public bool InterpreteNextAST()
{
if (Input.IsEnd())
{
return(false);
}
try
{
switch (Input.Peek().ASTType)
{
// Valid cases...
case AST.Classification.Say:
InterpreteSay();
return(true);
case AST.Classification.Set:
InterpreteSet();
return(true);
case AST.Classification.Choice:
InterpreteChoice();
return(true);
case AST.Classification.Label:
InterpreteLabel();
return(true);
case AST.Classification.Jump:
InterpreteJump();
return(true);
case AST.Classification.Return:
InterpreteReturn();
return(true);
case AST.Classification.LineBreak:
break;
// Some invalid cases... Not a statement.
case AST.Classification.Identifier:
throw new InvalidStatementPassedException("An identifier cannot be used as a statement.");
case AST.Classification.String:
throw new InvalidStatementPassedException("A string cannot be used as a statement.");
case AST.Classification.Boolean:
throw new InvalidStatementPassedException("A boolean value cannot be used as a statement.");
case AST.Classification.Number:
throw new InvalidStatementPassedException("A number value cannot be used as a statement.");
case AST.Classification.Of:
throw new InvalidStatementPassedException("Of statements cannot be used alone. They must be used with Set statements.");
default:
throw new InvalidStatementPassedException($"Invalid statement AST {Input.Peek().ASTType} was passed. An element such as Number cannot be a statement.");
}
if (Input.Peek().ASTType != AST.Classification.LineBreak)
{
throw new InvalidStatementPassedException("Each statements must be separated by line break.");
}
Input.Read(); // Remove the line break AST
}
catch (Exception e)
{
OutputManager.Exception(e);
}
return(true);
}
public AST ParseNextToken()
{
if (Input.IsEnd())
{
return(null);
}
AST ParsedAST = null;
// Keyword Parsing
if (IsKeyword("set"))
{
ParsedAST = ParseSet();
}
else if (IsKeyword("true") || IsKeyword("false"))
{
ParsedAST = ParseBoolean();
}
else if (IsKeyword("choice"))
{
ParsedAST = ParseChoice();
}
else if (IsKeyword("label"))
{
ParsedAST = ParseLabel();
}
else if (IsKeyword("return") || IsKeyword("done"))
{
ParsedAST = ParseReturn();
}
else if (IsKeyword("Jump"))
{
ParsedAST = ParseJump();
}
// Literals and Identifiers
else if (Input.Peek().TokenType == Token.Classification.Number)
{
ParsedAST = ParseNumber();
}
else if (Input.Peek().TokenType == Token.Classification.String)
{
ParsedAST = ParseString();
}
else if (Input.Peek().TokenType == Token.Classification.Identifier)
{
ParsedAST = Maybe(ParseSay, ParseOf);
}
else if (Input.Peek().TokenType == Token.Classification.LineBreak)
{
ParsedAST = ParseLineBreak();
}
// Highly unlikely, but just in case...
else
{
throw new UnexpectedTokenException($"The type of provided token is unknown ({Input.Peek().TokenType}). What have you done.");
}
return(ParsedAST);
}
