! :folding=indent:collapseFolds=1: ! $Id$ ! ! Copyright (C) 2003, 2004 Slava Pestov. ! ! Redistribution and use in source and binary forms, with or without ! modification, are permitted provided that the following conditions are met: ! ! 1. Redistributions of source code must retain the above copyright notice, ! this list of conditions and the following disclaimer. ! ! 2. Redistributions in binary form must reproduce the above copyright notice, ! this list of conditions and the following disclaimer in the documentation ! and/or other materials provided with the distribution. ! ! THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, ! INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND ! FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ! DEVELOPERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, ! SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, ! PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; ! OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, ! WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR ! OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ! ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. IN: namespaces USE: hashtables USE: kernel USE: kernel-internals USE: lists USE: vectors ! Other languages have classes, objects, variables, etc. ! Factor has similar concepts. ! ! 5 "x" set ! "x" get 2 + . ! 7 ! 7 "x" set ! "x" get 2 + . ! 9 ! ! get ( name -- value ) and set ( value name -- ) search in ! the namespaces on the namespace stack, in top-down order. ! ! At the bottom of the namespace stack, is the global ! namespace; it is always present. ! ! bind ( namespace quot -- ) executes a quotation with a ! namespace pushed on the namespace stack. : namestack ( -- ns ) 3 getenv ; inline : set-namestack ( ns -- ) 3 setenv ; inline : namespace ( -- namespace ) #! Push the current namespace. namestack car ; inline : >n ( namespace -- n:namespace ) #! Push a namespace on the namespace stack. >vector namestack cons set-namestack ; inline : n> ( n:namespace -- namespace ) #! Pop the top of the namespace stack. namestack uncons set-namestack ; inline : global ( -- g ) 4 getenv ; : set-global ( g -- ) 4 setenv ; : init-namespaces ( -- ) global >n ; : ( -- n ) #! Create a new namespace. 23 ; : (get) ( var ns -- value ) #! Internal word for searching the namestack. dup [ 2dup car hash* dup [ nip nip cdr ( found ) ] [ drop cdr (get) ( keep looking ) ] ifte ] [ 2drop f ] ifte ; : get ( variable -- value ) #! Push the value of a variable by searching the namestack #! from the top down. namestack (get) ; : set ( value variable -- ) namespace set-hash ; : put ( variable value -- ) swap set ; : nest ( variable -- hash ) #! If the variable is set in the current namespace, return #! its value, otherwise set its value to a new namespace. dup namespace hash dup [ nip ] [ drop >r dup r> set ] ifte ; : change ( var quot -- ) #! Execute the quotation with the variable value on the #! stack. The set the variable to the return value of the #! quotation. >r dup get r> rot slip set ; inline : bind ( namespace quot -- ) #! Execute a quotation with a namespace on the namestack. swap >n call n> drop ; inline : with-scope ( quot -- ) #! Execute a quotation with a new namespace on the #! namestack. >n call n> drop ; inline : extend ( object code -- object ) #! Used in code like this: #! : #! [ #! .... #! ] extend ; over >r bind r> ; inline : on ( var -- ) t put ; : off ( var -- ) f put ;