Backing up.

Makefile

@@ -1,7 +1,7 @@
 lib/lisp_parser.js: lib/lisp_parser.peg
 	node_modules/.bin/pegjs $< $@
 
-test: lib/lisp_parser.js
+tests: lib/lisp_parser.js
 	node_modules/.bin/coffee bin/lisp test.scm
 
 

lib/reader.coffee

@@ -0,0 +1,197 @@
+{car, cdr, cons, nil, nilp, listp} = require './lists'
+
+NEWLINES   = ["\n", "\r", "\x0B", "\x0C"]
+WHITESPACE = [" ", "\t"].concat(NEWLINES)
+
+EOF = new (class)
+EOO = new (class)
+
+class Source
+  constructor: (@inStream) ->
+    @index = 0
+    @max = @inStream.length - 1
+    @line = 0
+    @column = 0
+
+  peek: -> @inStream[@index]
+
+  position: -> [@line, @column]
+
+  next: ->
+    c = @peek()
+    return EOF if @done()
+    @index++
+    [@line, @column] = if @peek() in NEWLINES then [@line + 1, 0] else [@line, @column + 1]
+    c
+
+  done: -> @index > @max
+
+# IO -> IO
+skipWS = (inStream) -> 
+  while inStream.peek() in WHITESPACE then inStream.next()
+
+# (type, value, line, column) -> (node {type, value, line, column)}
+makeObj = (type, value, line, column) -> 
+  cons type, (cons value, (cons line, (cons column)))
+
+# msg -> (IO -> Node => Error)
+handleError = (message) ->
+  (line, column) -> makeObj('error', message, line, column)
+
+# IO -> Node => Comment
+readComment = (inStream) ->
+  [line, column] = inStream.position()
+  r = (while inStream.peek() != "\n" and not inStream.done()
+    inStream.next()).join("")
+  if not inStream.done()
+    inStream.next()
+  makeObj 'comment', r, line, column
+
+# IO -> (Node => Literal => String) | Error
+readString = (inStream) ->
+  [line, column] = inStream.position()
+  inStream.next()
+  string = until inStream.peek() == '"' or inStream.done()
+    if inStream.peek() == '\\'
+      inStream.next()
+    inStream.next()
+  if inStream.done()
+    return handleError("end of file seen before end of string.")(line, column)
+  inStream.next()
+  makeObj 'string', (string.join ''), line, column
+
+# (String) -> (Node => Literal => Number) | Nothing
+readMaybeNumber = (symbol) ->
+  if symbol[0] == '+'
+    return readMaybeNumber symbol.substr(1)
+  if symbol[0] == '-'
+    ret = readMaybeNumber symbol.substr(1)
+    return if ret? then -1 * ret else undefined
+  if symbol.search(/^0x[0-9a-fA-F]+$/) > -1
+    return parseInt(symbol, 16)
+  if symbol.search(/^0[0-9a-fA-F]+$/) > -1
+    return parseInt(symbol, 8)
+  if symbol.search(/^[0-9]+$/) > -1
+    return parseInt(symbol, 10)
+  if symbol.search(/^nil$/) > -1
+    return nil
+  undefined
+
+# (IO, macros) -> (IO, Node => Number | Symbol) | Error
+readSymbol = (inStream, tableKeys) ->
+  [line, column] = inStream.position()
+  symbol = (until (inStream.done() or inStream.peek() in tableKeys or inStream.peek() in WHITESPACE)
+    inStream.next()).join ''
+  number = readMaybeNumber symbol
+  if number?
+    return makeObj 'number', number, line, column
+  makeObj 'symbol', symbol, line, column
+  
+
+# (Delim, TypeName) -> IO -> (IO, node) | Error
+makeReadPair = (delim, type) ->
+  # IO -> (IO, Node) | Error
+  (inStream) ->
+    inStream.next()
+    skipWS inStream
+    [line, column] = inStream.position()
+    if inStream.peek() == delim
+      inStream.next()
+      return makeObj(type, nil, line, column)
+
+    # IO -> (IO, Node) | Error
+    readEachPair = (inStream) ->
+      [line, column] = inStream.position()
+      obj = read inStream, true, null, true
+      if inStream.peek() == delim then return cons obj, nil
+      if inStream.done() then return handleError("Unexpected end of input")(line, column)
+      return obj if (car obj) == 'error'
+      cons obj, readEachPair(inStream)
+
+    ret = makeObj type, readEachPair(inStream), line, column
+    inStream.next()
+    ret
+
+# Type -> (IO -> (IO, Node))
+prefixReader = (type) ->
+  # IO -> (IO, Node)
+  (inStream) ->
+    [line, column] = inStream.position()
+    inStream.next()
+    [line1, column1] = inStream.position()
+    obj = read inStream, true, null, true
+    return obj if (car obj) == 'error'
+    makeObj "list", cons((makeObj("symbol", type, line1, column1)), cons(obj)), line, column
+
+# I really wanted to make anything more complex than a list (like an
+# object or a vector) something handled by a read macro.  Maybe in a
+# future revision I can vertically de-integrate these.
+
+readMacros =
+  '"': readString
+  '(': makeReadPair ')', 'list'
+  ')': handleError "Closing paren encountered"
+  '[': makeReadPair ']', 'vector'
+  ']': handleError "Closing bracket encountered"
+  '{': makeReadPair('}', 'record', (res) ->
+      res.length % 2 == 0 and true or mkerr "record key without value")
+  '}': handleError "Closing curly without corresponding opening."
+  "`": prefixReader 'back-quote'
+  "'": prefixReader 'quote'
+  ",": prefixReader 'unquote'
+  ";": readComment
+
+
+# Given a stream, reads from the stream until a single complete lisp
+# object has been found and returns the object
+
+# IO -> Form
+read = (inStream, eofErrorP = false, eofError = EOF, recursiveP = false, inReadMacros = null, keepComments = false) ->
+  inStream = if inStream instanceof Source then inStream else new Source inStream
+  inReadMacros = if InReadMacros? then inReadMacros else readMacros
+  inReadMacroKeys = (i for i of inReadMacros)
+
+  c = inStream.peek()
+
+  # (IO, Char) -> (IO, Node) | Error
+  matcher = (inStream, c) ->
+    if inStream.done()
+      return if recursiveP then handleError('EOF while processing nested object')(inStream) else nil
+    if c in WHITESPACE
+      inStream.next()
+      return nil
+    if c == ';'
+      return readComment(inStream)
+    ret = if c in inReadMacroKeys then inReadMacros[c](inStream) else readSymbol(inStream, inReadMacroKeys)
+    skipWS inStream
+    ret
+
+  while true
+    form = matcher inStream, c
+    skip = (not nilp form) and (car form == 'comment') and not keepComments
+    break if (not skip and not nilp form) or inStream.done()
+    c = inStream.peek()
+    null
+  form
+
+# readForms assumes that the string provided contains zero or more
+# forms.  As such, it always returns a list of zero or more forms.
+
+# IO -> (Form* | Error)
+readForms = (inStream) ->
+    inStream = if inStream instanceof Source then inStream else new Source inStream
+    return nil if inStream.done()
+
+    # IO -> (FORM*, IO) | Error
+    [line, column] = inStream.position()
+    readEach = (inStream) ->
+      obj = read inStream, true, null, false
+      return nil if (nilp obj)
+      return obj if (car obj) == 'error'
+      cons obj, readEach inStream
+
+    obj = readEach inStream
+    if (car obj) == 'error' then obj else makeObj "list", obj, line, column
+
+exports.read = read
+exports.readForms = readForms

lib/reduce.coffee

@@ -0,0 +1,50 @@
+{car, cdr, cons, listp, nilp, nil, list, listToString} = require './lists'
+
+reduce = (lst, iteratee, memo, context) ->
+  count = 0
+  ptr = lst
+  while not nilp ptr
+    [item, ptr] = [(car ptr), (cdr ptr)]
+    memo = iteratee.call(context, memo, item, count, lst)
+    count++
+  iteratee.call(context, memo, nil, count, lst)
+
+map = (lst, iteratee, context) ->
+  return nil if nilp lst
+  root = cons("")
+
+  reducer = (memo, item, count) ->
+    next = cons(iteratee.call(context, item, count, lst))
+    memo[1] = next
+    next
+
+  reduce(lst, reducer, root, context)
+  (cdr root)
+
+rmap = (lst, iteratee, context) ->
+  reducer = (memo, item, count) ->
+    cons(iteratee.call(context, item, count, lst), memo)
+  reduce(lst, reducer, nil, context)
+
+
+filter = (lst, iteratee, context) ->
+  return nil if nilp lst
+  root = cons("")
+
+  reducer = (memo, item, count) ->
+    if iteratee.call(context, item, count, lst)
+      next = cons(item)
+      memo[1] = next
+      next
+    else
+      memo
+
+  reduce(lst, reducer, root, context)
+  (cdr root)
+
+module.exports =
+  reduce: reduce
+  map: map
+  rmap: rmap
+  filter: filter
+  

test/t.scm

@@ -0,0 +1 @@
+true