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Lazy and Eager Bindings

• Extended syntax:
  • E ::= E₁:=E₂ | ... | newint
    | lazy I=E | eager I=E
    | E₁,E₂ | with E₁ do E₂ | I | lambdaI:theta. E | E₁ E₂
• Examples:
  • var X: newint
    = eager X = newint
  • class K =
    record var Y: newint, proc P = skip end
    = lazy K =
    (eager Y = newint, lazy P = skip)
  • module M =
    { var Y: newint, proc P = skip }
    = eager K =
    (eager Y = newint, lazy P = skip)
• Lambda abstractions:
  • lambdaI:tauexp. E takes unevaluated phrases.
  • lambdaI:tau. E takes only evaluated phrases.