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18 Commits

Author SHA1 Message Date
Karim Bouchez
e16f4ec85f Merge 15337dfd71 into 9c0c9222f9 2024-12-27 11:43:51 -03:00
jbranchaud
9c0c9222f9 Add Create A Slice From An Array as a Go TIL 2024-12-26 09:47:12 -07:00
jbranchaud
855251e478 Add Clamp To An Endless Range as a Ruby TIL 2024-12-25 22:07:58 -07:00
jbranchaud
4e5ba0ce4c Add Write A Custom Scan Function For File IO as a Go TIL 2024-12-24 11:12:32 -06:00
jbranchaud
63a92cbc29 Add Use External Diff Tool Like Difftastic as a Git TIL 2024-12-23 15:41:11 -06:00
jbranchaud
8438025005 Add Deterministically Seed A Random Number Generator as a Go TIL 2024-12-22 15:04:31 -06:00
jbranchaud
a3be570a32 Add Show Linting Errors In Zed as a Workflow TIL 2024-12-21 19:14:48 -06:00
jbranchaud
464a2af6db Add Produce The Zero Value Of A Generic Type as a Go TIL 2024-12-20 15:19:10 -06:00
jbranchaud
8801f39df0 Add Manually Pass Two Git Files To Delta as a Unix TIL 2024-12-19 18:24:27 -06:00
jbranchaud
aeb55efc3c Add Detect If Stdin Comes From A Redirect as a Go TIL 2024-12-18 11:05:29 -06:00
jbranchaud
a92af09fea Add Explore The Database Schema as a SQLite TIL 2024-12-17 12:28:13 -06:00
jbranchaud
43e6433fd6 Add Check If Cobra Flag Was Set as a Go TIL 2024-12-17 01:08:50 -06:00
jbranchaud
88e675b9a3 Add Better Diffs With Delta as a Git TIL 2024-12-15 18:31:25 -06:00
jbranchaud
f5286c1f41 Add Format Date And Time With Time Constants as a Go TIL 2024-12-14 10:52:36 -06:00
jbranchaud
8787e43458 Add Fix Whitespace Errors Throughout Branch Commits as a Git TIL 2024-12-13 14:32:11 -06:00
jbranchaud
f658a31435 Add Redirect File To Stdin During Delve Debug as a Go TIL 2024-12-12 18:40:23 -06:00
jbranchaud
db00ec69c2 Add Highlight Extra Whitespace In Diff Output as a Git TIL 2024-12-11 18:43:08 -06:00
Karim Bouchez
15337dfd71 Update the old way to capture a GitHub Actions output
See [here](https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/) for more explanations:
> We are monitoring telemetry for the usage of these commands and plan to fully disable them on 31st May 2023. Starting 1st June 2023 workflows using save-state or set-output commands via stdout will fail with an error.
2023-02-12 10:36:45 +01:00
18 changed files with 635 additions and 4 deletions

View File

@@ -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).
_1534 TILs and counting..._
_1550 TILs and counting..._
---
@@ -283,6 +283,7 @@ _1534 TILs and counting..._
- [Add Only Tracked Files From A Directory](git/add-only-tracked-files-from-a-directory.md)
- [Amend Author Of Previous Commit](git/amend-author-of-previous-commit.md)
- [Auto-Squash Those Fixup Commits](git/auto-squash-those-fixup-commits.md)
- [Better Diffs With Delta](git/better-diffs-with-delta.md)
- [Caching Credentials](git/caching-credentials.md)
- [Change The Start Point Of A Branch](git/change-the-start-point-of-a-branch.md)
- [Check How A File Is Being Ignored](git/check-how-a-file-is-being-ignored.md)
@@ -311,12 +312,14 @@ _1534 TILs and counting..._
- [Find And Remove Files That Match A Name](git/find-and-remove-files-that-match-a-name.md)
- [Find The Date That A File Was Added To The Repo](git/find-the-date-that-a-file-was-added-to-the-repo.md)
- [Find The Initial Commit](git/find-the-initial-commit.md)
- [Fix Whitespace Errors Throughout Branch Commits](git/fix-whitespace-errors-throughout-branch-commits.md)
- [Get Latest Commit Timestamp For A File](git/get-latest-commit-timestamp-for-a-file.md)
- [Get The Name Of The Current Branch](git/get-the-name-of-the-current-branch.md)
- [Get The Short Version Of The Latest Commit](git/get-the-short-version-of-the-latest-commit.md)
- [Grab A Single File From A Stash](git/grab-a-single-file-from-a-stash.md)
- [Grep For A Pattern On Another Branch](git/grep-for-a-pattern-on-another-branch.md)
- [Grep Over Commit Messages](git/grep-over-commit-messages.md)
- [Highlight Extra Whitespace In Diff Output](git/highlight-extra-whitespace-in-diff-output.md)
- [Ignore Changes To A Tracked File](git/ignore-changes-to-a-tracked-file.md)
- [Ignore Files Specific To Your Workflow](git/ignore-files-specific-to-your-workflow.md)
- [Include A Message With Your Stashed Changes](git/include-a-message-with-your-stashed-changes.md)
@@ -380,6 +383,7 @@ _1534 TILs and counting..._
- [Untrack A Directory Of Files Without Deleting](git/untrack-a-directory-of-files-without-deleting.md)
- [Untrack A File Without Deleting It](git/untrack-a-file-without-deleting-it.md)
- [Update The URL Of A Remote](git/update-the-url-of-a-remote.md)
- [Use External Diff Tool Like Difftastic](git/use-external-diff-tool-like-difftastic.md)
- [Using Commands With A Relative Date Format](git/using-commands-with-a-relative-date-format.md)
- [Verbose Commit Message](git/verbose-commit-message.md)
- [Viewing A File On Another Branch](git/viewing-a-file-on-another-branch.md)
@@ -400,16 +404,24 @@ _1534 TILs and counting..._
- [Access Go Docs Offline](go/access-go-docs-offline.md)
- [Add A Method To A Struct](go/add-a-method-to-a-struct.md)
- [Build For A Specific OS And Architecture](go/build-for-a-specific-os-and-architecture.md)
- [Check If Cobra Flag Was Set](go/check-if-cobra-flag-was-set.md)
- [Combine Two Slices](go/combine-two-slices.md)
- [Create A Slice From An Array](go/create-a-slice-from-an-array.md)
- [Detect If Stdin Comes From A Redirect](go/detect-if-stdin-comes-from-a-redirect.md)
- [Deterministically Seed A Random Number Generator](go/deterministically-seed-a-random-number-generator.md)
- [Do Something N Times](go/do-something-n-times.md)
- [Find Executables Installed By Go](go/find-executables-installed-by-go.md)
- [Format Date And Time With Time Constants](go/format-date-and-time-with-time-constants.md)
- [Not So Random](go/not-so-random.md)
- [Parse A String Into Individual Fields](go/parse-a-string-into-individual-fields.md)
- [Parse Flags From CLI Arguments](go/parse-flags-from-cli-arguments.md)
- [Produce The Zero Value Of A Generic Type](go/produce-the-zero-value-of-a-generic-type.md)
- [Redirect File To Stdin During Delve Debug](go/redirect-file-to-stdin-during-delve-debug.md)
- [Replace The Current Process With An External Command](go/replace-the-current-process-with-an-external-command.md)
- [Sleep For A Duration](go/sleep-for-a-duration.md)
- [Sort Slice In Ascending Or Descending Order](go/sort-slice-in-ascending-or-descending-order.md)
- [Upgrading From An Older Version On Mac](go/upgrading-from-an-older-version-on-mac.md)
- [Write A Custom Scan Function For File IO](go/write-a-custom-scan-function-for-file-io.md)
### GROQ
@@ -1206,6 +1218,7 @@ _1534 TILs and counting..._
- [Check If A URL Resolves To 200](ruby/check-if-a-url-resolves-to-200.md)
- [Check If An Object Includes A Module](ruby/check-if-an-object-includes-a-module.md)
- [Check Return Status Of Running A Shell Command](ruby/check-return-status-of-running-a-shell-command.md)
- [Clamp To An Endless Range](ruby/clamp-to-an-endless-range.md)
- [Click On Text With Capybara](ruby/click-on-text-with-capybara.md)
- [Colorful Output With MiniTest](ruby/colorful-output-with-minitest.md)
- [Comparing Class Hierarchy Relationships](ruby/comparing-class-hierarchy-relationships.md)
@@ -1354,6 +1367,7 @@ _1534 TILs and counting..._
### SQLite
- [Display Results In Readable Column Format](sqlite/display-results-in-readable-column-format.md)
- [Explore The Database Schema](sqlite/explore-the-database-schema.md)
### Streaming
@@ -1520,6 +1534,7 @@ _1534 TILs and counting..._
- [Load Env Vars In Bash Script](unix/load-env-vars-in-bash-script.md)
- [Look Through All Files That Have Been Git Stashed](unix/look-through-all-files-that-have-been-git-stashed.md)
- [Make Direnv Less Noisy](unix/make-direnv-less-noisy.md)
- [Manually Pass Two Git Files To Delta](unix/manually-pass-two-git-files-to-delta.md)
- [Map A Domain To localhost](unix/map-a-domain-to-localhost.md)
- [Negative Look-Ahead Search With ripgrep](unix/negative-look-ahead-search-with-ripgrep.md)
- [Occupy A Local Port With Netcat](unix/occupy-a-local-port-with-netcat.md)
@@ -1787,6 +1802,7 @@ _1534 TILs and counting..._
- [See Overlaps For A Set Of Time Zones](workflow/see-overlaps-for-a-set-of-time-zones.md)
- [Send A Message To A Discord Channel](workflow/send-a-message-to-a-discord-channel.md)
- [Set Recurring Reminders In Slack](workflow/set-recurring-reminders-in-slack.md)
- [Show Linting Errors In Zed](workflow/show-linting-errors-in-zed.md)
- [Toggle Between Stories In Storybook](workflow/toggle-between-stories-in-storybook.md)
- [Update asdf Plugins With Latest Package Versions](workflow/update-asdf-plugins-with-latest-package-versions.md)
- [View The PR For The Current GitHub Branch](workflow/view-the-pr-for-the-current-github-branch.md)

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@@ -0,0 +1,43 @@
# Better Diffs With Delta
A `git diff` from the command line is relatively bare bones. It shows you
removed lines and added lines that make up a changeset with the former text in
red and the later text in green. All other contextual text is in white. I've
found this to be good enough for most of the life of my git usage. I've been
missing out though.
By using [`delta`](https://github.com/dandavison/delta) as the pager and diff
filter for `git`, I get a bunch of nice visual improvements.
- Removals and additions are red and green shaded backgrounds
- Syntax highlighting for most languages
- Highlight specific part of a line that has changed
- Visual spacing and layout is clearer
To get all of this, all I had to do was install `delta`:
```bash
$ brew install delta
```
And then add `delta` as both the _core_ pager and `diffFilter` in my global git
config file:
```
[core]
pager = delta
[interactive]
singleKey = true # unrelated, but nice to have
diffFilter = delta --color-only
```
It's also recommended that you use `zdiff3` for your merge conflict style,
which I already had:
```
[merge]
conflictstyle = zdiff3
```
Once you have ths all configred, try a `git diff` or `git add --patch` and see
how much more visual info you get.

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@@ -0,0 +1,39 @@
# Fix Whitespace Errors Throughout Branch Commits
Let's say we've been working on some changes to our repository on a branch.
We've made several commits. We are close to putting up a PR, but we want to
make sure everything is tidied up.
We run a check and see that there are some whitespace errors that should be
fixed.
```bash
$ git diff main --check
README.md:1: trailing whitespace.
+# git-playground
script.sh:9: trailing whitespace.
+
```
This post isn't able to show the highlighted whitespace errors, but we can see
the warnings above.
Rather than cluttering things with an additional commit that fixes these errors
or manually cleaning up each commit, we can ask `git` to fix it for us.
```bash
$ git rebase --whitespace=fix main
```
That will do a manual rebase of each commit addressing the whitespace errors.
We can run the error check again and see no output, which means we are good to
go.
```bash
$ git diff main --check
```
See the section on `--whitespace` in `man git-apply` for more details.
[source](https://git-scm.com/book/en/v2/Customizing-Git-Git-Configuration)

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@@ -0,0 +1,30 @@
# Highlight Extra Whitespace In Diff Output
When running a `git diff` (or `git add --patch`) I'll sometimes come across
lines that don't have any visible changes. This is usually because some
whitespace characters were either added (on accident) or removed (often by a
autoformatter).
Depending on the `core.whitespace` config, you'll probably see at least some of
the whitespace errors that git provides. By default, git only highlights
whitespace errors on added (`new`) lines. However if some extra whitespace was
originally committed and is now being removed, it won't be highlighted on the
`old` line in the diff.
We can have git always highlight whitespace errors by setting
`wsErrorHighlight` to `all` in the global git config.
```bash
$ git config --global diff.wsErrorHighlight all
```
Which updates the global gitconfig file with the following line:
```
[diff]
wsErrorHighlight = all
```
The `all` option is a shorthand for `old,new,context`.
See `man git-diff` for more details.

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@@ -0,0 +1,23 @@
# Use External Diff Tool Like Difftastic
Assuming we already have a tool like `difft`
([difftastic](https://difftastic.wilfred.me.uk/introduction.html)) available on
our machine, we can use it as a diff viewer for the various `git` commands that
display a diff.
This requires a manual override which involve two pieces — an inline
configuration of `diff.external` specifying the binary of the external differ
and the `--ext-diff` flag which tells these commands to use the external diff
binary.
Here is what `git show` looks like with `difft`:
```bash
$ git -c diff.external=difft show --ext-diff
```
Without the `--ext-diff` flag, it will fallback to the default differ despite
`diff.external` being set.
See `man git-diff` and friends for the `--ext-diff` flag. See `man git-config`
for `diff.external`.

View File

@@ -23,11 +23,11 @@ version from my `.tool-versions` file with a step that uses `set-output`.
- name: Read Node.js version to install from `.tool-versions`
id: nodejs
run: >-
echo "::set-output name=NODE_VERSION::$(
echo "NODE_VERSION=$(
cat .tool-versions |
grep nodejs |
sed 's/nodejs \(.*\)$/\1/'
)"
)" >> $GITHUB_OUTPUT
```
`echo` runs the command in the string which sets `NODE_VERSION` as an output
@@ -45,4 +45,4 @@ This output value can be referenced in a later step.
`steps` has a reference to the `nodejs` step (note the `id` above) which then
has `outputs` like the `NODE_VERSION`.
[source](https://docs.github.com/en/actions/reference/workflow-commands-for-github-actions#using-workflow-commands-to-access-toolkit-functions)
[source](https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#setting-an-output-parameter)

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@@ -0,0 +1,41 @@
# Check If Cobra Flag Was Set
When using [Cobra](https://github.com/spf13/cobra) to define a CLI, we can
specify a flag for a command like so:
```go
var Seed int64
myCmd.PersistentFlags().Int64VarP(&Seed, "seed", "", -1, "set a seed")
```
This `--seed` flag has a _default_ of `-1`. If the flag isn't specified, then
when we access that flag's value, we'll get `-1`.
But how do we differentiate between the _default_ `-1` and someone passing `-1`
to the `--seed` flag when running the program?
In the command definition, we can look at the flags and see, by name, if
specific ones were changed by user input rather than being the defaults.
```go
myCommand := &cobra.Command{
// coommand setup ...
Run: func(cmd *cobra.Command, args []string) {
if cmd.Flags().Changed("seed") {
seed, err := cmd.Flags().GetInt64("seed")
if err != nil {
fmt.Println("Seed flag is missing from `cmdFlags()`")
os.Exit(1)
}
fmt.Printf("Seed was set to %d\n", seed)
} else {
fmt.Println("Seed was not set")
}
}
}
```
If we don't want to rely on the default and instead want to specify some other
behavior when the flag is not manually set by the user, we can detect that
scenario like this.

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@@ -0,0 +1,44 @@
# Create A Slice From An Array
Slices in Go are a flexible abstraction over arrays. We can create a slice from
an array with the `[n:m]` _slicing_ syntax. We specify the left and right
(exclusive) bounds of the array that we want to create the slice relative to.
We can exclude the lower bound which translates to the `0` index of the array.
We can exclude the left bound which translates to the end of the array. We can
even exclude both ends of the _slicing_ syntax which means creating a slice of
the entire array.
Here is an example of each of those:
```go
package main
import "fmt"
func main() {
arr := [...]string{
"taco",
"burrito",
"torta",
"enchilada",
"quesadilla",
"pozole",
}
firstTwo := arr[:2]
lastTwo := arr[len(arr)-2:]
all := arr[:]
fmt.Println("First two:", firstTwo)
// First two: [taco burrito]
fmt.Println("Last two:", lastTwo)
// Last two: [quesadilla pozole]
fmt.Println("All:", all)
// All: [taco burrito torta enchilada quesadilla pozole
}
```
[source](https://go.dev/blog/slices-intro#slices)

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@@ -0,0 +1,59 @@
# Detect If Stdin Comes From A Redirect
Reading lines of input from `stdin` is flexible. And we may need our program to
behave differently depending on where that input is coming from. For instance,
if data is redirected or piped to our program, we scan and process it directly.
Otherwise, we need to prompt the user to enter in specific info and go from
there.
We can detect whether [`os.Stdin`](https://pkg.go.dev/os#pkg-variables) is
being piped to, redirected to, or whether we should prompt the user by looking
at the file mode descriptor of
[`os.Stdin.Stat()`](https://pkg.go.dev/os#File.Stat).
```go
package main
import (
"bufio"
"fmt"
"os"
)
func main() {
file, err := os.Stdin.Stat()
if err != nil {
fmt.Printf("Error checking stdin: %v\n", err)
os.Exit(1)
}
fromTerminal := (file.Mode() & os.ModeCharDevice) != 0
fromAPipe := (file.Mode() & os.ModeNamedPipe) != 0
if fromTerminal {
fmt.Println("This is Char Device mode, let's prompt user for input")
termScanner := bufio.NewScanner(os.Stdin)
for termScanner.Scan() {
fmt.Printf("- %s\n", termScanner.Text())
break;
}
} else if fromAPipe {
fmt.Println("This is Named Pipe mode, contents piped in")
pipeScanner := bufio.NewScanner(os.Stdin)
for pipeScanner.Scan() {
fmt.Printf("- %s\n", pipeScanner.Text())
}
} else {
fmt.Println("This means the input was redirected")
redirectScanner := bufio.NewScanner(os.Stdin)
for redirectScanner.Scan() {
fmt.Printf("- %s\n", redirectScanner.Text())
}
}
}
```
If `os.ModeCharDevice` then we are connected to a character device, like the
terminal. We can see if input is being piped in by checking against
`os.ModeNamedPipe`. Otherwise, there are a variety of file modes and I'm
willing to assume we're dealing with a regular file redirect at that point.

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@@ -0,0 +1,49 @@
# Deterministically Seed A Random Number Generator
If you need a random number in Go, you can always reach for the various
functions in the `rand` package.
```go
package main
import (
"fmt"
"math/rand"
)
func main() {
for range 5 {
roll := rand.Intn(6) + 1
fmt.Printf("- %d\n", roll)
}
}
```
Each time I run that, I get a random set of values. Often in programming, we
want some control over the randomness. We want to _seed_ the randomness so that
it is deterministic. We want random, but the kind of random where we know how
we got there.
```go
package main
import (
"fmt"
"math/rand"
)
func main() {
seed := int64(123)
src := rand.NewSource(seed)
rng := rand.New(src)
for range 5 {
roll := rng.Intn(6) + 1
fmt.Printf("- %d\n", roll)
}
}
```
In this second snippet, we create a `Source` with a specific seed value that we
can use with a custom `Rand` struct. We can then deterministically get random
numbers from it.

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@@ -0,0 +1,51 @@
# Format Date And Time With Time Constants
The Go [`time` package](https://pkg.go.dev/time) has a [`Format`
function](https://pkg.go.dev/time#Time.Format) for displaying the parts of a
date and time in standard and custom ways. It works a bit different than you
might be used to from other languages. Rather than using `strftime` identifiers
like in this string `"%B %d, %Y"`, there is a canonical date that is used as a
reference point.
That canonical date is from Janary 2nd, 2006. That was a Monday. It was at 5
seconds after 3:04PM. The Unix format of it looks like `"Mon Jan _2 15:04:05
MST 2006"`.
```
package main
import (
"fmt"
"time"
)
func main() {
// This specific time pulled from `time.Format` docs
t, _ := time.Parse(time.UnixDate, "Wed Feb 25 11:06:39 PST 2015")
// Reference date and time:
// "Mon Jan _2 15:04:05 MST 2006"
strf1 := t.Format("|2006|02|01|03:04:05|Day: Mon|")
fmt.Println("strf1:", strf1)
// strf1: |2015|25|02|11:06:39|Day: Wed|
strf2 := t.Format(time.DateTime)
strf3 := t.Format(time.RubyDate)
strf4 := t.Format(time.Kitchen)
fmt.Println("DateTime:", strf2) // DateTime: 2015-02-25 11:06:39
fmt.Println("RubyDate:", strf3) // RubyDate: Wed Feb 25 11:06:39 +0000 2015
fmt.Println("Kitchen:", strf4) // Kitchen: 11:06AM
}
```
Though there are a [variety of useful formatting
constants](https://pkg.go.dev/time#pkg-constants) already available like
`DateTime`, `RubyDate`, `Kitchen`, etc., we can also define our own formatting
string by using the reference values for each part of a date and time.
If you want to reference the year, whether as `YYYY` or `YY`, it is always
going to be a form of `2006`, so `2006` or `06` respectively. Even though the
above time variable is in February, our format strings will always need to use
one of `Jan`, `January`, `01` or `1`.

View File

@@ -0,0 +1,32 @@
# Produce The Zero Value For A Generic Type
While writing a _pop_ function that would work with slices of a generic type, I
ran into the issue of needing to produce a zero value of type `T` when
returning early for an empty slice.
The way to arbitrarily get the zero value of a generic in Go is with `*new(T)`.
I was able to use this in my `Pop` function like so:
```go
func Pop[T any](slice []T) (T, error) {
if len(slice) == 0 {
return *new(T), fmt.Errorf("cannot pop an empty slice")
}
lastItem := slice[len(slice)-1]
slice = slice[:len(slice)-1]
return lastItem, nil
}
```
If this is happening in multiple functions and we want a more self-documenting
approach, we can pull it out into a function `zero`:
```go
func zero[T any]() T {
return *new(T)
}
```

View File

@@ -0,0 +1,39 @@
# Redirect File To Stdin During Delve Debug
I have a go program that accepts input from stdin. The way I've been running
the program as I develop it is to redirect the output of some sample files to
the program.
```bash
$ go run . < sample/001.txt
```
When I then go to debug this program with
[Delve](https://github.com/go-delve/delve), I'd still like to be able to
redirect a file into the program to reproduce the exact behavior I'm seeing.
The following won't work:
```bash
$ dlv debug . < samples/001.txt
Stdin is not a terminal, use '-r' to specify redirects for the target process or --allow-non-terminal-interactive=true if you really want to specify a redirect for Delve
```
Fortunately, `dlv` sees what I'm trying to do and makes a recommendation. The
`-r` flag can be used to specify redirects for the target process. The [`dlv`
redirect
docs](https://github.com/go-delve/delve/blob/master/Documentation/usage/dlv_redirect.md)
explain that `-r` can be passed a `source:destination`. The `source` is `stdin`
by default, but can also be `stdout` and `stderr`.
I can redirect my file into the debugging session of my program like so:
```bash
$ dlv debug . -r stdin:samples/001.txt
```
Or even more succinctly:
```bash
$ dlv debug . -r samples/001.txt
```

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@@ -0,0 +1,58 @@
# Write A Custom Scan Function For File IO
By default a [`bufio.Scanner`](https://pkg.go.dev/bufio#Scanner) will scan
input line-by-line. In other words, splitting on newlines such that each
iteration will emit everything up to the next newline character.
We can write our own `SplitFunc` and override the default one by calling
`scanner.Split` with it. Our custom scan function needs to match the type
signature of [`SplitFunc`](https://pkg.go.dev/bufio#SplitFunc).
Here is a custom one that emits each individual character but omits the
newlines.
```go
func ScanChar(data []byte, atEOF bool) (int, []byte, error) {
if atEOF || len(data) == 0 {
return 0, nil, nil
}
start := 0
for start < len(data) {
if !utf8.FullRune(data[start:]) {
return 0, nil, nil
}
r, size := utf8.DecodeRune(data[start:])
if r == utf8.RuneError {
return 0, nil, fmt.Errorf("invalid UTF-8 encoding")
}
if r != '\n' {
return start + size, data[start:start+size], nil
}
// found a \n, advance the start position
start += size
}
return start, nil, nil
}
```
We can then use thi `ScanChar` function with a `bufio.Scanner` like so:
```go
func ReadFileByCharacter(file io.Reader) {
scanner := bufio.NewScanner(file)
// override default SplitFunc
scanner.Split(scanChar)
for scanner.Scan() {
char := scanner.Text()
fmt.Printf("- %s\n", char)
}
}
```

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# Clamp To An Endless Range
The
[`Comparable#clamp`](https://ruby-doc.org/3.3.6/Comparable.html#method-i-clamp)
method allows us to specify the bounds of a value we want. If the target value
is between the bounds, then we get that value. Otherwise, we gets the nearest
end of the bounds.
We can even pass a range to `#clamp` instead of separate lower and upper bound
values. Because Ruby has beginless and endless ranges, this gives us the
ergonomics to, say, clamp to any non-negative value with a `0..` endless range.
Here is what that looks like:
```ruby
> 22.clamp(0..)
=> 22
> (-33).clamp(0..)
=> 0
> 0.clamp(0..)
=> 0
```

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# Explore The Database Schema
The first thing I like to do when connecting to a database is get a quick lay
of the land. What are the tables and what do they look like?
I can list all tables with the `.tables` dot-command.
```sql
sqlite> .tables
ingredient_amounts ingredients recipes
```
I can then look at the `create table` statement for specific tables to see what
their schema looks like:
```sql
sqlite> .schema recipes
CREATE TABLE recipes (
id integer primary key,
name varchar not null,
description text not null,
instructions text not null
);
```
The `.schema` dot-command can also be used without any argument and it will
display the schema for all tables of all connected databases.
Run `.help` from the `sqlite3` prompt for more dot-command options.
[source](https://www.sqlite.org/cli.html#querying_the_database_schema)

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# Manually Pass Two Git Files To Delta
I recently [wired up `delta` as my default pager and differ for
`git`](git/better-diffs-with-delta.md). However, when I installed `delta`, I
first wanted to see what its diff output looked like.
How can I pass two versions of the same file from `git` to `delta`?
I can show the current contents of a file with `git show` referencing the
`HEAD` commit.
```bash
$ git show HEAD:main.go
```
Similiarly, I can show the contents of that file _one_ commit ago with `HEAD~`.
```bash
$ git show HEAD~:main.go
```
I can then pass each of those commands as virtual files to `delta` using the
`<()` syntax. The older file goes first and the newer second.
```bash
$ delta <(git show HEAD~:main.go) <(git show HEAD:main.go)
```
That works and comes in handy if you need to compare two things that aren't
necessarily files or aren't necessarily under version control. However, in
hindsight, I'd say it is easier to add delta as the pager and differ and try it
out directly.

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# Show Linting Errors In Zed
When working in a language like TypeScript or Go, the language server tooling
in [Zed](https://zed.dev/) can draw my attention to errors in my code. This
could be an unrecognized function or variable, a type error, or a syntax error.
When these linting errors are detected, the editor underlines them with a red
squiggly. I can hover over offending token or statement and see what the error
is.
There are also a few mouse-free ways to do this.
First, I can hit `F8` to jump to the next one of these errors in the current
file. That will move my cursor to that location and display a small overlay
with the error details.
Second, assuming Vim mode, I can navigate my cursor over a specific highlighted
token and then hit `Shift+k`. That will pop open the same small overlay to
display the error details.
Third, I can hit `Cmd+Shift+M` to open the _Project Diagnostics_ tab which
displays a series of file buffer results with the offending lines and the error
description.