csv parser example

5 files changed, 61 insertions, 0 deletions

diff --git a/xmd/Cargo.toml b/xmd/Cargo.toml
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+++ b/xmd/Cargo.toml
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+[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
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+++ b/xmd/numbers.csv
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+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
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+++ b/xmd/src/csv.pest
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+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
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+++ b/xmd/src/lib.rs
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+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
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+++ b/xmd/src/main.rs
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+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);
+}