423 lines
17 KiB
C#
423 lines
17 KiB
C#
using System.Reflection;
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using Jellyfin.Plugin.SmartPlaylist.Lisp.Compiler;
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namespace Jellyfin.Plugin.SmartPlaylist.Lisp {
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using Function = Func<IEnumerable<Expression>, Expression>;
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using FunctionLater = Func<Executor, IEnumerable<Expression>, Expression>;
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public interface IEnvironment<K, V> {
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public V? Get(K k);
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public void Set(K k, V v);
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public IEnvironment<K, V>? Find(K k);
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public IEnvironment<K, V> Parent(bool recursive);
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}
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public class Environment : Dictionary<string, Expression>, IEnvironment<string, Expression> {
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public Expression? Get(string k) {
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if (TryGetValue(k, out Expression? v)) {
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return v;
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}
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return null;
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}
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public void Set(string k, Expression v) {
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this[k] = v;
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}
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public IEnvironment<string, Expression>? Find(string k) {
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if (ContainsKey(k)) {
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return this;
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}
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return null;
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}
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public IEnvironment<string, Expression> Parent(bool recursive) {
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return this;
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}
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}
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public class DefaultEnvironment: Environment {
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public DefaultEnvironment() {
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var e = new Executor();
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this["null"] = new Symbol("not");
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this["list"] = e.eval("(lambda (. args) args)");
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this["find"] = e.eval("(lambda (item list_) (if (null list_) nil (if (= item (car list_)) (car list_) (find item (cdr list_)))))");
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this["map"] = e.eval("(lambda (fc l) (if (null l) nil (cons (fc (car l)) (map fc (cdr l)))))");
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this["fold"] = e.eval("(lambda (fc i l) (if (null l) i (fold fc (fc i (car l)) (cdr l))))");
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this["any"] = e.eval("(lambda (fc l) (apply or (map fc l)))");
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this["all"] = e.eval("(lambda (fc l) (apply and (map fc l)))");
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}
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}
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public class SubEnvironment : Dictionary<string, Expression>, IEnvironment<string, Expression> {
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private IEnvironment<string, Expression> _super;
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public SubEnvironment(IEnvironment<string, Expression> super) {
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_super = super;
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}
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public Expression? Get(string k) {
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if (TryGetValue(k, out Expression? v)) {
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return v;
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}
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return null;
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}
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public void Set(string k, Expression v) {
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Add(k, v);
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}
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public IEnvironment<string, Expression>? Find(string k) {
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if (ContainsKey(k)) {
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return this;
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}
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return _super.Find(k);
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}
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public IEnvironment<string, Expression> Parent(bool recursive) {
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if (recursive) {
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return this._super.Parent(recursive);
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}
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return this._super;
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}
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}
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public class Builtins : Dictionary<string, Function> {
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public Builtins() : base() {
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this["atom"] = _atom;
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this["eq"] = _eq;
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this["car"] = _car;
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this["cdr"] = _cdr;
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this["cons"] = _cons;
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this["begin"] = _begin;
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this["+"] = (x) => _agg((Integer a, Integer b) => a + b, x);
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this["-"] = (x) => _agg((Integer a, Integer b) => a - b, x);
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this["*"] = (x) => _agg((Integer a, Integer b) => a * b, x);
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this["/"] = (x) => _agg((Integer a, Integer b) => a / b, x);
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this["%"] = (x) => _agg((Integer a, Integer b) => a % b, x);
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this["="] = (x) => _cmp((Integer a, Integer b) => a == b, x);
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this["eq?"] = (x) => _cmp((Integer a, Integer b) => a == b, x);
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this["<"] = (x) => _cmp((Integer a, Integer b) => a < b, x);
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this["<="] = (x) => _cmp((Integer a, Integer b) => a <= b, x);
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this[">"] = (x) => _cmp((Integer a, Integer b) => a > b, x);
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this[">="] = (x) => _cmp((Integer a, Integer b) => a >= b, x);
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this["!="] = (x) => _cmp((Integer a, Integer b) => a != b, x);
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this["not"] = (x) => {
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return (x.First() == Boolean.FALSE) ? Boolean.TRUE : Boolean.FALSE;
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};
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this["haskeys"] = _haskeys;
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this["getitems"] = _getitems;
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this["invoke"] = _invoke;
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}
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private static T _agg<T>(Func<T, T, T> op, IEnumerable<Expression> args) where T : Expression {
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T agg = (T) args.First();
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foreach (var arg in args.Skip(1)) {
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var arg_ = (T) arg;
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agg = op(agg, arg_);
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}
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return agg;
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}
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private static E _cmp<T, E>(Func<T, T, E> op, IEnumerable<Expression> args) where T : Expression where E : Expression {
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return op((T) args.First(), (T) args.Skip(1).First());
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}
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private static Expression _atom(IEnumerable<Expression> args) {
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return (args.First() is Atom) ? Boolean.TRUE : Boolean.FALSE;
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}
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private static Expression _eq(IEnumerable<Expression> args) {
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return args.First().Equals(args.Skip(1).First()) ? Boolean.TRUE : Boolean.FALSE;
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}
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private static Expression _car(IEnumerable<Expression> args) {
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return ((Cons)args.First()).Item1;
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}
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private static Expression _cdr(IEnumerable<Expression> args) {
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return ((Cons)args.First()).Item2;
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}
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private static Expression _cons(IEnumerable<Expression> args) {
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return new Cons(args.First(), args.Skip(1).First());
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}
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private static Expression _begin(IEnumerable<Expression> args) {
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return args.Last();
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}
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private static Expression _haskeys(IEnumerable<Expression> args) {
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Object o = new Object(((IInner) args.First()).Inner());
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foreach (var e in args.Skip(1)) {
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String s = (String) e;
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PropertyInfo? pi = o.Value().GetType().GetProperty(s.Value());
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if (pi != null) {
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continue;
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}
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MethodInfo? mi = o.Value().GetType().GetMethod(s.Value());
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if (mi != null) {
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continue;
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}
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FieldInfo? fi = o.Value().GetType().GetField(s.Value());
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if (fi != null) {
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continue;
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}
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return Boolean.FALSE;
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}
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return Boolean.TRUE;
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}
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private static Expression _getitems(IEnumerable<Expression> args) {
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Object o = new Object(((IInner) args.First()).Inner());
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IList<Expression> r = new List<Expression>();
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foreach (var e in args.Skip(1)) {
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String s = (String) e;
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PropertyInfo? pi = o.Value().GetType().GetProperty(s.Value());
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if (pi != null) {
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r.Add(Object.FromBase(pi.GetValue(o.Value())));
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continue;
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}
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FieldInfo? fi = o.Value().GetType().GetField(s.Value());
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if (fi != null) {
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r.Add(Object.FromBase(fi.GetValue(o.Value())));
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continue;
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}
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throw new ApplicationException($"{o.Value()} has no property or field {s.Value()}");
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}
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return Cons.FromList(r);
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}
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private static Expression _invoke(IEnumerable<Expression> args) {
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Object o = new Object(((IInner) args.First()).Inner());
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String s = (String) args.Skip(1).First();
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IEnumerable<Expression> l;
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if (args.Skip(2).First() is Boolean lb && lb == Boolean.FALSE) {
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l = new List<Expression>();
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} else if (args.Skip(2).First() is Cons lc) {
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l = lc.ToList();
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} else {
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throw new ApplicationException($"Expected a list of arguments, got {args.Skip(2).First()}");
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}
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object[]? l_ = l.Select<Expression, object>(x => {
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switch (x) {
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case Integer s:
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return s.Value();
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case Boolean b:
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return b.Value();
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case String s:
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return s.Value();
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case Object o:
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return o.Value();
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case Cons c:
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return c.ToList().ToList();
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}
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throw new ApplicationException($"Unhandled value {x} (type {x.GetType()})");
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}).ToArray();
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Type[] l_types = l_.Select( x => {
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return x.GetType();
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}).ToArray();
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IList<Expression> r = new List<Expression>();
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MethodInfo? mi = o.Value().GetType().GetMethod(s.Value(), l_types);
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if (mi == null) {
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throw new ApplicationException($"{o.Value()} has not method {s.Value()}");
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}
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return Object.FromBase(mi.Invoke(o.Value(), l_));
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}
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}
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public class BuiltinsLater : Dictionary<string, FunctionLater> {
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public BuiltinsLater() : base() {
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this["quote"] = _quote;
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this["eval"] = _eval;
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this["cond"] = _cond;
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this["if"] = _if;
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this["define"] = _define;
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this["let"] = _let;
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this["let*"] = _let_star;
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this["lambda"] = _lambda;
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this["lambda*"] = _lambda_star;
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this["apply"] = _apply;
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this["and"] = (e, x) => {
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Expression? r = null;
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foreach (var xi in x) {
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r = e.eval(xi);
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if (r == Boolean.FALSE) {
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return r;
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}
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}
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if (r is null) {
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return Boolean.FALSE;
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}
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return r;
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};
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this["or"] = (e, x) => {
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foreach (var xi in x) {
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var r = e.eval(xi);
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if (r != Boolean.FALSE) {
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return r;
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}
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}
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return Boolean.FALSE;
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};
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}
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private static Expression _quote(Executor e, IEnumerable<Expression> args) {
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return args.First();
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}
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private static Expression _eval(Executor e, IEnumerable<Expression> args) {
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return e.eval(e.eval(args.First()));
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}
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private static Expression _cond(Executor e, IEnumerable<Expression> args) {
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foreach (var a in args) {
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if (a is Cons a_cons) {
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var a_ = a_cons.ToList();
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if (!e.eval(a_.First()).Equals(Boolean.FALSE)) {
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return e.eval(a_.Skip(1).First());
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}
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} else {
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throw new ApplicationException($"Incorrect arguments to cond, expected list: {args}");
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}
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}
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return Boolean.FALSE;
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}
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private static Expression _if(Executor e, IEnumerable<Expression> args) {
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if (e.eval(args.First()).Equals(Boolean.FALSE)) {
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return e.eval(args.Skip(2).First());
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}
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return e.eval(args.Skip(1).First());
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}
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private static Expression _define(Executor e, IEnumerable<Expression> args) {
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Symbol refname = (Symbol) args.First();
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e.environment.Parent(true).Set(refname.Name(), args.Skip(1).Select(x => e.eval(x)).First());
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return Boolean.TRUE;
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}
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private static Expression _let_star(Executor e, IEnumerable<Expression> args) {
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Executor new_e = new Executor(new SubEnvironment(e.environment), e.builtins, e.builtinsLater);
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foreach (var pair in args.SkipLast(1)) {
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if (pair is not Cons pair_cons) {
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throw new ApplicationException("No expression for let*");
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}
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Symbol refname = (Symbol) pair_cons.Item1;
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Expression exp = ((Cons) pair_cons.Item2).Item1;
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new_e.environment.Set(refname.Name(), new_e.eval(exp));
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}
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return new_e.eval(args.Last());
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}
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private static Expression _let(Executor e, IEnumerable<Expression> args) {
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Executor new_e = new Executor(new SubEnvironment(e.environment), e.builtins, e.builtinsLater);
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List<(Symbol, Expression)> vars = new List<(Symbol, Expression)>();
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foreach (var pair in args.SkipLast(1)) {
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if (pair is not Cons pair_cons) {
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throw new ApplicationException("");
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}
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Symbol refname = (Symbol) pair_cons.Item1;
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Expression exp_ = ((Cons) pair_cons.Item2).Item1;
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vars.Add((refname, e.eval(exp_)));
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}
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foreach (var pair in vars) {
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new_e.environment.Set(pair.Item1.Name(), pair.Item2);
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}
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return new_e.eval(args.Last());
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}
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private static Expression _lambda(Executor e, IEnumerable<Expression> args) {
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IEnumerable<Symbol> proc_args;
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if (args.First() is Cons proc_args_) { proc_args = proc_args_.ToList().Select(x => (Symbol) x); }
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else if (args.First() == Boolean.FALSE) { proc_args = new List<Symbol>(); }
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else {
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throw new ApplicationException("");
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}
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return new Procedure(proc_args, args.Skip(1).First(), true);
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}
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private static Expression _lambda_star(Executor e, IEnumerable<Expression> args) {
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IEnumerable<Symbol> proc_args;
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if (args.First() is Cons proc_args_) { proc_args = proc_args_.ToList().Select(x => (Symbol) x); }
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else if (args.First() == Boolean.FALSE) { proc_args = new List<Symbol>(); }
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else {
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throw new ApplicationException("");
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}
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return new Procedure(proc_args, args.Skip(1).First(), false);
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}
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private static Expression _apply(Executor e, IEnumerable<Expression> args) {
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return e.eval(new Cons(args.First(), e.eval(args.Skip(1).First())));
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}
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}
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public class Executor {
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IEnvironment<string, Expression> _environment;
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Builtins _builtins;
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BuiltinsLater _builtinsLater;
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public Executor(IEnvironment<string, Expression> environment, Builtins builtins, BuiltinsLater builtinsLater) {
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_environment = environment;
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_builtins = builtins;
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_builtinsLater = builtinsLater;
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}
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public Executor(IEnvironment<string, Expression> environment) {
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_environment = environment;
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_builtins = new Builtins();
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_builtinsLater = new BuiltinsLater();
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}
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public Executor() {
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_environment = new Environment();
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_builtins = new Builtins();
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_builtinsLater = new BuiltinsLater();
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}
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public IEnvironment<string, Expression> environment { get => _environment; }
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public Builtins builtins { get => _builtins; }
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public BuiltinsLater builtinsLater { get => _builtinsLater; }
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public Expression? EvalFunction(Symbol fcname, IEnumerable<Expression> args) {
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if (builtins.ContainsKey(fcname.Name())) {
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return builtins[fcname.Name()](args.Select(x => eval(x)).ToList()); // call ToList for sideeffect
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}
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if (builtinsLater.ContainsKey(fcname.Name())) {
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return builtinsLater[fcname.Name()](this, args);
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}
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return null;
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}
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public Expression eval(Expression expression) {
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switch (expression) {
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case Symbol s:
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if (_environment.Find(s.Name()) is not IEnvironment<string, Expression> env) {
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throw new ApplicationException($"Could not find '{s.Name()}'");
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}
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var r_ = env.Get(s.Name());
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if (r_ is null) {
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throw new ApplicationException($"Could not find '{s.Name()}'");
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}
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return r_;
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case Boolean b:
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return b;
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case Integer i:
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return i;
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case String s:
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return s;
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case Object o:
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return o;
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case Procedure p:
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return p;
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case Cons cons:
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var l = cons.ToList();
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if (cons.Item1 is Symbol cons_item1_symbol) {
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Expression? r = EvalFunction(cons_item1_symbol, l.Skip(1));
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if (r is not null) { return r; }
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}
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var eval_Item1 = eval(cons.Item1);
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if (eval_Item1 is Symbol eval_item1_symbol1) {
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Expression? r = EvalFunction(eval_item1_symbol1, l.Skip(1));
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if (r is not null) { return r; }
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}
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if (eval_Item1 is Procedure eval_item1_procedure) {
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return eval_item1_procedure.Call(this, l.Skip(1).Select(x => x).ToList());
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}
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throw new ApplicationException($"Not handled case (type = {eval_Item1.GetType()}) '{cons}'");
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}
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throw new ApplicationException($"Not handled case '{expression}'");
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}
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public Expression eval(Parser p) {
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return eval(p.parse());
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}
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public Expression eval(StringTokenStream sts) {
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return eval(new Parser(sts));
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}
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public Expression eval(string p) {
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return eval(StringTokenStream.generate(p));
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}
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}
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}
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