Change atoms to vars in gungnir.model

Currently the model namespace keeps track of registered models and creates maps for "quick" mapping (e.g. mapping a model field to table column). This is mainly for performance benefits.

gungnir/src/cljc/gungnir/model.cljc

Lines 12 to 17 in 54fa3b8

    
           ;; TODO Might want to turn these into dynamic vars for performance benefits 
        
           (defonce models (atom {})) 
        
           (defonce table->model (atom {})) 
        
           (defonce model->table (atom {})) 
        
           (defonce field->column (atom {})) 
        
           (defonce column->field (atom {}))

These maps are stored in atoms. However it might be nice to actually store then in ^:dynamic defs and change them with alter-var!. This would remove the deref overhead and possibly improve performance slightly. I don't think there's much risk in changing these to defs since they are only set during model registration. Which generally only happens once at system startup.

I don't think there's much risk in changing these to defs since they are only set during model registration. Which generally only happens once at system startup.

I think it is part of normal workflow to re- mode/register! in the repl when working out the kinks in a model. Will that still be supported?

I don't see why not. The point of atoms is to handle parallelism and make sure data stays in sync. I can't imagine having two threads calling model/register! at the same time. Other than that the current behavior will not change.

	;; TODO Might want to turn these into dynamic vars for performance benefits
	(defonce models (atom {}))
	(defonce table->model (atom {}))
	(defonce model->table (atom {}))
	(defonce field->column (atom {}))
	(defonce column->field (atom {}))