Message: 1
Date: Mon, 27 Aug 2012 21:18:08 -0400
From: Tarl Neustaedter <tarl-b2@tarl.net>
To: The OpenBIOS Mailinglist <openbios@openbios.org>
Subject: Re: [OpenBIOS] [PATCH] Adds local variable support to
OpenBIOS.
Message-ID: <503C1C50.408@tarl.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

[...]

And don't use CamelCase.

Is this some official naming convention, or your own taste?

In general (at least in the 1275 world), Forth is case-insensitive. The 
rare cases where it is made case sensitive (there are a couple in Sun's 
Openboot - see dropins.src) make use of mixed case very painful. The 
general standard is that methods and variables are lower case, defined 
constants and structure offsets are upper case. In some code, even they 
are lower case.

Mixed-case is generally confined to comments.

Factor this?  You shouldn't ever use a variable that is used as a temp

inside a word.

I'm not sure why you suggest this. It is just such a pain having to 

deal with the stack.

Because using a global variable gets you in trouble in recursion or when 
the same code is called at alarm level. As for stack being a pain, yes, 
that's forth. Stack manipulation as a way of life. Personally, I prefer 
"2over nip" rather than "2 pick" :-)

+48 CONSTANT localTableSize

+

+\ Declare the local variable table

+localTableSize ARRAY localVariableTable

You have 48 but can only access 12?

That is four fields per local variable: 48 / 4 = 12.

At a minimum, any derived constants should be derived explicitly. Like:

12 constant #local-variables     \ Feels right. If you need more, add 
more code after Locals11.
4 constant /local-variable       \ Datastructures require four cells
#local-variables /local-variable * constant locals-table-size \ Size in 
cells, not bytes.

Ah. That points out another convention. When mashing together multiple 
words for a method or variable name, we tend to use dashes as separators 
(and please, don't use underscores. There is someone I know who *mixes* 
underscores and dashes in variable names!). Another is that sizes of 
things are usually /object (such as /n, /l, ...) and counts of objects 
are usually #object.

+: getLocalRecordCount

+arrayCount 4 /

+;

Oh.  Use a struct?

The little documentation on struct I found did not indicate it was a 

better replacement for Array.

Struct will allow you define what the four separate words used in each 
local variable entry are used for. If you use structs, I'd expect to see 
something like:

struct
   /n field >LOCAL-INIT
   /n field >LOCAL-ORDER
   /n field >LOCAL-LEN
   /n field >LOCAL-ADDR
constant /local-variable
12 constant #local-variables
/local-variable #local-variables constant locals-table-size

Note that the above provides the table size in bytes, rather than cells.

To use the above (assuming you are still using alloc-mem), you'd see 
something like:

    locals-table-size alloc-mem     ( table )
    #local-variables 0 do           ( table )
      i /local-variable *           ( table entry )
      0 over >LOCAL-INIT !          ( table entry )
      0 over >LOCAL-ORDER !         ( table entry )
      0 over >LOCAL-LEN !           ( table entry )
      0 swap >LOCAL-ADDR !          ( table )
   loop                             ( table )