Programming Languages: Design, Specification, and Implementation

1
Programming LanguagesDesign, Specification, and
Implementation

• G22.2210-001
• Rob Strom
• November 9, 2006

2
Other readings on ML

• http//www.dcs.ed.ac.uk/home/stg/NOTES/notes.html

3
Readings (week 1)

• Theoretical and Historical Papers on Concurrency
• The Readers/Writers Problem
• http//www.md.chalmers.se/ptrianta/SynCCo/LIT/la
  mp77.pdf.gz
• Shared Registers (Part II)
• http//users.ece.gatech.edu/dblough/6102/lamport_
  consistency.pdf
• Wait-free synchronization
• http//www.cs.brown.edu/mph/Herlihy91/p124-herlih
  y.pdf
• Partially-ordered time.
• http//research.microsoft.com/users/lamport/pubs/t
  ime-clocks.pdf
• Concurrency models in object-oriented languages
• Ada Reference Manual Section 9
• Java Reference Manual Chapter 17
• Thinking in C, chapter 11
• http//web.mit.edu/merolish/ticpp/TicV2.html_Toc5
  3985862

4
Readings (week 2)

• Problems with the Memory Model
• Java Memory model is Broken
• http//www.cs.umd.edu/pugh/java/broken.pdf
• Thread-Safe Programming
• Compiler-Enforced Thread-Safety (Guava)
  http//researchweb.watson.ibm.com/people/d/dfb/pap
  ers/Bacon00Guava.ps
• Safe Reader-Writer Parallelism (Optimistic
  Readers) http//www.research.ibm.com/distributedm
  essaging/paper13.html

5
Programming Project on Concurrency due Nov. 30

• Extend the room world of the previous assignment
  so that multiple people can enter rooms and do
  things
• Each thing someone does is an atomic unit of
  work, e.g.
• Get things from factories and put them in the
  room
• Pick up a bunch of objects and put them in a
  container
• Pick up 2 containers and a funnel and transfer
  liquid from one container to the other
• Dont deadlock
• Anticipate contention e.g. youve picked up
  object A and try to pick up object B, but
  discover its gone because someone else picked up
  object B. You may need to give up your scripted
  action.
• The implementation should have the same realism
  properties as the non-concurrent implementation
  did e.g. things shouldnt spontaneously
  disappear or appear in multiple places.
• You may use any one of C, Java, or Ada
  (probably the same language you used for previous
  assignment, but this is not required)

6
Notes on Grading of Projects

• The bulk of the points should go for
  understanding the assignment and correctly using
  the features of the languages being tested (e.g.
  in the polymorphism assignment, triggering
  run-time dispatching, and sharing a common
  interface).
• The next group of points is for clear
  documentation of the components, and what they
  do.
• The last group of points should be for
  correctness, freedom from bugs, conformity to
  test cases.

7
HomeworkML Type Inference Problem

• Type inference
• fun zip f nil nil nil
• zip f (ht) (is) f(h,i)zip f t s
• What does it do?
• What is its most general type?
• Consider these two expressions
• (1) fun f g g 7 g false
• (2) let val g fn (x) gt 20 in g 7 g false
• Why is (1) incorrectly typed and (2) correctly
  typed?
• What is the type of g in (2)?