# A doubly linked list permits bidirectional traversal. container duplex-list:_elem [ value:_elem next:address:duplex-list:_elem prev:address:duplex-list:_elem ] recipe push x:_elem, in:address:duplex-list:_elem -> result:address:duplex-list:_elem [ local-scope load-ingredients result <- new {(duplex-list _elem): type} val:address:_elem <- get-address *result, value:offset *val <- copy x next:address:address:duplex-list:_elem <- get-address *result, next:offset *next <- copy in reply-unless in prev:address:address:duplex-list:_elem <- get-address *in, prev:offset *prev <- copy result ] recipe first in:address:duplex-list:_elem -> result:_elem [ local-scope load-ingredients reply-unless in, 0 result <- get *in, value:offset ] recipe next in:address:duplex-list:_elem -> result:address:duplex-list:_elem [ local-scope load-ingredients reply-unless in, 0 result <- get *in, next:offset ] recipe prev in:address:duplex-list:_elem -> result:address:duplex-list:_elem [ local-scope load-ingredients reply-unless in, 0 result <- get *in, prev:offset reply result ] scenario duplex-list-handling [ run [ # reserve locations 0, 1 and 2 to check for missing null check 1:number <- copy 34 2:number <- copy 35 3:address:duplex-list:character <- push 3, 0 3:address:duplex-list:character <- push 4, 3:address:duplex-list:character 3:address:duplex-list:character <- push 5, 3:address:duplex-list:character 4:address:duplex-list:character <- copy 3:address:duplex-list:character 5:character <- first 4:address:duplex-list:character 4:address:duplex-list:character <- next 4:address:duplex-list:character 6:character <- first 4:address:duplex-list:character 4:address:duplex-list:character <- next 4:address:duplex-list:character 7:character <- first 4:address:duplex-list:character 8:address:duplex-list:character <- next 4:address:duplex-list:character 9:character <- first 8:address:duplex-list:character 10:address:duplex-list:character <- next 8:address:duplex-list:character 11:address:duplex-list:character <- prev 8:address:duplex-list:character 4:address:duplex-list:character <- prev 4:address:duplex-list:character 12:character <- first 4:address:duplex-list:character 4:address:duplex-list:character <- prev 4:address:duplex-list:character 13:character <- first 4:address:duplex-list:character 14:boolean <- equal 3:address:duplex-list:character, 4:address:duplex-list:character ] memory-should-contain [ 0 <- 0 # no modifications to null pointers 1 <- 34 2 <- 35 5 <- 5 # scanning next 6 <- 4 7 <- 3 8 <- 0 # null 9 <- 0 # first of null 10 <- 0 # next of null 11 <- 0 # prev of null 12 <- 4 # then start scanning prev 13 <- 5 14 <- 1 # list back at start ] ] # Inserts 'x' after 'in'. Returns some pointer into the list. recipe insert x:_elem, in:address:duplex-list:_elem -> new-node:address:duplex-list:_elem [ local-scope load-ingredients new-node <- new {(duplex-list _elem): type} val:address:_elem <- get-address *new-node, value:offset *val <- copy x next-node:address:duplex-list:_elem <- get *in, next:offset # in.next = new-node y:address:address:duplex-list:_elem <- get-address *in, next:offset *y <- copy new-node # new-node.prev = in y <- get-address *new-node, prev:offset *y <- copy in # new-node.next = next-node y <- get-address *new-node, next:offset *y <- copy next-node # if next-node is not null reply-unless next-node, new-node # next-node.prev = new-node y <- get-address *next-node, prev:offset *y <- copy new-node reply new-node # just signalling something changed; don't rely on the result ] scenario inserting-into-duplex-list [ run [ 1:address:duplex-list:character <- push 3, 0 1:address:duplex-list:character <- push 4, 1:address:duplex-list:character 1:address:duplex-list:character <- push 5, 1:address:duplex-list:character 2:address:duplex-list:character <- next 1:address:duplex-list:character # 2 points inside list 2:address:duplex-list:character <- insert 6, 2:address:duplex-list:character # check structure like before 2:address:duplex-list:character <- copy 1:address:duplex-list:character 3:character <- first 2:address:duplex-list:character 2:address:duplex-list:character <- next 2:address:duplex-list:character 4:character <- first 2:address:duplex-list:character 2:address:duplex-list:character <- next 2:address:duplex-list:character 5:character <- first 2:address:duplex-list:character 2:address:duplex-list:character <- next 2:address:duplex-list:character 6:character <- first 2:address:duplex-list:character 2:address:duplex-list:character <- prev 2:address:duplex-list:character 7:character <- first 2:address:duplex-list:character 2:address:duplex-list:character <- prev 2:address:duplex-list:character 8:character <- first 2:address:duplex-list:character 2:address:duplex-list:character <- prev 2:address:duplex-list:character 9:character <- first 2:address:duplex-list:character 10:boolean <- equal 1:address:duplex-list:character, 2:address:duplex-list:character ] memory-should-contain [ 3 <- 5 # scanning next 4 <- 4 5 <- 6 # inserted element 6 <- 3 7 <- 6 # then prev 8 <- 4 9 <- 5 10 <- 1 # list back at start ] ] scenario inserting-at-end-of-duplex-list [ run [ 1:address:duplex-list:character <- push 3, 0 1:address:duplex-list:character <- push 4, 1:address:duplex-list:character 1:address:duplex-list:character <- push 5, 1:address:duplex-list:character 2:address:duplex-list:character <- next 1:address:duplex-list:character # 2 points inside list 2:address:duplex-list:character <- next 2:address:duplex-list:character # now at end of list 2:address:duplex-list:character <
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<html><head><title>Python: module posixpath</title>
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<font color="#ffffff" face="helvetica, arial">&nbsp;<br><big><big><strong>posixpath</strong></big></big></font></td
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><font color="#ffffff" face="helvetica, arial"><a href=".">index</a><br><a href="file:/usr/lib/python3.1/posixpath.py">/usr/lib/python3.1/posixpath.py</a><br><a href="http://docs.python.org/library/posixpath">Module Docs</a></font></td></tr></table>
    <p><tt>Common&nbsp;operations&nbsp;on&nbsp;Posix&nbsp;pathnames.<br>
&nbsp;<br>
Instead&nbsp;of&nbsp;importing&nbsp;this&nbsp;module&nbsp;directly,&nbsp;import&nbsp;os&nbsp;and&nbsp;refer&nbsp;to<br>
this&nbsp;module&nbsp;as&nbsp;os.path.&nbsp;&nbsp;The&nbsp;"os.path"&nbsp;name&nbsp;is&nbsp;an&nbsp;alias&nbsp;for&nbsp;this<br>
module&nbsp;on&nbsp;Posix&nbsp;systems;&nbsp;on&nbsp;other&nbsp;systems&nbsp;(e.g.&nbsp;Mac,&nbsp;Windows),<br>
os.path&nbsp;provides&nbsp;the&nbsp;same&nbsp;operations&nbsp;in&nbsp;a&nbsp;manner&nbsp;specific&nbsp;to&nbsp;that<br>
platform,&nbsp;and&nbsp;is&nbsp;an&nbsp;alias&nbsp;to&nbsp;another&nbsp;module&nbsp;(e.g.&nbsp;macpath,&nbsp;ntpath).<br>
&nbsp;<br>
Some&nbsp;of&nbsp;this&nbsp;can&nbsp;actually&nbsp;be&nbsp;useful&nbsp;on&nbsp;non-Posix&nbsp;systems&nbsp;too,&nbsp;e.g.<br>
for&nbsp;manipulation&nbsp;of&nbsp;the&nbsp;pathname&nbsp;component&nbsp;of&nbsp;URLs.</tt></p>
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<font color="#ffffff" face="helvetica, arial"><big><strong>Modules</strong></big></font></td></tr>
    
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<td width="100%"><table width="100%" summary="list"><tr><td width="25%" valign=top><a href="genericpath.html">genericpath</a><br>
</<