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Add solutions to 5.5.1

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1 parent b4704e9 commit 7e47584a138d39fe30e888e7de6ac26e43d8a6a2 @fastred committed Jan 7, 2013
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  1. +23 −0 5_31.scm
  2. +293 −0 5_32.scm
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23 5_31.scm
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+1. saves and restores the env register around the evaluation of the operator
+2. saves and restores env around the evaluation of each operand (except the final one)
+3. saves and restores argl around the evaluation of each operand
+4. saves and restores proc around the evaluation of the operand sequence
+
+(f 'x 'y)
+1-4 can be safely removed
+
+((f) 'x 'y)
+1-4 can be removed because f doesn't take any arguments.
+
+(f (g 'x) y)
+1 can be removed. We need 3 and 4 because of an application of g.
+We also need 2 because the application of g could interfere with current environment.
+Compound procedure application is done via ev-sequence, which saves and restores
+env between evaluation of every expression, besides the last one. So if the last
+expression in the definition of g were to include for example (define y 1) it would
+change the value returned by this expression.
+
+(f (g 'x) 'y)
+Last argument in an application is a symbol so we don't need 2. We also don't
+need 1.
+
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293 5_32.scm
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+; a) solution is below
+; b) If we were to recognize more cases we would decrease the number of
+; stack operations but generated machine code would be longer, with more
+; tests and branches. Additionally all these tests would have to be done at
+; the runtime.
+
+(load "load-eceval.scm")
+
+(define eceval-operations
+ (list
+ ;;primitive Scheme operations
+ (list 'read read)
+
+ ;;operations in syntax.scm
+ (list 'self-evaluating? self-evaluating?)
+ (list 'quoted? quoted?)
+ (list 'text-of-quotation text-of-quotation)
+ (list 'variable? variable?)
+ (list 'assignment? assignment?)
+ (list 'assignment-variable assignment-variable)
+ (list 'assignment-value assignment-value)
+ (list 'definition? definition?)
+ (list 'definition-variable definition-variable)
+ (list 'definition-value definition-value)
+ (list 'lambda? lambda?)
+ (list 'lambda-parameters lambda-parameters)
+ (list 'lambda-body lambda-body)
+ (list 'if? if?)
+ (list 'if-predicate if-predicate)
+ (list 'if-consequent if-consequent)
+ (list 'if-alternative if-alternative)
+ (list 'begin? begin?)
+ (list 'begin-actions begin-actions)
+ (list 'last-exp? last-exp?)
+ (list 'first-exp first-exp)
+ (list 'rest-exps rest-exps)
+ (list 'application? application?)
+ (list 'operator operator)
+ (list 'operands operands)
+ (list 'no-operands? no-operands?)
+ (list 'first-operand first-operand)
+ (list 'rest-operands rest-operands)
+
+ ;;operations in eceval-support.scm
+ (list 'true? true?)
+ (list 'make-procedure make-procedure)
+ (list 'compound-procedure? compound-procedure?)
+ (list 'procedure-parameters procedure-parameters)
+ (list 'procedure-body procedure-body)
+ (list 'procedure-environment procedure-environment)
+ (list 'extend-environment extend-environment)
+ (list 'lookup-variable-value lookup-variable-value)
+ (list 'set-variable-value! set-variable-value!)
+ (list 'define-variable! define-variable!)
+ (list 'primitive-procedure? primitive-procedure?)
+ (list 'apply-primitive-procedure apply-primitive-procedure)
+ (list 'prompt-for-input prompt-for-input)
+ (list 'announce-output announce-output)
+ (list 'user-print user-print)
+ (list 'empty-arglist empty-arglist)
+ (list 'adjoin-arg adjoin-arg)
+ (list 'last-operand? last-operand?)
+ (list 'no-more-exps? no-more-exps?) ;for non-tail-recursive machine
+ (list 'get-global-environment get-global-environment)
+
+ (list 'symbol? symbol?)
+ ))
+
+(define eceval
+ (make-machine
+ '(exp env val proc argl continue unev)
+ eceval-operations
+ '(
+;;SECTION 5.4.4
+read-eval-print-loop
+ (perform (op initialize-stack))
+ (perform
+ (op prompt-for-input) (const ";;; EC-Eval input:"))
+ (assign exp (op read))
+ (assign env (op get-global-environment))
+ (assign continue (label print-result))
+ (goto (label eval-dispatch))
+print-result
+;;**following instruction optional -- if use it, need monitored stack
+ (perform (op print-stack-statistics))
+ (perform
+ (op announce-output) (const ";;; EC-Eval value:"))
+ (perform (op user-print) (reg val))
+ (goto (label read-eval-print-loop))
+
+unknown-expression-type
+ (assign val (const unknown-expression-type-error))
+ (goto (label signal-error))
+
+unknown-procedure-type
+ (restore continue)
+ (assign val (const unknown-procedure-type-error))
+ (goto (label signal-error))
+
+signal-error
+ (perform (op user-print) (reg val))
+ (goto (label read-eval-print-loop))
+
+;;SECTION 5.4.1
+eval-dispatch
+ (test (op self-evaluating?) (reg exp))
+ (branch (label ev-self-eval))
+ (test (op variable?) (reg exp))
+ (branch (label ev-variable))
+ (test (op quoted?) (reg exp))
+ (branch (label ev-quoted))
+ (test (op assignment?) (reg exp))
+ (branch (label ev-assignment))
+ (test (op definition?) (reg exp))
+ (branch (label ev-definition))
+ (test (op if?) (reg exp))
+ (branch (label ev-if))
+ (test (op lambda?) (reg exp))
+ (branch (label ev-lambda))
+ (test (op begin?) (reg exp))
+ (branch (label ev-begin))
+ (test (op application?) (reg exp))
+ (branch (label ev-application))
+ (goto (label unknown-expression-type))
+
+ev-self-eval
+ (assign val (reg exp))
+ (goto (reg continue))
+ev-variable
+ (assign val (op lookup-variable-value) (reg exp) (reg env))
+ (goto (reg continue))
+ev-quoted
+ (assign val (op text-of-quotation) (reg exp))
+ (goto (reg continue))
+ev-lambda
+ (assign unev (op lambda-parameters) (reg exp))
+ (assign exp (op lambda-body) (reg exp))
+ (assign val (op make-procedure)
+ (reg unev) (reg exp) (reg env))
+ (goto (reg continue))
+
+ev-application
+ (save continue)
+ (assign unev (op operands) (reg exp))
+ (save unev)
+ (assign exp (op operator) (reg exp))
+ (test (op symbol?) (reg exp))
+ (goto (label ev-appl-symbolic-operator))
+ (save env)
+ (assign continue (label ev-appl-did-operator))
+ (goto (label eval-dispatch))
+ev-appl-symbolic-operator
+ (assign continue (label ev-appl-after-symbolic-operator))
+ (goto (label eval-dispatch))
+ev-appl-did-operator
+ (restore env)
+ev-appl-after-symbolic-operator ; when operator is a symbol
+ (restore unev)
+ (assign argl (op empty-arglist))
+ (assign proc (reg val))
+ (test (op no-operands?) (reg unev))
+ (branch (label apply-dispatch))
+ (save proc)
+ev-appl-operand-loop
+ (save argl)
+ (assign exp (op first-operand) (reg unev))
+ (test (op last-operand?) (reg unev))
+ (branch (label ev-appl-last-arg))
+ (save env)
+ (save unev)
+ (assign continue (label ev-appl-accumulate-arg))
+ (goto (label eval-dispatch))
+ev-appl-accumulate-arg
+ (restore unev)
+ (restore env)
+ (restore argl)
+ (assign argl (op adjoin-arg) (reg val) (reg argl))
+ (assign unev (op rest-operands) (reg unev))
+ (goto (label ev-appl-operand-loop))
+ev-appl-last-arg
+ (assign continue (label ev-appl-accum-last-arg))
+ (goto (label eval-dispatch))
+ev-appl-accum-last-arg
+ (restore argl)
+ (assign argl (op adjoin-arg) (reg val) (reg argl))
+ (restore proc)
+ (goto (label apply-dispatch))
+apply-dispatch
+ (test (op primitive-procedure?) (reg proc))
+ (branch (label primitive-apply))
+ (test (op compound-procedure?) (reg proc))
+ (branch (label compound-apply))
+ (goto (label unknown-procedure-type))
+
+primitive-apply
+ (assign val (op apply-primitive-procedure)
+ (reg proc)
+ (reg argl))
+ (restore continue)
+ (goto (reg continue))
+
+compound-apply
+ (assign unev (op procedure-parameters) (reg proc))
+ (assign env (op procedure-environment) (reg proc))
+ (assign env (op extend-environment)
+ (reg unev) (reg argl) (reg env))
+ (assign unev (op procedure-body) (reg proc))
+ (goto (label ev-sequence))
+
+;;;SECTION 5.4.2
+ev-begin
+ (assign unev (op begin-actions) (reg exp))
+ (save continue)
+ (goto (label ev-sequence))
+
+ev-sequence
+ (assign exp (op first-exp) (reg unev))
+ (test (op last-exp?) (reg unev))
+ (branch (label ev-sequence-last-exp))
+ (save unev)
+ (save env)
+ (assign continue (label ev-sequence-continue))
+ (goto (label eval-dispatch))
+ev-sequence-continue
+ (restore env)
+ (restore unev)
+ (assign unev (op rest-exps) (reg unev))
+ (goto (label ev-sequence))
+ev-sequence-last-exp
+ (restore continue)
+ (goto (label eval-dispatch))
+
+;;;SECTION 5.4.3
+
+ev-if
+ (save exp)
+ (save env)
+ (save continue)
+ (assign continue (label ev-if-decide))
+ (assign exp (op if-predicate) (reg exp))
+ (goto (label eval-dispatch))
+ev-if-decide
+ (restore continue)
+ (restore env)
+ (restore exp)
+ (test (op true?) (reg val))
+ (branch (label ev-if-consequent))
+ev-if-alternative
+ (assign exp (op if-alternative) (reg exp))
+ (goto (label eval-dispatch))
+ev-if-consequent
+ (assign exp (op if-consequent) (reg exp))
+ (goto (label eval-dispatch))
+
+ev-assignment
+ (assign unev (op assignment-variable) (reg exp))
+ (save unev)
+ (assign exp (op assignment-value) (reg exp))
+ (save env)
+ (save continue)
+ (assign continue (label ev-assignment-1))
+ (goto (label eval-dispatch))
+ev-assignment-1
+ (restore continue)
+ (restore env)
+ (restore unev)
+ (perform
+ (op set-variable-value!) (reg unev) (reg val) (reg env))
+ (assign val (const ok))
+ (goto (reg continue))
+
+ev-definition
+ (assign unev (op definition-variable) (reg exp))
+ (save unev)
+ (assign exp (op definition-value) (reg exp))
+ (save env)
+ (save continue)
+ (assign continue (label ev-definition-1))
+ (goto (label eval-dispatch))
+ev-definition-1
+ (restore continue)
+ (restore env)
+ (restore unev)
+ (perform
+ (op define-variable!) (reg unev) (reg val) (reg env))
+ (assign val (const ok))
+ (goto (reg continue))
+ )))
+
+
+(define the-global-environment (setup-environment))
+
+(start eceval)

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