Structured Variable Assignment - )more

[Hans-Peter Sorge]

Hi Jürgen,

Concerning the erasure of a variable, other language have such 
functionality too.
Like "unset VAR" or "VAR=", by that ignoring variable content.
Even ⎕EX does not care.

Protecting names is done by )PCOPY. or ⍫, though locking a function 
renders it unreadable.

And as I mentioned, when using structured variables the sequence
      A.B.C←1
      A ← 2
will ⎕EX 'A.B'. The name-tree is not being protected:
      A
2

To protect variables against erasure/changes, functionality should be 
implemented on a common level.
eg.  Quad Protect Variable -> ⎕PV

 ⎕PV 'name'
0
⍝ name is unprotected.


1 ⎕PV 'name'
  ⎕EX 'name'
0
⍝ name is protected against erasure

2 ⎕PV 'name'
name ← 'new data'
PROTECTED
name ← 'new data'
^
⍝ name is protected against modification

0 ⎕PV 'name'
⍝ unprotect name


I have to apologize for my endless train of ideas.
Working 45 years with APL, I have 45 years worth of ideas on my mind :-)

Best Regards
hans-Peter