I've pretty much given up on Protoge as a tool for ontology development because I find I make more mistakes using Protoge than I make editing Turtle files with a plain text editor.
It seems like it would be really nice to have a Eclipse or jEdit plugin with features like syntax validation, autocompletion and all that. It would be particularly to have something that can connect to a SPARQL endpoint to drive autocompletion?
What's the current status of IDEs for Turtle?
TopBraid Composer is an Eclipse plug-in whose free version lets you edit data and models (RDFS or OWL) with autocompletion, although the autocompletion works from locally loaded models. It also lets you enter and run SPARQL queries with keyword highlighting, syntax completion, and dynamic identification of potential structural errors, which really does help to make it more of an IDE. (The version you pay for lets you develop applications, convert between triples and a wide variety of other formats as part of those applications, and test hosted applications on a local personal server.)
Editing of data is done with forms (although a "source" view is available) so whether you're editing Turtle or RDF/XML the only difference most people see is the extension used to save the file.
There is a N3 Bundle that does pretty syntax highlighting for Texmate (OSX app) but you can also use it also with other compatible apps :
- For windows, E-texteditorsupports also texmate bundles,
SublimeText2 (should work but throws an error :" Unexpected capture value")
Not a full IDE, but I have some settings files and a lexer for SciTE:
It syntax highlights N3, Turtle, NTriples, SPARQL 1.0, NQuads, TriG and anything else syntactically close enough to trick the lexer.
There are various settings towards the end of the "SciTE.properties" file for "compiling" Turtle to RDF/XML with a single keystroke, looking up prefixes on prefix.cc, etc. These you'd probably need to customise.