From 80bd718677080227f7b2e26744456cb13debca27 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Wed, 11 Sep 2019 22:42:15 +0200
Subject: Various tweaks

---
 pest_consume/examples/csv/main.rs | 44 ++++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 19 deletions(-)

(limited to 'pest_consume/examples/csv/main.rs')

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());
 }
-- 
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