The work on SQL/PSM compiler started

There are a basic code for plpsm language implementation. It's downloadable from github. Now only basic statements are supported - see a test.sql file.

pavel=# create or replace function test12(a int)
returns int as $$
begin
  declare b,c,d int default 0;
  set b = a + 1, c = b + 1, d = c + 1;
  return d;
end;
$$ language psm0;
NOTICE:  
   Datums: 4 variables 
   Size: 16 instruction

    0  CopyParam 0, 0, size:4, byval:BYVAL
    1  ExecExpr "SELECT (0)::integer",{}
    2  SaveTo 1, size:4, byval:BYVAL
    3  ExecExpr "SELECT (0)::integer",{}
    4  SaveTo 2, size:4, byval:BYVAL
    5  ExecExpr "SELECT (0)::integer",{}
    6  SaveTo 3, size:4, byval:BYVAL
    7  ExecExpr "SELECT ($1 + 1)::integer",{23,23,23,23}
    8  SaveTo 1, size:4, byval:BYVAL
    9  ExecExpr "SELECT ($2 + 1)::integer",{23,23,23,23}
   10  SaveTo 2, size:4, byval:BYVAL
   11  ExecExpr "SELECT ($3 + 1)::integer",{23,23,23,23}
   12  SaveTo 3, size:4, byval:BYVAL
   13  ExecExpr "SELECT ($4)::integer",{23,23,23,23}
   14  Return size:4, byval:BYVAL
   15  Done.

CREATE FUNCTION