Use duplicate crate to implement FromStr.

Cargo.lock

@@ -172,6 +172,16 @@ dependencies = [
  "dtoa",
 ]
 
+[[package]]
+name = "duplicate"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a0a4be4cd710e92098de6ad258e6e7c24af11c29c5142f3c6f2a545652480ff8"
+dependencies = [
+ "heck",
+ "proc-macro-error",
+]
+
 [[package]]
 name = "ego-tree"
 version = "0.6.2"
@@ -250,6 +260,12 @@ version = "0.26.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "22030e2c5a68ec659fde1e949a745124b48e6fa8b045b7ed5bd1fe4ccc5c4e5d"
 
+[[package]]
+name = "heck"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2540771e65fc8cb83cd6e8a237f70c319bd5c29f78ed1084ba5d50eeac86f7f9"
+
 [[package]]
 name = "html5ever"
 version = "0.26.0"
@@ -533,6 +549,30 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "925383efa346730478fb4838dbe9137d2a47675ad789c546d150a6e1dd4ab31c"
 
+[[package]]
+name = "proc-macro-error"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "da25490ff9892aab3fcf7c36f08cfb902dd3e71ca0f9f9517bea02a73a5ce38c"
+dependencies = [
+ "proc-macro-error-attr",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "version_check",
+]
+
+[[package]]
+name = "proc-macro-error-attr"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1be40180e52ecc98ad80b184934baf3d0d29f979574e439af5a55274b35f869"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "version_check",
+]
+
 [[package]]
 name = "proc-macro-hack"
 version = "0.5.19"
@@ -854,6 +894,7 @@ name = "tildes-parser"
 version = "0.1.0"
 dependencies = [
  "color-eyre",
+ "duplicate",
  "insta",
  "lazy_static",
  "regex",
@@ -926,6 +967,12 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
 
+[[package]]
+name = "version_check"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
+
 [[package]]
 name = "wasi"
 version = "0.9.0+wasi-snapshot-preview1"

Cargo.toml

@@ -12,6 +12,7 @@ path = "source/lib.rs"
 
 [dependencies]
 color-eyre = "^0.6.2"
+duplicate = "^0.4.1"
 lazy_static = "^1.4.0"
 regex = "^1.6.0"
 scraper = "^0.13.0"

source/from_str.rs

@@ -0,0 +1,21 @@
+//! Implements [`FromStr`] for parser structs.
+
+use std::str::FromStr;
+
+use {color_eyre::eyre::Error, duplicate::duplicate_item, scraper::Html};
+
+use crate::{Group, GroupList};
+
+#[duplicate_item(
+  _Struct;
+  [Group];
+  [GroupList];
+)]
+impl FromStr for _Struct {
+  type Err = Error;
+
+  fn from_str(s: &str) -> Result<Self, Self::Err> {
+    let html = Html::parse_document(s);
+    _Struct::from_html(&html)
+  }
+}

source/group.rs

@@ -1,11 +1,6 @@
 //! Parsing for `/~<group>`.
 
-use std::str::FromStr;
-
-use {
-  color_eyre::{eyre::Error, Result},
-  scraper::Html,
-};
+use {color_eyre::Result, scraper::Html};
 
 use crate::{
   regexes::GROUP_SUBSCRIBERS_RE,
@@ -47,15 +42,6 @@ pub struct GroupWikiLink {
   pub url: String,
 }
 
-impl FromStr for Group {
-  type Err = Error;
-
-  fn from_str(s: &str) -> Result<Self, Self::Err> {
-    let html = Html::parse_document(s);
-    Self::from_html(&html)
-  }
-}
-
 impl Group {
   /// Parses a [`Group`] from a [`scraper::Html`] tree.
   pub fn from_html(html: &Html) -> Result<Self> {

source/group_list.rs

@@ -1,11 +1,6 @@
 //! Parsing for [`/groups`](https://tildes.net/groups).
 
-use std::str::FromStr;
-
-use {
-  color_eyre::{eyre::Error, Result},
-  scraper::Html,
-};
+use {color_eyre::Result, scraper::Html};
 
 use crate::{
   regexes::{DUPLICATE_WHITESPACE_RE, GROUP_LIST_ACTIVITY_RE},
@@ -37,15 +32,6 @@ pub struct GroupListSummary {
   pub topic_activity: Option<i32>,
 }
 
-impl FromStr for GroupList {
-  type Err = Error;
-
-  fn from_str(s: &str) -> Result<Self, Self::Err> {
-    let html = Html::parse_document(s);
-    Self::from_html(&html)
-  }
-}
-
 impl GroupList {
   /// Parses a [`GroupList`] from a [`scraper::Html`] tree.
   pub fn from_html(html: &Html) -> Result<Self> {

source/lib.rs

@@ -24,6 +24,7 @@ pub mod regexes;
 pub mod selectors;
 pub mod utilities;
 
+pub(crate) mod from_str;
 pub(crate) mod group;
 pub(crate) mod group_list;