这是一个相对简单（并且希望易于扩展）的解决方案：
public delegate object Acceptor(Token token, string match);
public class Symbol
{
public Symbol(string id) { Id = id ?? Guid.NewGuid().ToString("P"); }
public override string ToString() => Id;
public string Id { get; private set; }
}
public class Token : Symbol
{
internal Token(string id) : base(id) { }
public Token(string pattern, Acceptor acceptor) : base(pattern) { Regex = new Regex(string.Format("^({0})", !string.IsNullOrEmpty(Pattern = pattern) ? Pattern : ".*"), RegexOptions.Compiled); ValueOf = acceptor; }
public string Pattern { get; private set; }
public Regex Regex { get; private set; }
public Acceptor ValueOf { get; private set; }
}
public class SExpressionSyntax
{
private readonly Token Space = Token("\\s+", Echo);
private readonly Token Open = Token("\\(", Echo);
private readonly Token Close = Token("\\)", Echo);
private readonly Token Quote = Token("\\'", Echo);
private Token comment;
private static Exception Error(string message, params object[] arguments) => new Exception(string.Format(message, arguments));
private static object Echo(Token token, string match) => new Token(token.Id);
private static object Quoting(Token token, string match) => NewSymbol(token, match);
private Tuple<Token, string, object> Read(ref string input)
{
if (!string.IsNullOrEmpty(input))
{
var found = null as Match;
var sofar = input;
var tuple = Lexicon.FirstOrDefault(current => (found = current.Item2.Regex.Match(sofar)).Success && (found.Length > 0));
var token = tuple != null ? tuple.Item2 : null;
var match = token != null ? found.Value : null;
input = match != null ? input.Substring(match.Length) : input;
return token != null ? Tuple.Create(token, match, token.ValueOf(token, match)) : null;
}
return null;
}
private Tuple<Token, string, object> Next(ref string input)
{
Tuple<Token, string, object> read;
while (((read = Read(ref input)) != null) && ((read.Item1 == Comment) || (read.Item1 == Space))) ;
return read;
}
public object Parse(ref string input, Tuple<Token, string, object> next)
{
var value = null as object;
if (next != null)
{
var token = next.Item1;
if (token == Open)
{
var list = new List<object>();
while (((next = Next(ref input)) != null) && (next.Item1 != Close))
{
list.Add(Parse(ref input, next));
}
if (next == null)
{
throw Error("unexpected EOF");
}
value = list.ToArray();
}
else if (token == Quote)
{
var quote = next.Item3;
next = Next(ref input);
value = new[] { quote, Parse(ref input, next) };
}
else
{
value = next.Item3;
}
}
else
{
throw Error("unexpected EOF");
}
return value;
}
protected Token TokenOf(Acceptor acceptor)
{
var found = Lexicon.FirstOrDefault(pair => pair.Item2.ValueOf == acceptor);
var token = found != null ? found.Item2 : null;
if ((token == null) && (acceptor != Commenting))
{
throw Error("missing required token definition: {0}", acceptor.Method.Name);
}
return token;
}
protected IList<Tuple<string, Token>> Lexicon { get; private set; }
protected Token Comment { get { return comment = comment ?? TokenOf(Commenting); } }
public static Token Token(string pattern, Acceptor acceptor) => new Token(pattern, acceptor);
public static object Commenting(Token token, string match) => Echo(token, match);
public static object NewSymbol(Token token, string match) => new Symbol(match);
public static Symbol Symbol(object value) => value as Symbol;
public static string Moniker(object value) => Symbol(value) != null ? Symbol(value).Id : null;
public static string ToString(object value)
{
return
value is object[] ?
(
((object[])value).Length > 0 ?
((object[])value).Aggregate(new StringBuilder("("), (result, obj) => result.AppendFormat(" {0}", ToString(obj))).Append(" )").ToString()
:
"( )"
)
:
(value != null ? (value is string ? string.Concat('"', (string)value, '"') : (value is bool ? value.ToString().ToLower() : value.ToString())).Replace("\\\r\n", "\r\n").Replace("\\\n", "\n").Replace("\\t", "\t").Replace("\\n", "\n").Replace("\\r", "\r").Replace("\\\"", "\"") : null) ?? "(null)";
}
public SExpressionSyntax()
{
Lexicon = new List<Tuple<string, Token>>();
Include(Space, Open, Close, Quote);
}
public SExpressionSyntax Include(params Token[] tokens)
{
foreach (var token in tokens)
{
Lexicon.Add(new Tuple<string, Token>(token.Id, token));
}
return this;
}
public object Parse(string input)
{
var next = Next(ref input);
var value = Parse(ref input, next);
if ((next = Next(ref input)) != null)
{
throw Error("unexpected ", next.Item1);
}
return value;
}
}
public class CustomSExpressionSyntax : SExpressionSyntax
{
public CustomSExpressionSyntax()
: base()
{
Include
(
// "//" comments
Token("\\/\\/.*", SExpressionSyntax.Commenting),
// Obvious
Token("false", (token, match) => false),
Token("true", (token, match) => true),
Token("null", (token, match) => null),
Token("\\-?[0-9]+\\.[0-9]+", (token, match) => double.Parse(match)),
Token("\\-?[0-9]+", (token, match) => int.Parse(match)),
// String literals
Token("\\\"(\\\\\\n|\\\\t|\\\\n|\\\\r|\\\\\\\"|[^\\\"])*\\\"", (token, match) => match.Substring(1, match.Length - 2)),
// Identifiers
Token("[_A-Za-z][_0-9A-Za-z]*", NewSymbol)
);
}
}
public class Node { }
public class HearPerceptorState : Node
{
public string Ident { get; set; }
public double Value { get; set; }
}
public class HingeJointState : Node
{
public string Ident { get; set; }
public double Value { get; set; }
}
public class Polar : Tuple<double, double, double>
{
public Polar(double a, double b, double c) : base(a, b, c) { }
}
public class ForceResistancePerceptorState : Node
{
public string Ident { get; set; }
public Polar Polar { get; set; }
}
public class Test
{
public static void Main()
{
var input = @"
(
(Hear 12.3 HelloWorld)
(HJ LAJ1 -0.42)
(FRP lf (pos 2.3 1.7 0.4))
)
";
// visit DRY helpers
Func<object, object[]> asRecord = value => (object[])value;
Func<object, Symbol> symbol = value => SExpressionSyntax.Symbol(value);
Func<object, string> identifier = value => symbol(value).Id;
// the SExpr visit, proper
Func<object[], Node[]> visitAll = null;
Func<object[], Node> visitHear = null;
Func<object[], Node> visitHJ = null;
Func<object[], Node> visitFRP = null;
visitAll =
all =>
all.
Select
(
item =>
symbol(asRecord(item)[0]).Id != "Hear" ?
(
symbol(asRecord(item)[0]).Id != "HJ" ?
visitFRP(asRecord(item))
:
visitHJ(asRecord(item))
)
:
visitHear(asRecord(item))
).
ToArray();
visitHear =
item =>
new HearPerceptorState { Value = (double)asRecord(item)[1], Ident = identifier(asRecord(item)[2]) };
visitHJ =
item =>
new HingeJointState { Ident = identifier(asRecord(item)[1]), Value = (double)asRecord(item)[2] };
visitFRP =
item =>
new ForceResistancePerceptorState
{
Ident = identifier(asRecord(item)[1]),
Polar =
new Polar
(
(double)asRecord(asRecord(item)[2])[1],
(double)asRecord(asRecord(item)[2])[2],
(double)asRecord(asRecord(item)[2])[3]
)
};
var syntax = new CustomSExpressionSyntax();
var sexpr = syntax.Parse(input);
var nodes = visitAll(asRecord(sexpr));
Console.WriteLine("SO_3051254");
Console.WriteLine();
Console.WriteLine(nodes.Length == 3);
Console.WriteLine(nodes[0] is HearPerceptorState);
Console.WriteLine(nodes[1] is HingeJointState);
Console.WriteLine(nodes[2] is ForceResistancePerceptorState);
}
}
可在此处测试：
https://repl.it/CnLC/1
'HTH,