Grammar

gistfile1.txt

using System.Linq;
using System.Runtime.CompilerServices;

using Eto.Parse;
using Eto.Parse.Parsers;

namespace TestSpace.Grammar
{
    /// <summary>
    /// A macro grammar definition.
    /// </summary>
    internal static class MacroGrammar
    {
        private static readonly Parser Digits = Terminals.Digit.Repeat();
        private static readonly Parser FloatingNumber = Digits & ('.' & Digits).Optional();

        private static readonly Parser Whitespace = Terminals.SingleLineWhiteSpace.Repeat();
        private static readonly Parser OptWhitespace = Whitespace.Optional();

        private static readonly Parser Eol = Terminals.Eol | Terminals.End;
        private static readonly Parser AnyUntilEol = Terminals.AnyChar.Except(Terminals.Eol).Repeat(0).Until(Eol);

        private static readonly Parser Quote = Terminals.Set('"');
        private static readonly Parser Ident = (Terminals.LetterOrDigit | "'").Repeat();

        private static readonly Parser Comment = (Terminals.Set('#') | "//") & AnyUntilEol.Named("comment");
        private static readonly Parser EolWhitespaceOrComment = OptWhitespace & Comment.Optional();

        private static readonly Parser ActionParser =
            ((Literal("/action") | Literal("/ac")
            & Whitespace & Identifier("actionName")).Named("command")
            & EolWhitespaceOrComment).Named("actionCommand");

        public static Eto.Parse.Grammar Definition { get; } = new(
            Terminals.Start
            & (Whitespace | ActionParser | Comment).Repeat(0).SeparatedBy(Terminals.Eol)
            & Terminals.End);

        private static Parser Literal(string value) => new LiteralTerminal(value) { CaseSensitive = false };

        private static Parser Identifier(string name) => Ident.Named(name) | (Quote & Ident.Repeat().SeparatedBy(Whitespace).Named(name) & Quote);
    }
}