[feat] Lambda-only interpreter. NOT WORKING.
This commit is contained in:
Ken Elf Mathieu Sternberg
parent
1e38327b2a
commit
ea522f6cf6
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@ -10,6 +10,7 @@ bin/_mocha
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bin/mocha
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bin/coffee
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bin/cake
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bin/coffeelint
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test-reports.xml
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LisperatorLanguage
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chapter?/test.coffee
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@ -2,7 +2,7 @@
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cadr, caadr, cadar, caddr, nilp, nil, setcdr,
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metacadr, setcar} = require "cons-lists/lists"
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{normalizeForms, normalizeForm} = require "../chapter1/astToList"
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{Node, Symbol} = require '../chapter1/reader_types'
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{Node, Comment, Symbol} = require '../chapter1/reader_types'
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class LispInterpreterError extends Error
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name: 'LispInterpreterError'
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@ -27,79 +27,142 @@ astSymbolsToLispSymbols = (node) ->
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cadddr = metacadr('cadddr')
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metadata_evaluation =
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listp: (node) -> node.type == 'list'
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symbolp: (node) -> node.type == 'symbol'
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numberp: (node) -> node.type == 'number'
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stringp: (node) -> node.type == 'string'
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commentp: (node) -> node.type == 'comment'
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nvalu: (node) -> node.value
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mksymbols: (list) -> astSymbolsToLispSymbols(list)
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intlistp = (node) -> node.type == 'list'
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intsymbolp = (node) -> node.type == 'symbol'
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intnumberp = (node) -> node.type == 'number'
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intstringp = (node) -> node.type == 'string'
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intcommentp = (node) -> node.type == 'comment'
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intnvalu = (node) -> if (node.type == 'symbol') then node.value.name else node.value
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intatomp = (node) -> node.type in ['symbol', 'number', 'string']
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intmksymbols = (list) -> astSymbolsToLispSymbols(list)
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# The hairness of this makes me doubt the wisdom of using Javascript.
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straight_evaluation =
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listp: (cell) -> cell.__type == 'list'
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symbolp: (cell) -> typeof cell == 'string' and cell.length > 0 and cell[0] not in ["\"", ";"]
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commentp: (cell) -> typeof cell == 'string' and cell.length > 0 and cell[0] == ";"
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numberp: (cell) -> typeof cell == 'number'
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stringp: (cell) -> typeof cell == 'string' and cell.length > 0 and cell[0] == "\""
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boolp: (cell) -> typeof cell == 'boolean'
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nullp: (cell) -> cell == null
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vectorp: (cell) -> (not straight_evaluation.listp cell) and toString.call(cell) == '[object Array]'
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recordp: (cell) -> (not cell._prototype?) and toSTring.call(cell) == '[object Object]'
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objectp: (cell) -> (cell._prototype?) and toString.call(cell) == '[object Object]'
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nilp: (cell) -> nilp(cell)
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nvalu: (cell) -> cell
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mksymbols: (cell) -> cell
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sType = new Symbol 'type'
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sBehavior = new Symbol 'behavior'
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sBehavior = new Symbol 'behavior'
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sBoolean = new Symbol 'boolean'
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sBoolify = new Symbol 'boolify'
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sFunction = new Symbol 'function'
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sName = new Symbol 'name'
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sNull = new Symbol 'null'
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sTag = new Symbol 'tag'
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sType = new Symbol 'type'
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sValue = new Symbol 'value'
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sPair = new Symbol 'pair'
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sCar = new Symbol 'car'
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sCdr = new Symbol 'cdr'
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sSetCar = new Symbol 'setcar'
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sSetCdr = new Symbol 'setcdr'
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prox =
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"quote": (body, env, mem, kont) -> evaluateQuote (cadr body), env, mem, kont
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"if": (body, env, mem, kont) -> evaluateIf (cadr body), (caddr body), (cadddr body), env, mem, kont
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"begin": (body, env, mem, kont) -> evaluateBegin (cdr body), env, mem, kont
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"set!": (body, env, mem, kont) -> evaluateSet (intnvalu cadr body), (caddr body), env, mem, kont
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"lambda": (body, env, mem, kont) -> evaluateLambda (intmksymbols cadr body), (cddr body), env, mem, kont
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"or": (body, env, mem, kont) -> evaluateOr (car body), (cdr body), env, mem, kont
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# ___ _ _
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# | __|_ ____ _| |_ _ __ _| |_ ___ _ _
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# | _|\ V / _` | | || / _` | _/ _ \ '_|
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# |___|\_/\__,_|_|\_,_\__,_|\__\___/_|
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#
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transcode = (value, mem, qont) ->
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forms = [
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[intnullp, -> q theEmptyList, mem],
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[((v) -> intsymbolp(v) and v in ['#t', '#f']), (-> q (createBoolean value), mem)]
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[intsymbolp, (-> q (createSymbol value), mem)]
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[intnumberp, (-> q (createNumber value), mem)]
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[intpairp, (-> transcode (car intnvalu value), mem, (addr, mem2) ->
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(transcode (cdr intvalu value), mem2, (d, mem3) ->
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(allocatePair addr, d, mem3, qont)))]
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]
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form = form[1] for form in forms when form[0](value)
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if len(form) != 1
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throw new LispInterpreterError "Bad form match for #{value}"
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form[0]()
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evaluate = (exp, env, mem, kont) ->
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if intatomp exp
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if intsymbolp exp
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evaluateVariable exp, env, mem, kont
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else
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evaluateQuote exp, env, mem, kont
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else
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body = intnvalu exp
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head = car body
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if prox[(intnvalu head)]?
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prox[(intnvalu head)](body, env, mem, kont, ix)
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else
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evaluateApplication body, (cadr body), env, mem, kont
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# Page 129
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env_init = (id) -> throw LispInterpreterError "No binding for #{id}"
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# Page 129
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# We don't have an initial value for mem yet?
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update = (mem, addr, value) ->
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(addra) -> if (addra == addr) then value else mem(addra)
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# This is basically the core definition of 'mem': it returns a
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# function enclosing the address (a monotomically increasing number as
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# memory is allocated) and the value. Update is passed the current
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# memory, the address, and the value; it returns a function that says
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# "If the requested address is my address, return my value, otherwise
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# I'll call the memory handed to me at creation time with the address,
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# and it'll go down the line." Update basically adds to a 'stack'
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# built entirely out of pointers to the base mem.
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update = (mem, addr, value) ->
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(addra) -> if (eq addra, addr) then value else (mem addra)
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# Page 130
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updates = (mem, addrs, values) ->
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if (pairp addrs)
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updates (update mem, (car addrs), (car values)), (cdr addrs), (cdr values)
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else
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mem
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# Page 130
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# Memory location zero contains the position of the stack.
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expandStore = (highLocation, mem) ->
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update mem, 0, highLocation
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mem_init = expandStore 0, (a) ->
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throw new LispInterpreterError "No such address #{a}"
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newLocation = (mem) ->
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(mem 0) + 1
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evaluateVariable = (name, env, mem, kont) ->
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kont mem, (env name), mem
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kont (mem (env name)), mem
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# Page 130
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evaluateSet = (name, exp, env, mem, kont) ->
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evaluate exp, env, mem, (value, newmem) ->
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kont value, (update newmem, (env name), value)
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evaluate exp, env, mem, (value, mem2) ->
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kont value, (update mem2, (env name), value)
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# Page 131
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# TODO: I don't know that I trust this.
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evaluateApplication = (exp, exprs, env, mem, kont) ->
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# In chapter 3, this was a series of jumping continuations chasing
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# each other. Here, all of the continuations are kept in one place,
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# and the argument list is built by tail-calls to evaluateArguments
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# until the list is exhausted, at which point the continuation is
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# called. The continuation is built in the second paragraph below.
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evaluateArguments = (exprs, env, mem, kont) ->
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if (pairp exprs)
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evaluate (car exprs), env, mem, (value, mem2) ->
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evaluateArguments (cdr exprs), env, mem2, (value2, mems3) ->
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kont (cons value, value2), mems3
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evaluateArguments (cdr exprs), env, mem2, (value2, mem3) ->
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kont (cons value, value2), mem3
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else
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kont cons(), mem
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evaluate exp, env, mem, (fun, mems) ->
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evaluateArguments exprs, env, mems, (value2, mem3) ->
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evaluate exp, env, mem, (fun, mem2) ->
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evaluateArguments exprs, env, mem2, (value2, mem3) ->
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if eq (fun sType), sFunction
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(fun sBehavior) value2, mem3, kont
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else
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throw new LispInterpreterError "Not a function #{(car value2)}"
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# Creates a memory address for the function, then creates a new memory
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# address for each argument, then evaluates the expressions in the
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# lambda, returning the value of the last one.
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evaluateLambda = (names, exprs, env, mem, kont) ->
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allocate 1, mem, (addrs, mem2) ->
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kont (createFunction (car addrs), (values, mem, kont) ->
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@ -109,29 +172,20 @@ evaluateLambda = (names, exprs, env, mem, kont) ->
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else
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throw new LispInterpreterError "Incorrect Arrity"), mem2
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allocate = (num, mem, q) ->
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if (num > 0)
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do ->
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addr = newLocation s
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allocate (num - 1), (expandStore addr, mem), (addrs, mem2) ->
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q (cons addr, addrs), mem2
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else
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q cons(), mem
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expandStore = (highLocation, mem) ->
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update mem, 0, highLocation
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newLocation = (mem) ->
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(mem 0) + 1
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# Page 128
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evaluateIf = (expc, expt, expf, env, mem, kont) ->
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evaluate expc, env, mem, (env, mems) ->
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evaluate ((env "boolify") expt, expf), env, mems, kont
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evaluate ((env sBoolify) expt, expf), env, mems, kont
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evaluateQuote = (c, env, mem, kont) ->
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transcode (normalizeForms c), mem, kont
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# By starting over "from here," we undo all side-effect assignments
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# that were effected by expression 1
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evaluateOr = (exp1, exp2, env, mem, kont) ->
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evaluate exp1, env, mem, (value, mem2) ->
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(value sBoolify) (-> kont value, mem2), (-> evaluate exp2, env, mem, kont)
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# Page 129
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# I like how, in this version, we explicitly throw away the meaning of
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# all but the last statement in evaluateBegin.
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evaluateBegin = (exps, env, mem, kont) ->
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@ -141,25 +195,216 @@ evaluateBegin = (exps, env, mem, kont) ->
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else
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evaluate (car exps), env, mem, kont
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theEmptyList = (msg) ->
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switch msg
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when sType then sNull
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when sBoolify then (x, y) -> x
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prox =
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"quote": (body, env, mem, kont, ix) -> evaluateQuote (cadr body), env, mem, kont
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"if": (body, env, mem, kont, ix) -> evaluateIf (cadr body), (caddr body), (cadddr body), env, mem, kont
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"begin": (body, env, mem, kont, ix) -> evaluateBegin (cdr body), env, mem, kont
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"set!": (body, env, mem, kont, ix) -> evaluateSet (ix.nvalu cadr body), (caddr body), env, mem, kont
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"lambda": (body, env, mem, kont, ix) -> evaluateLambda (ix.mksymbols cadr body), (cddr body), env, mem, kont
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createBoolean = (value) ->
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combinator = if value then ((x, y) -> x) else ((x, y) -> y)
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(msg) ->
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switch msg
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when sType then sBoolean
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when sBoolify then combinator
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makeEvaluator = (ix = straight_evaluation) ->
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(exp, env, mem, kont) ->
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if ix.atomp exp
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if ix.symbolp exp
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evaluateVariable exp, env, mem, kont
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else
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evaluateQuote exp, env, mem, kont
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createSymbol = (value) ->
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(msg) ->
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switch msg
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when sType then sValue
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when sName then value
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when sBoolify then (x, y) -> x
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createNumber = (value) ->
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(msg) ->
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switch msg
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when sType then sNumber
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when sValue then value
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when sBoolify then (x, y) -> x
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createFunction = (tag, behavior) ->
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(msg) ->
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switch msg
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when sType then sNumber
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when sBoolify then (x, y) -> x
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when sTag then tag
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when sBehavior then behavior
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# I'm not sure I get the difference between allocate and update.
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# Update appears to have the power to append to the memory list
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# without updating highLocation. If I'm reading this correct, then
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# what we're actually looking at is a simulation of a memory
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# subsystem, with expandStore/newLocation/allocate taking on the duty
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# of "managing" our stack, and update actually just doing the managing
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# the stack, and letting the garbage collector do its thing when a
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# pointer to memory function goes out of scope. In short: the
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# allocate collection of functions is "going through the motions" of
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# managing memory; had this been a real memory manager, you'd have
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# a lot more work to do.
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allocate = (num, mem, q) ->
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if (num > 0)
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do ->
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addr = newLocation mem
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allocate (num - 1), (expandStore addr, mem), (addrs, mem2) ->
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q (cons addr, addrs), mem2
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else
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q cons(), mem
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allocateList = (values, mem, q) ->
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consify = (values, q) ->
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if (pairp values)
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consify (cdr values), (value, mem2) ->
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allocatePair (car values), value, mem2, q
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else
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body = ix.nvalu exp
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head = car body
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if prox[(ix.nvalu head)]?
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prox[(ix.nvalue head)](body, env, mem, kont, ix)
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q theEmptyList, mem
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consify values, q
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allocatePair = (addr, d, mem, q) ->
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allocate 2, mem, (addrs, mem2) ->
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q (createPair (car addrs), (cadr addrs)), (update (update mem2, (car addrs), addr), (cadr addrs), d)
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createPair = (a, d) ->
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(msg) ->
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switch msg
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when sType then sPair
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when sBoolify then (x, y) -> x
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when sSetCar then (mem, val) -> update mem, a, val
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when sSetCdr then (mem, val) -> update mem, d, val
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when sCar then a
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when sCdr then d
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env_global = env_init
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mem_global = mem_init
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# The name is pushed onto the global environment, with a corresponding
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# address. The address is pushed onto the current memory, with the
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# corresponding boxed value.
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defInitial = (name, value) ->
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allocate 1, mem_global, (addrs, mem2) ->
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env_global = update env_global, (new Symbol name), (car addrs)
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mem_global = update mem2, (car addrs), value
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defPrimitive = (name, arity, value) ->
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defInitial name, allocate 1, mem_global, (addrs, mem2) ->
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mem_global = expandStore (car addrs), mem2
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createFunction (car addrs), (values, mem, kont) ->
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if (eq arity (length values))
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value values, mem, kont
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else
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evaluateApplication body, (cadr body), env, mem, kont
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throw new LispInterpreterError "Wrong arity for #{name}"
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# ___ _ _ _ _ _ _ _
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# |_ _|_ _ (_) |_(_) (_)_____ _| |_(_)___ _ _
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# | || ' \| | _| | | |_ / _` | _| / _ \ ' \
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# |___|_||_|_|\__|_|_|_/__\__,_|\__|_\___/_||_|
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#
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defInitial "true", createBoolean true
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defInitial "false", createBoolean false
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defInitial "nil", null
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defPrimitive "<=", 2, (values, mem, kont) ->
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if (eq ((car values) sType), sNumber) and (eq ((cadr values) sName), sNumber)
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kont (createBoolean (((car values) sValue) <= ((cadr values) sValue))), mem
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else
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throw new LispInterpreterError "Comparison requires numbers"
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defPrimitive "<", 2, (values, mem, kont) ->
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if (eq ((car values) sType), sNumber) and (eq ((cadr values) sName), sNumber)
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kont (createBoolean (((car values) sValue) < ((cadr values) sValue))), mem
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else
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throw new LispInterpreterError "Comparison requires numbers"
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defPrimitive ">=", 2, (values, mem, kont) ->
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if (eq ((car values) sType), sNumber) and (eq ((cadr values) sName), sNumber)
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kont (createBoolean (((car values) sValue) >= ((cadr values) sValue))), mem
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else
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throw new LispInterpreterError "Comparison requires numbers"
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defPrimitive ">", 2, (values, mem, kont) ->
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if (eq ((car values) sType), sNumber) and (eq ((cadr values) sName), sNumber)
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kont (createBoolean (((car values) sValue) > ((cadr values) sValue))), mem
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else
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throw new LispInterpreterError "Comparison requires numbers"
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defPrimitive "=", 2, (values, mem, kont) ->
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if (eq ((car values) sType), sNumber) and (eq ((cadr values) sName), sNumber)
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kont (createBoolean (((car values) sValue) == ((cadr values) sValue))), mem
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else
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throw new LispInterpreterError "Comparison requires numbers"
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defPrimitive "*", 2, (values, mem, kont) ->
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if (eq ((car values) sType), sNumber) and (eq ((cadr values) sName), sNumber)
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kont (createNumber (((car values) sValue) * ((cadr values) sValue))), mem
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else
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throw new LispInterpreterError "Multiplication requires numbers"
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defPrimitive "+", 2, (values, mem, kont) ->
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if (eq ((car values) sType), sNumber) and (eq ((cadr values) sName), sNumber)
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kont (createNumber (((car values) sValue) + ((cadr values) sValue))), mem
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else
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throw new LispInterpreterError "Addition requires numbers"
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defPrimitive "/", 2, (values, mem, kont) ->
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if (eq ((car values) sType), sNumber) and (eq ((cadr values) sName), sNumber)
|
||||
kont (createNumber (((car values) sValue) / ((cadr values) sValue))), mem
|
||||
else
|
||||
throw new LispInterpreterError "Division requires numbers"
|
||||
|
||||
defPrimitive "*", 2, (values, mem, kont) ->
|
||||
if (eq ((car values) sType), sNumber) and (eq ((cadr values) sName), sNumber)
|
||||
kont (createNumber (((car values) sValue) - ((cadr values) sValue))), mem
|
||||
else
|
||||
throw new LispInterpreterError "Subtraction requires numbers"
|
||||
|
||||
defPrimitive "cons", 2, (values, mem, kont) ->
|
||||
allocatePair (car values), (cadr values), mem, kont
|
||||
|
||||
defPrimitive "car", 1, (values, mem, kont) ->
|
||||
if (eq ((car values) sType) sPair)
|
||||
kont (mem ((car values) sCar)), mem
|
||||
else
|
||||
throw new LispInterpreterError "Not a pair"
|
||||
|
||||
defPrimitive "cdr", 1, (values, mem, kont) ->
|
||||
if (eq ((car values) sType) sPair)
|
||||
kont (mem ((car values) sCdr)), mem
|
||||
else
|
||||
throw new LispInterpreterError "Not a pair"
|
||||
|
||||
defPrimitive "setcdr", 2, (values, mem, kont) ->
|
||||
if (eq ((car values) sType) sPair)
|
||||
pair = (car values)
|
||||
kont pair, ((pair sSetCdr) mem, (cadr values))
|
||||
else
|
||||
throw new LispInterpreterError "Not a pair"
|
||||
|
||||
defPrimitive "setcar", 2, (values, mem, kont) ->
|
||||
if (eq ((car values) sType) sPair)
|
||||
pair = (car values)
|
||||
kont pair, ((pair sSetCar) mem, (cadr values))
|
||||
else
|
||||
throw new LispInterpreterError "Not a pair"
|
||||
|
||||
defPrimitive "eqv?", (values, mem, kont) ->
|
||||
kont createBoolean (
|
||||
if (eq ((car values) sType) ((cadr values) sType))
|
||||
switch ((car values) sType)
|
||||
when sBoolean
|
||||
((car values) sBoolify) (((cadr values) sBoolify) true, false), (((cadr values) sBoolify) false, true)
|
||||
when sSymbol
|
||||
eq ((car values) sName), ((cadr values) sName)
|
||||
when sNumber
|
||||
((car values) sName) == ((cadr values) sName)
|
||||
when sPair
|
||||
(((car values) sCar) == ((cadr values) sCar) and
|
||||
((car values) sCdr) == ((cadr values) sCdr))
|
||||
when sFunction
|
||||
((car value) sTag) == ((cadr value) sTag)
|
||||
else false
|
||||
else false)
|
||||
|
||||
module.exports = (ast, kont) ->
|
||||
evaluate ast, env_global, mem_global, kont
|
||||
|
|
|
|||
|
|
@ -1,255 +0,0 @@
|
|||
// Generated by CoffeeScript 1.9.1
|
||||
(function() {
|
||||
var LispInterpreterError, Node, Symbol, astSymbolsToLispSymbols, caadr, caar, cadar, cadddr, caddr, cadr, car, cdar, cddr, cdr, cons, env_init, eq, evaluateApplication, evaluateBegin, evaluateIf, evaluateLambda, evaluateSet, evaluateVariable, listToString, listToVector, makeEvaluator, metacadr, metadata_evaluation, nil, nilp, normalizeForm, normalizeForms, pairp, prox, ref, ref1, ref2, sBehavior, sFunction, sType, setcar, setcdr, straight_evaluation, the_false_value, update, updates,
|
||||
extend = function(child, parent) { for (var key in parent) { if (hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
|
||||
hasProp = {}.hasOwnProperty;
|
||||
|
||||
ref = require("cons-lists/lists"), listToString = ref.listToString, listToVector = ref.listToVector, pairp = ref.pairp, cons = ref.cons, car = ref.car, cdr = ref.cdr, caar = ref.caar, cddr = ref.cddr, cdar = ref.cdar, cadr = ref.cadr, caadr = ref.caadr, cadar = ref.cadar, caddr = ref.caddr, nilp = ref.nilp, nil = ref.nil, setcdr = ref.setcdr, metacadr = ref.metacadr, setcar = ref.setcar;
|
||||
|
||||
ref1 = require("../chapter1/astToList"), normalizeForms = ref1.normalizeForms, normalizeForm = ref1.normalizeForm;
|
||||
|
||||
ref2 = require('../chapter1/reader_types'), Node = ref2.Node, Symbol = ref2.Symbol;
|
||||
|
||||
LispInterpreterError = (function(superClass) {
|
||||
extend(LispInterpreterError, superClass);
|
||||
|
||||
LispInterpreterError.prototype.name = 'LispInterpreterError';
|
||||
|
||||
function LispInterpreterError(message) {
|
||||
this.message = message;
|
||||
}
|
||||
|
||||
return LispInterpreterError;
|
||||
|
||||
})(Error);
|
||||
|
||||
the_false_value = cons("false", "boolean");
|
||||
|
||||
eq = function(id1, id2) {
|
||||
if (id1 instanceof Symbol && id2 instanceof Symbol) {
|
||||
return id1.name === id2.name;
|
||||
}
|
||||
return id1 === id2;
|
||||
};
|
||||
|
||||
astSymbolsToLispSymbols = function(node) {
|
||||
var handler;
|
||||
if (nilp(node)) {
|
||||
return nil;
|
||||
}
|
||||
if (!node.type === 'list') {
|
||||
throw new LispInterpreterError("Not a list of variable names");
|
||||
}
|
||||
handler = function(cell) {
|
||||
if (nilp(cell)) {
|
||||
return nil;
|
||||
}
|
||||
return cons((car(cell)).value, handler(cdr(cell)));
|
||||
};
|
||||
return handler(node.value);
|
||||
};
|
||||
|
||||
cadddr = metacadr('cadddr');
|
||||
|
||||
metadata_evaluation = {
|
||||
listp: function(node) {
|
||||
return node.type === 'list';
|
||||
},
|
||||
symbolp: function(node) {
|
||||
return node.type === 'symbol';
|
||||
},
|
||||
numberp: function(node) {
|
||||
return node.type === 'number';
|
||||
},
|
||||
stringp: function(node) {
|
||||
return node.type === 'string';
|
||||
},
|
||||
commentp: function(node) {
|
||||
return node.type === 'comment';
|
||||
},
|
||||
nvalu: function(node) {
|
||||
return node.value;
|
||||
},
|
||||
mksymbols: function(list) {
|
||||
return astSymbolsToLispSymbols(list);
|
||||
}
|
||||
};
|
||||
|
||||
straight_evaluation = {
|
||||
listp: function(cell) {
|
||||
return cell.__type === 'list';
|
||||
},
|
||||
symbolp: function(cell) {
|
||||
var ref3;
|
||||
return typeof cell === 'string' && cell.length > 0 && ((ref3 = cell[0]) !== "\"" && ref3 !== ";");
|
||||
},
|
||||
commentp: function(cell) {
|
||||
return typeof cell === 'string' && cell.length > 0 && cell[0] === ";";
|
||||
},
|
||||
numberp: function(cell) {
|
||||
return typeof cell === 'number';
|
||||
},
|
||||
stringp: function(cell) {
|
||||
return typeof cell === 'string' && cell.length > 0 && cell[0] === "\"";
|
||||
},
|
||||
boolp: function(cell) {
|
||||
return typeof cell === 'boolean';
|
||||
},
|
||||
nullp: function(cell) {
|
||||
return cell === null;
|
||||
},
|
||||
vectorp: function(cell) {
|
||||
return (!straight_evaluation.listp(cell)) && toString.call(cell) === '[object Array]';
|
||||
},
|
||||
recordp: function(cell) {
|
||||
return (cell._prototype == null) && toSTring.call(cell) === '[object Object]';
|
||||
},
|
||||
objectp: function(cell) {
|
||||
return (cell._prototype != null) && toString.call(cell) === '[object Object]';
|
||||
},
|
||||
nilp: function(cell) {
|
||||
return nilp(cell);
|
||||
},
|
||||
nvalu: function(cell) {
|
||||
return cell;
|
||||
},
|
||||
mksymbols: function(cell) {
|
||||
return cell;
|
||||
}
|
||||
};
|
||||
|
||||
sType = new Symbol('type');
|
||||
|
||||
sBehavior = new Symbol('behavior');
|
||||
|
||||
sFunction = new Symbol('function');
|
||||
|
||||
env_init = function(id) {
|
||||
throw LispInterpreterError("No binding for " + id);
|
||||
};
|
||||
|
||||
update = function(mem, addr, value) {
|
||||
return function(addra) {
|
||||
if (addra === addr) {
|
||||
return value;
|
||||
} else {
|
||||
return mem(addra);
|
||||
}
|
||||
};
|
||||
};
|
||||
|
||||
updates = function(mem, addrs, values) {
|
||||
if (pairp(addrs)) {
|
||||
return updates(update(mem, car(addrs), car(values)), cdr(addrs), cdr(values));
|
||||
} else {
|
||||
return mem;
|
||||
}
|
||||
};
|
||||
|
||||
evaluateVariable = function(name, env, mem, kont) {
|
||||
return kont(mem, env(name), mem);
|
||||
};
|
||||
|
||||
evaluateSet = function(name, exp, env, mem, kont) {
|
||||
return evaluate(exp, env, mem, function(value, newmem) {
|
||||
return kont(value, update(newmem, env(name), value));
|
||||
});
|
||||
};
|
||||
|
||||
evaluateApplication = function(exp, exprs, env, mem, kont) {
|
||||
var evaluateArguments;
|
||||
evaluateArguments = function(exprs, env, mem, kont) {
|
||||
if (pairp(exprs)) {
|
||||
return evaluate(car(exprs), env, mem, function(value, mem2) {
|
||||
return evaluateArguments(cdr(exprs), env, mem2, function(value2, mems3) {
|
||||
return kont(cons(value, value2), mems3);
|
||||
});
|
||||
});
|
||||
} else {
|
||||
return kont(cons(), mem);
|
||||
}
|
||||
};
|
||||
return evaluate(exp, env, mem, function(fun, mems) {
|
||||
return evaluateArguments(exprs, env, mems, function(value2, mem3) {
|
||||
if (eq(fun(sType), sFunction)) {
|
||||
return (fun(sBehavior))(value2, mem3, kont);
|
||||
} else {
|
||||
throw new LispInterpreterError("Not a function " + (car(value2)));
|
||||
}
|
||||
});
|
||||
});
|
||||
};
|
||||
|
||||
evaluateLambda = function(names, exprs, env, mem, kont) {
|
||||
return allocate(1, mem, function(addrs, mem2) {
|
||||
return kont(createFunction(car(addrs), function(values, mem, kont) {
|
||||
if (eq(length(names), length(values))) {
|
||||
return allocate(length(names), mem, function(addrs, mem2) {
|
||||
return evaluateBegin(exprs, updates(env, names, addrs), updates(mem2, addrs, values), kont);
|
||||
});
|
||||
} else {
|
||||
throw new LispInterpreterError("Incorrect Arrity");
|
||||
}
|
||||
}), mem2);
|
||||
});
|
||||
};
|
||||
|
||||
evaluateIf = function(expc, expt, expf, env, mem, kont) {
|
||||
return evaluate(expc, env, mem, function(env, mems) {
|
||||
return evaluate((env("boolify"))(expt, expf), env, mems, kont);
|
||||
});
|
||||
};
|
||||
|
||||
evaluateBegin = function(exps, env, mem, kont) {
|
||||
if (pairp(cdr(exps))) {
|
||||
return evaluate(car(exps), env, mem, function(_, mems) {
|
||||
return evaluateBegin(cdr(exps), env, mems, kont);
|
||||
});
|
||||
} else {
|
||||
return evaluate(car(exps), env, mem, kont);
|
||||
}
|
||||
};
|
||||
|
||||
prox = {
|
||||
"quote": function(body, env, mem, kont, ix) {
|
||||
return evaluateQuote(cadr(body), env, mem, kont);
|
||||
},
|
||||
"if": function(body, env, mem, kont, ix) {
|
||||
return evaluateIf(cadr(body), caddr(body), cadddr(body), env, mem, kont);
|
||||
},
|
||||
"begin": function(body, env, mem, kont, ix) {
|
||||
return evaluateBegin(cdr(body), env, mem, kont);
|
||||
},
|
||||
"set!": function(body, env, mem, kont, ix) {
|
||||
return evaluateSet(ix.nvalu(cadr(body)), caddr(body), env, mem, kont);
|
||||
},
|
||||
"lambda": function(body, env, mem, kont, ix) {
|
||||
return evaluateLambda(ix.mksymbols(cadr(body)), cddr(body), env, mem, kont);
|
||||
}
|
||||
};
|
||||
|
||||
makeEvaluator = function(ix) {
|
||||
if (ix == null) {
|
||||
ix = straight_evaluation;
|
||||
}
|
||||
return function(exp, env, mem, kont) {
|
||||
var body, head;
|
||||
if (ix.atomp(exp)) {
|
||||
if (ix.symbolp(exp)) {
|
||||
return evaluateVariable(exp, env, mem, kont);
|
||||
} else {
|
||||
return evaluateQuote(exp, env, mem, kont);
|
||||
}
|
||||
} else {
|
||||
body = ix.nvalu(exp);
|
||||
head = car(body);
|
||||
if (prox[ix.nvalu(head)] != null) {
|
||||
return prox[ix.nvalue(head)](body, env, mem, kont, ix);
|
||||
} else {
|
||||
return evaluateApplication(body, cadr(body), env, mem, kont);
|
||||
}
|
||||
}
|
||||
};
|
||||
};
|
||||
|
||||
}).call(this);
|
||||
|
|
@ -0,0 +1,40 @@
|
|||
chai = require 'chai'
|
||||
chai.should()
|
||||
expect = chai.expect
|
||||
|
||||
{cons} = require "cons-lists/lists"
|
||||
olisp = require '../chapter4/interpreter'
|
||||
{read, readForms} = require '../chapter4/reader'
|
||||
|
||||
the_false_value = (cons "false", "boolean")
|
||||
|
||||
lisp = (ast) ->
|
||||
ret = undefined
|
||||
olisp ast, (i) -> ret = i
|
||||
return ret
|
||||
|
||||
describe "Core interpreter #4: Pure Lambda Memory", ->
|
||||
it "Understands equality", ->
|
||||
expect(lisp read "(eq? 'a 'b)").to.equal(false)
|
||||
expect(lisp read "(eq? 'a 'a)").to.equal(true)
|
||||
expect(lisp read "(eq? (cons 1 2) (cons 1 2))").to.equal(false)
|
||||
expect(lisp read "((lambda (a) (eq? a a)) (cons 1 2))").to.equal(true)
|
||||
expect(lisp read "((lambda (a) (eq? a a)) (lambda (x) x))").to.equal(true)
|
||||
expect(lisp read "(eq? (lambda (x) 1) (lambda (x y) 2))").to.equal(false)
|
||||
|
||||
it "Understands equivalence", ->
|
||||
expect(lisp read "(eqv? '1 '2)").to.equal(false)
|
||||
expect(lisp read "(eqv? 1 1)").to.equal(true)
|
||||
expect(lisp read "(eqv? 'a 'b)").to.equal(false)
|
||||
expect(lisp read "(eqv? 'a 'a)").to.equal(true)
|
||||
expect(lisp read "(eqv? (cons 1 2) (cons 1 2))").to.equal(false)
|
||||
expect(lisp read "((lambda (a) (eqv? a a)) (cons 1 2))").to.equal(true)
|
||||
expect(lisp read "((lambda (a) (eqv? a a)) (lambda (x) x))").to.equal(true)
|
||||
expect(lisp read "(eqv? (lambda (x) 1) (lambda (x y) 2))").to.equal(false)
|
||||
|
||||
it "Does special OR (backtracking without side-effect)", ->
|
||||
expr1 = "((lambda (x) (or (begin (set! x (+ x 1)) #f) (if (= x 1) \"OK\" \"KO\"))) 1)"
|
||||
expect(lisp read expr1).to.equal("OK")
|
||||
expr2 = "((lambda (x) (or (begin (set! x (+ x 1)) #f) (if (= x 1) (begin (set! x 3) x) \"KO\"))) 1)"
|
||||
expect(lisp read expr2).to.equal(3)
|
||||
|
||||
Loading…
Reference in New Issue