revamp of nix organization

nix/home/programs/direnv/default.nix

@@ -0,0 +1,9 @@
+{pkgs, ...}:
+let
+in with builtins;
+{
+  programs.direnv = {
+    enable = true;
+    stdlib = readFile ./direnvrc;
+  };
+}

nix/home/programs/direnv/direnvrc

@@ -0,0 +1,40 @@
+layout_postgres() {
+  export PGDATA="$(direnv_layout_dir)/tmp/pgdata"
+  export PGHOST="$PGDATA"
+  if [[ ! -d "$PGDATA" ]]; then
+    initdb --locale=$LANG
+    cat <<EOF >>"$PGDATA/postgresql.conf"
+listen_addresses = 'localhost'
+unix_socket_directories = '$PGHOST'
+EOF
+    echo "CREATE DATABASE $USER;" | postgres --single -E postgres
+  fi
+}
+
+layout_go() {
+  export GOPATH="$(direnv_layout_dir)/tmp/golibs"
+  if [[ ! -d "$GOPATH" ]]; then
+    mkdir -p $GOPATH
+  fi
+
+  export PATH="$GOPATH/bin:$PATH"
+}
+
+layout_mysql() {
+  export MYSQL_HOME="$(direnv_layout_dir)/mysql"
+  export MYSQLDATA="$MYSQL_HOME/data"
+  if [[ ! -d "$MYSQLDATA" ]]; then
+    mkdir -p $MYSQL_HOME
+    cat <<EOF >>"$MYSQL_HOME/my.cnf"
+[mysqld]
+table_open_cache=400
+socket=/tmp/mysql.sock
+max_allowed_packet=256M
+datadir=$MYSQLDATA
+
+[client]
+socket=/tmp/mysql.sock
+EOF
+    mysqld --initialize-insecure
+  fi
+}