/// <summary>
/// Generates a standard error checking sequence.
/// E.g. if err != nil return err
/// </summary>
/// <param name="errorVar">The name of the error variable.</param>
/// <param name="onError">How the error should be handled.</param>
/// <returns>The root node of this error checking AST.</returns>
public static Node Generate(string errorVar, OnError onError)
{
if (string.IsNullOrWhiteSpace(errorVar))
{
throw new ArgumentException(nameof(errorVar));
}
Node handler = null;
switch (onError)
{
case OnError.Panic:
handler = FunctionCall.Generate("panic", new[]
{
new FuncCallParam(new Identifier(errorVar), TypeModifier.ByValue)
});
break;
case OnError.ReturnError:
var ret = new Return();
ret.AddChild(new Identifier(errorVar));
handler = ret;
break;
default:
throw new NotImplementedException($"OnError state {onError} NYI");
}
var node = IfBlock.Generate(BinaryOpSequence.Generate(BinaryOperatorType.NotEqualTo, new Identifier(errorVar), new Nil()), new[]
{
handler
});
return(node);
}
/// <summary>
/// Generates a standard error checking sequence.
/// E.g. if err != nil return var1, var2, varN
/// </summary>
/// <param name="errorVar">The name of the error variable.</param>
/// <param name="toReturn">
/// List of variables to return. All variables in
/// this list will be returned in the specified order.
/// </param>
/// <returns>The root node of this error checking AST.</returns>
public static Node Generate(string errorVar, IReadOnlyList <Node> toReturn)
{
var ret = new Return();
ret.AddChild(DelimitedSequence.Generate(UnaryDelimiterType.Comma, toReturn));
var node = IfBlock.Generate(BinaryOpSequence.Generate(BinaryOperatorType.NotEqualTo, new Identifier(errorVar), new Nil()), new[]
{
ret
});
return(node);
}
/// <summary>
/// Generates a return statement with optional list of variables.
/// </summary>
/// <param name="varNames">Optional list of variables to be returned. Pass null if there are no variables to return.</param>
/// <returns>Root node in this return statement AST.</returns>
public static Node Generate(IReadOnlyList <string> varNames)
{
if (varNames != null && varNames.Count == 0)
{
throw new ArgumentException("pass null for no arguments to return");
}
var ret = new Return();
if (varNames != null)
{
Node[] returnVars = new Node[varNames.Count];
for (int i = 0; i < returnVars.Length; ++i)
{
returnVars[i] = new Identifier(varNames[i]);
}
ret.AddChild(DelimitedSequence.Generate(UnaryDelimiterType.Comma, returnVars));
}
return(ret);
}