From 3873192547f6544d9d58d143d62d7c0735401116 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Barra=20=C3=93=20Cath=C3=A1in?= <barra@ocathain.ie>
Date: Mon, 20 Nov 2023 21:32:53 +0000
Subject: [PATCH] Basic Scheme implementations of player structures and
 messaging.

---
 lisp/messaging.scm  | 18 ++++++++++++
 lisp/structures.scm | 67 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+)
 create mode 100644 lisp/messaging.scm
 create mode 100644 lisp/structures.scm

diff --git a/lisp/messaging.scm b/lisp/messaging.scm
new file mode 100644
index 0000000..fdf7dc4
--- /dev/null
+++ b/lisp/messaging.scm
@@ -0,0 +1,18 @@
+;;;; This file is part of SilverMUD.
+;;;; structures.scm defines various variables and functions used for interacting with the player's
+;;;; via chat output from the Scheme enviroment of SilverMUD.
+(define-module (silvermud messaging))
+(use-modules (silvermud primitives))
+
+(define message-everyone (lambda (name content)
+						   (push-output-message *global-output-queue* #f *global-player-list*
+												8 name content)))
+(define system-message (lambda (contennt)
+						 (push-output-message *global-output-queue* #f *global-player-list*
+											  0 "" content)))
+
+(define message-expression (lambda (expression)
+							 (system-message (format #f "~a" expression))))
+
+;; Export everything!
+(export message-everyone system-message message-expression)
diff --git a/lisp/structures.scm b/lisp/structures.scm
new file mode 100644
index 0000000..cc45cc1
--- /dev/null
+++ b/lisp/structures.scm
@@ -0,0 +1,67 @@
+;;;; This file is part of SilverMUD.
+;;;; structures.scm defines various variables and functions used for interacting with C structures
+;;;; from the Scheme enviroment of SilverMUD.
+(define-module (silvermud structures))
+(use-modules (system foreign)
+			 (silvermud primitives))
+
+;;; struct PlayerList:
+
+;; The layout of the struct PlayerList:
+(define *player-list-structure* (list size_t '* '*))
+
+;; Pretty-format the player list header:
+(define (player-list-header->string player-list-pointer)
+  "Format a struct PlayerList pointer into a string."
+  (if (not (null-pointer? player-list-pointer))
+	  (let ((structure (parse-c-struct player-list-pointer *player-list-structure*)))
+		(format #f
+				"Players in list: ~d.\nHead: ~a. \nTail: ~a.\n"
+				(list-ref structure 0) (list-ref structure 1) (list-ref structure 2)))))
+
+;; Create a list of strings representing all players in a list:
+(define (list-players player-list-pointer)
+  "List all players in a given C PlayerList as a list of strings."
+  (if (not (null-pointer? player-list-pointer)) ; Check we're not dereferencing a null pointer.
+	  (build-list-players
+	   (list-ref (parse-c-struct player-list-pointer *player-list-node-structure*) 2))))
+
+(define (build-list-players pointer)
+  (if (not (null-pointer? pointer))
+	  (let* ((node (parse-c-struct pointer *player-list-node-structure*))
+			(player (parse-c-struct (list-ref node 0) *player-structure*)))
+		(cons (pointer->string (list-ref player 1)) (build-list-players (list-ref node 1))))
+	  '()))
+
+;;; struct PlayerListNode:
+
+;; Used to interact with struct PlayerListNode:
+(define *player-list-node-structure* (list '* '* '*))
+
+;; Pretty-format the player list node:
+(define (player-list-node->string player-list-node-pointer)
+  "Format a struct PlayerListNode pointer into a string."
+  (if (not (null-pointer? player-list-node-pointer))
+	  (let ((structure (parse-c-struct player-list-node-pointer *player-list-node-structure*)))
+		(format #f
+				"Player pointer: ~a.\nNext: ~a. \nPrevious: ~a.\n"
+				(list-ref structure 0) (list-ref structure 1) (list-ref structure 2)))))
+
+;;; struct Player:
+
+; Used to interact with struct Player:
+(define *player-structure* (list '* '*))
+
+(define (player->string player-info-pointer)
+  "Format a struct Player pointer into a string."
+  (if (not (null-pointer? player-info-pointer))
+	  (let ((structure (parse-c-struct player-info-pointer *player-structure*)))
+		(display (null-pointer? (list-ref structure 1)))
+		(format #f
+				"Player Name: ~a\n" (if (null-pointer? (list-ref structure 1))	 
+										(pointer->bytevector (list-ref structure 1) 64)
+										#f)))))
+
+;; Export everything!
+(export *player-list-structure* *player-list-node-structure* *player-structure*
+		player->string player-list-header->string player-list-node->string list-players)