-- BBEvalQuote.mesa
-- Russ Atkinson, November 19, 1982 12:42 pm

-- The EvalQuote facility is provided to allow users to augment the language interpreted by BugBane.  The user supplies a procedure 
to be registered with BugBane under a given name such that the procedure will be called with the syntax tree for its invocation 
rather than have its arguments interpreted by BugBane.

DIRECTORY
  BBEval USING [EvalHead, Tree],
  Rope USING [ROPE],
  RTBasic USING [nullType, TV, Type];

BBEvalQuote: CEDAR DEFINITIONS = BEGIN OPEN Rope, RTBasic;
  
  EvalQuoteProc: TYPE = PROC
    [head: BBEval.EvalHead, tree: BBEval.Tree, target: Type _ nullType, data: REF _ NIL]
    RETURNS [return: TV];
  -- this is the type of proc the user supplies to perform evalQuote functions

  Register: PROC [name: ROPE, proc: EvalQuoteProc, data: REF _ NIL];
  -- registers the EvalQuoteProc with BugBane
  
  UnRegister: PROC [name: ROPE];
  -- unregisters the name with BugBane
  
  Lookup: PROC [name: ROPE] RETURNS [proc: EvalQuoteProc, data: REF];
  -- finds the named EvalQuoteProc (if any), returns [NIL, NIL] if no such proc
  
  Pairs: PROC [visit: VisitProc];
  -- enumerates the registered procedures
  
  VisitProc: TYPE = PROC
    [name: ROPE, proc: EvalQuoteProc, data: REF _ NIL]
    RETURNS [stop: BOOL _ FALSE];
  -- this is the type of callback proc the user supplies to iterate over the registered commands

  END.