Details of the Environment Model

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  1. Variable: look it up in the environment.
  2. lambda expression: create a compound procedure ("double bubble"). The text (i.e. parameters and body) come from the lambda expression; the environment is the one you are using to evaluate the lambda expression.
  3. Combination: "Evaluate, then apply". To apply a compound procedure ("double bubble"):
    • Create a new frame [parameters].
    • Fill the frame [arguments].
    • Link the frame to make it an environment [environment].
    • Evaluate the body using the new environment [body].

Jim Miller W3C