Scanner
, String
, and Random
. Questions should be quick to answer. Please avoid obscure trivia and showboating.Learning to code requires a mix of writing your own code and reading other people’s. Let’s do a little reading of other people’s code with some What Does This Do? The following code snippets are missing some names. What does these methods do, and what should appear in place of the question marks?
/usr/lib/ruby/2.7.0/rubygems/dependency.rb:311:in `to_specs': Could not find 'coderay' (>= 0) among 57 total gem(s) (Gem::MissingSpecError) Checked in 'GEM_PATH=/.gem/ruby/2.7.0:/var/lib/gems/2.7.0:/usr/lib/ruby/gems/2.7.0:/usr/share/rubygems-integration/2.7.0:/usr/share/rubygems-integration/all:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.7.0:/home/johnch/.gems', execute `gem env` for more information from /usr/lib/ruby/2.7.0/rubygems/dependency.rb:323:in `to_spec' from /usr/lib/ruby/2.7.0/rubygems/core_ext/kernel_gem.rb:62:in `gem' from ./coderay:24:in `'
/usr/lib/ruby/2.7.0/rubygems/dependency.rb:311:in `to_specs': Could not find 'coderay' (>= 0) among 57 total gem(s) (Gem::MissingSpecError) Checked in 'GEM_PATH=/.gem/ruby/2.7.0:/var/lib/gems/2.7.0:/usr/lib/ruby/gems/2.7.0:/usr/share/rubygems-integration/2.7.0:/usr/share/rubygems-integration/all:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.7.0:/home/johnch/.gems', execute `gem env` for more information from /usr/lib/ruby/2.7.0/rubygems/dependency.rb:323:in `to_spec' from /usr/lib/ruby/2.7.0/rubygems/core_ext/kernel_gem.rb:62:in `gem' from ./coderay:24:in `'
/usr/lib/ruby/2.7.0/rubygems/dependency.rb:311:in `to_specs': Could not find 'coderay' (>= 0) among 57 total gem(s) (Gem::MissingSpecError) Checked in 'GEM_PATH=/.gem/ruby/2.7.0:/var/lib/gems/2.7.0:/usr/lib/ruby/gems/2.7.0:/usr/share/rubygems-integration/2.7.0:/usr/share/rubygems-integration/all:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.7.0:/home/johnch/.gems', execute `gem env` for more information from /usr/lib/ruby/2.7.0/rubygems/dependency.rb:323:in `to_spec' from /usr/lib/ruby/2.7.0/rubygems/core_ext/kernel_gem.rb:62:in `gem' from ./coderay:24:in `'
/usr/lib/ruby/2.7.0/rubygems/dependency.rb:311:in `to_specs': Could not find 'coderay' (>= 0) among 57 total gem(s) (Gem::MissingSpecError) Checked in 'GEM_PATH=/.gem/ruby/2.7.0:/var/lib/gems/2.7.0:/usr/lib/ruby/gems/2.7.0:/usr/share/rubygems-integration/2.7.0:/usr/share/rubygems-integration/all:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.7.0:/home/johnch/.gems', execute `gem env` for more information from /usr/lib/ruby/2.7.0/rubygems/dependency.rb:323:in `to_spec' from /usr/lib/ruby/2.7.0/rubygems/core_ext/kernel_gem.rb:62:in `gem' from ./coderay:24:in `'
Now let’s flip things a bit. Let’s play some Method Guess Who:
String
or the primitives, but not Scanner
or Random
or convoluted expressions.)When we write methods, we create little isolated worlds of computation that fit into larger worlds. Control gets passed back and forth between these worlds, and having a proper mental model of what’s actually happening inside the computer is essential to exploiting them effectively. We’re going to investigate how memory changes as we declare variables and call methods.
/usr/lib/ruby/2.7.0/rubygems/dependency.rb:311:in `to_specs': Could not find 'coderay' (>= 0) among 57 total gem(s) (Gem::MissingSpecError) Checked in 'GEM_PATH=/.gem/ruby/2.7.0:/var/lib/gems/2.7.0:/usr/lib/ruby/gems/2.7.0:/usr/share/rubygems-integration/2.7.0:/usr/share/rubygems-integration/all:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.7.0:/home/johnch/.gems', execute `gem env` for more information from /usr/lib/ruby/2.7.0/rubygems/dependency.rb:323:in `to_spec' from /usr/lib/ruby/2.7.0/rubygems/core_ext/kernel_gem.rb:62:in `gem' from ./coderay:24:in `'
/usr/lib/ruby/2.7.0/rubygems/dependency.rb:311:in `to_specs': Could not find 'coderay' (>= 0) among 57 total gem(s) (Gem::MissingSpecError) Checked in 'GEM_PATH=/.gem/ruby/2.7.0:/var/lib/gems/2.7.0:/usr/lib/ruby/gems/2.7.0:/usr/share/rubygems-integration/2.7.0:/usr/share/rubygems-integration/all:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.7.0:/home/johnch/.gems', execute `gem env` for more information from /usr/lib/ruby/2.7.0/rubygems/dependency.rb:323:in `to_spec' from /usr/lib/ruby/2.7.0/rubygems/core_ext/kernel_gem.rb:62:in `gem' from ./coderay:24:in `'
We’ve seen two strategies for thinking about code now, neither of which require a computer:
Don’t forget to think away from the machine. It’s not better than you. That said, this Java Visualizer does a decent job of automatically tracing execution.
Let’s do one more:
/usr/lib/ruby/2.7.0/rubygems/dependency.rb:311:in `to_specs': Could not find 'coderay' (>= 0) among 57 total gem(s) (Gem::MissingSpecError) Checked in 'GEM_PATH=/.gem/ruby/2.7.0:/var/lib/gems/2.7.0:/usr/lib/ruby/gems/2.7.0:/usr/share/rubygems-integration/2.7.0:/usr/share/rubygems-integration/all:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.7.0:/home/johnch/.gems', execute `gem env` for more information from /usr/lib/ruby/2.7.0/rubygems/dependency.rb:323:in `to_spec' from /usr/lib/ruby/2.7.0/rubygems/core_ext/kernel_gem.rb:62:in `gem' from ./coderay:24:in `'
/usr/lib/ruby/2.7.0/rubygems/dependency.rb:311:in `to_specs': Could not find 'coderay' (>= 0) among 57 total gem(s) (Gem::MissingSpecError) Checked in 'GEM_PATH=/.gem/ruby/2.7.0:/var/lib/gems/2.7.0:/usr/lib/ruby/gems/2.7.0:/usr/share/rubygems-integration/2.7.0:/usr/share/rubygems-integration/all:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.7.0:/home/johnch/.gems', execute `gem env` for more information from /usr/lib/ruby/2.7.0/rubygems/dependency.rb:323:in `to_spec' from /usr/lib/ruby/2.7.0/rubygems/core_ext/kernel_gem.rb:62:in `gem' from ./coderay:24:in `'
/usr/lib/ruby/2.7.0/rubygems/dependency.rb:311:in `to_specs': Could not find 'coderay' (>= 0) among 57 total gem(s) (Gem::MissingSpecError) Checked in 'GEM_PATH=/.gem/ruby/2.7.0:/var/lib/gems/2.7.0:/usr/lib/ruby/gems/2.7.0:/usr/share/rubygems-integration/2.7.0:/usr/share/rubygems-integration/all:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.7.0:/home/johnch/.gems', execute `gem env` for more information from /usr/lib/ruby/2.7.0/rubygems/dependency.rb:323:in `to_spec' from /usr/lib/ruby/2.7.0/rubygems/core_ext/kernel_gem.rb:62:in `gem' from ./coderay:24:in `'
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