Index: ossp-pkg/var/TODO
RCS File: /v/ossp/cvs/ossp-pkg/var/Attic/TODO,v
rcsdiff -q -kk '-r1.6' '-r1.7' -u '/v/ossp/cvs/ossp-pkg/var/Attic/TODO,v' 2>/dev/null
--- TODO	2001/11/20 15:33:07	1.6
+++ TODO	2001/12/13 09:20:37	1.7
@@ -62,3 +62,71 @@
    Callback Array-Elemente abgefragt.
 
  - Abgabe: 6.12.2001 zum Nikolaustag im CVS.
+
+ **** CLARIFICATION ****
+
+    <            [ $HOME ${ARRAY} ] 
+    is same as > [ $HOME ${ARRAY[0]} ] 
+    must use   > [ $HOME ${ARRAY[#]} ]
+
+    Correction to termination condition: we loop unless all ARRAYs containing
+    '#' somewhere in the index expression return undefined. Any array using an
+    constant index and scalar variables are ignored when evaluating the
+    termination condition. Additionally we need support for explicit indexing,
+    ranges and stepping using the following "regex-style" quantifiers:
+
+                 [ ... body ... ]{begin,step,end}
+                 [ ... body ... ]{begin,end}
+
+                 begin, step and end can be digits or arithmetic expressions
+                 using variables (exactly like the index expressions) or empty
+                 string with default for the empty string
+                 - begin = 0
+                 - step  = 1
+                 - end   = maximum of all $#{anyvar} where  ${anyvar[...#...]}
+                           occurs in body.
+
+                 {,,} is same as {0,end} and can be omitted.
+
+    <            ${ARRAY:s/foo/bar:#}
+    is same as > ${ARRAY[0]:s/foo/bar/:#}
+    
+    This means that operation has nothing to do with arrays but works on
+    scalars.
+
+    Correction to index variable from var_cb_t: this is a signed integer and
+    allows negative, zero and positive indexes. It's up to the lookup callback
+    to decide what is undefined. Some callbacks may support negative indices
+    to support indexing from the end backwards through the array.
+
+    This means negative numbers can not be used as the magic identifier for
+    "gimme the number of elements for this variable".
+    
+    The callback needs another input, enum { VAR_LOOKUP_VALUE,
+    VAR_LOOKUP_ELEMENTS, ... } var_lookup_t which tells the callback what to
+    look up. Initially, only these modes are supported but we have room for
+    future expansion here.
+
+    The syntax change to adopt these changes is: $#{foo} returns the number of
+    elements in foo while ${foo:#} returns the number of characters in the
+    expanded value of foo. This keeps :# an command and makes ${foo} executing
+    callback with VAR_LOOKUP_VALUE and $#{foo} executing callback with
+    VAR_LOOKUP_ELEMENTS. Additionally it adopts Perl syntax. Extreme case:
+    $#{foo:#} tells you how many digits the number of elements of foo has.
+
+    Examples now working correctly:
+
+    - Creation of a Newsgroups: header from To: headers w/o the last comma
+
+        Newsgroup: [${To[#]}${To[#+1]:+${Separator} }]
+        Newsgroup: [${To[#-1]:+${Separator} }${To[#]}]
+
+    - Assume index zero is a header and the last element is a footer. Print a
+      table with header, ruler, body, ruler and footer.
+
+        ${foo[0]}
+        ${empty:p/-/${foo[0]:#}/}
+        [$foo{#}\n]{1,$#{foo}-1}
+        ${empty:p/-/${foo[$#{foo}]:#}/}
+        ${foo[$#{foo}]}
+