Make strings iterable. Fixes #152

mitsuhiko · Dec 4, 2022 · fb5991d · fb5991d
1 parent 0a8b338
commit fb5991d
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Showing 5 changed files with 36 additions and 9 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -20,6 +20,7 @@ All notable changes to MiniJinja are documented here.
 - Added `indent` filter. (#151)
 - Added the `map`, `select` / `selectattr` and `reject` / `rejectattr` filters.
 - Added `safe` / `escaped` test.
+- Strings now have the same iteration behavior as in Jinja2. (#152)
 
 ## Breaking Changes
 

diff --git a/minijinja/src/filters.rs b/minijinja/src/filters.rs
@@ -593,15 +593,10 @@ mod builtins {
     /// an empty list is returned.
     #[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
     pub fn list(value: Value) -> Result<Value, Error> {
-        if let Some(s) = value.as_str() {
-            Ok(Value::from(s.chars().map(Value::from).collect::<Vec<_>>()))
-        } else {
-            let iter = ok!(value.try_iter().map_err(|err| {
-                Error::new(ErrorKind::InvalidOperation, "cannot convert value to list")
-                    .with_source(err)
-            }));
-            Ok(Value::from(iter.collect::<Vec<_>>()))
-        }
+        let iter = ok!(value.try_iter().map_err(|err| {
+            Error::new(ErrorKind::InvalidOperation, "cannot convert value to list").with_source(err)
+        }));
+        Ok(Value::from(iter.collect::<Vec<_>>()))
     }
 
     /// Converts the value into a boolean value.

diff --git a/minijinja/src/value/mod.rs b/minijinja/src/value/mod.rs
@@ -923,6 +923,10 @@ impl Value {
     pub(crate) fn try_iter_owned(&self) -> Result<OwnedValueIterator, Error> {
         let (iter_state, len) = match self.0 {
             ValueRepr::None | ValueRepr::Undefined => (ValueIteratorState::Empty, 0),
+            ValueRepr::String(ref s, _) => (
+                ValueIteratorState::Chars(0, Arc::clone(s)),
+                s.chars().count(),
+            ),
             ValueRepr::Seq(ref seq) => (ValueIteratorState::Seq(0, Arc::clone(seq)), seq.len()),
             #[cfg(feature = "preserve_order")]
             ValueRepr::Map(ref items, _) => {
@@ -1093,6 +1097,7 @@ impl fmt::Debug for OwnedValueIterator {
 
 enum ValueIteratorState {
     Empty,
+    Chars(usize, Arc<String>),
     Seq(usize, Arc<Vec<Value>>),
     StaticStr(usize, &'static [&'static str]),
     ArcStr(usize, Vec<Arc<String>>),
@@ -1107,6 +1112,12 @@ impl ValueIteratorState {
     fn advance_state(&mut self) -> Option<Value> {
         match self {
             ValueIteratorState::Empty => None,
+            ValueIteratorState::Chars(offset, ref s) => {
+                s.as_str()[*offset..].chars().next().map(|c| {
+                    *offset += c.len_utf8();
+                    Value::from(c)
+                })
+            }
             ValueIteratorState::Seq(idx, items) => items
                 .get(*idx)
                 .map(|x| {

diff --git a/minijinja/tests/inputs/loop_over_string.txt b/minijinja/tests/inputs/loop_over_string.txt
@@ -0,0 +1,5 @@
+{}
+---
+{% for char in "abcdefg" -%}
+  {{ char }}
+{% endfor %}
diff --git a/minijinja/tests/snapshots/test_templates__vm@loop_over_string.txt.snap b/minijinja/tests/snapshots/test_templates__vm@loop_over_string.txt.snap
@@ -0,0 +1,15 @@
+---
+source: minijinja/tests/test_templates.rs
+description: "{% for char in \"abcdefg\" -%}\n  {{ char }}\n{% endfor %}"
+info: {}
+input_file: minijinja/tests/inputs/loop_over_string.txt
+---
+a
+b
+c
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+e
+f
+g
+
+