
Statements statements = new Statements();
Statement st;
while ((st = this.ParseStatement()) != null)
{
statements.AddStatement(st);
}
return(statements);
}
public Program Parse(List <Token> tokens)
{
this.tokens = tokens;
Program prog = new Program();
Statements st = this.ParseStatements();
if (st != null)
{
prog.AddStatement(st);
}
return(prog);
}
private Function ParseFunction()
{
string name = "";
if (this.CurrentType == TokenType.ALPHANUMERIC)
{
name = this.Pop().Value;
}
if (this.CurrentType != TokenType.L_PAREN)
{
return(null);
}
this.Pop();
List <string> parameters = new List <string>();
while (this.CurrentType == TokenType.ALPHANUMERIC)
{
parameters.Add(this.Pop().Value);
if (this.CurrentType == TokenType.COMMA)
{
this.Pop();
}
}
if (this.CurrentType != TokenType.R_PAREN)
{
return(null);
}
this.Pop();
if (this.CurrentType != TokenType.L_BRACE)
{
return(null);
}
this.Pop();
Statements st = this.ParseStatements();
Expression returnValue = null;
if (this.CurrentType == TokenType.RETURN)
{
this.Pop();
returnValue = this.ParseExpression();
if (this.CurrentType != TokenType.SEMI)
{
return(null);
}
this.Pop();
}
if (this.CurrentType != TokenType.R_BRACE)
{
return(null);
}
this.Pop();
return(new Function(name, st, parameters, returnValue));
}
private Statement ParseStatement()
{
while (this.CurrentType == TokenType.LINE_END)
{
this.Pop();
}
TokenType type = this.CurrentType;
if (type == TokenType.FUNCTION)
{
this.Pop();
Function fun = this.ParseFunction();
return(new FunctionStatement(StatementType.FUNC_DECL, fun));
}
else if (type == TokenType.IF)
{
this.Pop();
Condition cnd = this.ParseCondition();
if (this.CurrentType != TokenType.L_BRACE)
{
return(null);
}
this.Pop();
Statements st1 = this.ParseStatements();
if (this.CurrentType != TokenType.R_BRACE)
{
return(null);
}
this.Pop();
if (this.CurrentType == TokenType.ELSE)
{
this.Pop();
if (this.CurrentType != TokenType.L_BRACE)
{
return(null);
}
this.Pop();
Statements st2 = this.ParseStatements();
if (this.CurrentType != TokenType.R_BRACE)
{
return(null);
}
this.Pop();
return(new IfElseStatement(StatementType.IF_ELSE, cnd, st1, st2));
}
else
{
return(new IfStatement(StatementType.IF, cnd, st1));
}
}
else if (type == TokenType.WHILE)
{
this.Pop();
Condition cnd = this.ParseCondition();
if (this.CurrentType != TokenType.L_BRACE)
{
return(null);
}
this.Pop();
Statements st = this.ParseStatements();
if (this.CurrentType != TokenType.R_BRACE)
{
return(null);
}
this.Pop();
return(new WhileStatement(StatementType.WHILE, cnd, st));
}
else if (type == TokenType.RETURN)
{
this.Pop();
Expression returnValue = this.ParseExpression();
if (this.CurrentType != TokenType.SEMI)
{
return(null);
}
this.Pop();
return(new FunctionStatement(StatementType.RETURN, returnValue));
}
else
{
if (this.NextType != TokenType.L_PAREN)
{
Assignment asg = this.ParseAssignment();
if (asg == null)
{
return(null);
}
else
{
return(new AssignmentStatement(StatementType.ASSIGN, asg));
};
}
else
{
Expression fun = this.ParseExpression();
if (fun == null)
{
return(null);
}
else
{
if (this.CurrentType != TokenType.SEMI)
{
return(null);
}
this.Pop();
return(new FunctionStatement(StatementType.FUNCTION, fun));
}
}
}
}
public void AddStatement(Statements st)
{
this.statemets.AddRange(st.statemets);
}
public Function(string name, Statements inner, List <string> parameters, Expression returnValue)
{
this.Name = name;
this.Parameters = parameters;
this.innerStatements = inner;
}