Elnu 1 year ago
parent 23dfa06d15
commit 359c46d776

@ -7,3 +7,5 @@ edition = "2021"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
pest = "2.6.0"
pest_derive = "2.6.0"

@ -0,0 +1,5 @@
65279,1179403647,1463895090
3.1415927,2.7182817,1.618034
-40,-273.15
13,42
65537
1 65279,1179403647,1463895090
2 3.1415927,2.7182817,1.618034
3 -40,-273.15
4 13,42
5 65537

@ -1,5 +1,5 @@
use renrs;
fn main() {
renrs::hello();
renrs::parse("demo.csv");
}

@ -0,0 +1,9 @@
// + indicates one or more times
field = { (ASCII_DIGIT | "." | "-")+ }
// ~ indicates directly followed by
// * indicates zero or more times (optional)
record = { field ~ ("," ~ field)* }
// SOI - start of input
// END - end of input
// There may be trailing newlines at the end
file = { SOI ~ (record ~ ("\r\n" | "\n"))* ~ "\n"* ~ EOI }

@ -1,3 +1,35 @@
pub fn hello() {
println!("Hello, world!");
use std::fs;
use pest::Parser;
use pest_derive::Parser;
#[derive(Parser)]
#[grammar = "csv.pest"]
struct CSVParser;
pub fn parse(file_path: &str) {
let unparsed_file = fs::read_to_string(file_path).expect("cannot find file");
let file = CSVParser::parse(Rule::file, &unparsed_file)
.expect("unsuccessful parse") // unwrap the parse result
.next().unwrap(); // get and unwrap the `file` rule; never fails
let mut field_sum = 0.0;
let mut record_count: u64 = 0;
for record in file.into_inner() {
match record.as_rule() {
Rule::record => {
record_count += 1;
for field in record.into_inner() {
field_sum += field.as_str().parse::<f64>().unwrap();
}
},
Rule::EOI => (),
_ => unreachable!(),
}
}
println!("Sum of fields: {field_sum}");
println!("Number of records: {record_count}");
}

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