2021-11-28 | Paul Boddie | file changeset files shortlog | Introduced support for values that can be allocated on a special thread-local stack, copied around and overwritten/mutated, demonstrating the concept using integer and floating-point numbers. Various complications arise with special attributes (such as __data__) due to the way references are tagged to indicate mutable values, and attribute slots must be cleared in locals, objects and fragments before values are stored since target slots are tested for mutable values. | tagged-address-values |
paul@2 | 1 | def f(): |
paul@2 | 2 | l = [1, 2, 3] |
paul@2 | 3 | x = l |
paul@2 | 4 | a, b, c = l |
paul@2 | 5 | d, e, f = [1, 2, 3] |
paul@243 | 6 | print a, b, c # 1, 2, 3 |
paul@243 | 7 | print d, e, f # 1, 2, 3 |
paul@243 | 8 | print x # [1, 2, 3] |
paul@2 | 9 | |
paul@2 | 10 | def g(x): |
paul@2 | 11 | l = [1, 2, 3] |
paul@2 | 12 | m = [4, l, 6] |
paul@2 | 13 | if x: |
paul@2 | 14 | n = l |
paul@2 | 15 | else: |
paul@2 | 16 | n = m |
paul@173 | 17 | print n |
paul@2 | 18 | |
paul@560 | 19 | def h(): |
paul@560 | 20 | return 7, 8, 9 |
paul@560 | 21 | |
paul@561 | 22 | def i(): |
paul@561 | 23 | a, b, c = h() |
paul@561 | 24 | print a, b, c |
paul@561 | 25 | |
paul@561 | 26 | # Test assignment operations within functions. |
paul@561 | 27 | |
paul@197 | 28 | f() |
paul@243 | 29 | g(0) # [4, [1, 2, 3], 6] |
paul@243 | 30 | g(1) # [1, 2, 3] |
paul@197 | 31 | |
paul@561 | 32 | # Test aliasing, assignment of list elements and direct assignment of elements. |
paul@561 | 33 | |
paul@2 | 34 | l = [1, 2, 3] |
paul@2 | 35 | x = l |
paul@2 | 36 | a, b, c = l |
paul@2 | 37 | d, e, f = [1, 2, 3] |
paul@560 | 38 | |
paul@560 | 39 | print a, b, c # 1 2 3 |
paul@560 | 40 | print d, e, f # 1 2 3 |
paul@243 | 41 | print x # [1, 2, 3] |
paul@560 | 42 | |
paul@561 | 43 | # Test embedding of sequences in sequences. |
paul@561 | 44 | |
paul@2 | 45 | m = [4, l, 6] |
paul@561 | 46 | |
paul@561 | 47 | # Test sequence truth value interpretation. |
paul@561 | 48 | |
paul@2 | 49 | if x: |
paul@2 | 50 | n = l |
paul@2 | 51 | else: |
paul@2 | 52 | n = m |
paul@560 | 53 | |
paul@243 | 54 | print n # [1, 2, 3] |
paul@560 | 55 | |
paul@561 | 56 | # Test temporary variable usage at module level. |
paul@561 | 57 | |
paul@560 | 58 | a, b, c = h() |
paul@560 | 59 | print a, b, c # 7 8 9 |
paul@561 | 60 | |
paul@561 | 61 | # Test temporary variable usage in functions. |
paul@561 | 62 | |
paul@561 | 63 | i() # 7 8 9 |
paul@561 | 64 | |
paul@561 | 65 | # Test temporary variable usage in classes. |
paul@561 | 66 | |
paul@561 | 67 | class C: |
paul@561 | 68 | a, b, c = h() |
paul@561 | 69 | print a, b, c # 7 8 9 |