Add player values for relational placeholder structure

src/main/java/io/github/apickledwalrus/skriptplaceholders/skript/elements/ExprRelationalPlayers.java

@@ -0,0 +1,74 @@
+package io.github.apickledwalrus.skriptplaceholders.skript.elements;
+
+import ch.njol.skript.Skript;
+import ch.njol.skript.doc.Description;
+import ch.njol.skript.doc.Examples;
+import ch.njol.skript.doc.Name;
+import ch.njol.skript.doc.Since;
+import ch.njol.skript.lang.Expression;
+import ch.njol.skript.lang.ExpressionType;
+import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.skript.lang.util.SimpleExpression;
+import ch.njol.util.Kleenean;
+import io.github.apickledwalrus.skriptplaceholders.skript.RelationalPlaceholderEvent;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Event;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+@Name("Relational Placeholder Players")
+@Description("The two players involved in a relational placeholder request.")
+@Examples({
+	"on placeholderapi placeholder request for the relational prefix \"skriptplaceholders\":",
+		"\tif the identifier is \"rel_longer_name\": # Placeholder is \"%skriptplaceholders_author%\"",
+			"\t\tif the length of the name of the first player > the length of the name of the second player:",
+				"\t\t\tset the result to the name of the first player",
+			"\t\telse:",
+				"\t\t\tset the result to the name of the second player"
+})
+@Since("1.7.0")
+public class ExprRelationalPlayers extends SimpleExpression<Player> {
+
+	static {
+		Skript.registerExpression(ExprRelationalPlayers.class, Player.class, ExpressionType.SIMPLE,
+				"[the] first player",
+				"[the] second player"
+		);
+	}
+
+	private boolean first;
+
+	@Override
+	public boolean init(Expression<?> @NotNull [] expressions, int matchedPattern, @NotNull Kleenean kleenean, @NotNull ParseResult parseResult) {
+		if (!getParser().isCurrentEvent(RelationalPlaceholderEvent.class)) {
+			Skript.error("'the " + (first ? "first" : "second") + " player' can only be used in custom relational placeholders.");
+		}
+		first = matchedPattern == 0;
+		return true;
+	}
+
+	@Override
+	protected Player @NotNull [] get(@NotNull Event e) {
+		if (!(e instanceof RelationalPlaceholderEvent)) {
+			return new Player[0];
+		}
+		RelationalPlaceholderEvent event = (RelationalPlaceholderEvent) e;
+		return new Player[]{first ? event.getPlayer() : event.getOther()};
+	}
+
+	@Override
+	public boolean isSingle() {
+		return true;
+	}
+
+	@Override
+	public @NotNull Class<? extends Player> getReturnType() {
+		return Player.class;
+	}
+
+	@Override
+	public @NotNull String toString(@Nullable Event event, boolean debug) {
+		return "the " + (first ? "first" : "second") + " player";
+	}
+
+}

src/main/java/io/github/apickledwalrus/skriptplaceholders/skript/elements/StructPlaceholder.java

@@ -42,6 +42,12 @@
 	"on placeholderapi placeholder request for the prefix \"skriptplaceholders\":",
 		"\tif the identifier is \"author\": # Placeholder is \"%skriptplaceholders_author%\"",
 			"\t\tset the result to \"APickledWalrus\"",
+	"on placeholderapi placeholder request for the relational prefix \"skriptplaceholders\":",
+		"\tif the identifier is \"rel_longer_name\": # Placeholder is \"%skriptplaceholders_author%\"",
+			"\t\tif the length of the name of the first player > the length of the name of the second player:",
+				"\t\t\tset the result to the name of the first player",
+			"\t\telse:",
+				"\t\t\tset the result to the name of the second player",
 	"on mvdw placeholder request for the placeholder \"skriptplaceholders_author\":",
 		"\t# Placeholder is \"{skriptplaceholders_author}\"",
 		"\tset the result to \"APickledWalrus\""