revamped snippet text element parsing

Snippet text elements can contain escape sequences
that must be treated properly. Furthermore snippets
must always escape certain characters (like `}`
or `\`). The function has been updated to account
for that. `text` is now also included with
`anything` to match the grammar and can also
match empty text. To avoid infinite loops the
`non-empty` combinator has been added which is
automatically used in the `one_or_more` and
`zero_or more` combinator where the problemn would
occur.

1 files changed, 13 insertions, 0 deletions

diff --git a/helix-parsec/src/lib.rs b/helix-parsec/src/lib.rs
index e09814b8..846d02d6 100644
--- a/helix-parsec/src/lib.rs
+++ b/helix-parsec/src/lib.rs
@@ -459,6 +459,7 @@ pub fn zero_or_more<'a, P, T>(parser: P) -> impl Parser<'a, Output = Vec<T>>
 where
     P: Parser<'a, Output = T>,
 {
+    let parser = non_empty(parser);
     move |mut input| {
         let mut values = Vec::new();
 
@@ -491,6 +492,7 @@ pub fn one_or_more<'a, P, T>(parser: P) -> impl Parser<'a, Output = Vec<T>>
 where
     P: Parser<'a, Output = T>,
 {
+    let parser = non_empty(parser);
     move |mut input| {
         let mut values = Vec::new();
 
@@ -559,3 +561,14 @@ where
         Ok((input, values))
     }
 }
+
+pub fn non_empty<'a, T>(p: impl Parser<'a, Output = T>) -> impl Parser<'a, Output = T> {
+    move |input| {
+        let (new_input, res) = p.parse(input)?;
+        if new_input.len() == input.len() {
+            Err(input)
+        } else {
+            Ok((new_input, res))
+        }
+    }
+}