I am having a similar issue to this person: Problems while creating a deps.edn file
However, I'm on MacOS and trying to follow the book and use deps.edn instead of leiningen, so I wasn't able to solve my issue from reading the answers in that post.
I'm using my terminal window and just text files, or Emacs.
Within the terminal, I created a folder called tennisProject. Then I created 2 files, deps.edn and tennisProject.clj inside that folder. Then I put the csv file of tennis data in that folder.
Then I go back to the terminal and restart it. I make tennisProject the current directory. I type in "clj" to start a repl. Then I do (in-ns 'packt-clj.tennisProject) to get into the right namespace. Then, I type (first-match "match_scores_1991-2016_unindexed_csv.csv"), and I get an error:
Syntax error compiling at (REPL:1:1). Unable to resolve symbol: first-match in this context
The contents are as follows (I copied and pasted from the book).
deps.edn:
{:deps
{org.clojure/data.csv {:mvn/version "1.0.0"}
semantic-csv/semantic-csv {:mvn/version "0.2.1-alpha1"}}}
tennisProject.clj:
(ns packt-clj.tennisProject
(:require
[clojure.data.csv :as csv]
[clojure.java.io :as io]
[semantic-csv.core :as sc]))
(defn first-match [csv]
(with-open [r (io/reader csv)]
(->> (csv/read-csv r)
sc/mappify
first)))
I have a few things different than the book: I changed the name from tennis to tennisProject because I kept making new folders after getting errors. I also changed the data.csv version from "0.1.4" to "1.0.0" because that's what was in the answer I linked, but that didn't resolve my issue. Then I also have semantic-csv/semantic-csv but in the book it's just semantic-csv. I changed that because the repl advised me to make the change.
If I just require the dependencies one by one in the repl, and define the function in the repl, everything works fine, but I really want to understand how all these files work together and I appreciate your help!
By default, the Clojure CLI / deps.edn assumes your source code is going to be in a tree under a folder called src.
The namespace in a Clojure file must "match" its filepath relative to src so for packt-clj.tennisProject, the file should be src/packt_clj/tennisProject.clj -- note the - in a namespace corresponds to an _ in the filepath.
If you reorganize your project like that, and restart your REPL, you should be able to require your code and work with it.
As a stylistic note, we don't use camelCase much in Clojure: it would be more idiomatic to have tennis-project as the namespace (which means tennis_project.clj as the filename).
(edited to add this example session)
(! 556)-> pwd
/Users/sean/clojure/tennisProject
(! 557)-> ls
deps.edn example.csv src
(! 558)-> tree
.
|____deps.edn
|____example.csv
|____src
| |____packt_clj
| | |____tennisProject.clj
(! 559)-> clj
Clojure 1.10.3
user=> (require 'packt-clj.tennisProject)
nil
user=> (in-ns 'packt-clj.tennisProject)
#object[clojure.lang.Namespace 0x128c502c "packt-clj.tennisProject"]
packt-clj.tennisProject=> (first-match "example.csv")
{:some "42", :headers "A value", :in "1", :this "2", :file "3.333"}
packt-clj.tennisProject=> ^D
(! 560)-> cat src/packt_clj/tennisProject.clj
(ns packt-clj.tennisProject
(:require
[clojure.data.csv :as csv]
[clojure.java.io :as io]
[semantic-csv.core :as sc]))
(defn first-match [csv]
(with-open [r (io/reader csv)]
(->> (csv/read-csv r)
sc/mappify
first)))
(! 561)-> cat example.csv
some,headers,in,this,file
42,"A value",1,2,3.333