Theo Todman's Web Page - Notes Pages

Website Documentation

Website Generator Documentation - Functors

(Text as at 06/07/2023 00:43:12)

Introduction

• This Note covers the use of Functors₁ within the generators of my website. Their purpose is to enable calculated or derived text or data to be inserted automatically into my web pages. Updating such data manually used to be immensely tedious and error-prone.
• The basic idea is to embed encoded instructions in HTML Comments in the Notes text files that are used to generate the Notes’ HTML pages, ie. in < ! - - > (with the spaces omitted). There’s a start comment and an end comment, and the further text generated by the indicated Functor is inserted between the two, after any previously-generated text has been removed (that’s why the end-tags are needed). Because the instructions are within comments, they do not display when the page is rendered in HTML. The instructions are in the start comment, which is recognised by the string ‘FUNCTOR_ID=’. The end comment is recognised by the string ‘FUNCTOR_END ID=’.
• The information embedded now includes the Functor ID, the Option (within ID) and the Parameter (within Option, within ID). Both Option and Parameter are optional. There can’t be a parameter without an Option. If Option is omitted, it is assumed to be “01”. IDs are in the range “00” to “99”. Options are numeric. Parameters are strings, which may themselves have instructions for the Functor. So, the format of the text withing the HTML comment is ID, Option, Parameter.
• To avoid the time-dependent text generated by Functors being replaced each time the Note is regenerated, Functors only do anything (ie. Functor is only called) when the Note status is set to Temp. So, the Functor text in Live (and Archived) Notes is fixed.
• I have, however, allowed some specific Functors to work on Live Notes. This is the case with those used for the reading lists for my Personal Identity Notes. Footnote₂. In that case, processing is as normal if the Note status is “Temp”, but if it is Live (ie. Status is Null) then the Note text is updated and then copied to the latest (ie, corresponding) Archive Note, replacing its existing text.
• I now allow for nested Functors. Consequently, the Functor_End tag has to contain the Functor ID. If it does not, the Functor procedure looks for the next End tag without an ID, takes that and issues a warning message to Debug.Print.
• Functors are currently only embedded in Notes, but they also work in Note Write-ups that end up embedded in Paper Abstracts.