Merge pull request #134 from codecrafters-io/andy/feat

Add Elixir to SQLite

Author: andy1li

compiled_starters/elixir/.codecrafters/compile.sh

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+#!/bin/sh
+#
+# This script is used to compile your program on CodeCrafters
+#
+# This runs before .codecrafters/run.sh
+#
+# Learn more: https://codecrafters.io/program-interface
+
+set -e # Exit on failure
+
+mix escript.build
+mv codecrafters_sqlite /tmp/codecrafters-build-sqlite-elixir

compiled_starters/elixir/.codecrafters/run.sh

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+#!/bin/sh
+#
+# This script is used to run your program on CodeCrafters
+#
+# This runs after .codecrafters/compile.sh
+#
+# Learn more: https://codecrafters.io/program-interface
+
+set -e # Exit on failure
+
+exec /tmp/codecrafters-build-sqlite-elixir "$@"

compiled_starters/elixir/.formatter.exs

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+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

compiled_starters/elixir/.gitattributes

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+* text=auto

compiled_starters/elixir/.gitignore

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+# Database files used for testing
+*.db
+
+# Ignore the compiled binary
+/codecrafters_sqlite
+
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+app-*.tar
+

compiled_starters/elixir/README.md

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+![progress-banner](https://codecrafters.io/landing/images/default_progress_banners/sqlite.png)
+
+This is a starting point for Elixir solutions to the
+["Build Your Own SQLite" Challenge](https://codecrafters.io/challenges/sqlite).
+
+In this challenge, you'll build a barebones SQLite implementation that supports
+basic SQL queries like `SELECT`. Along the way we'll learn about
+[SQLite's file format](https://www.sqlite.org/fileformat.html), how indexed data
+is
+[stored in B-trees](https://jvns.ca/blog/2014/10/02/how-does-sqlite-work-part-2-btrees/)
+and more.
+
+**Note**: If you're viewing this repo on GitHub, head over to
+[codecrafters.io](https://codecrafters.io) to try the challenge.
+
+# Passing the first stage
+
+The entry point for your SQLite implementation is in `lib/main.ex`. Study and
+uncomment the relevant code, and push your changes to pass the first stage:
+
+```sh
+git commit -am "pass 1st stage" # any msg
+git push origin master
+```
+
+Time to move on to the next stage!
+
+# Stage 2 & beyond
+
+Note: This section is for stages 2 and beyond.
+
+1. Ensure you have `mix` installed locally
+1. Run `./your_program.sh` to run your program, which is implemented in
+   `lib/main.ex`.
+1. Commit your changes and run `git push origin master` to submit your solution
+   to CodeCrafters. Test output will be streamed to your terminal.
+
+# Sample Databases
+
+To make it easy to test queries locally, we've added a sample database in the
+root of this repository: `sample.db`.
+
+This contains two tables: `apples` & `oranges`. You can use this to test your
+implementation for the first 6 stages.
+
+You can explore this database by running queries against it like this:
+
+```sh
+$ sqlite3 sample.db "select id, name from apples"
+1|Granny Smith
+2|Fuji
+3|Honeycrisp
+4|Golden Delicious
+```
+
+There are two other databases that you can use:
+
+1. `superheroes.db`:
+   - This is a small version of the test database used in the table-scan stage.
+   - It contains one table: `superheroes`.
+   - It is ~1MB in size.
+1. `companies.db`:
+   - This is a small version of the test database used in the index-scan stage.
+   - It contains one table: `companies`, and one index: `idx_companies_country`
+   - It is ~7MB in size.
+
+These aren't included in the repository because they're large in size. You can
+download them by running this script:
+
+```sh
+./download_sample_databases.sh
+```
+
+If the script doesn't work for some reason, you can download the databases
+directly from
+[codecrafters-io/sample-sqlite-databases](https://github.com/codecrafters-io/sample-sqlite-databases).

compiled_starters/elixir/codecrafters.yml

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+# Set this to true if you want debug logs.
+#
+# These can be VERY verbose, so we suggest turning them off
+# unless you really need them.
+debug: false
+
+# Use this to change the Elixir version used to run your code
+# on Codecrafters.
+#
+# Available versions: elixir-1.18
+language_pack: elixir-1.18

compiled_starters/elixir/download_sample_databases.sh

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+#!/bin/sh
+
+echo "Downloading superheroes.db: ~1MB (used in stage 7)"
+curl -Lo superheroes.db https://raw.githubusercontent.com/codecrafters-io/sample-sqlite-databases/master/superheroes.db
+
+echo "Downloading companies.db: ~7MB (used in stage 8)"
+curl -Lo companies.db https://raw.githubusercontent.com/codecrafters-io/sample-sqlite-databases/master/companies.db
+
+echo "Sample databases downloaded."

compiled_starters/elixir/lib/main.ex

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+defmodule CLI do
+  def main(args) do
+    case args do
+      [database_file_path, command] ->
+        case command do
+          ".dbinfo" ->
+            file = File.open!(database_file_path, [:read, :binary])
+
+            # You can use print statements as follows for debugging, they'll be visible when running tests.
+            IO.puts(:stderr, "Logs from your program will appear here!")
+            
+            # Uncomment this to pass the first stage
+            # :file.position(file, 16) # Skip the first 16 bytes of the header
+            # <<page_size::16>> = IO.binread(file, 2)
+            # IO.puts("database page size: #{page_size}")
+        end
+      _ ->
+        IO.puts("Usage: your_program <database_file> <command>")
+    end
+  end
+end

compiled_starters/elixir/mix.exs

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+defmodule App.MixProject do
+  # NOTE: You do not need to change anything in this file.
+  use Mix.Project
+
+  def project do
+    [
+      app: :codecrafters_sqlite,
+      version: "1.0.0",
+      elixir: "~> 1.18",
+      start_permanent: Mix.env() == :prod,
+      deps: deps(),
+      escript: [main_module: CLI]
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+    ]
+  end
+end