University Homepage School Homepage School Contacts School Search

Quick questions on xtext

Bold ( :-) ) experiment: using three lines of JavaScript for this set of revision questions, just to show/hide model solutions, rather than either not giving model solutions or sticking them on a separate page. Please let me know if it doesn't work. (Obviously it won't if you have JavaScript turned off, but I'm guessing that's rare these days.)

1. Write a rule, called Song, in xtext, which specifies that a Song is specified by the keyword song followed by an ID, which should be assigned to variable opus. Show solution

   Song:
     'song' opus=ID;
   

2. (a different style for telling you what to write!) Write a rule called Concerto that should let users write lines like:
   concerto k466 "piano in D minor"
   where "concerto" is a fixed keyword in the DSL, "k466" is an ID, which should be saved in variable opus, and "piano in D minor" is a STRING which should be saved in variable description. Show solution

   Concerto:
     'concerto' opus=ID description=STRING;
   

3. Write a rule called Work that specifies that a Work is either a Song or a Concerto. Show solution

   Work:
     Song | Concerto;
   

4. Write a rule called Concert that specifies that a Concert is given by the keyword "concert" followed by a list of Works in curly brackets. The list of Works should be called programme. Show solution

   Concert:
     'concert' '{'
       (programme+=Work)*
     '}';
   

---

This page is maintained by Perdita Stevens (perdita@inf.ed.ac.uk)