EOPL

try to write the note while I'm reading the book of Essientials Of Programming Languages

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Chapter3

variables are saved to the ENV, when execute code, find variable from ENV first, and then use it for the code.
ways to observe working code:

(require "top.scm")
(run "let f = proc (x) -(x,1) in (f 30)")


(require "lang.scm")
(scan&parse "let f = proc (x) -(x,1) in (f 30)")

(require "interp.scm")
(define parsed (a-program (let-exp 'f (proc-exp 'x (diff-exp (var-exp 'x) (const-exp 1))) (call-exp (var-exp 'f) (const-exp 30)))))


(define inner-parsed (let-exp 'f (proc-exp 'x (diff-exp (var-exp 'x) (const-exp 1))) (call-exp (var-exp 'f) (const-exp 30))))

(require "environments.scm")
(value-of inner-parsed (init-env))
(value-of (proc-exp 'x (diff-exp (var-exp 'x) (const-exp 1))) (init-env))

the args of procedure would be extend to env first, it will fetch the args in env by the time of executing the body of a procedure.
explained the static properties and lexical scoping.
how to implement flatten variables to env.

chapter4

(require "top.scm")
(run "let x = newref(17) in deref(x)")

IMPLICIT-REFS: Locations are created with each binding operation: at each procedure call, let, or letrec.

chapter5

Continuations are an abstraction of the notion of control context, much as environments are an abstraction of data contexts.

(require  "top-interp.scm")
(run "1")
(run  "(proc(x) -(x,1)  30)")

chapter6

chapter7

(require "top.scm")
(check "11")
(check "zero?(-(3,2))")


(require "lang.scm")
(require "checker.scm")
(type-of-program (scan&parse "zero?(-1)"))

yanyingwang/EOPL