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
Working through the steps (checking that the Info,plist matches exactly), run the demo game and what appears is grey but does not fill th...
New
Title: Hands-on Rust: question about get_component (page 295)
(feel free to respond. “You dug you’re own hole… good luck”)
I have somet...
New
Hi Travis! Thank you for the cool book! :slight_smile:
I made a list of issues and thought I could post them chapter by chapter. I’m rev...
New
I can’t setup the Rails source code. This happens in a working directory containing multiple (postgres) Rails apps.
With:
ruby-3.0.0
s...
New
I found an issue in Chapter 7 regarding android:backgroundTint vs app:backgroundTint.
How to replicate:
load chapter-7 from zipfile i...
New
Hi all,
currently I wonder how the Tailwind colours work (or don’t work).
For example, in app/views/layouts/application.html.erb I have...
New
Book: Programming Phoenix LiveView, page 142 (157/378), file lib/pento_web/live/product_live/form_component.ex, in the function below:
d...
New
When running the program in chapter 8, “Implementing Combat”, the printout Health before attack was never printed so I assumed something ...
New
I am using Android Studio Chipmunk | 2021.2.1 Patch 2
Build #AI-212.5712.43.2112.8815526, built on July 10, 2022
Runtime version: 11.0....
New
Other popular topics
What chair do you have while working… and why?
Is there a ‘best’ type of chair or working position for developers?
New
New
New
New
Saw this on TikTok of all places! :lol:
Anyone heard of them before?
Lite:
New
Rails 7 completely redefines what it means to produce fantastic user experiences and provides a way to achieve all the benefits of single...
New
Author Spotlight
Erin Dees
@undees
Welcome to our new author spotlight! We had the pleasure of chatting with Erin Dees, co-author of ...
New
Hello,
I’m a beginner in Android development and I’m facing an issue with my project setup. In my build.gradle.kts file, I have the foll...
New
This is a very quick guide, you just need to:
Download LM Studio: https://lmstudio.ai/
Click on search
Type DeepSeek, then select the o...
New
Curious what kind of results others are getting, I think actually prefer the 7B model to the 32B model, not only is it faster but the qua...
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /emacs
- /haskell
- /java
- /svelte
- /onivim
- /typescript
- /kotlin
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /elm
- /flutter
- /vscode
- /ash
- /html
- /opensuse
- /zig
- /centos
- /deepseek
- /php
- /scala
- /react-native
- /lisp
- /textmate
- /sublime-text
- /nixos
- /debian
- /agda
- /django
- /kubuntu
- /deno
- /arch-linux
- /nodejs
- /ubuntu
- /revery
- /manjaro
- /spring
- /lua
- /diversity
- /julia
- /markdown
- /c








