Hi.
1° Enclosed value is incorrectly rendered using only parentheses as if
it were part of a strand expression even if it's not. The generated
representation is wrong, and then parsing it back correctly gives the
same value as ⍎ would.
XX←X←⊂,1
2⎕TF ⎕← 2⎕TF'X'
X←(,1)
X
XX≡X
0
YY←Y←(⊂1 2)3
2⎕TF ⎕← 2⎕TF'Y'
Y←((1 2)) 3
Y
YY≡Y
0
If I understand the Appendix B of APL2 Language Reference correctly,
these representations should be “⊂1⍴1” for X and “(⊂1 2)3” for Y.
According to that Appendix, using “,1” for one-element vector in
transfer form isn't correct either, but I have no idea what APL2 does.
2° Some parentheses seem to confuse the parser. I took the “A” below
from an example in APL2 Language Reference and I believe in this case
the transfer form generated is correct, but then parsing it back with
2⎕TF gives incorrect nesting.
8⎕CR AA←A←('' (⍳0))('Q' 3.2)(2+3×⍳4) 'Don''t'
┌→────────────────────────────────────┐
│┌→──────┐ ┌→────┐ ┌→────────┐ ┌→────┐│
││┌⊖┐ ┌⊖┐│ │Q 3.2│ │5 8 11 14│ │Don't││
│││ │ │0││ └─────┘ └─────────┘ └─────┘│
││└─┘ └─┘│ │
│└∊──────┘ │
└∊∊───────────────────────────────────┘
2⎕TF ⎕← 2⎕TF'A'
A←('' (0⍴0)) ('Q' 3.2000000000000002) (5 8 11 14) 'Don''t'
A
AA≡A
0
8⎕CR A
┌→──────────────────────────────────┐
│┌⊖┐ ┌⊖┐ ┌→────┐ ┌→────────┐ ┌→────┐│
││ │ │0│ │Q 3.2│ │5 8 11 14│ │Don't││
│└─┘ └─┘ └─────┘ └─────────┘ └─────┘│
└∊──────────────────────────────────┘
The transfer form of A shown in the apl2lrm (page 337) is
A←(''(0⍴0))('Q' 3.2)(5-3×⎕IO-⍳4)'Don''t'
using a “progression” instead of explicit vector.
The Appendix says that redundant blanks and parentheses are prohibited,
so I'm not sure if what GNU APL gives is strictly correct with regard to
blanks, but the parenthesizing is the same and it certainly is correct
in terms of ⍎. It's parsing it back what fails in this case.
-k
