Sep 12, 2003
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- Back to "times"
	- "times" of our lives and their bindings
		- Birth
			- sex
			- parents
			- siblings (possibly)
			- dob
		- Christening
			- name
			- nickname
		- Education
			- degree
		- Living
			- spouses
		- Death
			- beneficiary of a will

- Some are static, some are dynamic
	- static: unchangeable and usually means upfront
	- dynamic: modifiable

- "Earlier" times mean
	- safety
	- reliability
	- efficiency

- "Later" times mean
	- flexibility

- Interpreted languages
	- most bindings happen at runtime

- Compiled languages
	- many bindings are static

- Names, an important concept in imperative languages
	- used for variables, labels, procedures, functions
	- earlier languages had pre-defined names

- Attributes of a name
	- length
	- connector characters
	- case sensitivity
	- reserved words and keywords

- When used for variables, new attributes
	- name
	- address
	- value
	- type
	- scope
	- lifetime

- Think about
	- x = x+1
		- what does this mean?

- Difference between
	- l-value
	- r-value

- Associations between addresses to names
	- one-one (regular variables)
	- one-many (aliasing)
	- many-one (local variables)

- Type
	- a set of values with defined operations

- Scope
	- region of program where var is visible

- Lifetime
	- time during which variable is associated with
	  a memory cell

- What are types useful for?
	- compliance check
	- better allocate storage

- type equivalence
	- structural equivalence
		- C (except for structs)
		  FORTRAN, ALGOL
	- name equivalence
		- C++, Ada
	- declaration equivalence
		- Modula, Pascal 

- Handout containing type declarations in
  various languages