;;;; Assembly context protocol (symbol table, accumulated output)

(defvar *context* nil "Current assembly context")

(defgeneric context-emit (context vector)
  (:documentation "Emit a vector of bytes into the assembly context"))

(defgeneric context-address (context)
  (:documentation "Returns current virtual address of the context"))

(defgeneric (setf context-address) (address context)
  (:documentation "Set the current virtual address of the context"))

(defgeneric context-find-label (context symbol)
  (:documentation "Returns a promise for the address of a symbol, or nil."))

(defgeneric context-set-label (context symbol &optional address)
  (:documentation "Set the address of a label. If not supplied, the current address is used."))

(defgeneric context-emit-instruction (context vector)
  (:documentation "Emit an instruction into the assembly context. This
  exists to provide additional information to the context.")
  (:method (context vector) (context-emit context vector)))

(defgeneric link (context)
  (:documentation "Prepare and return final, assembled output.")
  (:method (context) (resolve-vector (context-code-vector context))))