Go backward to Semantics of Variables Go up to Top Go forward to Type-Structure Abstractions

Type-Structures

D in Declaration
T in Type-structure
    D ::= ...| var I:T
    T ::= newint

• Type structure T
  • Allocates storage!
• Declaration var I:T
  • Activates T.
  • Binds result value to I.
• Contrast to procedures
  • proc I=C alters storage only when procedure is invoked (lazy evaluation).
  • var I:T alters storage when variable is declared (eager evaluation).