/// <summary>
/// Visit a parse tree produced by <see cref="Z80EvalParser.literalExpr"/>.
/// <para>
/// The default implementation returns the result of calling <see cref="AbstractParseTreeVisitor{Result}.VisitChildren(IRuleNode)"/>
/// on <paramref name="context"/>.
/// </para>
/// </summary>
/// <param name="context">The parse tree.</param>
/// <return>The visitor result.</return>
public override object VisitLiteralExpr(Z80EvalParser.LiteralExprContext context)
{
if (IsInvalidContext(context))
{
return(null);
}
var token = context.GetText();
ushort value;
// --- Hexadecimal literals
if (token.StartsWith("#"))
{
value = ushort.Parse(token.Substring(1), NumberStyles.HexNumber);
}
else if (token.StartsWith("0x"))
{
value = ushort.Parse(token.Substring(2), NumberStyles.HexNumber);
}
else if (token.EndsWith("h", StringComparison.OrdinalIgnoreCase))
{
value = (ushort)int.Parse(token.Substring(0, token.Length - 1),
NumberStyles.HexNumber);
}
// --- Binary literals
else if (token.StartsWith("%"))
{
value = (ushort)Convert.ToInt32(token.Substring(1).Replace("_", ""), 2);
}
else if (token.StartsWith("0b"))
{
value = (ushort)Convert.ToInt32(token.Substring(2).Replace("_", ""), 2);
}
// --- Character literals
else if (token.StartsWith("'"))
{
var charExpr = context.GetText();
var bytes = SyntaxHelper.SpectrumStringToBytes(charExpr.Substring(1, charExpr.Length - 2));
value = bytes.Count == 0 ? (ushort)0x00 : bytes[0];
}
// --- Decimal literals
else
{
value = int.TryParse(context.GetText(), out var shortVal) ? (ushort)shortVal : (ushort)0;
}
return(new LiteralNode(value, token));
}
/// <summary>
/// Visit a parse tree produced by <see cref="Z80EvalParser.literalExpr"/>.
/// <para>
/// The default implementation returns the result of calling <see cref="AbstractParseTreeVisitor{Result}.VisitChildren(IRuleNode)"/>
/// on <paramref name="context"/>.
/// </para>
/// </summary>
/// <param name="context">The parse tree.</param>
/// <return>The visitor result.</return>
public virtual Result VisitLiteralExpr([NotNull] Z80EvalParser.LiteralExprContext context)
{
return(VisitChildren(context));
}
/// <summary>
/// Exit a parse tree produced by <see cref="Z80EvalParser.literalExpr"/>.
/// <para>The default implementation does nothing.</para>
/// </summary>
/// <param name="context">The parse tree.</param>
public virtual void ExitLiteralExpr([NotNull] Z80EvalParser.LiteralExprContext context)
{
}
