commands: add basic command parser infrastructure

1 files changed, 57 insertions, 0 deletions

diff --git a/Scripts/Commands/LookCommand.cs b/Scripts/Commands/LookCommand.cs
new file mode 100644
index 0000000..08783a9
--- /dev/null
+++ b/Scripts/Commands/LookCommand.cs
@@ -0,0 +1,57 @@
+using System.Linq;
+
+namespace Texty.Scripts.Commands
+{
+    public enum LookModifier
+    {
+        At,
+        Around
+    }
+
+    public class LookCommand : Command
+    {
+        public LookCommand()
+        {
+        }
+
+        public LookCommand(string[] arguments) : base(CommandType.Look, arguments)
+        {
+            (Modifier, arguments) = TryParseModifier(arguments);
+            Target = string.Join(" ", arguments);
+        }
+
+        public string Target { get; }
+        public LookModifier? Modifier { get; }
+
+        /// <summary>
+        ///     Access this <c>LookCommand</c>'s modifier as a string.
+        /// </summary>
+        /// <remarks>
+        ///     This function is provided as a means for testing the modifier parsing from GDScript.
+        /// </remarks>
+        private string ModifierAsString => Modifier?.ToString();
+
+        public override string ToString()
+        {
+            return $"look {ModifierAsString?.ToLower()} {string.Join(" ", Target)}";
+        }
+
+        /// <summary>
+        ///     Try to parse this <c>LookCommand</c>'s modifier from the given arguments.
+        /// </summary>
+        /// <param name="arguments">The arguments given to this look commands</param>
+        /// <returns>A pair consisting of the parse modifier and the remaining arguments</returns>
+        private static (LookModifier?, string[]) TryParseModifier(string[] arguments)
+        {
+            if (arguments.Length == 0)
+                return (null, arguments);
+
+            return arguments[0].ToLower() switch
+            {
+                "at" => (LookModifier.At, arguments.Skip(1).ToArray()),
+                "around" => (LookModifier.Around, new string[] { }),
+                _ => (null, arguments)
+            };
+        }
+    }
+}
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