From ac2ee2c756df052512b1bcce3c45813957a7a943 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sat, 4 Apr 2020 20:51:10 -0400
Subject: [PATCH] Add support for filters

---
 src/duster/parser.rs | 40 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 37 insertions(+), 3 deletions(-)

diff --git a/src/duster/parser.rs b/src/duster/parser.rs
index a0024c3..117be9c 100644
--- a/src/duster/parser.rs
+++ b/src/duster/parser.rs
@@ -5,8 +5,10 @@ use nom::bytes::complete::take_until;
 use nom::combinator::map;
 use nom::combinator::recognize;
 use nom::combinator::value;
+use nom::multi::many0;
 use nom::multi::separated_list;
 use nom::sequence::delimited;
+use nom::sequence::preceded;
 use nom::sequence::tuple;
 use nom::IResult;
 
@@ -39,6 +41,18 @@ struct Path<'a> {
 #[derive(Clone, Debug)]
 struct Reference<'a> {
     path: Path<'a>,
+    filters: Vec<Filter>,
+}
+
+#[derive(Clone, Debug)]
+enum Filter {
+    HtmlEncode,
+    DisableHtmlEncode,
+    JavascriptStringEncode,
+    EncodeUri,
+    EncodeUriComponent,
+    JsonStringify,
+    JsonParse,
 }
 
 fn dust_tag(i: &str) -> IResult<&str, DustTag> {
@@ -83,7 +97,27 @@ fn path(i: &str) -> IResult<&str, Path> {
 }
 
 fn reference(i: &str) -> IResult<&str, Reference> {
-    // TODO: Add support for filters
-    let (remaining, p) = delimited(tag("{"), path, tag("}"))(i)?;
-    Ok((remaining, Reference { path: p }))
+    let (remaining, (p, filters)) = delimited(tag("{"), tuple((path, many0(filter))), tag("}"))(i)?;
+    Ok((
+        remaining,
+        Reference {
+            path: p,
+            filters: filters,
+        },
+    ))
+}
+
+fn filter(i: &str) -> IResult<&str, Filter> {
+    preceded(
+        tag("|"),
+        alt((
+            value(Filter::JsonStringify, tag("js")),
+            value(Filter::JsonParse, tag("jp")),
+            value(Filter::EncodeUriComponent, tag("uc")),
+            value(Filter::HtmlEncode, tag("h")),
+            value(Filter::DisableHtmlEncode, tag("s")),
+            value(Filter::JavascriptStringEncode, tag("j")),
+            value(Filter::EncodeUri, tag("u")),
+        )),
+    )(i)
 }