[Info-vax] DCL's flaws (both scripting and UI)

[Simon Clubley]

I think it's time once again to build a list of DCL's flaws now that
VSI are around. Don't forget however that DCL is both a scripting
language and a UI. My initial list is below.

Some of DCL's UI flaws:

1) You can't edit commands across line boundaries. Even Windows CLIs
can do this.

2) You can't save your command history automatically, bash style, and
have it restored automatically at the next session.

With bash, you can have multiple shells active at the same time and
only the commands entered during a specific session will be added to
the history file when that session exits even though the shell has the
full command history from previous shells available (up to a user
defined limit).

Any implementation needs to think about the multiple shells active at
the same time issue before proposing a solution to this.

3) No filename completion. This is _really_ annoying especially since
it even exists (after a fashion) in the command prompt on current
versions of Windows.

4) No elegant incremental search through the command history (bash
Ctrl-R style).

Some of DCL's scripting limitations:

1) No structured programming constructs such as (for example) while
loops.

2) No ability to iterate cleanly over a list of items (bash "for i in"
style)

3) No ability to add site specific lexicals.

4) The output from the lexicals should be an immutable collection of
objects which you can then iterate over without having to worry about
the state changing during iteration.

5) No regex support (this is also a UI issue).

6) Pathetic limits on the maximum size of symbol contents.

7) No array or collection of objects support. (In addition to normal
arrays, DCL should also support associative arrays.)

DCL has absolutely no way to group related variables together in the
way you can with structs in C or objects in other languages.

8) You cannot delete a directory tree in one go.

9) differences is very limited by today's standards. The functionality
in GNU diff, with (for example) it's ability to find differences in
whole directory trees and produce patch files for the differences
in an entire tree, should be the minimum baseline for functionality
these days.

I also find the unified diff output to be a _lot_ more readable than
the output from the DCL differences command.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
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