Isolate each example in its own workspace. (#50)

It's time to make space for more than one example!

This PR adds a skeleton of what will become the `realworld` API
implementation for `pavex`.
To make examples realistic, I restructured the `examples` folder in such
a way that each example gets its own workspace. A new script (`ci.sh`)
has been added to make it easy to check all examples for correctness.

.gitignore

@@ -1,6 +1,6 @@
-/test-target
-/ui_test_envs
-/target
+/libs/ui_test_envs
+/libs/target
+/examples/**/target
 /vendor
 .DS_Store
 *.snap

CONTRIBUTING.md

@@ -39,9 +39,19 @@ The generated code or the graph diagnostics may not match our expectations.
 The test runner will save the unexpected output in a file named like the expectation file with an additional `.snap` suffix. You can then choose to update the saved snapshot via our utility CLI:
 
 ```bash
-# It must be run from the root folder of the workspace
+# It must be run from the root folder of the libs workspace
 cargo r --bin snaps
 ```
 
 It will cycle through all `.snap` files and print the changeset with respect to our previous expectations.  
 You will then be prompted to decide if you want to update the saved snapshot to match the new value or if you prefer to keep it as it.
+
+# Checking examples
+
+Each example project under the `examples` folder is its own workspace.  
+The easiest way to check that everything compiles and works as expected is to rely on the `./ci.sh` script at root of the repository.  
+It runs whatever `cargo` command you specify against all workspaces in this project (i.e. `libs` + all examples).
+
+E.g. `./ci.sh check` will run `cargo check` in each workspace. 
+
+It will also forward any flag to `cargo`—e.g. `./ci.sh check --all-features` will run `cargo check --all-features` in all workspaces.

README.md

@@ -109,14 +109,14 @@ We publish project updates every 4-6 weeks:
 
 You can see `pavex` at work in the [`/examples` folder](./examples):
 
-- In [`examples/app_blueprint/src/lib.rs`](./examples/app_blueprint/src/lib.rs) we specify the app's behavior in
+- In [`examples/skeleton/app_blueprint/src/lib.rs`](./examples/skeleton/app_blueprint/src/lib.rs) we specify the app's behavior in
   a `Blueprint`—
   the endpoints it exposes and their request handlers, as well as the required constructors for the application state;
-- In [`examples/app_blueprint/src/bin.rs`](./examples/app_blueprint/src/bin.rs) we serialize the `Blueprint` and
+- In [`examples/skeleton/app_blueprint/src/bin.rs`](./examples/skeleton/app_blueprint/src/bin.rs) we serialize the `Blueprint` and
   invoke `pavex`'s CLI to generate the server code that will execute at runtime, which you can find in
-  [`examples/generated_app/src/lib.rs`](./examples/generated_app/src/lib.rs).
+  [`examples/skeleton/generated_app/src/lib.rs`](./examples/skeleeton/generated_app/src/lib.rs).
 
-In [`examples/app_blueprint/blueprint.ron`](./examples/app_blueprint/blueprint.ron) you can have a peek at what
+In [`examples/app_blueprint/blueprint.ron`](./examples/skeleton/app_blueprint/blueprint.ron) you can have a peek at what
 the `Blueprint` looks like when serialized.
 
 ## Architectural Overview

ci.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+# Check that the first argument is not empty
+if [ -z "$1" ]; then
+    echo "Usage: ./ci.sh <cargo command> [<cargo options>]"
+    echo "Runs a 'cargo' command on all Rust workspaces in the current directory and its subdirectories."
+    exit 1
+fi
+
+# Get the cargo command and options from the arguments
+CARGO_CMD=$1
+shift
+CARGO_OPTS=${*:-""}
+
+# Find all directories that contain a Cargo.toml file and have a [workspace] section in the file
+WORKSPACES=$(find . -type f -name Cargo.toml -exec grep -q "\[workspace\]" {} \; -print | xargs -n1 dirname | sort | uniq)
+
+# Exclude test directory 
+TOP_WORKSPACES=()
+for workspace in $WORKSPACES; do
+    if [[ ! "$workspace" =~ "/ui_test_envs/" ]]; then
+        TOP_WORKSPACES+=("$workspace")
+    fi
+done
+
+# Iterate over each workspace and run `cargo check`
+for workspace in "${TOP_WORKSPACES[@]}"; do
+    echo "Running 'cargo $CARGO_CMD $CARGO_OPTS' in workspace: $workspace"
+    (cd "$workspace" && cargo $CARGO_CMD $CARGO_OPTS)
+done

examples/realworld/Cargo.toml

@@ -0,0 +1,2 @@
+[workspace]
+members = ["api_bp"]

examples/realworld/api_bp/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "api_bp"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]