Further side-quest to become comfortable with IEx/mix/dbg/pry. Learning commandline debugging since I’ve not been able to figure out how to launch a debuggable commandline program from VSCode.

IEx

A quick introduction to IEx functionality: 8 + 1 things….

# Start and run the mix script:
iex -S mix

# Run specific function
iex -S mix run -e "Issues.CLI.run(['arg1', 'arg2'])"

# Recompile changed mix project files.
recompile

Mix

# Create new project tree
mix new project_name

mix test

# Show dependencies
mix deps

# Fetch dependencies
mix deps.get

# Run Chapter 13 exercise:
mix run -e 'Issues.CLI.run(["rgacote", "ProgrammingElixirExercises"])'

Debugging

Use the Elixir dbg() statement.

IEx drops you into pry.

# See variable bindings
binding()

# Execution stack
whereami()

Cannot continue after a piped dbg() because it returns ``:ok`.
Use break! from IEx.
```
break! Issues.CLI.run/1
```
Pry is not a debugger. You can only examine local information.

Creating a CLI

Builds the commandline interface in the home directory.

Add a main(argv) function to the CLI module.
Add line to mix.exs def project section:
```
escript: [main_module: Issues.CLI],
```
Build:
```
mix escript.build
```

All notes and comments are my own opinion. Follow me at @rgacote@genserver.social