>From "module system considered harmful"
----------------------------------------------------------------------
2) Suppose you have a source file where you write,
IN: foo
: a ;
: b a ;
You load the source file into Factor. Then you add a new word definition
: c b ; but you add it _before_ the definition of b. The file still
loads, however, because the definition of b is present in the vocabulary
when c is parsed.
But if you start Factor with a clean image, the source file won't load
(and bottom-up ordering of definitions a good thing; in CL,
automatically interning symbols in the wrong package can be a source of
problems).
--
The new module system can fix the problem (which is that the modified
source file could load without an error in the first place) as follows.
You start by marking words in a module with a special flag before
reloading the module; then as each definition is read, the word's flag
is reset. If a definition refers to a word with the flag still set, a
parse-time error is raised. When the module is finished loading, the
module system can also check if any words which have the flag set are
still referenced by words in other modules; if so, a message can be
printing instructing the programmer to either reintroduce the word, or
refactor those modules, etc.
----------------------------------------------------------------------
Is there something wrong with simply doing this:
"foo" words [ forget ] each
when foo is reloaded?
I had considered this:
"foo" vocabularies get remove-hash
or
"foo" vocabularies get hash clear-hash
but the problem with those is that existing vocabularies that reference foo
words keep the references. forget seems to do the job of telling everyone
that they are gone.
-------------------------------------------------------------------------
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