Hello,
Here's demo of a tree of named namespaces which is is navigable. I borrowed
names from UNIX filesystem manipulation to make it clear what's going on.
Use the vocabulary
( scratchpad ) USE: name-tree
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----------
List the variables in the current namespace
( scratchpad ) ls
{ in use }
----------
----------
What namespace are we in?
( scratchpad ) pwd
""
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----------
Let's make a namespace
( scratchpad ) "francophone" mkdir
----------
----------
Check the variables again. There's our new namespace.
( scratchpad ) ls
{ "francophone" in use }
----------
----------
Switch to that namespace
( scratchpad ) "francophone" cd
----------
----------
Check the 'pwd' again
( scratchpad ) pwd
"francophone"
----------
----------
Look at the variables
( scratchpad ) ls
{ in dir-name }
----------
----------
Make some new variables
( scratchpad ) t "algeria" set
----------
----------
( scratchpad ) t "france" set
----------
----------
( scratchpad ) t "quebec" set
----------
----------
List them
( scratchpad ) ls
{ dir-name "france" "quebec" "algeria" in }
----------
----------
Let's make a namespace and switch to it
( scratchpad ) "other" mkdir
----------
----------
( scratchpad ) "other" cd
----------
----------
What "directory" are we in?
( scratchpad ) pwd
"francophone:other"
----------
----------
Let's switch to the parent namespace
( scratchpad ) up
----------
----------
( scratchpad ) pwd
"francophone"
----------
----------
( scratchpad ) ls
{ dir-name "france" "quebec" "algeria" "other" in }
----------
----------
As is often the case with Factor, the implementation is delightfully short;
six one liners.
Ed
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USING: kernel namespaces namespaces.private
sequences assocs prettyprint math newfx ;
IN: name-tree
SYMBOL: dir-name
: def ( var val -- ) swap set ;
: ls ( -- ) namespace keys . ;
: up ( -- ) namestack length 2 > [ ndrop ] when ;
: cd ( name -- ) get >n ;
: mkdir ( name -- ) H{ } clone dir-name pick is def ;
: pwd ( -- ) namestack 2 tail [ dir-name at ] map ":" join . ;
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