From 817e8deb2704b89d5e7106f81188e68be6ae900c Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas <jashkenas@gmail.com>
Date: Sun, 24 Jan 2010 12:52:15 -0500
Subject: [PATCH] adding soaked method calls, with caching

---
 examples/computer_science/README              |  4 +++
 .../computer_science/binary_search.coffee     | 25 +++++++++++++++++++
 examples/computer_science/bubble_sort.coffee  | 11 ++++++++
 lib/coffee_script/nodes.rb                    | 12 +++++++--
 test/fixtures/execution/test_existence.coffee | 12 ++++++++-
 test/unit/test_execution.rb                   |  3 ++-
 6 files changed, 63 insertions(+), 4 deletions(-)
 create mode 100644 examples/computer_science/README
 create mode 100644 examples/computer_science/binary_search.coffee
 create mode 100644 examples/computer_science/bubble_sort.coffee

diff --git a/examples/computer_science/README b/examples/computer_science/README
new file mode 100644
index 00000000..1046f9f9
--- /dev/null
+++ b/examples/computer_science/README
@@ -0,0 +1,4 @@
+Ported from Nicholas Zakas' collection of computer science fundamentals, written
+in JavaScript. Originals available here:
+
+http://github.com/nzakas/computer-science-in-javascript
diff --git a/examples/computer_science/binary_search.coffee b/examples/computer_science/binary_search.coffee
new file mode 100644
index 00000000..e5447fa4
--- /dev/null
+++ b/examples/computer_science/binary_search.coffee
@@ -0,0 +1,25 @@
+# Uses a binary search algorithm to locate a value in the specified array.
+binary_search: items, value =>
+
+  start: 0
+  stop:  items.length - 1
+  pivot: Math.floor((start + stop) / 2)
+
+  while items[pivot] isnt value and start < stop
+
+    # Adjust the search area.
+    stop:   pivot - 1 if value < items[pivot]
+    start:  pivot + 1 if value > items[pivot]
+
+    # Recalculate the pivot.
+    pivot: Math.floor((stop + start) / 2)
+
+  # Make sure we've found the correct value.
+  if items[pivot] is value then pivot else -1
+
+
+# Test the function.
+print(2 is binary_search([10, 20, 30, 40, 50], 30))
+print(4 is binary_search([-97, 35, 67, 88, 1200], 1200))
+print(0 is binary_search([0, 45, 70], 0))
+print(-1 is binary_search([0, 45, 70], 10))
\ No newline at end of file
diff --git a/examples/computer_science/bubble_sort.coffee b/examples/computer_science/bubble_sort.coffee
new file mode 100644
index 00000000..f5578780
--- /dev/null
+++ b/examples/computer_science/bubble_sort.coffee
@@ -0,0 +1,11 @@
+# A bubble sort implementation, sorting the given array in-place.
+bubble_sort: list =>
+  for i in [0...list.length]
+    for j in [0...list.length - i]
+      [list[j], list[j+1]]: [list[j+1], list[j]] if list[j] > list[j+1]
+  list
+
+
+# Test the function.
+print(bubble_sort([3, 2, 1]).join(' ') is '1 2 3')
+print(bubble_sort([9, 2, 7, 0, 1]).join(' ') is '0 1 2 7 9')
\ No newline at end of file
diff --git a/lib/coffee_script/nodes.rb b/lib/coffee_script/nodes.rb
index 8f7cb20f..77016db4 100644
--- a/lib/coffee_script/nodes.rb
+++ b/lib/coffee_script/nodes.rb
@@ -332,6 +332,9 @@ module CoffeeScript
     children :base, :properties
     attr_reader :last, :source
 
+    # Soak up undefined properties and call attempts.
+    SOAK = " == undefined ? undefined : "
+
     def initialize(base, properties=[])
       @base, @properties = base, [properties].flatten
     end
@@ -375,14 +378,19 @@ module CoffeeScript
       props.each do |prop|
         if prop.is_a?(AccessorNode) && prop.soak
           soaked = true
-          parts[-1] << " == undefined ? undefined : #{baseline += prop.compile(o)}"
+          if @base.is_a?(CallNode) && prop == props.first
+            temp = o[:scope].free_variable
+            parts[-1] = "(#{temp} = #{baseline})#{SOAK}#{baseline = temp.to_s + prop.compile(o)}"
+          else
+            parts[-1] << "#{SOAK}#{baseline += prop.compile(o)}"
+          end
         else
           parts << prop.compile(o)
         end
       end
       @last = parts.last
       @source = parts.length > 1 ? parts[0...-1].join('') : nil
-      code = parts.join('')
+      code = parts.join('').gsub(')())', '()))')
       write(soaked ? "(#{code})" : code)
     end
   end
diff --git a/test/fixtures/execution/test_existence.coffee b/test/fixtures/execution/test_existence.coffee
index 22720631..a532b8e7 100644
--- a/test/fixtures/execution/test_existence.coffee
+++ b/test/fixtures/execution/test_existence.coffee
@@ -41,4 +41,14 @@ obj: {
 
 print(obj?.prop is "hello")
 
-print(obj?.prop?.non?.existent?.property is undefined)
\ No newline at end of file
+print(obj?.prop?.non?.existent?.property is undefined)
+
+
+# Soaks and caches method calls as well.
+
+arr: ["--", "----"]
+
+print(arr.pop()?.length is 4)
+print(arr.pop()?.length is 2)
+print(arr.pop()?.length is undefined)
+print(arr.pop()?.length?.non?.existent()?.property is undefined)
diff --git a/test/unit/test_execution.rb b/test/unit/test_execution.rb
index 81db6a6d..8eea7479 100644
--- a/test/unit/test_execution.rb
+++ b/test/unit/test_execution.rb
@@ -6,7 +6,8 @@ class ExecutionTest < Test::Unit::TestCase
 
   SOURCES = [
     'test/fixtures/execution/*.coffee',
-    'examples/beautiful_code/*.coffee'
+    'examples/beautiful_code/*.coffee',
+    'examples/computer_science/*.coffee'
   ]
 
   # This is by far the most important test. It evaluates all of the