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-rw-r--r--pest_consume/examples/csv/main.rs44
1 files changed, 25 insertions, 19 deletions
diff --git a/pest_consume/examples/csv/main.rs b/pest_consume/examples/csv/main.rs
index bb9f8fc..efb83ad 100644
--- a/pest_consume/examples/csv/main.rs
+++ b/pest_consume/examples/csv/main.rs
@@ -1,57 +1,60 @@
#![feature(slice_patterns)]
-use pest_consume::{match_nodes, Parser};
-
-#[derive(pest_derive::Parser)]
-#[grammar = "../examples/csv/csv.pest"]
-struct CSVParser;
-
-type ParseResult<T> = Result<T, pest::error::Error<Rule>>;
-type Node<'i> = pest_consume::Node<'i, Rule, ()>;
+use pest_consume::{match_nodes, Error, Parser};
#[derive(Debug)]
enum CSVField<'a> {
Number(f64),
String(&'a str),
}
-
type CSVRecord<'a> = Vec<CSVField<'a>>;
type CSVFile<'a> = Vec<CSVRecord<'a>>;
+type Result<T> = std::result::Result<T, Error<Rule>>;
+type Node<'i> = pest_consume::Node<'i, Rule, ()>;
+
+#[derive(Parser)]
+#[grammar = "../examples/csv/csv.pest"]
+struct CSVParser;
+
#[pest_consume::parser(CSVParser, Rule)]
impl CSVParser {
- fn EOI(_input: Node) -> ParseResult<()> {
+ fn EOI(_input: Node) -> Result<()> {
Ok(())
}
- fn number(input: Node) -> ParseResult<f64> {
- Ok(input.as_str().parse().unwrap())
+ fn number(input: Node) -> Result<f64> {
+ input
+ .as_str()
+ .parse::<f64>()
+ // `input.error` links the error to the location in the input file where it occurred.
+ .map_err(|e| input.error(e.to_string()))
}
- fn string(input: Node) -> ParseResult<&str> {
+ fn string(input: Node) -> Result<&str> {
Ok(input.as_str())
}
- fn field(input: Node) -> ParseResult<CSVField> {
+ fn field(input: Node) -> Result<CSVField> {
Ok(match_nodes!(input.children();
[number(n)] => CSVField::Number(n),
[string(s)] => CSVField::String(s),
))
}
- fn record(input: Node) -> ParseResult<CSVRecord> {
+ fn record(input: Node) -> Result<CSVRecord> {
Ok(match_nodes!(input.children();
[field(fields)..] => fields.collect(),
))
}
- fn file(input: Node) -> ParseResult<CSVFile> {
+ fn file(input: Node) -> Result<CSVFile> {
Ok(match_nodes!(input.children();
[record(records).., EOI(_)] => records.collect(),
))
}
}
-fn parse_csv(input_str: &str) -> ParseResult<CSVFile> {
+fn parse_csv(input_str: &str) -> Result<CSVFile> {
let inputs = CSVParser::parse(Rule::file, input_str)?;
Ok(match_nodes!(<CSVParser>; inputs;
[file(e)] => e,
@@ -59,6 +62,9 @@ fn parse_csv(input_str: &str) -> ParseResult<CSVFile> {
}
fn main() {
- let parsed = parse_csv("-273.15, ' a string '\n\n42, 0");
- println!("{:?}", parsed);
+ let successful_parse = parse_csv("-273.15, ' a string '\n\n42, 0");
+ println!("success: {:?}", successful_parse.unwrap());
+
+ let unsuccessful_parse = parse_csv("0, 273.15.12");
+ println!("failure: {}", unsuccessful_parse.unwrap_err());
}