Updates

Author: eoinkelly

README.md

@@ -1,8 +1,31 @@
-My learning notes pushed up here so I can refer to them easily. These represent
-my understanding of various topics so are probably inaccurate in places and
-usually incomplete.
+# My learning notes
 
-If you are unusually kind you might alert me to things I have wrong via an
-issue.
+_These are quite likely incomplete and sometimes incorrect_. They are after all
+topics that I am still learning. YMMV.
 
-YMMV.
+
+# How I think about learning
+
+* Commit to finishing a page, not a book. I should remain nimble about the
+  depth I learn a particular topic. To commit to a whole book lets the author
+  decide on the depth that might not be a good investment of time for me.
+
+* Organise notes by topic, not by source. Notes are for
+    1. Revising what I have learned
+    2. Express what I have learned to help me find holes in my understanding
+  Notes organised by topic are more suitable for these goals - I will keep track
+  of which resources I have finished separately
+* It's ok for notes to be messy/wrong. Building them up is an iterative process
+  and there is as much value in re-reading and improving them as creating the
+  initial draft.
+
+
+# Possible approaches to learning stuff
+
+* my learning is a very iterative process that is shaped by questions I ask as a
+  result of something I read - I follow the trail as long as it seems interesting.
+
+* decide on a structure before I begin a topic, follow a cirriculum decided by
+  me based on some resource e.g. a book
+
+I'm not sure which of these is best...

c/000-progress.md

@@ -0,0 +1,12 @@
+
+# Questions
+
+# TODO
+
+* get extern variables working between files in my Xcode example
+
+
+# Completed sources
+
+* A Guide to C Programming
+    * complete

c/TODO.md

@@ -0,0 +1,9 @@
+# Generic pointers
+
+```
++ allows you to avoid type checking
++ can point to anything
+- must be cast to another pointer before it can be dereferenced
+    - the programmer must keep track of this
+- cannot do pointer arithmetic on them
+```

c/generic-pointers.md

@@ -0,0 +1,19 @@
+
+# Questions
+
+
+Q: can you get at instance variables wihout a getter/setter in objc?
+
+Q: what does @selector do?
+
+Q: What are best practices for managing files in Xcode?
+
+# Completed
+
+A source is _complete_ if I have understood it and taken notes from it i.e.
+there is no value in going back to it because I have notes.
+
+* Big Nerd Ranch Guide
+    * chap 1
+* NSScreencasts
+    * episode 1

ios-swift-objc/000-progress.md

@@ -156,11 +156,6 @@ means they will be copied into the resulting `.app` directory.
 It seems in Xcode you  have to manage your project navigator view and your
 filesystem separately.
 
-#### Questions
-
-Q: How does this work in practice?
-Q: What are best practices for managing files in Xcode?
-
 
 ### Building Interfaces
 

ios-swift-objc/big-nerd-ranch-guide.md

@@ -188,6 +188,4 @@ TODO: find out more about it
 
 
 
-Q: can you get at instance variables wihout a getter/setter in objc?
-Q: what does @selector do?
 

ios-swift-objc/ns-screencasts.md

@@ -1,40 +1,44 @@
 # UIWebView
 
+_IIRC these are notes on the new webview in iOS 8+_
+
 * has a `delegate` property
-  ???
+    * which is sent messages while the content is loading
+    * can implement methods to talk to the UIWebView instance
 
 * Ancestors: `UIView < UIResponder < NSObject`
-* part of UIKit "framework" `import UIKit` to get it
-* conforms to 7 interfaces
-
-has a delegate
-  * which is sent messages while the content is loading
-  * can implement methods to talk to the UIWebView instance
+* part of UIKit "framework" `#import UIKit` to get it
+* conforms to 7 interfaces. These are ???
 
 
 ## Plugins
 
 One instance of a plugin object is created for the life of each UIWebView
 
-Plugins are ordinarily instantiated when first referenced by a call from JavaScript. Otherwise they can be instantiated by setting a param named onload to true in the config.xml file
+Plugins are ordinarily instantiated when first referenced by a call from
+JavaScript. Otherwise they can be instantiated by setting a param named onload
+to true in the config.xml file
 
-methods to implement (where???)
-  onReset - called when the webview is refreshed or moves to different screen
-  pluginInitialize - called when your plugin is initailzied
-  action
-    * this is what the javascript exec() will hit in your class
+* methods to implement (where???)
+  * onReset - called when the webview is refreshed or moves to different screen
+  * pluginInitialize - called when your plugin is initailzied action
+      * this is what the javascript exec() will hit in your class
 
-the pattern is that JS initiates all work done on the iOS side
+* the pattern is that JS initiates all work done on the iOS side
 
-messages from JS -> iOS
+* messages from JS -> iOS
   * sent to the action method of the given plugin class
   * can have arbitrary num of args
 
-
-messages from iOS -> JS
-  * You can use CDVPluginResult to return a variety of result types back to the JavaScript callbacks, using class methods
-  * You can create String, Int, Double, Bool, Array, Dictionary, ArrayBuffer, and Multipart types. You can also leave out any arguments to send a status, or return an error, or even choose not to send any plugin result, in which case neither callback fires.
+* messages from iOS -> JS
+  * You can use CDVPluginResult to return a variety of result types back to the
+    JavaScript callbacks, using class methods
+  * You can create String, Int, Double, Bool, Array, Dictionary, ArrayBuffer,
+    and Multipart types. You can also leave out any arguments to send a status, or
+    return an error, or even choose not to send any plugin result, in which case
+    neither callback fires.
   * you seem to return an instance of CDVpluginResult  that encapsulates the response
 
 
-There doesn't seem to be a way for the iOS to send a message to JS without the JS polling
+There doesn't seem to be a way for the iOS to send a message to JS without the
+JS polling ???

ios-swift-objc/uiwebview.md

@@ -1,2 +1,16 @@
 Are multiple classes in the same file a bad idea in rails? Even if it just for a
 while before we refactor it out?
+
+how to do chaining methods in ruby?
+
+how to implement a delegate patter in ruby
+
+
+AR observers vs callbacks
+
+    http://samuelmullen.com/2013/05/the-problem-with-rails-callbacks/
+    http://blog.crowdint.com/2013/04/23/fun-with-activerecord-observer.html
+    http://robots.thoughtbot.com/post/9123160250/activerecord-caching-and-the-single-responsibility
+    http://blog.bignerdranch.com/1658-the-only-acceptable-use-for-callbacks-in-rails-ever/
+
+

rails/questions.md

@@ -0,0 +1,40 @@
+# Rails Performance
+
+##  http://confreaks.com/videos/4107-rdrc2014-speed-up-rails-speed-up-your-code
+
+* Typically we trade off time and memory space when improving performance
+    * Implications:
+        * To improve speed, we use more RAM
+        * To improve RAM usage, we go slower
+* There is also the possibility of finding a better algorightm but this is less
+  common.
+
+Tools
+
+What do we measure?
+
+We measure the performance of individual methods.
+? Does it make sense to measure performance of a class?
+
+`benchmark/ips`
+* iterations per second
+* provides standar deviations
+* you give it a block to run as many times as it can in X seconds
+
+* ruby has `benchmark` gem built-in.
+
+Things to watch out for
+
+* Noise - how much other work is your machine doing at the same time? How much
+does this change between benchmarks
+    * It is handy to have a standard deviation here so you can see how noisy
+      your result is.
+    "say the slowest was X and the fastest Y and it was mostly in the middle at Z"
+    TODO refresh std dev
+    * `benchmark/ips` can show you std dev
+
+
+stackprof
+GC.stat()
+GC.stat(:total_allocated_objects) # num of objects allocated in the system since start
+allocation_tracer gem

rails/rails-perf.md

@@ -51,7 +51,7 @@ end
   the table
     * why is this bad?
 
-```
+```ruby
 class Owner
 end
 
@@ -71,7 +71,7 @@ end
 
 he thinks about his data models as db columns first
 
-```
+```ruby
 # if shout.content is a polymorphic relationship, render will render the partial
 # name based on the type - this is a pretty neat pattern!
 render shout.content

rails/thoughtbot-learn/workshops/intermediate-rails/part-2.md

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+# Intro to TDD
+
+## Notes
+
+## Questions for Rose
+
+* Talk me through what the `red->green->refactor` means.
+* Tell me what these do
+    * Factory girl
+    * Rspec
+    * Shoulda matchers
+    * Timecop
+    * Capybara
+
+* What is the command to create a new rails app but not setup the default
+  testing framework
+* Show me the repo you setup with rspec

rails/thoughtbot-learn/workshops/tdd-rails/01-intro.md

@@ -0,0 +1,10 @@
+
+* http://comonad.com/reader/2014/letter-to-a-young-haskell-enthusiast/
+    > s this really what you want to do? Do you want to help people, do you want to
+    > teach people new wonderful things? Do you want to share the things that excite
+    > you? Or do you want to feel better about yourself, confirm that you are
+    > programming better, confirm that you are smarter and know more, reassure
+    > yourself that your adherence to a niche language is ok by striking out against
+    > the mainstream? Of course, you want to do the former. But a part of you probably
+    > secretly wants to do the latter, because in my experience that part is in all of
+    > us.

random.md

@@ -0,0 +1,13 @@
+# look(ahead|behind)
+
+```
+(?<!a)b   # matches a "b" that is not preceded by an "a (negative look behind)
+(?<=a)b   # matches a "b" only if it is preceded by an "a" (positive look behind)
+a(?!b)    # matches "a" only if it is not followed by a "b" (negative lookahead)
+a(?=b)i   # matches "a" only if it is followed by a "b" (positive lookahead)
+```
+
+Oddities
+
+* JS regexps do not support negative lookahead/lookbehind
+