5. A computer-programming tool as claimed in claim 1 , wherein the first data structure comprises further linked nodes representative of a language extension, the language extension being an extension to said computer-programming language.
5. A computer-programming tool as claimed in claim 1 , wherein the first data structure comprises further linked nodes representative of a language extension, the language extension being an extension to said computer-programming language. 9. A computer-programming tool as claimed in claim 5 , wherein said language extension is at least part of a language other than said computer-programming language.