Alternate Structures

Oftentimes a text is referred to using more than one overlapping scheme. In cases like this, alternate structures may be specified on Index records. Examples of this are Torah, which has both a chapter-verse addressing schema, and a parsha-aliyah addressing schema, and Talmud which has both a daf addressing schema and a chapter-mishnah schema.

One structure, the one with the greatest detail, is used as the storage format of the text. It is specified in the schema attribute of the Index record. The other formats are specified in the alt_structs attribute of the Index record.

alt_structs is a dictionary, mapping structure keys (which can be arbitrary) to alt structures. Alt structures look very much like the Index Schema but with a few differences:

• The nodeType is generally ArrayMapNode
• The root node has no titles. It uses the titles of the schema root.
• All nodes of the alt structure do not have key fields.
• Terminal nodes in an alt structure have mappings to underlying references, using one or two attributes:
  • wholeRef: A single string, which has a ref to the whole range covered by this node
  • refs: (required only when depth is greater than zero) A jagged array of refs the correspond to how wholeRef is broken into sections named by sectionNames.
• Display attributes can be set which affect how an alternate structure is visualized in its Table of Contents:
  • includeSections: when True, the node will include links to each individual section within wholeRef underneath the alternate node name (e.g., Zohar).

Here is an example of one section of the alternate structure of the book of Exodus:

   "alt_structs" : {
        "Parasha" : {
            "nodes" : [ 
                {
                    "sharedTitle" : "Shemot",
                    "nodeType" : "ArrayMapNode",
                    "depth" : 1,
                    "sectionNames" : [ 
                       "Aliyah"
                    ],
                    "wholeRef" : "Exodus 1:1-6:1",
                    "refs" : [ 
                        "Exodus 1:1-1:17", 
                        "Exodus 1:18-2:10", 
                        "Exodus 2:11-2:25", 
                        "Exodus 3:1-3:15", 
                        "Exodus 3:16-4:17", 
                        "Exodus 4:18-4:31", 
                        "Exodus 5:1-6:1"
                    ],
                    "addressTypes" : [ 
                        "Integer"
                    ]
                }, 
                {
                    "sharedTitle" : "Vaera",
                    "nodeType" : "ArrayMapNode",
                    "depth" : 1,
                    "sectionNames" : [ 
                        "Aliyah"
                    ],
                    "wholeRef" : "Exodus 6:2-9:35",
                    "refs" : [ 
                        "Exodus 6:2-6:13", 
                        "Exodus 6:14-6:28", 
                        "Exodus 6:29-7:7", 
                        "Exodus 7:8-8:6", 
                        "Exodus 8:7-8:18", 
                        "Exodus 8:19-9:16", 
                        "Exodus 9:17-9:35"
                    ],
                    "addressTypes" : [ 
                        "Integer"
                    ]
                }, 
                {
                    "sharedTitle" : "Bo",
                    "nodeType" : "ArrayMapNode",
                    "depth" : 1,
                    "sectionNames" : [ 
                        "Aliyah"
                    ],
                    "wholeRef" : "Exodus 10:1-13:16",
                    "refs" : [ 
                        "Exodus 10:1-10:11", 
                        "Exodus 10:12-10:23", 
                        "Exodus 10:24-11:3", 
                        "Exodus 11:4-12:20", 
                        "Exodus 12:21-12:28", 
                        "Exodus 12:29-12:51", 
                        "Exodus 13:1-13:16"
                    ],
                    "addressTypes" : [ 
                        "Integer"
                    ]
                }, 
...