Lets start with a green field

.gitignore

@@ -0,0 +1 @@
+packages

dependencies/homebrew.txt

@@ -0,0 +1,2 @@
+rbenv
+nodenv

dependencies/zsh.txt

@@ -0,0 +1 @@
+git@github.com:geometry-zsh/geometry.git

install.zsh

@@ -0,0 +1,68 @@
+#!/bin/zsh
+
+function zsh_check_installed() {
+    ls . | grep $1 > /dev/null
+    result=$?
+    return $result
+}
+
+function brew_check_installed() {
+    brew info $1 | grep "Not installed" > /dev/null
+    result=$?
+    ((result ^= 1))
+    return $result
+}
+
+INSTALL_DIR=$HOME/.files
+
+mkdir -p packages
+pushd packages
+
+# Install ZSH packages
+which git > /dev/null
+if (( $? == 0 )); then
+    while IFS= read -r line; do
+        directory=${${line%.git}#*/}
+        zsh_check_installed $directory
+
+        if [[ $? != 0 ]]; then
+            echo "Cloning $line into packages..."
+            git clone -q $line
+        else
+            echo "$directory already installed"
+        fi
+    done < ../dependencies/zsh.txt
+else
+    echo "Install git before continuing"
+    exit 1
+fi
+
+which brew > /dev/null
+if (( $? == 0 )); then
+    # Install Homebrew packages
+    while IFS= read -r line; do
+        brew_check_installed $line
+        if [[ $? != 0 ]]; then
+            echo "Installing $line with Homebrew"
+            brew install $line
+        else
+            echo "$line already installed"
+        fi
+    done < ../dependencies/homebrew.txt
+else
+    echo "Install homebrew before continuing"
+    exit 1
+fi
+
+popd
+
+mkdir -p $INSTALL_DIR
+cp -rf packages $INSTALL_DIR/packages
+cp -f zshrc $INSTALL_DIR/zshrc
+
+# Insert the INSTALL_DIR variable into the installed run control file
+sed -i -e "1 i\\
+INSTALL_DIR=$INSTALL_DIR\\
+" $INSTALL_DIR/zshrc
+
+ln -sf $INSTALL_DIR/zshrc ~/.zshrc

zshrc

@@ -0,0 +1,7 @@
+eval "$(rbenv init -)"
+eval "$(nodenv init -)"
+
+source $INSTALL_DIR/packages/geometry/geometry.zsh
+
+setopt auto_cd
+cdpath=($HOME/Projects)