APE or Assistant for Philological Explorations is a free and open source (MPL/GPL licenses) stand alone computer program (that is, non web based but rather to be installed and run on a local machine). Its functional purpose is to assist in the exploration and interpretation of text corpora stored on a local computer system. APE allows users to create annotations locally, so they remain stored on the local machine. But APE is also able to link information found on the Internet to the text of a computer stored file as annotation. APE contains an editor that allows for the display of primary sources (such as facsimile and transcriptions) and the creation and addition of annotations to such primary sources.

APE's latest version has been developed for Windows '98/NT in Delphi 7. Tested compatibility is up to Windows 7, but APE is likely to work seamlessly with Windows 8 as well.

APE differs from most annotation tools in that it goes to length to support canonical referencing — i.e. references such as "De finibus, book 1, sections 32–3" that point to particular sections in a work rather than to places in concrete instances of  the work in, for instance, books. To this end it applies a DNS or middleware-like strategy that maps such canonical references to concrete links that point into concrete digital representations of the text. This means that links associated with canonical references are not hard links (i.e. directly to some digital resource) but identifiers (URNs) that must be resolved by an external process. One can compare this process to how a contacts list works. The canonical reference is the name used in everyday life, e.g. 'Louisa'. The formal name of this person (e.g. 'Louisa C. Radtcliff') which is listed in the contacts list is the URN (formal identifier). The contacts list gives the phone number (the actual link) of the phone that will connect you to the person identified by that particular name. Therefore if the person changes her phone number, her (canonical referenced) identity remains the same, and only the phone number needs to be updated in the list. APE supports this type of reference inter alia by letting users define a canonical referencing system in separate XML files.

This strategy gives APE two advantages. The first is that if a webpage's address (http link) changes, only one change has to be made in the annotation system. As can be perused from the example in table 1, the user would only change the one concrete link (in the rightmost column), while all the canonical references used in the texts and annotations would remain the same. The second advantage is that users can keep to a well known and well established referencing system rather than having to adopt a hypertext-based referencing system not specifically fitted for referencing the textual resources worked with.

Canonical reference used/read by userURN/Identifier used by machineResolved http link to actual web page
Genesis 1:4//bible/kingjamesversion/genesis/1/4https://www.biblegateway.com/passage/?search=Genesis+1-4&version=KJV
Genesis 1:4//bible/statenvertaling/genesis/1/4http://www.statenvertaling.net/bijbel/gene/1.html
Genesis 1:4 (Statenvertaling)//bible/statenvertaling/genesis/1/4http://www.statenvertaling.net/bijbel/gene/1.html

Table 1: Tabular example of resolving canonical references as hypertext links to concrete information on the Internet.

References

– Boot, Peter. 2009. Mesotext: Digitised Emblems, Modelled Annotations and Humanities Scholarship. Amsterdam: Amsterdam University Press. 
– Köhler, Dieter. 2006. “Persistent Links for the Internet: Fundamentals and Implementation.” In Literary and Linguistic Computing 21 (Suppl. Issue): 77–86.
– ———. 2015. APE: “Assistant for Philological Explorations.” Personal web page for Dieter Köhler. Accessed 5 October 2015. http://www.philo.de/ape/.

JZ