Emacs is an advanced and extensible editor. A Major Mode customizes Emacs for editing text of a particular sort. PSGML is a major mode for SGML documents. PSGML has several functions for editing SGML documents. Indentation according to element nesting depth and identification of structural errors (but it is not a validating SGML parser). Menus and commands for inserting tags with only the contextually valid tags. Attribute values can be edited in a separate window with information about types and defaults. Structure based editing includes movement and killing; and also several commands for folding editing.
Emacs is an advanced and extensible editor. A Major Mode customizes Emacs for editing text of a particular sort. PSGML is a major mode for SGML documents. PSGML has several functions for editing SGML documents. Indentation according to element nesting depth and identification of structural errors (but it is not a validating SGML parser). Menus and commands for inserting tags with only the contextually valid tags. Attribute values can be edited in a separate window with information about types and defaults. Structure based editing includes movement and killing; and also several commands for folding editing.
To install psgml, run the following command in macOS terminal (Applications->Utilities->Terminal)
sudo port install psgml
To see what files were installed by psgml, run:
port contents psgml
To later upgrade psgml, run:
sudo port selfupdate && sudo port upgrade psgml
Reporting an issue on MacPorts Trac
The MacPorts Project uses a system called Trac to file tickets to report bugs and enhancement requests.
Though anyone may search Trac for tickets, you must have a GitHub account in order to login to Trac to create tickets.