ITEC 380 2012fall ibarland tlewis32

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hw-ec-racket-way-questions
The Racket Way
comprehension questions

The video+slide presentation below is nice. However, probably a more technically useful bit would be reading “Creating Languages in Racket”, ACM Queue, 2011.Nov.

For 10 hw points: Watch the following presentation Racket, 50min (approx).
(Try to watch on a large monitor, so you can see the slides at the same time as watching the video feed. Be sure not to full-screen the video feed, else you won't see the slides at all; slides+audio is more helpful than the video.)

• (1pt)What did the third princess wish for? What is that third wish an analogy for?
• (Note that the images are from slide-show library, not from image.ss.)
• (1pt) In Scrbl, most test is plain-text. What character escapes into “program” mode? What does php use, in a similar way¹?
• (1pt) How is a killing off a custodian different from killing off a process?
• (1pt) One of the slides demo's calling the method show for a frame% object. What keyword is used, to call a method, in racket's object system?
• (1pt) How is parameterize different from let (for example, parameterizing the standard-error-port to be a file, as opposed to assigning a local variable `standard-error-port` to be a file?                 
• (2pts each) For each version, of the text-adventure, what is the major feature between that and the previous version? (1 sentence each)

  Note:Full source code for the evolving versions is linked from “Creating Languages in Racket”,$Aj ACM Queue, 2011.Nov.

  • v0, “Longhand version”:                 
  • v1, “Syntactic Abstraction”:                 
  • v2, “Syntactic extension”:                 
  • v3, “Module language”:                 
  • v4, “Types”:                 
  • v5, “new language”:                 
  • v6, “environment support”:                 

For 15pts of extra-credit, related to the last question above:
For each of versions v0, v1, and v5 of the text-adventure game:

Note:Full source code for the evolving versions is linked from “Creating Languages in Racket”, ACM Queue, 2011.Nov.

• add a lantern, which can be light'd and douse'd, as well as grabbed and dropped (and other synonyms). The lantern is initially in the house's room.
• add a basement to the (house's) room. In the basement, if you try moving any direction (n/s/e/w/down/up) but your lantern is not lit, printf "you are eaten by a lurking grue" and (exit). Otherwise, the result is “you cannot go that way” for most directions, and up brings the player back to the room.

For significant extra credit (but commensurate difficulty!): introduce a new concept to the game (something besides a place, item, or verb), and then add support for that concept to v2/v3, v4, and v6.
For example, perhaps there are colors; each place and item has one color, and the explorer has a set of colors. The explorer can only enter places whose color is one they have, and grabbing/dropping items causes the explorer to gain/lose those colors. You would add such support to the macros in v2, the type-checking in v4, the syntax-colorer in v6, etc.

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©2012, Ian Barland, Radford University Last modified 2012.Nov.20 (Tue)

Please mail any suggestions (incl. typos, broken links) to ibarlandradford.edu