[GHC] #7111: record single inheritance, partial solution to record problem

[GHC]

#7111: record single inheritance, partial solution to record problem
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 Reporter:  centaurian_slug   |          Owner:                  
     Type:  feature request   |         Status:  new             
 Priority:  normal            |      Component:  Compiler        
  Version:  7.4.2             |       Keywords:                  
       Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
  Failure:  None/Unknown      |       Testcase:                  
Blockedby:                    |       Blocking:                  
  Related:                    |  
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Comment(by centaurian_slug):

 apologies for formatting above

 data Base = Base { slotA::Int32, slotB::Int32 }

 data Foo = Foo extends Base { foo :: Int32 }

 data Bar = Bar extends Base { bar1 :: Float,bar2 ::Float }

 By analogy to  assembly-language:-

 ; declare 'Base' datsstructure elements
 RSRESET         ;clear structure offset counter
 slotA    RW 1   ; reserve 1 word for 'slotA'
 slotB    RW 1
 baseSize RW 0

 ; declare 'Foo' datastructure elements

 RSSET baseSize  ; 'Foo' extends 'Base', set counter to end of 'Base'

 foo      RW 1

 fooSize  RW 0

 ; declare  'Bar' datastructure members

 RSSET baseSize ; 'Bar' extends 'Base'

 bar1      RW 1

 bar2      RW 1

 barSize  RW 0

 ;result:- (4byte words)

 ;slotA=0, slotB=4, foo=8,  bar1=8, bar2=12

 ; baseSize=0;  fooSize=12;   barSize=16

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7111#comment:1>
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