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--*           id AA23885; Thu, 3 Nov 1994 22:26:44 +0100
--* Date: Thu, 3 Nov 1994 22:26:44 +0100
--* From: hemmecke@aix550.informatik.uni-leipzig.de (Ralf Hemmecke)
--* Message-Id: <9411032126.AA23885@aix550.informatik.uni-leipzig.de>
--* To: asbugs@watson.ibm.com
--* Subject: [5] problems in using "default"

--@ Fixed  by:  SSD   Mon Jan 30 13:38:22 EST 1995 
--@ Tested by:  none 
--@ Summary:    Fixed the type inference of category constructors in the presence of default declarations for the types of the parameters. 

-- Command line: asharp -DC1 xxx.as
-- Version: A# version 0.36.5 for AIX RS/6000
-- Original bug file name: xxx.as

-- Author: Ralf Hemmecke, University of Leipzig
-- Date: 03-NOV-94
-- A# version 0.36.5 for AIX RS/6000

-- What is wrong with "default R:BT;"?
-- Compiling this code via
--      asharp -DC1 xxx.as
-- gives the error message

--:"xxx.as", line 24:   extend D(R,E:BT):Cat(R,E,E) == add {
--:                   .................................^
--:[L24 C34] #1 (Error) The domain is missing some exports.
--:        Missing leadingTerm: % -> T

-- whereas
--      asharp -DC2 xxx.as
-- compiles without any message.

-- The only differences of versions C1 and C2 are marked with "--!!".
-- C1 uses "default" while C2 does not.
-------------------------------------------------------------------
#include "aslib.as"

macro BT == BasicType;

#if C1
  default R:BT;                                                --!!
  -----------------------------------------------------------------
  D(R,E:BT): BT;                                               --!!
  == add {
    Monomial ==> Record(term:E);
    Rep ==> List Monomial; -- polynomial
    import from Rep,Monomial;
    (p:TextWriter) << (x:%):TextWriter == p;
    (x:%)=(y:%):Boolean == true;
    sample:% == per empty();
    degree(x:%):E == (first rep x).term;
  }
  -----------------------------------------------------------------
  Cat(R,E:BT,T:BT): Category == with {                         --!!
    leadingTerm: % -> T;
  }
  -----------------------------------------------------------------
  extend D(R,E:BT): Cat(R,E,E) == add {                        --!!
    leadingTerm(x:%):E == sample;
  }
  -----------------------------------------------------------------
#elseif C2
  -----------------------------------------------------------------
  D(R:BT,E:BT): BT;                                            --!!
  == add {
    Monomial ==> Record(term:E);
    Rep ==> List Monomial; -- polynomial
    import from Rep,Monomial;
    (p:TextWriter) << (x:%):TextWriter == p;
    (x:%)=(y:%):Boolean == true;
    sample:% == per empty();
    degree(x:%):E == (first rep x).term;
  }
  -----------------------------------------------------------------
  Cat(R:BT,E:BT,T:BT): Category == with {                      --!!
    leadingTerm: % -> T;
  }
  -----------------------------------------------------------------
  extend D(R:BT,E:BT): Cat(R,E,E) == add {                     --!!
    leadingTerm(x:%):E == sample;
  }
  -----------------------------------------------------------------
#endif