From 741dd5f43f8a6774f3dc4b24b122069e22a7b7d9 Mon Sep 17 00:00:00 2001
From: James Gilles <jhgilles@mit.edu>
Date: Fri, 3 May 2019 16:50:46 -0400
Subject: Simplify parser with nom's list combinators

---
 askama_derive/src/parser.rs | 165 ++++++++++++--------------------------------
 1 file changed, 44 insertions(+), 121 deletions(-)

diff --git a/askama_derive/src/parser.rs b/askama_derive/src/parser.rs
index c880202..a37a112 100644
--- a/askama_derive/src/parser.rs
+++ b/askama_derive/src/parser.rs
@@ -208,21 +208,16 @@ named!(expr_num_lit<Input, Expr>, map!(num_lit,
     |s| Expr::NumLit(s)
 ));
 
-named!(expr_array_lit<Input, Expr>, do_parse!(
-    ws!(tag!("[")) >>
-    first: expr_any >>
-    rest: many0!(do_parse!(
-        ws!(tag!(",")) >>
-        part: expr_any >>
-        (part)
-    )) >>
-    ws!(tag!("]")) >>
-    ({
-        let mut elements = vec![first];
-        elements.extend(rest);
-        Expr::Array(elements)
-    })
-));
+named!(expr_array_lit<Input, Expr>,
+    delimited!(
+        ws!(tag!("[")),
+        map!(separated_nonempty_list!(
+            ws!(tag!(",")),
+            expr_any
+        ), |arr| Expr::Array(arr)),
+        ws!(tag!("]"))
+    )
+);
 
 named!(variant_num_lit<Input, MatchVariant>, map!(num_lit,
     |s| MatchVariant::NumLit(s)
@@ -253,11 +248,8 @@ named!(expr_var<Input, Expr>, map!(identifier,
 
 named!(expr_path<Input, Expr>, do_parse!(
     start: call!(identifier) >>
-    rest: many1!(do_parse!(
-        tag!("::") >>
-        part: identifier >>
-        (part)
-    )) >>
+    tag!("::") >>
+    rest: separated_nonempty_list!(tag!("::"), identifier) >>
     ({
         let mut path = vec![start];
         path.extend(rest);
@@ -265,42 +257,25 @@ named!(expr_path<Input, Expr>, do_parse!(
     })
 ));
 
-named!(variant_path<Input, MatchVariant>, do_parse!(
-    start: call!(identifier) >>
-    rest: many1!(do_parse!(
-        tag!("::") >>
-        part: identifier >>
-        (part)
-    )) >>
-    ({
-        let mut path = vec![start];
-        path.extend(rest);
-        MatchVariant::Path(path)
-    })
-));
+named!(variant_path<Input, MatchVariant>,
+    map!(
+        separated_nonempty_list!(tag!("::"), identifier),
+        |path| MatchVariant::Path(path)
+    )
+);
 
 named!(target_single<Input, Target>, map!(identifier,
     |s| Target::Name(s)
 ));
 
-named!(target_tuple<Input, Target>, do_parse!(
-    tag!("(") >>
-    args: opt!(do_parse!(
-        arg0: ws!(identifier) >>
-        args: many0!(do_parse!(
-            tag!(",") >>
-            argn: ws!(identifier) >>
-            (argn)
-        )) >>
-        ({
-           let mut res = vec![arg0];
-           res.extend(args);
-           res
-        })
-    )) >>
-    opt!(ws!(tag!(","))) >>
-    tag!(")") >>
-    (Target::Tuple(args.unwrap_or_default()))
+named!(target_tuple<Input, Target>, delimited!(
+    tag!("("),
+    do_parse!(
+        res: separated_list!(tag!(","), ws!(identifier)) >>
+        opt!(ws!(tag!(","))) >>
+        (Target::Tuple(res))
+    ),
+    tag!(")")
 ));
 
 named!(variant_name<Input, MatchVariant>, map!(identifier,
@@ -311,23 +286,10 @@ named!(param_name<Input, MatchParameter>, map!(identifier,
     |s| MatchParameter::Name(s)
 ));
 
-named!(arguments<Input, Vec<Expr>>, do_parse!(
-    tag!("(") >>
-    args: opt!(do_parse!(
-        arg0: ws!(expr_any) >>
-        args: many0!(do_parse!(
-            tag!(",") >>
-            argn: ws!(expr_any) >>
-            (argn)
-        )) >>
-        ({
-           let mut res = vec![arg0];
-           res.extend(args);
-           res
-        })
-    )) >>
-    tag!(")") >>
-    (args.unwrap_or_default())
+named!(arguments<Input, Vec<Expr>>, delimited!(
+    tag!("("),
+    separated_list!(tag!(","), ws!(expr_any)),
+    tag!(")")
 ));
 
 named!(macro_arguments<Input, &str>,
@@ -384,23 +346,10 @@ fn nested_parenthesis(i: Input) -> Result<(Input, &str), nom::Err<Input>> {
     }
 }
 
-named!(parameters<Input, Vec<&str>>, do_parse!(
-    tag!("(") >>
-    vals: opt!(do_parse!(
-        arg0: ws!(identifier) >>
-        args: many0!(do_parse!(
-            tag!(",") >>
-            argn: ws!(identifier) >>
-            (argn)
-        )) >>
-        ({
-            let mut res = vec![arg0];
-            res.extend(args);
-            res
-        })
-    )) >>
-    tag!(")") >>
-    (vals.unwrap_or_default())
+named!(parameters<Input, Vec<&str>>, delimited!(
+    tag!("("),
+    separated_list!(tag!(","), ws!(identifier)),
+    tag!(")")
 ));
 
 named!(with_parameters<Input, MatchParameters>, do_parse!(
@@ -409,42 +358,16 @@ named!(with_parameters<Input, MatchParameters>, do_parse!(
     (value)
 ));
 
-named!(match_simple_parameters<Input, MatchParameters>, do_parse!(
-    ws!(tag!("(")) >>
-    vals: opt!(do_parse!(
-        arg0: ws!(match_parameter) >>
-        args: many0!(do_parse!(
-            tag!(",") >>
-            argn: ws!(match_parameter) >>
-            (argn)
-        )) >>
-        ({
-            let mut res = vec![arg0];
-            res.extend(args);
-            res
-        })
-    )) >>
-    tag!(")") >>
-    (MatchParameters::Simple(vals.unwrap_or_default()))
-));
-
-named!(match_named_parameters<Input, MatchParameters>, do_parse!(
-    ws!(tag!("{")) >>
-    vals: opt!(do_parse!(
-        arg0: ws!(match_named_parameter) >>
-        args: many0!(do_parse!(
-            tag!(",") >>
-            argn: ws!(match_named_parameter) >>
-            (argn)
-        )) >>
-        ({
-            let mut res = vec![arg0];
-            res.extend(args);
-            res
-        })
-    )) >>
-    tag!("}") >>
-    (MatchParameters::Named(vals.unwrap_or_default()))
+named!(match_simple_parameters<Input, MatchParameters>, delimited!(
+    ws!(tag!("(")),
+    map!(separated_list!(tag!(","), ws!(match_parameter)), |mps| MatchParameters::Simple(mps)),
+    tag!(")")
+));
+
+named!(match_named_parameters<Input, MatchParameters>, delimited!(
+    ws!(tag!("{")),
+    map!(separated_list!(tag!(","), ws!(match_named_parameter)), |mps| MatchParameters::Named(mps)),
+    tag!("}")
 ));
 
 named!(expr_group<Input, Expr>, map!(
-- 
cgit