generated from ElnuDev/rust-project
parent
23dfa06d15
commit
359c46d776
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@ -1,5 +1,5 @@
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use renrs;
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fn main() {
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renrs::hello();
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renrs::parse("demo.csv");
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}
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@ -0,0 +1,9 @@
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// + indicates one or more times
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field = { (ASCII_DIGIT | "." | "-")+ }
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// ~ indicates directly followed by
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// * indicates zero or more times (optional)
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record = { field ~ ("," ~ field)* }
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// SOI - start of input
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// END - end of input
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// There may be trailing newlines at the end
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file = { SOI ~ (record ~ ("\r\n" | "\n"))* ~ "\n"* ~ EOI }
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@ -1,3 +1,35 @@
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pub fn hello() {
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println!("Hello, world!");
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use std::fs;
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use pest::Parser;
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use pest_derive::Parser;
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#[derive(Parser)]
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#[grammar = "csv.pest"]
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struct CSVParser;
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pub fn parse(file_path: &str) {
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let unparsed_file = fs::read_to_string(file_path).expect("cannot find file");
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let file = CSVParser::parse(Rule::file, &unparsed_file)
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.expect("unsuccessful parse") // unwrap the parse result
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.next().unwrap(); // get and unwrap the `file` rule; never fails
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let mut field_sum = 0.0;
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let mut record_count: u64 = 0;
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for record in file.into_inner() {
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match record.as_rule() {
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Rule::record => {
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record_count += 1;
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for field in record.into_inner() {
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field_sum += field.as_str().parse::<f64>().unwrap();
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}
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},
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Rule::EOI => (),
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_ => unreachable!(),
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}
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}
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println!("Sum of fields: {field_sum}");
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println!("Number of records: {record_count}");
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}
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