record single inheritance, partial solution to record problem

[centaurian_slug]

The record system reminded me of the situation in assembly language. Could "single inheritance of records" allow some shared field names as a stopgap solution without breaking much of the existing language and source, or precluding future solutions to this issue;

Under this proposal, accessor functions in the same namespace would always access the same slot.

imagine a keyword 'extends' in a data constructor that creates any boilerplate behind the scenes.

data Base = Base { slotA::Int32, slotB::Int32 }
data Foo = Foo extends Base { foo :: Int32 }
data Bar = Bar extends Base { bar1 :: Float,bar2 ::Float }

'slotA' is now always a function to extract the first element of a 2,3,4 element tuple 'slotB' is now always a function to extract the second element of a 2,3,4 element tuple 'foo' is a functions to extract the 3rd slot. 'bar1','bar2' are functions to extract the 3rd,4th slots by analogy with c++,

struct Base {
  int32 slotA,int32 slotB;
};  'a' now corresponds to an memory offset of 0
    'b' now corresponds to an memory offset of 4
struct Foo : public Base
{
  int32 foo;
};
   'foo' now corresponds to a memory offset of 8
struct Bar : public Base
{
  float bar1;
  float bar2;
};
 //  'bar1' now corresponds to a memory offset of 8
 //  'bar2' now corresponds to a memory offset of 12
 //  'a' corresponds to a ptr offset of 0, for all types
//   'b' corresponds to a ptr offset of 4 for all types

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

[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

[igloo]

Thanks for the suggestion. However, I think record system extensions need some more discussion and design work, for which the mailing lists and wikis are better forums than tickets, so I'm closing this ticket.