From 9b2c730c6502369f959fc1f60d88d1cb0c4481c6 Mon Sep 17 00:00:00 2001
From: Rasmus Kaj <kaj@kth.se>
Date: Sun, 6 Feb 2022 14:39:21 +0100
Subject: [PATCH] Allow declaring named lifetimes.

---
 CHANGELOG.md                                  |  2 +-
 examples/simple/src/main.rs                   |  9 +++++
 .../simple/templates/with_lifetime2.rs.html   |  6 ++++
 src/template.rs                               | 33 ++++++++++++++++---
 4 files changed, 44 insertions(+), 6 deletions(-)
 create mode 100644 examples/simple/templates/with_lifetime2.rs.html

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1192e40..a9f235a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,7 +11,7 @@ project adheres to
 
 * Breaking change: The generated template functions have a simpler
   signature.
-* Allow litetimes in template argument types.  Issue #106.
+* Allow litetimes in template argument types.  Issue #106, PR #110.
 * Improve error handling in optional warp support, PR #109.
 * Current stable rust is 1.57, MSRV is now 1.46.0.
 * Update nom dependency to 7.1.0.
diff --git a/examples/simple/src/main.rs b/examples/simple/src/main.rs
index 943edac..67c69ce 100644
--- a/examples/simple/src/main.rs
+++ b/examples/simple/src/main.rs
@@ -329,3 +329,12 @@ fn lifetimes() {
         "\n  <p>foo</p>\n\n  <p>bar</p>\n\n",
     );
 }
+
+/// [Issue #106](https://github.com/kaj/ructe/issues/106)
+#[test]
+fn lifetimes2() {
+    assert_eq!(
+        r2s(|o| with_lifetime2(o, &["foo", "bar"])),
+        "\n  <p>foo</p>\n\n  <p>bar</p>\n\n",
+    );
+}
diff --git a/examples/simple/templates/with_lifetime2.rs.html b/examples/simple/templates/with_lifetime2.rs.html
new file mode 100644
index 0000000..cda2784
--- /dev/null
+++ b/examples/simple/templates/with_lifetime2.rs.html
@@ -0,0 +1,6 @@
+@* There can be lifetime annotations in argument types. *@
+@<'a>(arg: &[&'a str])
+
+@for x in arg {
+  <p>@x</p>
+}
diff --git a/src/template.rs b/src/template.rs
index f2afdaf..d4f5a6a 100644
--- a/src/template.rs
+++ b/src/template.rs
@@ -9,13 +9,14 @@ use nom::bytes::complete::tag;
 use nom::character::complete::{char, multispace0};
 use nom::combinator::{map, map_res, opt, recognize};
 use nom::error::context;
-use nom::multi::{many0, many_till, separated_list0};
+use nom::multi::{many0, many_till, separated_list0, separated_list1};
 use nom::sequence::{delimited, preceded, terminated, tuple};
 use std::io::{self, Write};
 
 #[derive(Debug, PartialEq, Eq)]
 pub struct Template {
     preamble: Vec<String>,
+    type_args: String,
     args: Vec<String>,
     body: Vec<TemplateExpression>,
 }
@@ -40,11 +41,14 @@ impl Template {
         writeln!(
             out,
             "\n\
-             pub fn {name}<W>(_ructe_out_: &mut W{args}) -> io::Result<()> where W: Write {{\n\
+             pub fn {name}<{ta}{ta_sep}W>(_ructe_out_: &mut W{args}) -> io::Result<()>\n\
+             where W: Write {{\n\
              {body}\
              Ok(())\n\
              }}",
             name = name,
+            ta = self.type_args,
+            ta_sep = if self.type_args.is_empty() { "" } else { ", " },
             args =
                 self.args.iter().format_with("", |arg, f| f(&format_args!(
                     ", {}",
@@ -70,10 +74,28 @@ pub fn template(input: &[u8]) -> PResult<Template> {
                 ),
                 String::from,
             )),
+            context("expected '@('...')' template declaration.", tag("@")),
+            opt(delimited(
+                terminated(tag("<"), multispace0),
+                context(
+                    "expected type argument or '>'",
+                    map_res(
+                        recognize(separated_list1(
+                            terminated(tag(","), multispace0),
+                            context(
+                                "expected lifetime declaration",
+                                preceded(tag("'"), rust_name),
+                            ),
+                        )),
+                        input_to_str,
+                    ),
+                ),
+                tag(">"),
+            )),
             delimited(
                 context(
-                    "expected '@('...')' template declaration.",
-                    terminated(tag("@("), multispace0),
+                    "expected '('...')' template arguments declaration.",
+                    terminated(tag("("), multispace0),
                 ),
                 separated_list0(
                     terminated(tag(","), multispace0),
@@ -95,8 +117,9 @@ pub fn template(input: &[u8]) -> PResult<Template> {
                 end_of_file,
             ),
         )),
-        |((), preamble, args, body)| Template {
+        |((), preamble, _, type_args, args, body)| Template {
             preamble,
+            type_args: type_args.map(String::from).unwrap_or_default(),
             args,
             body: body.0,
         },