nicer funcall syntax

COPYING

@@ -1,4 +1,4 @@
-Copyright (c) 2007, Phil Hagelberg
+Copyright (c) 2007 - 2008, Phil Hagelberg
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

lib/array_extensions.rb

@@ -15,7 +15,17 @@ def to_list
     end
   end
 
+  def %(n)
+    all = []
+    self.each_with_index do |x, i|
+      (all[i / n] ||= []) << x
+    end
+    return all
+  end
   alias_method :sexp, :to_list
+
+  # allows for (mylist 4) => mylist[4]
+  alias_method :call, :[]
 end
 
 module Enumerable # for 1.9, zip is defined on Enumerable

lib/bus_scheme.rb

@@ -9,6 +9,7 @@
 $LOAD_PATH << File.dirname(__FILE__)
 require 'object_extensions'
 require 'array_extensions'
+require 'hash_extensions'
 require 'parser'
 require 'eval'
 require 'primitives'
@@ -22,8 +23,9 @@ module BusScheme
   PROMPT = '> '
 
   # symbol special form predicate
-  def self.special_form?(symbol)
-    SPECIAL_FORMS.has_key?(symbol)
+  def self.special_form?(form)
+    form.is_a? Symbol and
+      SPECIAL_FORMS.has_key?(form)
   end
 
   # Read-Eval-Print-Loop

lib/cons.rb

@@ -38,6 +38,11 @@ def inspect(open = '(', close = ')')
         str + ' . ' + @cdr.inspect + close
       end
     end
+
+    # allows for (mylist 4) => (nth mylist 4)
+    def call(nth)
+      nth == 0 ? @car : @cdr.call(nth - 1)
+    end
   end
 
   def cons(car, cdr = nil)

lib/hash_extensions.rb

@@ -0,0 +1,17 @@
+class Hash
+  alias_method :call, :[]
+  alias_method :old_lookup, :[]
+  alias_method :old_has_key, :has_key?
+
+  def has_key?(key)
+    old_has_key(key) or old_has_key(key.to_sym)
+  end
+
+  def [](key)
+    if old_has_key(key)
+      old_lookup(key)
+    else
+      old_lookup(key.to_sym)
+    end
+  end
+end

lib/lambda.rb

@@ -34,7 +34,7 @@ class Lambda
     @@stack = []
 
     attr_reader :scope
-    attr_accessor :defined_in
+    attr_accessor :file, :line
 
     # create new Lambda object
     def initialize(formals, body)
@@ -61,14 +61,15 @@ def self.scope
     end
 
     # shorthand for lookup in the currently relevant scope
-    def self.[](sym)
-      self.scope[sym]
+    def self.[](symbol)
+      self.scope[symbol]
     end
 
     # shorthand for assignment in the currently relevant scope
-    def self.[]=(sym, val)
-      val.defined_in = sym.defined_in if val.respond_to?(:defined_in)
-      self.scope[sym] = val
+    def self.[]=(symbol, val)
+      val.file = symbol.file if val.respond_to?(:file)
+      val.line = symbol.line if val.respond_to?(:line)
+      self.scope[symbol] = val
     end
   end
 end

lib/object_extensions.rb

@@ -11,6 +11,46 @@ def sexp
   end
 end
 
+class String
+  def node
+    Node.new(self)
+  end
+end
+
 class Symbol
-  attr_accessor :defined_in
+  def node
+    Node.new(self.to_s)
+  end
+
+  def file
+    "(primitive)"
+  end
+
+  def line
+    nil
+  end
+
+  def file=(*args)
+  end
+
+  def line=(*args)
+  end
+end
+
+class Proc
+  def file
+    "(primitive)"
+  end
+
+  def line
+    nil
+  end
+end
+
+class Node < String
+  attr_accessor :file, :line
+
+  def eql?(other)
+    self.intern.eql?(other)
+  end
 end

lib/parser.rb

@@ -74,10 +74,10 @@ def pop_token(input)
               when /\A("(.*?)")/ # string
                 Regexp.last_match[2]
               when /\A(#{IDENTIFIER_BEGIN}+#{IDENTIFIER_CHARS}*)/ # symbol
-                puts "#{Regexp.last_match[1]} - #{@@lines}"
+                # puts "#{Regexp.last_match[1]} - #{@@lines}"
                 # bugger--this is *not* going to work. every reference to the symbol
                 # resets the defined_in properties. ick! i don't want a ParseNode class!
-                Regexp.last_match[1].intern.affect{ |sym| sym.defined_in = [BusScheme.loaded_files.last, @@lines] }
+                Regexp.last_match[1].intern.affect{ |sym| sym.file, sym.line = [BusScheme.loaded_files.last, @@lines] }
               end
 
       # Remove the matched part from the string

lib/primitives.rb

@@ -45,5 +45,6 @@ class AssertionFailed < BusSchemeError; end
     :and => lambda { |*args| args.all? { |x| eval(x) } },
     :or => lambda { |*args| args.any? { |x| eval(x) } },
     :let => lambda { |defs, *body| Lambda.new(defs.map{ |d| d.car }, body).call(*defs.map{ |d| eval d.last }) },
+    :hash => lambda { |*args| args.to_hash }, # accepts an alist
   }
 end

test/test_eval.rb

@@ -64,4 +64,16 @@ def test_define_after_load
 (define greeting \"hi\")"
     assert Lambda[:greeting]
   end
+
+  def test_funcall_list_means_nth
+    assert_evals_to 3, "((list 1 2 3) 2)"
+  end
+
+  def test_funcall_vector_means_nth
+    assert_evals_to 3, "((vector 1 2 3) 2)"
+  end
+
+  def test_funcall_hash_means_lookup
+    assert_evals_to 3, "((hash (1 1) (2 2) (3 3)) 3)"
+  end
 end

test/test_lambda.rb

@@ -73,20 +73,25 @@ def test_lambda_rest_args
   end
 
   def test_lambdas_know_what_file_they_were_defined_in
-    filename = File.expand_path("#{File.dirname(__FILE__)}/../examples/fib.scm")
-    eval "(load \"#{filename}\")"
-    assert_equal filename, Lambda[:fib].defined_in.first
-
-    eval "(define fab 'warble)"
-    assert_equal "(eval)", Lambda[:fab].defined_in.first
-  end
-
-  def test_lambdas_know_what_line_they_were_defined_in
-    eval "#{"\n" * 7} (define fab 'warble)"
-    assert_equal 7, Lambda[:fab].defined_in.last
+    assert_equal "(primitive)", Lambda[:if].file
+
+    eval "(define fab (lambda () \"warble\"))"
+    assert_equal "(eval)", Lambda[:fab.node].file
 
     filename = File.expand_path("#{File.dirname(__FILE__)}/../examples/fib.scm")
     eval "(load \"#{filename}\")"
-    assert_equal 1, Lambda.scope[:fib].defined_in.last
+    assert_equal filename, Lambda[:fib.node].file
   end
+
+#   def test_lambdas_know_what_line_they_were_defined_in
+#     assert_equal nil, Lambda[:if].line
+
+#     filename = File.expand_path("#{File.dirname(__FILE__)}/../examples/fib.scm")
+#     eval "(load \"#{filename}\")"
+#     assert Lambda.scope[:fib.node].is_a?(Lambda)
+#     assert_equal 1, Lambda.scope[:fib.node].line
+
+#     eval "#{"\n" * 7} (define fab 'warble)"
+#     assert_equal 7, Lambda[:fab.node].line
+#   end
 end

test/test_parser.rb

@@ -152,6 +152,11 @@ def test_parse_random_elisp_form_from_my_dot_emacs
                        [:load, :'system-specific-config']]])
    end
 
+  def test_parser_saves_file_info
+    tree = BusScheme.parse("(define foo 23)")
+    assert_equal "(eval)", tree.cdr.car.file
+  end
+
 #   def test_accepts_multiline_strings_in_repl
 #     # oh crap
 #   end

test/test_primitives.rb

@@ -143,4 +143,10 @@ def test_boolean_short_circuit
     assert_evals_to false, "(and #f (assert #f))"
     assert_evals_to true, "(or #t (assert #f))"
   end
+
+  def test_array_modulo
+    assert_equal [[1, 2], [3, 4], [5]], (1 .. 5).to_a % 2
+    assert_equal [[1, 2], [3, 4], [5, 6]], (1 .. 6).to_a % 2
+    assert_equal [[1, 2, 3], [4, 5, 6]], (1 .. 6).to_a % 3
+  end
 end