An important new feature has been added to the interactive base network editor: the ability to automatically generate a transcript file which faithfully records all interactive changes made during an editing session with module 2.12.
This transcript file can serve well for many purposes. In the most simple case, it can just be used as an audit trail which allows a project manager to keep a trace of the exact history of all network changes made in a data bank.
Since transcript files are written using the batch input format accepted by the new version of module 2.11, they can also be used to automatically repeat the network modifications. This is not only useful for backing up the interactive work while it is being done, but it is also a big help in cases in which the same network change has to be applied to several existing scenarios. In this case, once the modification is done interactively for the first scenario, all that remains to be done is to read the resulting transcript file into all other scenarios using module 2.11.
The transcript file does not only contain the details regarding the operations that were performed, it also preserves all information that was lost due to these operations. This means that when a node or link is deleted, all related attribute values of the deleted element are written to the transcript file, as are the old attribute values when an element is modified. With this information, the transcript file becomes invertible, which means that it contains all the necessary information to reverse or undo the operations that were carried out during the editing session.
Since the transcript file has to comply with the standard network input format used by module 2.11, all ``undo'' information is contained in comment cards. For every operation the transcript file also contains the corresponding inverse operation, hidden away in a comment card. For example the inverse operation of a link deletion operation is a link addition operation using the attributes of the deleted link.
The following example shows a transcript file of a very short editing session, in which one two-way link was split into two, by the insertion of an intermediate node:
c======================================================================= c 92-10-04 07:30:30 m=2.12 s= 2000 u=..HS network= 154/ 903/ 2975 t nodes cd1081 a1081,-.49551,.00106,0,17.5,.53,STFD ct nodes t links ca936,935,.18,cp,4,1.0,1,0,0,0 d936,935 ca935,936,.18,cp,4,1.0,1,0,0,0 d935,936 cd936,1081 a936,1081,.09,cp,4,1.0,1,0,0,0 cd1081,936 a1081,936,.09,cp,4,1.0,1,0,0,0 cd1081,935 a1081,935,.09,cp,4,1.0,1,0,0,0 cd935,1081 a935,1081,.09,cp,4,1.0,1,0,0,0 ct links c 92-10-04 07:35:01 m=2.12 s= 2000 u=..HS network= 154/ 905/ 2977 c-----------------------------------------------------------------------With the new utility E2UNDO, transcript files can be inverted, i.e. transformed from the ``do'' form to the corresponding ``undo'' form, which can then be used to reverse the effect of the modifications made in the editing session. E2UNDO reverses the order of the lines in the transcript file, puts a ``c'' in front of all ``a'', ``d'', ``m'' and ``t'' cards to render them comments, and removes the leading ``c'' from all cards beginning with ``ca'', ``cd'', ``cm'' and ``ct''. Here is the ``undo'' file obtained by applying E2UNDO to the above example:
c----------------------------------------------------------------------- c 92-10-04 07:35:01 m=2.12 s= 2000 u=..HS network= 154/ 905/ 2977 t links ca935,1081,.09,cp,4,1.0,1,0,0,0 d935,1081 ca1081,935,.09,cp,4,1.0,1,0,0,0 d1081,935 ca1081,936,.09,cp,4,1.0,1,0,0,0 d1081,936 ca936,1081,.09,cp,4,1.0,1,0,0,0 d936,1081 cd935,936 a935,936,.18,cp,4,1.0,1,0,0,0 cd936,935 a936,935,.18,cp,4,1.0,1,0,0,0 ct links t nodes ca1081,-.49551,.00106,0,17.5,.53,STFD d1081 ct nodes c 92-10-04 07:30:30 m=2.12 s= 2000 u=..HS network= 154/ 903/ 2975 c=======================================================================The generation of transcript files is controlled by a new module parameter in module 2.12. If activated, a transcript file is written to a batch output file, using the usual naming conventions, as defined by the flexible file naming scheme.