Initial work for UCI mode

src/Chess/board.nim

@@ -2079,6 +2079,17 @@ proc handlePositionCommand(board: var ChessBoard, command: seq[string]) =
             echo board.pretty()
 
 
+proc handleUCICommand(board: var ChessBoard, command: seq[string]): bool =
+    if len(command) != 1:
+        echo "error: uci: invalid number of arguments"
+        return false
+    echo "id name Nimfish 0.1"
+    echo "id author Nocturn9x & Contributors (see LICENSE)"
+    # TODO
+    echo "uciok"
+    return true
+
+
 const HELP_TEXT = """Nimfish help menu:
     - go: Begin a search
           Subcommands: 
@@ -2112,26 +2123,33 @@ const HELP_TEXT = """Nimfish help menu:
     - pretty: Shorthand for "position pretty"
     - print: Shorthand for "position print"
     - get <square>: Get the piece on the given square
+    - uci: enter UCI mode (WIP)
 """
 
 
 proc main: int =
     ## Nimfish's control interface
     echo "Nimfish by nocturn9x (see LICENSE)"
-    var board = newDefaultChessboard()
+    var 
+        board = newDefaultChessboard()
+        uciMode = false
     while true:
         var
             cmd: seq[string]
             cmdStr: string
         try:
-            stdout.write(">>> ")
-            stdout.flushFile()
+            if not uciMode:
+                stdout.write(">>> ")
+                stdout.flushFile()
             cmdStr = readLine(stdin).strip(leading=true, trailing=true, chars={'\t', ' '})
             if cmdStr.len() == 0:
                 continue
             cmd = cmdStr.splitWhitespace(maxsplit=2)
 
             case cmd[0]:
+                of "uci":
+                    if handleUCICommand(board, cmd):
+                        uciMode = true
                 of "clear":
                     echo "\x1Bc"
                 of "help":
@@ -2156,12 +2174,12 @@ proc main: int =
                         echo "En passant target: None"
                 of "get":
                     if len(cmd) != 2:
-                        echo "get: invalid syntax"
+                        echo "error: get: invalid number of arguments"
                         continue
                     try:
                         echo board.getPiece(cmd[1])
                     except ValueError:
-                        echo "get: invalid square"
+                        echo "error: get: invalid square"
                         continue
                 of "castle":
                     let canCastle = board.canCastle()