Oct 15-20, 2003
-------------

- Oct 15
	- midterm

- Oct 17
	- midterm return
	- discussion of questions and solutions

- Oct 20
	- feedback form review
	- more discussion

- Control
	- guarded ifs and guarded dos

- Format of a guarded if
	- if B1 -> S1
	  |  B2 -> S2
	  |  B3 -> S3
	  |  ....
	  |  Bn -> Sn
	  fi

- Semantics of a guarded if
	- if exactly one B is true, corresponding S
	  is performed
	- if more than one B is true, one and exactly
	  one S is performed
	- if none of the Bs are true, <runtime error>

- Notice that
	- order of evaluation of Bs is left unspecified
	- how a S must be chosen when more than one B is true,
	  is also unspecified
		=> a non-deterministic construct

- Manifestations of guarded ifs in today's languages
	- if-then-else
		- danging else problem
		- can update grammar, or
		- use "fi" type of closing constructs
	- case construct
		- example from C
		- use of break, to break out of conditions
		- "collapsing" efects for multiple statements

- Format of a guarded do
	- do B1 -> S1
	  |  B2 -> S2
	  |  B3 -> S3
	  |  ....
	  |  Bn -> Sn
          od

- Semantics of a guarded do
	- akin to guarded if, except when none of the Bs
	  are true, skip out (not a runtime error)

- Manifestations of guarded dos
	- while
	- repeat
	- for
		- examples from C

- how while satisfies the guarded do conditions

- Simulating repeat using while

- how for satisfies the guarded do conditions