mvellandi
Exploring Graphs with Elixir: Out of scope variable won't print (105, 107)
Exploring Graphs with Elixir by @tonyhammond: P.105, 107 — Ch 3 > Visualizing Graphs > Rendering with Graphviz
In making the water molecule and after writing a graph file using a variable, we’re told in 2 examples to print out the variable to inspect it using IO.puts
iex> with {:ok, dot} = Graph.to_dot(g) do
...> write_graph(dot, "dot/h2o.dot")
...> end
#GraphCommons.Graph<type: native, file: "...", data: "strict graph {\n...">
iex> IO.puts dot
strict graph {
"O"
"H"
"H"
"H" -- "O" [weight=1]
"H" -- "O" [weight=1]
}
:ok
Maybe it’s just me, but this produces a function dot/0 not found error.
The variable “dot” is probably no longer in scope after having performed the first operation.
To make it print, I moved the print command above write_graph/2 command like so:
iex> with {:ok, dot} = Graph.to_dot(g) do
...> IO.puts dot
...> write_graph(dot, "dot/h2o.dot")
...> end
(graph output...)
#GraphCommons.Graph<type: native, file: "...", data: "strict graph {\n...">
Marked As Solved
tonyhammond
Author of Exploring Graphs with Elixir
Thanks for the catch.
I fixed this by reading it back in from the file store, as so:
iex> IO.puts read_graph(“dot/default.dot”).data
In two places.
Should be in the next beta.
Popular Pragmatic Bookshelf topics
Following the steps described in Chapter 6 of the book, I’m stuck with running the migration as described on page 84:
bundle exec sequel...
New
When I try the command to create a pair of migration files I get an error.
user=> (create-migration "guestbook")
Execution error (Ill...
New
This isn’t directly about the book contents so maybe not the right forum…but in some of the code apps (e.g. turbo/06) it sends a TURBO_ST...
New
Title: Build a Weather Station with Elixir and Nerves: Problem connecting to Postgres with Grafana on (page 64)
If you follow the defau...
New
Hey there,
I’m enjoying this book and have learned a few things alredayd. However, in Chapter 4 I believe we are meant to see the “>...
New
Modern Front-End Development for Rails - application does not start after run bin/setup (page xviii)
After some hassle, I was able to finally run bin/setup, now I have started the rails server but I get this error message right when I vis...
New
Title: Agile Web Development with Rails 7: (page 70)
I am running windows 11 pro with rails 7.0.3 and ruby 3.1.2p20 (2022-04-12 revision...
New
I got this error when executing the plot files on macOS Ventura 13.0.1 with Python 3.10.8 and matplotlib 3.6.1:
programming_ML/code/03_...
New
Getting an error when installing the dependencies at the start of this chapter:
could not compile dependency :exla, "mix compile" failed...
New
@mfazio23
Android Studio will not accept anything I do when trying to use the Transformations class, as described on pp. 140-141. Googl...
New
Other popular topics
Write Elixir tests that you can be proud of. Dive into Elixir’s test philosophy and gain mastery over the terminology and concepts that u...
New
I know that these benchmarks might not be the exact picture of real-world scenario, but still I expect a Rust web framework performing a ...
New
I’ve been hearing quite a lot of comments relating to the sound of a keyboard, with one of the most desirable of these called ‘thock’, he...
New
Thanks to @foxtrottwist’s and @Tomas’s posts in this thread: Poll: Which code editor do you use? I bought Onivim! :nerd_face:
https://on...
New
I have seen the keycaps I want - they are due for a group-buy this week but won’t be delivered until October next year!!! :rofl:
The Ser...
New
In case anyone else is wondering why Ruby 3 doesn’t show when you do asdf list-all ruby :man_facepalming: do this first:
asdf plugin-upd...
New
Think Again 50% Off Sale »
The theme of this sale is new perspectives on familiar topics.
Enter coupon code ThinkAgain2021 at checkout t...
New
A few weeks ago I started using Warp a terminal written in rust. Though in it’s current state of development there are a few caveats (tab...
New
Author Spotlight
Mike Riley
@mriley
This month, we turn the spotlight on Mike Riley, author of Portable Python Projects. Mike’s book ...
New
Hair Salon Games for Girls Fun
Girls Hair Saloon game is mainly developed for kids. This game allows users to select virtual avatars to ...
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /java
- /emacs
- /haskell
- /svelte
- /onivim
- /typescript
- /kotlin
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /flutter
- /elm
- /vscode
- /ash
- /html
- /opensuse
- /zig
- /centos
- /deepseek
- /php
- /scala
- /react-native
- /lisp
- /textmate
- /sublime-text
- /nixos
- /debian
- /agda
- /django
- /deno
- /kubuntu
- /arch-linux
- /nodejs
- /revery
- /ubuntu
- /spring
- /manjaro
- /diversity
- /lua
- /julia
- /markdown
- /slackware








