Replace match single binding with let else

query/src/optimizer.rs

@@ -2,15 +2,18 @@
 
 use chrono::prelude::*;
 
-use chrono_english::{parse_date_string, Dialect};
+use chrono_english::parse_date_string;
+use chrono_english::Dialect;
 
 use regex::escape;
 use regex::RegexBuilder;
 
 use fimfareader::archive::Story;
-use fimfareader::error::{Error, Result};
+use fimfareader::error::Error;
+use fimfareader::error::Result;
 
-use super::parser::{Operator, Source};
+use super::parser::Operator;
+use super::parser::Source;
 
 use Operator::*;
 use Source::*;
@@ -43,9 +46,9 @@ fn strfn(f: StrFn, op: Operator, value: &str) -> Result<Filter> {
         .size_limit(1_048_576)
         .build();
 
-    let regex = result.map_err(|e| match e {
+    let Ok(regex) = result else {
-        _ => Error::query("Invalid value for fuzzy match"),
+        return Err(Error::query("Invalid value for fuzzy match"));
-    })?;
+    };
 
     match op {
         Exact => ok!(move |s| f(s) == exact),
@@ -55,9 +58,9 @@ fn strfn(f: StrFn, op: Operator, value: &str) -> Result<Filter> {
 }
 
 fn intfn(f: IntFn, op: Operator, value: &str) -> Result<Filter> {
-    let value: i64 = value.parse().map_err(|e| match e {
+    let Ok(value) = value.parse() else {
-        _ => Error::query("Invalid value for number type"),
+        return Err(Error::query("Invalid value for number type"));
-    })?;
+    };
 
     match op {
         Exact => ok!(move |s| f(s) == value),
@@ -68,11 +71,9 @@ fn intfn(f: IntFn, op: Operator, value: &str) -> Result<Filter> {
 }
 
 fn dtufn(f: DtuFn, op: Operator, value: &str) -> Result<Filter> {
-    let parsed = parse_date_string(value, Utc::now(), Dialect::Uk);
+    let Ok(value) = parse_date_string(value, Utc::now(), Dialect::Uk) else {
-
+        return Err(Error::query("Invalid value for date type"));
-    let value: DateTime<Utc> = parsed.map_err(|e| match e {
+    };
-        _ => Error::query("Invalid value for date type"),
-    })?;
 
     match op {
         Exact => ok!(move |s| match f(s) {

query/src/parser.rs

@@ -110,9 +110,9 @@ fn item(input: &str) -> IResult<&str, Filter> {
     let result = tuple((source, operator, target))(input)?;
     let (left, (src, op, value)) = result;
 
-    let filter = optimize(src, op, &value).map_err(|e| match e {
+    let Ok(filter) = optimize(src, op, &value) else {
-        _ => Err::Failure((input, NomErrorKind::Permutation)),
+        return Err(Err::Failure((input, NomErrorKind::Permutation)));
-    })?;
+    };
 
     Ok((left, filter))
 }

src/archive/fetcher.rs

@@ -1,8 +1,10 @@
 //! Archive fetcher.
 
 use std::fs::File;
+use std::io::BufReader;
 use std::io::ErrorKind as IoErrorKind;
-use std::io::{BufReader, Read, Seek};
+use std::io::Read;
+use std::io::Seek;
 use std::path::Path;
 use std::sync::Mutex;
 
@@ -13,7 +15,8 @@ use zip::result::ZipError;
 
 use super::parser::parse;
 use super::story::Story;
-use crate::error::{Error, Result};
+use crate::error::Error;
+use crate::error::Result;
 
 pub struct Fetcher<T: Read + Seek> {
     archive: Mutex<ZipArchive<T>>,
@@ -75,9 +78,9 @@ impl<T: Read + Seek> Fetcher<T> {
 
         let path = &story.archive.path;
 
-        let mut archive = self.archive.lock().map_err(|e| match e {
+        let Ok(mut archive) = self.archive.lock() else {
-            _ => Error::archive("Could not acquire fetcher lock"),
+            return Err(Error::archive("Could not acquire fetcher lock"));
-        })?;
+        };
 
         let mut file = archive.by_name(path).map_err(|e| match e {
             FileNotFound => Error::archive("Missing story data"),
@@ -87,9 +90,9 @@ impl<T: Read + Seek> Fetcher<T> {
         let size = file.size() as usize;
         let mut buf = Vec::with_capacity(size);
 
-        file.read_to_end(&mut buf).map_err(|e| match e {
+        let Ok(_) = file.read_to_end(&mut buf) else {
-            _ => Error::archive("Could not read story data"),
+            return Err(Error::archive("Could not read story data"));
-        })?;
+        };
 
         Ok(buf)
     }

src/archive/interner.rs

@@ -16,7 +16,7 @@ where
     fn get(&self, value: &T) -> Option<&'static T> {
         let store = self.0.read().unwrap();
 
-        store.get(value).map(|value| *value)
+        store.get(value).copied()
     }
 
     fn set(&self, value: T) -> &'static T {

src/archive/parser.rs

@@ -1,7 +1,8 @@
 //! Index parser.
 
 use std::io::BufRead;
-use std::sync::mpsc::{channel, Receiver};
+use std::sync::mpsc::channel;
+use std::sync::mpsc::Receiver;
 use std::thread::spawn;
 
 use rayon::prelude::*;
@@ -20,9 +21,9 @@ pub fn parse(reader: impl BufRead) -> Result<Vec<Story>> {
     let rx = spawn_parser(rx);
 
     for line in reader.lines() {
-        let line = line.map_err(|e| match e {
+        let Ok(line) = line else {
-            _ => Error::custom("Could not read line"),
+            return Err(Error::custom("Could not read line"));
-        })?;
+        };
 
         if line.len() == 1 {
             wrappers.push_str(&line);
@@ -46,9 +47,11 @@ pub fn parse(reader: impl BufRead) -> Result<Vec<Story>> {
         return Err(Error::custom("Invalid file structure"));
     }
 
-    rx.recv().map_err(|e| match e {
+    let Ok(result) = rx.recv() else {
-        _ => Error::custom("Missing parser result"),
+        return Err(Error::custom("Missing parser result"));
-    })?
+    };
+
+    result
 }
 
 fn spawn_parser(stream: Receiver<String>) -> Receiver<Result<Vec<Story>>> {
@@ -92,9 +95,9 @@ fn deserialize(line: String) -> Result<Story> {
 
     let story: Story = from_str(json)?;
 
-    let key: i64 = skey.parse().map_err(|e| match e {
+    let Ok(key) = skey.parse::<i64>() else {
-        _ => Error::custom("Invalid line key"),
+        return Err(Error::custom("Invalid line key"));
-    })?;
+    };
 
     if key != story.id {
         return Err(Error::custom("Line key mismatch"));

src/archive/story.rs

@@ -3,7 +3,8 @@
 use chrono::prelude::*;
 use lazy_static::lazy_static;
 use serde::de::Error;
-use serde::{Deserialize, Deserializer};
+use serde::Deserialize;
+use serde::Deserializer;
 use serde_json::Value;
 
 use super::interner::Interner;
@@ -184,16 +185,16 @@ fn string_to_id<'de, D>(d: D) -> Result<i64, D::Error>
 where
     D: Deserializer<'de>,
 {
-    let value = Value::deserialize(d)?;
+    match Value::deserialize(d)? {
-
+        Value::Number(value) => match value.as_i64() {
-    if value.is_i64() {
+            Some(value) => Ok(value),
-        Ok(value.as_i64().unwrap())
+            _ => Err(Error::custom("Could not parse ID number")),
-    } else if value.is_string() {
+        },
-        value.as_str().unwrap().parse().map_err(|e| match e {
+        Value::String(value) => match value.parse::<i64>() {
-            _ => Error::custom("Could not parse ID string"),
+            Ok(value) => Ok(value),
-        })
+            _ => Err(Error::custom("Could not parse ID string")),
-    } else {
+        },
-        Err(Error::custom("Invalid type for ID value"))
+        _ => Err(Error::custom("Invalid type for ID value")),
     }
 }
 
@@ -218,9 +219,9 @@ impl<'de> Deserialize<'de> for Color {
             .and_then(|value| value.as_str())
             .ok_or_else(|| Error::custom("Color is missing hex value"))?;
 
-        let array = hex::decode(text).map_err(|e| match e {
+        let Ok(array) = hex::decode(text) else {
-            _ => Error::custom("Color hex has invalid value"),
+            return Err(Error::custom("Color hex has invalid value"));
-        })?;
+        };
 
         match array[..] {
             [red, green, blue] => Ok(Color { red, green, blue }),