Merge 460473a87f into 86972f41cc

.vimrc

@@ -9,3 +9,15 @@ function! CountTILs()
 endfunction
 
 nnoremap <leader>c :call CountTILs()<cr>
+
+augroup DisableMarkdownFormattingForTILReadme
+    autocmd!
+    autocmd BufRead ~/code/til/README.md autocmd! Format
+augroup END
+
+" local til_readme_group = vim.api.nvim_create_augroup('DisableMarkdownFormattingForTILReadme', { clear = true })
+" vim.api.nvim_create_autocmd('BufRead', {
+"   command = 'autocmd! Format',
+"   group = til_readme_group,
+"   pattern = vim.fn.expand '~/code/til/README.md',
+" })

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1510 TILs and counting..._
+_1512 TILs and counting..._
 
 ---
 
@@ -1020,6 +1020,7 @@ _1510 TILs and counting..._
 - [Serialize With fast_jsonapi In A Rails App](rails/serialize-with-fast-jsonapi-in-a-rails-app.md)
 - [Set A Timestamp Field To The Current Time](rails/set-a-timestamp-field-to-the-current-time.md)
 - [Set DateTime To Include Time Zone In Migrations](rails/set-datetime-to-include-time-zone-in-migrations.md)
+- [Set Default As SQL Function In Migration](rails/set-default-as-sql-function-in-migration.md)
 - [Set default_url_options For Entire Application](rails/set-default-url-options-for-entire-application.md)
 - [Set Schema Search Path](rails/set-schema-search-path.md)
 - [Set Statement Timeout For All Postgres Connections](rails/set-statement-timeout-for-all-postgres-connections.md)
@@ -1249,6 +1250,7 @@ _1510 TILs and counting..._
 - [Navigate Back In The Browser With Capybara](ruby/navigate-back-in-the-browser-with-capybara.md)
 - [Next And Previous Floats](ruby/next-and-previous-floats.md)
 - [Or Operator Precedence](ruby/or-operator-precedence.md)
+- [Output Bytecode For A Ruby Program](ruby/output-bytecode-for-a-ruby-program.md)
 - [Override The Initial Sequence Value](ruby/override-the-initial-sequence-value.md)
 - [Parallel Bundle Install](ruby/parallel-bundle-install.md)
 - [Parse JSON Into An OpenStruct](ruby/parse-json-into-an-open-struct.md)

javascript/immutable-remove-with-the-spread-operator.md

@@ -15,10 +15,8 @@ const remove = (items,index) => {
 };
 
 const list = [1,2,3,4,5];
-remove(list, 2);
+remove(list, 2); // [1,2,4,5]
-// [1,2,3,4]
+// list still [1,2,3,4,5]
-list
-// [1,2,3,4,5]
 ```
 
 It only took a couple lines of code and immutability is baked in.

postgres/between-symmetric.md

@@ -4,7 +4,9 @@ PostgreSQL's `between` construct allows you to make a comparison _between_
 two values (numbers, timestamps, etc.).
 
 ```sql
-> select * from generate_series(1,10) as numbers(a) where numbers.a between 3 and 6;
+> select *
+  from generate_series(1,10) as numbers(a)
+  where numbers.a between 3 and 6;
  a
 ---
  3
@@ -17,7 +19,9 @@ If you supply an empty range by using the larger of the two values first, an
 empty set will result.
 
 ```sql
-> select * from generate_series(1,10) as numbers(a) where numbers.a between 6 and 3;
+> select *
+  from generate_series(1,10) as numbers(a)
+  where numbers.a between 6 and 3;
  a
 ---
 ```
@@ -26,7 +30,9 @@ Tacking `symmetric` onto the `between` construct is one way to avoid this
 issue.
 
 ```sql
-> select * from generate_series(1,10) as numbers(a) where numbers.a between symmetric 6 and 3;
+> select *
+  from generate_series(1,10) as numbers(a)
+  where numbers.a between symmetric 6 and 3;
  a
 ---
  3
@@ -39,3 +45,5 @@ issue.
 > that the argument to the left of AND be less than or equal to the argument
 > on the right. If it is not, those two arguments are automatically swapped,
 > so that a nonempty range is always implied.
+
+[source](https://www.postgresql.org/docs/current/functions-comparison.html#:~:text=BETWEEN%20SYMMETRIC%20is%20like%20BETWEEN,nonempty%20range%20is%20always%20implied.)

rails/set-default-as-sql-function-in-migration.md

@@ -0,0 +1,52 @@
+# Set Default As SQL Function In Migration
+
+With static default values, like `0`, `true`, or `'pending'`, we can set them
+directly as the value of `default`.
+
+```ruby
+class CreateActionsTable < ActiveRecord::Migration[7.2]
+  def change
+    create_table :actions do |t|
+      t.string :status, default: 'pending'
+    end
+  end
+end
+```
+
+However, if we want our default value to be a SQL function like `now()`, we
+have to use a lambda.
+
+Let's extend the above example to see what that looks like:
+
+```ruby
+class CreateActionsTable < ActiveRecord::Migration[7.2]
+  def change
+    create_table :actions do |t|
+      t.string :status, default: 'pending'
+
+      t.column :created_at, :timestamptz, default: -> { 'now()' }, null: false
+    end
+  end
+end
+```
+
+If we need to alter the default of an existing table's column, we can do
+something like this:
+
+```ruby
+class AddDefaultTimestampsToActions < ActiveRecord::Migration[7.2]
+  def up
+    change_column_default :actions, :created_at, -> { "now()" }
+    change_column_default :actions, :updated_at, -> { "now()" }
+  end
+
+  def down
+    change_column_default :actions, :created_at, nil
+    change_column_default :actions, :updated_at, nil
+  end
+end
+```
+
+I believe this functionality is available to Rails 5.0 and later.
+
+[source](https://github.com/rails/rails/issues/27077#issuecomment-261155826)

ruby/output-bytecode-for-a-ruby-program.md

@@ -0,0 +1,42 @@
+# Output Bytecode For A Ruby Program
+
+The `ruby` CLI comes with a flag to dump the disassembled YARV bytecode for the
+given Ruby program. This can be a fun way to explore how a Ruby program is
+interpreted under the hood.
+
+Aaron Patterson demoed this behavior during his RubyConf 2024 talk.
+
+Pass the `--dump` flag with `insns` along with either the path to your file or
+an inline bit of Ruby.
+
+Here is a really basic example:
+
+```bash
+❯ ruby --dump=insns -e '2 + 3'
+== disasm: #<ISeq:<main>@-e:1 (1,0)-(1,5)> (catch: false)
+0000 putobject                              2                         (   1)[Li]
+0002 putobject                              3
+0004 opt_plus                               <calldata!mid:+, argc:1, ARGS_SIMPLE>[CcCr]
+0006 leave
+```
+
+And another quite basic example, but with local variables this time:
+
+```bash
+❯ ruby --dump=insns -e 'x = 2; y = 3; x + y'
+== disasm: #<ISeq:<main>@-e:1 (1,0)-(1,19)> (catch: false)
+local table (size: 2, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, kw: -1@-1, kwrest: -1])
+[ 2] x@0        [ 1] y@1
+0000 putobject                              2                         (   1)[Li]
+0002 setlocal_WC_0                          x@0
+0004 putobject                              3
+0006 setlocal_WC_0                          y@1
+0008 getlocal_WC_0                          x@0
+0010 getlocal_WC_0                          y@1
+0012 opt_plus                               <calldata!mid:+, argc:1, ARGS_SIMPLE>[CcCr]
+0014 leave
+```
+
+If you want to dig in to how to read everything that is going on in these
+outputs, I'd recommend checking out this [Advent of YARV
+series](https://kddnewton.com/2022/11/30/advent-of-yarv-part-0.html)