From f396a88bacd0d078738eaf7667f1ca96bdcfd9b3 Mon Sep 17 00:00:00 2001
From: Ryan Fleury <ryan.j.fleury@gmail.com>
Date: Fri, 13 Sep 2024 17:16:42 -0700
Subject: [PATCH] mdesk layer extensions for mutable tree manipulations

---
 src/mdesk/mdesk.c | 34 ++++++++++++++++++++++++++++++++++
 src/mdesk/mdesk.h |  3 +++
 2 files changed, 37 insertions(+)

diff --git a/src/mdesk/mdesk.c b/src/mdesk/mdesk.c
index 899d8c30..fe2e502c 100644
--- a/src/mdesk/mdesk.c
+++ b/src/mdesk/mdesk.c
@@ -197,6 +197,21 @@ md_push_node(Arena *arena, MD_NodeKind kind, MD_NodeFlags flags, String8 string,
   return node;
 }
 
+internal void
+md_node_insert_child(MD_Node *parent, MD_Node *prev_child, MD_Node *node)
+{
+  node->parent = parent;
+  DLLInsert_NPZ(&md_nil_node, parent->first, parent->last, prev_child, node, next, prev);
+}
+
+internal void
+md_node_insert_tag(MD_Node *parent, MD_Node *prev_child, MD_Node *node)
+{
+  node->kind = MD_NodeKind_Tag;
+  node->parent = parent;
+  DLLInsert_NPZ(&md_nil_node, parent->first_tag, parent->last_tag, prev_child, node, next, prev);
+}
+
 internal void
 md_node_push_child(MD_Node *parent, MD_Node *node)
 {
@@ -207,10 +222,29 @@ md_node_push_child(MD_Node *parent, MD_Node *node)
 internal void
 md_node_push_tag(MD_Node *parent, MD_Node *node)
 {
+  node->kind = MD_NodeKind_Tag;
   node->parent = parent;
   DLLPushBack_NPZ(&md_nil_node, parent->first_tag, parent->last_tag, node, next, prev);
 }
 
+internal void
+md_unhook(MD_Node *node)
+{
+  MD_Node *parent = node->parent;
+  if(!md_node_is_nil(parent))
+  {
+    if(node->kind == MD_NodeKind_Tag)
+    {
+      DLLRemove_NPZ(&md_nil_node, parent->first_tag, parent->last_tag, node, next, prev);
+    }
+    else
+    {
+      DLLRemove_NPZ(&md_nil_node, parent->first, parent->last, node, next, prev);
+    }
+    node->parent = &md_nil_node;
+  }
+}
+
 //- rjf: tree introspection
 
 internal MD_Node *
diff --git a/src/mdesk/mdesk.h b/src/mdesk/mdesk.h
index bc167109d..512f2a6b 100644
--- a/src/mdesk/mdesk.h
+++ b/src/mdesk/mdesk.h
@@ -270,8 +270,11 @@ internal MD_NodeRec md_node_rec_depth_first(MD_Node *node, MD_Node *subtree_root
 
 //- rjf: tree building
 internal MD_Node *md_push_node(Arena *arena, MD_NodeKind kind, MD_NodeFlags flags, String8 string, String8 raw_string, U64 src_offset);
+internal void md_node_insert_child(MD_Node *parent, MD_Node *prev_child, MD_Node *node);
+internal void md_node_insert_tag(MD_Node *parent, MD_Node *prev_child, MD_Node *node);
 internal void md_node_push_child(MD_Node *parent, MD_Node *node);
 internal void md_node_push_tag(MD_Node *parent, MD_Node *node);
+internal void md_unhook(MD_Node *node);
 
 //- rjf: tree introspection
 internal MD_Node *  md_node_from_chain_string(MD_Node *first, MD_Node *opl, String8 string, StringMatchFlags flags);