/// toplevelexpr ::= expression
private FunctionAST ParseTopLevelExpr()
{
ExprAST e = this.ParseExpression();
if (e == null)
{
return(null);
}
// Make an anonymous proto.
PrototypeAST proto = new PrototypeAST(string.Empty, new List <string>());
return(new FunctionAST(proto, e));
}
// definition ::= 'def' prototype expression
private FunctionAST ParseDefinition()
{
this.scanner.GetNextToken(); // eat def.
PrototypeAST proto = this.ParsePrototype();
if (proto == null)
{
return(null);
}
ExprAST body = this.ParseExpression();
if (body == null)
{
return(null);
}
return(new FunctionAST(proto, body));
}
public FunctionAST(PrototypeAST protptype, ExprAST body)
{
Protptype = protptype ?? throw new ArgumentNullException(nameof(protptype));
Body = body ?? throw new ArgumentNullException(nameof(body));
}