= Display for lexical scope
A table of <pointers> supporting direct access to active lexical environments without traversing a <static chain>. A conventional display is indexed by lexical level; a procedure-indexed alternative keeps the newest activation of each procedure and saves and restores the previous table entry on entry and return.
For direct calls under <lexical scope>, the executing activation's <static chain> contains the newest surviving activations of its enclosing procedures. This follows by <mathematical induction> on calls and returns: a direct call inherits a suffix of the caller's chain, and a return restores the previous chain after intervening activations finish. With <procedural parameters>, a passed <programming closure> can instead refer to an older still-active enclosing activation, so simply consulting the newest-activation table is insufficient.
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