private void WaddleFunctionDeclaration(FunctionDeclSyntax functionSyntax)
{
var parameters =
functionSyntax.Parameters.Select(param => new VariableDecl(param !.Name, param !.TypeSyntax.ToSymbol())).ToArray();
var function = new FunctionDecl(functionSyntax.Name, functionSyntax.ReturnType?.ToSymbol(),
functionSyntax.Body.Statements
.OfType <DeclStmtSyntax>()
.Select(stmt => new VariableDecl(stmt.ParameterDeclSyntax.Name, stmt.ParameterDeclSyntax.TypeSyntax.ToSymbol()))
.Concat(parameters),
parameters);
_functions.Add(function.Name, function);
}