86 lines
2.8 KiB
C#
86 lines
2.8 KiB
C#
using System.Diagnostics;
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using Jellyfin.Plugin.SmartPlaylist.Lisp;
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namespace Jellyfin.Plugin.SmartPlaylist.Lisp.Compiler {
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public class Parser {
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private StringTokenStream _sts;
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public Parser(StringTokenStream tokens) {
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_sts = tokens;
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}
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public Parser(string s) {
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_sts = StringTokenStream.generate(s);
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}
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public Expression parse() {
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Token<string> token = _sts.Get();
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switch (token) {
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case GroupingToken gt:
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return parse_grouping(gt, gt.closing_value);
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case AtomToken at:
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return parse_atom(at);
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case SpaceToken sp:
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return parse();
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}
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return parse();
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}
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Expression parse_string(GroupingToken start, GroupingToken? end) {
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Debug.Assert(end != null);
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Debug.Assert(start.value == end.value);
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Debug.Assert("\"".Contains(start.value));
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string r = "";
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while (_sts.Available() > 0) {
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Token<string> t = _sts.Get();
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if (t.value == end.value) {
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break;
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}
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r += t.value;
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}
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_sts.Commit();
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return new String(r);
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}
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Expression parse_quote(GroupingToken start, GroupingToken? end) {
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Debug.Assert(end == null);
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Debug.Assert("'".Contains(start.value));
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return Cons.FromList(new Expression[]{ new Symbol("quote"), parse()});
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}
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Expression parse_grouping(GroupingToken start, GroupingToken? end) {
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if ("\"".Contains(start.value)) {
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return parse_string(start, end);
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}
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if ("'".Contains(start.value)) {
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return parse_quote(start, end);
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}
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Debug.Assert(end != null);
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IList<Expression> expressions = new List<Expression>();
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while (_sts.Available() > 0) {
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Token<string> t = _sts.Get();
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if (t.value == end.value) {
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_sts.Commit();
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break;
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}
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_sts.Rewind(1);
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expressions.Add(parse());
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}
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return Cons.FromList(expressions);
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}
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Expression parse_atom(AtomToken at) {
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int parsed_value;
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if (int.TryParse(at.value, out parsed_value)) {
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_sts.Commit();
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return new Integer(parsed_value);
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}
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if (at.value.Equals("t")) {
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return Boolean.TRUE;
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}
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if (at.value.Equals("nil")) {
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return Boolean.FALSE;
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}
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_sts.Commit();
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return new Symbol(at.value);
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}
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}
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}
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