From 6558843e9be0689e0fbe5099f5ebba3a6b2d387c Mon Sep 17 00:00:00 2001
From: "Elf M. Sternberg" <elf.sternberg@gmail.com>
Date: Fri, 3 Apr 2015 20:30:02 -0700
Subject: [PATCH] First pass. Grief. Works with cons cells for tree structure.

---
 .gitignore        |  1 +
 bin/lisp          |  2 +-
 lib/eval.coffee   | 11 ++++++-----
 lib/fn.coffee     | 31 +++++++++++++++++--------------
 lib/lisp.coffee   | 17 +++++++++++------
 lib/parser.coffee |  8 --------
 lib/reader.coffee |  7 +++++--
 lib/scope.coffee  | 44 ++++++++++++++++++++++++--------------------
 test/t.scm        |  1 -
 9 files changed, 65 insertions(+), 57 deletions(-)
 delete mode 100644 lib/parser.coffee
 delete mode 100644 test/t.scm

diff --git a/.gitignore b/.gitignore
index 19cc150..9a389e0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@ npm-debug.log
 node_modules/*
 lib/lisp_parser.js
 tmp/
+test/
diff --git a/bin/lisp b/bin/lisp
index 1ac1e94..4b5a342 100644
--- a/bin/lisp
+++ b/bin/lisp
@@ -2,4 +2,4 @@ lisp = require '../lib/lisp'
 fs = require 'fs'
 {inspect} = require 'util'
 
-console.log inspect((lisp.run process.argv[2]), true, null, false)
+console.log lisp.run process.argv[2]
diff --git a/lib/eval.coffee b/lib/eval.coffee
index 405a6e4..35bdf14 100644
--- a/lib/eval.coffee
+++ b/lib/eval.coffee
@@ -1,16 +1,17 @@
 lookup = require './lookup'
+{car, cdr} = require './lists'
 
 lispeval = (element, scope) ->
+
   switch element.type
-    when 'boolean' then element.value == '#t'
     when 'number' then parseInt(element.value, 10)
     when 'symbol'
       lookup(scope, element.value)
     when 'list'
-      proc = lispeval(element.value[0], scope)
-      args = element.value.slice(1)
+      proc = lispeval((car element.value), scope)
+      args = (cdr element.value)
       proc args, scope
-
-    else throw new Error ("Unrecognized type in parse")
+    else throw new Error ("Unrecognized type in parse: #{element.type}")
 
 module.exports = lispeval
+
diff --git a/lib/fn.coffee b/lib/fn.coffee
index 230d559..b98c7cf 100644
--- a/lib/fn.coffee
+++ b/lib/fn.coffee
@@ -1,20 +1,23 @@
 lispeval = require './eval'
-{cons} = require './lists'
+{cons, nil, nilp, car, cdr, listToVector} = require './lists'
 
 module.exports = 
-  create_expression_evaluator: (defining_scope, params, body) ->
-    if body instanceof Function
-      (cells, scope) ->
-        args = cells.map (i) -> lispeval i, scope
-        body.apply null, args
-    else
-      (cells, scope) ->
-        args = cells.map (i) -> lispeval i, scope
-        new_scope = {}
-        params.forEach (name, i) -> new_scope[name] = args[i]
-        inner = cons(new_scope, defining_scope)
-        body.map((i) -> lispeval i, inner).pop()
-  
+  create_vm_expression_evaluator: (defining_scope, params, body) ->
+    (cells, scope) ->
+      args = listToVector(cells).map (i) -> lispeval i, scope
+      body.apply null, args
+
+  create_lisp_expression_evaluator: (defining_scope, params, body) ->
+    (cells, scope) ->
+      new_scope = (cmap = (cells, params, nscope) ->
+        return nscope if (nilp cells) or (nilp params)
+        nscope[(car params)] = lispeval (car cells), scope
+        cmap((cdr cells), (cdr params), nscope))(cells, params, {})
+      inner = cons(new_scope, defining_scope)
+      (nval = (body, memo) ->
+        return memo if nilp body
+        nval((cdr body), lispeval((car body), inner)))(body)
+
   create_special_form_evaluator: (defining_scope, params, body) ->
     (cells, scope) -> body(cells, scope)
 
diff --git a/lib/lisp.coffee b/lib/lisp.coffee
index e041ba1..3123878 100644
--- a/lib/lisp.coffee
+++ b/lib/lisp.coffee
@@ -1,12 +1,17 @@
 fs = require 'fs'
-{parse} = require './lisp_parser'
-lisp = require './parser'
-{scope} = require './scope'
-{inspect} = require 'util'
+{readForms} = require './reader'
+lispeval = require './eval'
+scope = require './scope'
+{car, cdr, nilp} = require './lists'
 
 module.exports =
   run: (pathname) ->
     text = fs.readFileSync(pathname, 'utf8')
-    ast = parse(text)
-    return lisp(ast, scope)
+    root = scope
+    ast = readForms(text)
+    (nval = (body, memo) ->
+      return memo if nilp body
+      nval((cdr body), lispeval((car body), root)))(ast.value)
+
+
     
diff --git a/lib/parser.coffee b/lib/parser.coffee
deleted file mode 100644
index ed527b3..0000000
--- a/lib/parser.coffee
+++ /dev/null
@@ -1,8 +0,0 @@
-lispeval = require './eval'
-
-lisp = (ast, scope) ->
-  ast.map((e) -> lispeval(e, scope)).pop()
-
-module.exports = lisp
-    
-
diff --git a/lib/reader.coffee b/lib/reader.coffee
index 3c60dc7..7fc816b 100644
--- a/lib/reader.coffee
+++ b/lib/reader.coffee
@@ -31,8 +31,11 @@ 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)))
+makeObj = (type, value, line, column) ->
+  'type': type
+  'value': value
+  'line': line
+  'column': column
 
 # msg -> (IO -> Node => Error)
 handleError = (message) ->
diff --git a/lib/scope.coffee b/lib/scope.coffee
index 416802e..ed185dc 100644
--- a/lib/scope.coffee
+++ b/lib/scope.coffee
@@ -1,28 +1,32 @@
-parser = require './parser'
 lispeval = require './eval'
-{cons, car, cdr, nilp} = require './lists'
-{create_expression_evaluator, create_special_form_evaluator} = require './fn'
-lookup = require './lookup'
+{cons, car, cdr, nilp, nil} = require './lists'
+{create_lisp_expression_evaluator, create_vm_expression_evaluator, create_special_form_evaluator} = require './fn'
 
 scope = cons
-  '+': create_expression_evaluator scope, [], (a, b) -> a + b
-  '-': create_expression_evaluator scope, [], (a, b) -> a - b
-  '*': create_expression_evaluator scope, [], (a, b) -> a * b
-  '/': create_expression_evaluator scope, [], (a, b) -> a / b
-  '==': create_expression_evaluator scope, [], (a, b) -> a == b
+  '+': create_vm_expression_evaluator scope, [], (a, b) -> a + b
+  '-': create_vm_expression_evaluator scope, [], (a, b) -> a - b
+  '*': create_vm_expression_evaluator scope, [], (a, b) -> a * b
+  '/': create_vm_expression_evaluator scope, [], (a, b) -> a / b
+  '==': create_vm_expression_evaluator scope, [], (a, b) -> a == b
+  '#t': true
+  '#f': false
 
-  'define': create_special_form_evaluator scope, [], (list, scope) ->
+  'define': create_special_form_evaluator scope, [], (nodes, scope) ->
     current = (car scope)
-    current[list[0].value] = lispeval(list[1], scope)
+    current[(car nodes).value] = lispeval((car cdr nodes), scope)
 
-  'lambda': create_special_form_evaluator scope, [], (list, scope) ->
-    params = list[0].value.map (n) -> return n.value
-    create_expression_evaluator(scope, params, list.slice(1))
+  'lambda': create_special_form_evaluator scope, [], (nodes, scope) ->
+    param_nodes = (car nodes).value
+    reducer = (l) ->
+      if (nilp l) then nil else cons((car l).value, reducer(cdr l))
+    param_names = reducer(param_nodes)
+
+    create_lisp_expression_evaluator(scope, param_names, (cdr nodes))
         
-  'if': create_special_form_evaluator scope, [], (list, scope) ->
-    lispeval(list[if lispeval(list[0], scope) then 1 else 2], scope)
+  'if': create_special_form_evaluator scope, [], (nodes, scope) ->
+    if lispeval((car nodes), scope)
+      lispeval((car cdr nodes), scope)
+    else
+      lispeval((car cdr cdr nodes), scope)
 
-
-module.exports =
-  lookup: lookup
-  scope: scope
+module.exports = scope
diff --git a/test/t.scm b/test/t.scm
deleted file mode 100644
index 27ba77d..0000000
--- a/test/t.scm
+++ /dev/null
@@ -1 +0,0 @@
-true