Lecture 4 Notes

By importing all the modules in its import specication

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Unformatted text preview:  ¡ % ©£ ¢ " ¢ ¡ ©  © £  ¡ £ © £ £   ¡ © ¤&¢&¡ £ ¡ § ¡ % £ ¢ ¤¢ © ¡ ¥£¡ ¢ ¢ ¡¡ ¡ A module value has an if and only if it is an environment in which each variable is bound to a value of the right type. 12 § 13 ¡ § ¡  ¢  ¢ £ ¡ ©  ©  6 ¥     ¡ ©  © £  ¡ £ © ¢ ¡ 6&£ ¢ ¦¡ ©  © £  ¡ £ © ¢ 8¡  ¢ £ 5  ¦¦  ¡ © §¡  % ¤ ¡ £ Last, we have one new expression, a qualified variable reference. § § ¡ £ § © ¤¢ ¢ ¡ ¦¤¢ ¢ ¦  ¡ £ £¡ ¥£¡    ¡ © £ © 8© ¡ £ ¡   £ ¢ ¢ £  £ ¥£ © ¤¡ ¢ ¡ ¤¡ £ §  ¡ © £ © © ¡ £ ¢   ¦   ¡ © ¦¨§¡  % ¤¥¡ ¢ ' ¢ ¡ ©  © £  ¡ £ © £  ¡ © £ © © ¡ £  ¢ $¢ § A module body consists of an arbitrary number of definitions. Each definition associates a variable with the value of an expression. 14 We modify to look only at and bindings, and we add a procedure to look up bindings made by . In general, we will use the name X Y for a procedure that looks up things of kind X in data structures of kind Y. © ¡ ¡ ¥£ ¡ ¤¡ ¡...
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This document was uploaded on 03/17/2014 for the course CSG 111 at Northeastern.

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