From cc268ccb4fa2f7573694af189089ca8f788b0597 Mon Sep 17 00:00:00 2001
From: Kjetil Orbekk <kj@orbekk.com>
Date: Wed, 16 Jun 2021 07:20:41 -0400
Subject: csv parser example

---
 xmd/Cargo.toml   | 11 +++++++++++
 xmd/numbers.csv  |  5 +++++
 xmd/src/csv.pest |  3 +++
 xmd/src/lib.rs   |  8 ++++++++
 xmd/src/main.rs  | 34 ++++++++++++++++++++++++++++++++++
 5 files changed, 61 insertions(+)
 create mode 100644 xmd/Cargo.toml
 create mode 100644 xmd/numbers.csv
 create mode 100644 xmd/src/csv.pest
 create mode 100644 xmd/src/lib.rs
 create mode 100644 xmd/src/main.rs

diff --git a/xmd/Cargo.toml b/xmd/Cargo.toml
new file mode 100644
index 0000000..fa4ca6a
--- /dev/null
+++ b/xmd/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "xmd"
+version = "0.1.0"
+authors = ["Kjetil Orbekk <kj@orbekk.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+pest = "2.0"
+pest_derive = "2.0"
diff --git a/xmd/numbers.csv b/xmd/numbers.csv
new file mode 100644
index 0000000..20a98c9
--- /dev/null
+++ b/xmd/numbers.csv
@@ -0,0 +1,5 @@
+65279,1179403647,1463895090
+3.1415927,2.7182817,1.618034
+-40,-273.15
+13,42
+65537
diff --git a/xmd/src/csv.pest b/xmd/src/csv.pest
new file mode 100644
index 0000000..bb9af51
--- /dev/null
+++ b/xmd/src/csv.pest
@@ -0,0 +1,3 @@
+field = { (ASCII_DIGIT | "." | "-")+ }
+record = { field ~ ("," ~ field)* }
+file = { SOI ~ (record ~ ("\r\n" | "\n"))* ~ EOI }
diff --git a/xmd/src/lib.rs b/xmd/src/lib.rs
new file mode 100644
index 0000000..8c98a57
--- /dev/null
+++ b/xmd/src/lib.rs
@@ -0,0 +1,8 @@
+extern crate pest;
+#[macro_use]
+extern crate pest_derive;
+
+use pest::Parser;
+#[derive(Parser)]
+#[grammar = "csv.pest"]
+pub struct CSVParser;
diff --git a/xmd/src/main.rs b/xmd/src/main.rs
new file mode 100644
index 0000000..42406df
--- /dev/null
+++ b/xmd/src/main.rs
@@ -0,0 +1,34 @@
+use pest::Parser;
+use std::fs;
+
+use xmd::CSVParser;
+use xmd::Rule;
+
+fn main() {
+    let unparsed_file = fs::read_to_string("numbers.csv").expect("cannot read file");
+
+    let file = CSVParser::parse(Rule::file, &unparsed_file)
+        .expect("unsuccessful parse")
+        .next()
+        .unwrap();
+
+    let mut sum: f64 = 0.0;
+    let mut records: i64 = 0;
+
+    for record in file.into_inner() {
+        match record.as_rule() {
+            Rule::record => {
+                records += 1;
+
+                for field in record.into_inner() {
+                    sum += field.as_str().parse::<f64>().unwrap();
+                }
+            }
+            Rule::EOI => (),
+            _ => unreachable!(),
+        }
+    }
+
+    println!("Sum of fields: {}", sum);
+    println!("Number of records: {}", records);
+}
-- 
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