Rob Cozens wrote:
The proposed assignment OPTION is consistent with several dozen
languages, many of which are still actively growing a strong rate,
as opposed to Pascal which is the only one which uses Pascal-style
assignment and is in rapid decline today.
The proposed OPTION would eliminate my current OPTION to replace code like:
if recordNumber = 1 then set the disabled of button
"Previous Record" to false
else set the disabled of button "Previous Record" to true
if recordNumber = recordCount then set the disabled of
button "Next Record" to false
else set the disabled of button "Next Record" to true
with
set the disabled of button "Previous Record" to (recordNumber = 1)
set the disabled of button "Next Record" to (recordNumber =
recordCount)
and break every script where I use this structure.
I can't believe you find the need for this OPTION so great that you
would advocate breaking existing syntax.
Not at all. I've tried (though apparently failed) to express that I
changed my opinion over the years to come to favor more consistent
support for "=" as an assignment operator based on two factors:
- It needn't break any existing syntax
- It already exists in Transcript
This second point is critical to this discussion, yet somehow overlooked
in half the posts here. What's on the table is not to make anything
new, but merely to make something that's already in place more consistent.
Statements begin with a command, and are parsed according to what's
expected based on that command.
Statements beginning with "if", "set", or really anything that isn't a
variable name or type declaration (such as those in the example above)
would not be affected by making support for "=" as an assignment
operator more consistently supported.
Currently when the command is "constant" then "=" can be used as an
assignment operator. But currently this only works in a script-local
context, and all other variable types and contexts are arbitrarily
excluded from using this assignment operator. The current partial
implementation introduces a "sometimes" rule into the language, and such
rules make learning unnecessarily difficult.
The proposal at hand would make the language simpler and more
consistent, and not break any existing code, by simply allowing
assignment when the first word of a statement is a variable name, and
removing the arbitrary restriction of its usage to script-locals only.
To the best of my knowledge, there is currently no context other than
the proposed in which a statement can begin with a variable name, thus
no conflict with existing usage. If we find an exception to that I'm
sure we could just as easily come up with a rule for the compiler to
account for it. After all, this isn't exactly splitting the atom;
dozens of languages have allowed this assignment operator for many
years, even languages that also use that token for comparison, so it's
not like it really requires much in the way of invention.
Some here may be glad to hear this will be my last post on this subject.
I haven't said much new since my first post in this thread, and I trust
I've restated things enough since then that anything I could hope to
contribute is about as clear as I can make it. If anything more needs
to be said I'll leave that to better writers....
--
Richard Gaskin
Managing Editor, revJournal
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