Add rendering based on document trait

milli/src/prompt/context.rs

@@ -3,23 +3,19 @@ use liquid::model::{
 };
 use liquid::{ObjectView, ValueView};
 
-use super::document::Document;
-use super::fields::Fields;
-use super::FieldsIdsMapWithMetadata;
-
 #[derive(Debug, Clone)]
-pub struct Context<'a> {
+pub struct Context<'a, D: ObjectView, F: ArrayView> {
-    document: &'a Document<'a>,
+    document: &'a D,
-    fields: Fields<'a>,
+    fields: &'a F,
 }
 
-impl<'a> Context<'a> {
+impl<'a, D: ObjectView, F: ArrayView> Context<'a, D, F> {
-    pub fn new(document: &'a Document<'a>, field_id_map: &'a FieldsIdsMapWithMetadata<'a>) -> Self {
+    pub fn new(document: &'a D, fields: &'a F) -> Self {
-        Self { document, fields: Fields::new(document, field_id_map) }
+        Self { document, fields }
     }
 }
 
-impl<'a> ObjectView for Context<'a> {
+impl<'a, D: ObjectView, F: ArrayView> ObjectView for Context<'a, D, F> {
     fn as_value(&self) -> &dyn ValueView {
         self
     }
@@ -56,7 +52,7 @@ impl<'a> ObjectView for Context<'a> {
     }
 }
 
-impl<'a> ValueView for Context<'a> {
+impl<'a, D: ObjectView, F: ArrayView> ValueView for Context<'a, D, F> {
     fn as_debug(&self) -> &dyn std::fmt::Debug {
         self
     }

milli/src/prompt/document.rs

@@ -1,10 +1,15 @@
 use std::cell::OnceCell;
 use std::collections::BTreeMap;
+use std::fmt::{self, Debug};
 
+use bumpalo::Bump;
 use liquid::model::{
-    DisplayCow, KString, KStringCow, ObjectRender, ObjectSource, State, Value as LiquidValue,
+    ArrayView, DisplayCow, KString, KStringCow, ObjectRender, ObjectSource, ScalarCow, State,
+    Value as LiquidValue,
 };
 use liquid::{ObjectView, ValueView};
+use raw_collections::{RawMap, RawVec};
+use serde_json::value::RawValue;
 
 use crate::update::del_add::{DelAdd, KvReaderDelAdd};
 use crate::FieldsIdsMap;
@@ -93,7 +98,7 @@ impl<'a> ObjectView for Document<'a> {
 }
 
 impl<'a> ValueView for Document<'a> {
-    fn as_debug(&self) -> &dyn std::fmt::Debug {
+    fn as_debug(&self) -> &dyn Debug {
         self
     }
 
@@ -128,4 +133,518 @@ impl<'a> ValueView for Document<'a> {
     fn as_object(&self) -> Option<&dyn ObjectView> {
         Some(self)
     }
+
+    fn is_object(&self) -> bool {
+        true
+    }
+}
+
+/// Implementation for any type that implements the Document trait
+use crate::update::new::document::Document as DocumentTrait;
+
+#[derive(Debug)]
+pub struct ParseableDocument<'doc, D> {
+    document: D,
+    doc_alloc: &'doc Bump,
+}
+
+impl<'doc, D> ParseableDocument<'doc, D> {
+    pub fn new(document: D, doc_alloc: &'doc Bump) -> Self {
+        Self { document, doc_alloc }
+    }
+}
+
+impl<'doc, D: DocumentTrait<'doc> + Debug> ObjectView for ParseableDocument<'doc, D> {
+    fn as_value(&self) -> &dyn ValueView {
+        self
+    }
+
+    fn size(&self) -> i64 {
+        self.document.len() as i64
+    }
+
+    fn keys<'k>(&'k self) -> Box<dyn Iterator<Item = KStringCow<'k>> + 'k> {
+        Box::new(self.document.iter_top_level_fields().map(|res| {
+            let (field, _) = res.unwrap();
+            KStringCow::from_ref(field)
+        }))
+    }
+
+    fn values<'k>(&'k self) -> Box<dyn Iterator<Item = &'k dyn ValueView> + 'k> {
+        Box::new(self.document.iter_top_level_fields().map(|res| {
+            let (_, value) = res.unwrap();
+            ParseableValue::new_bump(value, self.doc_alloc) as _
+        }))
+    }
+
+    fn iter<'k>(&'k self) -> Box<dyn Iterator<Item = (KStringCow<'k>, &'k dyn ValueView)> + 'k> {
+        Box::new(self.document.iter_top_level_fields().map(|res| {
+            let (field, value) = res.unwrap();
+            (KStringCow::from_ref(field), ParseableValue::new_bump(value, self.doc_alloc) as _)
+        }))
+    }
+
+    fn contains_key(&self, index: &str) -> bool {
+        self.document.top_level_field(index).unwrap().is_some()
+    }
+
+    fn get<'s>(&'s self, index: &str) -> Option<&'s dyn ValueView> {
+        let s = self.document.top_level_field(index).unwrap()?;
+        Some(ParseableValue::new_bump(s, self.doc_alloc))
+    }
+}
+
+impl<'doc, D: DocumentTrait<'doc> + Debug> ValueView for ParseableDocument<'doc, D> {
+    fn as_debug(&self) -> &dyn fmt::Debug {
+        self
+    }
+    fn render(&self) -> liquid::model::DisplayCow<'_> {
+        DisplayCow::Owned(Box::new(ObjectRender::new(self)))
+    }
+
+    fn source(&self) -> liquid::model::DisplayCow<'_> {
+        DisplayCow::Owned(Box::new(ObjectSource::new(self)))
+    }
+
+    fn type_name(&self) -> &'static str {
+        "object"
+    }
+
+    fn query_state(&self, state: liquid::model::State) -> bool {
+        match state {
+            State::Truthy => true,
+            State::DefaultValue | State::Empty | State::Blank => false,
+        }
+    }
+
+    fn to_kstr(&self) -> liquid::model::KStringCow<'_> {
+        let s = ObjectRender::new(self).to_string();
+        KStringCow::from_string(s)
+    }
+
+    fn to_value(&self) -> LiquidValue {
+        LiquidValue::Object(
+            self.document
+                .iter_top_level_fields()
+                .map(|res| {
+                    let (k, v) = res.unwrap();
+                    (k.to_string().into(), ParseableValue::new(v, self.doc_alloc).to_value())
+                })
+                .collect(),
+        )
+    }
+
+    fn as_object(&self) -> Option<&dyn ObjectView> {
+        Some(self)
+    }
+
+    fn is_object(&self) -> bool {
+        true
+    }
+}
+
+#[derive(Debug)]
+struct ParseableValue<'doc> {
+    value: raw_collections::Value<'doc>,
+}
+
+impl<'doc> ParseableValue<'doc> {
+    pub fn new(value: &'doc RawValue, doc_alloc: &'doc Bump) -> Self {
+        let value = raw_collections::Value::from_raw_value(value, doc_alloc).unwrap();
+        Self { value }
+    }
+
+    pub fn new_bump(value: &'doc RawValue, doc_alloc: &'doc Bump) -> &'doc Self {
+        doc_alloc.alloc(Self::new(value, doc_alloc))
+    }
+}
+
+// transparent newtype for implementing ValueView
+#[repr(transparent)]
+#[derive(Debug)]
+struct ParseableMap<'doc>(RawMap<'doc>);
+
+// transparent newtype for implementing ValueView
+#[repr(transparent)]
+#[derive(Debug)]
+struct ParseableArray<'doc>(RawVec<'doc>);
+
+impl<'doc> ParseableMap<'doc> {
+    pub fn as_parseable<'a>(map: &'a RawMap<'doc>) -> &'a ParseableMap<'doc> {
+        // SAFETY: repr(transparent)
+        unsafe { &*(map as *const RawMap as *const Self) }
+    }
+}
+
+impl<'doc> ParseableArray<'doc> {
+    pub fn as_parseable<'a>(array: &'a RawVec<'doc>) -> &'a ParseableArray<'doc> {
+        // SAFETY: repr(transparent)
+        unsafe { &*(array as *const RawVec as *const Self) }
+    }
+}
+
+impl<'doc> ArrayView for ParseableArray<'doc> {
+    fn as_value(&self) -> &dyn ValueView {
+        self
+    }
+
+    fn size(&self) -> i64 {
+        self.0.len() as _
+    }
+
+    fn values<'k>(&'k self) -> Box<dyn Iterator<Item = &'k dyn ValueView> + 'k> {
+        Box::new(self.0.iter().map(|v| ParseableValue::new_bump(v, self.0.bump()) as _))
+    }
+
+    fn contains_key(&self, index: i64) -> bool {
+        let index = convert_index(index, self.size());
+        index < self.size() && index >= 0
+    }
+
+    fn get(&self, index: i64) -> Option<&dyn ValueView> {
+        let index = convert_index(index, self.size());
+        if index <= 0 {
+            return None;
+        }
+        let v = self.0.get(index as usize)?;
+        Some(ParseableValue::new_bump(v, self.0.bump()))
+    }
+}
+
+impl<'doc> ValueView for ParseableArray<'doc> {
+    fn as_debug(&self) -> &dyn std::fmt::Debug {
+        self
+    }
+
+    fn render(&self) -> DisplayCow<'_> {
+        DisplayCow::Owned(Box::new(ArrayRender { s: &self.0 }))
+    }
+
+    fn source(&self) -> DisplayCow<'_> {
+        DisplayCow::Owned(Box::new(ArraySource { s: &self.0 }))
+    }
+
+    fn type_name(&self) -> &'static str {
+        "array"
+    }
+
+    fn query_state(&self, state: State) -> bool {
+        match state {
+            State::Truthy => true,
+            State::DefaultValue | State::Empty | State::Blank => self.0.is_empty(),
+        }
+    }
+
+    fn to_kstr(&self) -> KStringCow<'_> {
+        let s = ArrayRender { s: &self.0 }.to_string();
+        KStringCow::from_string(s)
+    }
+
+    fn to_value(&self) -> LiquidValue {
+        LiquidValue::Array(self.values().map(|v| v.to_value()).collect())
+    }
+
+    fn is_array(&self) -> bool {
+        true
+    }
+
+    fn as_array(&self) -> Option<&dyn ArrayView> {
+        Some(self as _)
+    }
+}
+
+impl<'doc> ObjectView for ParseableMap<'doc> {
+    fn as_value(&self) -> &dyn ValueView {
+        self
+    }
+
+    fn size(&self) -> i64 {
+        self.0.len() as i64
+    }
+
+    fn keys<'k>(&'k self) -> Box<dyn Iterator<Item = KStringCow<'k>> + 'k> {
+        Box::new(self.0.keys().map(Into::into))
+    }
+
+    fn values<'k>(&'k self) -> Box<dyn Iterator<Item = &'k dyn ValueView> + 'k> {
+        Box::new(self.0.values().map(|value| {
+            let doc_alloc = self.0.bump();
+            ParseableValue::new_bump(value, doc_alloc) as _
+        }))
+    }
+
+    fn iter<'k>(&'k self) -> Box<dyn Iterator<Item = (KStringCow<'k>, &'k dyn ValueView)> + 'k> {
+        Box::new(self.0.iter().map(|(k, v)| {
+            let doc_alloc = self.0.bump();
+            (k.into(), ParseableValue::new_bump(v, doc_alloc) as _)
+        }))
+    }
+
+    fn contains_key(&self, index: &str) -> bool {
+        self.0.get(index).is_some()
+    }
+
+    fn get<'s>(&'s self, index: &str) -> Option<&'s dyn ValueView> {
+        let v = self.0.get(index)?;
+        let doc_alloc = self.0.bump();
+        let value = ParseableValue::new(v, doc_alloc);
+        Some(doc_alloc.alloc(value) as _)
+    }
+}
+
+impl<'doc> ValueView for ParseableMap<'doc> {
+    fn as_debug(&self) -> &dyn std::fmt::Debug {
+        self
+    }
+
+    fn render(&self) -> liquid::model::DisplayCow<'_> {
+        DisplayCow::Owned(Box::new(ObjectRender::new(self)))
+    }
+
+    fn source(&self) -> liquid::model::DisplayCow<'_> {
+        DisplayCow::Owned(Box::new(ObjectSource::new(self)))
+    }
+
+    fn type_name(&self) -> &'static str {
+        "object"
+    }
+
+    fn query_state(&self, state: liquid::model::State) -> bool {
+        match state {
+            State::Truthy => true,
+            State::DefaultValue | State::Empty | State::Blank => self.0.is_empty(),
+        }
+    }
+
+    fn to_kstr(&self) -> liquid::model::KStringCow<'_> {
+        let s = ObjectRender::new(self).to_string();
+        KStringCow::from_string(s)
+    }
+
+    fn to_value(&self) -> LiquidValue {
+        LiquidValue::Object(
+            self.0
+                .iter()
+                .map(|(k, v)| {
+                    (k.to_string().into(), ParseableValue::new(v, self.0.bump()).to_value())
+                })
+                .collect(),
+        )
+    }
+
+    fn as_object(&self) -> Option<&dyn ObjectView> {
+        Some(self)
+    }
+
+    fn is_object(&self) -> bool {
+        true
+    }
+}
+
+impl<'doc> ValueView for ParseableValue<'doc> {
+    fn as_debug(&self) -> &dyn Debug {
+        self
+    }
+
+    fn render(&self) -> DisplayCow<'_> {
+        use raw_collections::value::Number;
+        use raw_collections::Value;
+        match &self.value {
+            Value::Null => LiquidValue::Nil.render(),
+            Value::Bool(v) => v.render(),
+            Value::Number(number) => match number {
+                Number::PosInt(x) => DisplayCow::Borrowed(x),
+                Number::NegInt(x) => x.render(),
+                Number::Finite(x) => x.render(),
+            },
+            Value::String(s) => s.render(),
+            Value::Array(raw_vec) => ParseableArray::as_parseable(raw_vec).render(),
+            Value::Object(raw_map) => ParseableMap::as_parseable(raw_map).render(),
+        }
+    }
+
+    fn source(&self) -> DisplayCow<'_> {
+        use raw_collections::value::Number;
+        use raw_collections::Value;
+        match &self.value {
+            Value::Null => LiquidValue::Nil.source(),
+            Value::Bool(v) => ValueView::source(v),
+            Value::Number(number) => match number {
+                Number::PosInt(x) => DisplayCow::Borrowed(x),
+                Number::NegInt(x) => x.source(),
+                Number::Finite(x) => x.source(),
+            },
+            Value::String(s) => s.source(),
+            Value::Array(raw_vec) => ParseableArray::as_parseable(raw_vec).source(),
+            Value::Object(raw_map) => ParseableMap::as_parseable(raw_map).source(),
+        }
+    }
+
+    fn type_name(&self) -> &'static str {
+        use raw_collections::value::Number;
+        use raw_collections::Value;
+        match &self.value {
+            Value::Null => LiquidValue::Nil.type_name(),
+            Value::Bool(v) => v.type_name(),
+            Value::Number(number) => match number {
+                Number::PosInt(_x) => "whole positive number",
+                Number::NegInt(x) => x.type_name(),
+                Number::Finite(x) => x.type_name(),
+            },
+            Value::String(s) => s.type_name(),
+            Value::Array(_raw_vec) => "array",
+            Value::Object(_raw_map) => "object",
+        }
+    }
+
+    fn query_state(&self, state: State) -> bool {
+        use raw_collections::Value;
+        match &self.value {
+            Value::Null => ValueView::query_state(&LiquidValue::Nil, state),
+            Value::Bool(v) => ValueView::query_state(v, state),
+            Value::Number(_number) => match state {
+                State::Truthy => true,
+                State::DefaultValue => false,
+                State::Empty => false,
+                State::Blank => false,
+            },
+            Value::String(s) => ValueView::query_state(s, state),
+            Value::Array(raw_vec) => ParseableArray::as_parseable(raw_vec).query_state(state),
+            Value::Object(raw_map) => ParseableMap::as_parseable(raw_map).query_state(state),
+        }
+    }
+
+    fn to_kstr(&self) -> KStringCow<'_> {
+        use raw_collections::Value;
+        match &self.value {
+            Value::Null => ValueView::to_kstr(&LiquidValue::Nil),
+            Value::Bool(v) => ValueView::to_kstr(v),
+            Value::Number(_number) => self.render().to_string().into(),
+            Value::String(s) => KStringCow::from_ref(*s),
+            Value::Array(raw_vec) => ParseableArray::as_parseable(raw_vec).to_kstr(),
+            Value::Object(raw_map) => ParseableMap::as_parseable(raw_map).to_kstr(),
+        }
+    }
+
+    fn to_value(&self) -> LiquidValue {
+        use raw_collections::Value;
+        match &self.value {
+            Value::Null => LiquidValue::Nil,
+            Value::Bool(v) => LiquidValue::Scalar(liquid::model::ScalarCow::new(*v)),
+            Value::Number(number) => match number {
+                raw_collections::value::Number::PosInt(number) => {
+                    let number: i64 = match (*number).try_into() {
+                        Ok(number) => number,
+                        Err(_) => {
+                            return LiquidValue::Scalar(ScalarCow::new(self.render().to_string()))
+                        }
+                    };
+                    LiquidValue::Scalar(ScalarCow::new(number))
+                }
+                raw_collections::value::Number::NegInt(number) => {
+                    LiquidValue::Scalar(ScalarCow::new(*number))
+                }
+                raw_collections::value::Number::Finite(number) => {
+                    LiquidValue::Scalar(ScalarCow::new(*number))
+                }
+            },
+            Value::String(s) => LiquidValue::Scalar(liquid::model::ScalarCow::new(s.to_string())),
+            Value::Array(raw_vec) => ParseableArray::as_parseable(raw_vec).to_value(),
+            Value::Object(raw_map) => ParseableMap::as_parseable(raw_map).to_value(),
+        }
+    }
+
+    fn as_scalar(&self) -> Option<liquid::model::ScalarCow<'_>> {
+        use raw_collections::value::Number;
+        use raw_collections::Value;
+        match &self.value {
+            Value::Bool(v) => Some(liquid::model::ScalarCow::new(*v)),
+            Value::Number(number) => match number {
+                Number::PosInt(number) => {
+                    let number: i64 = match (*number).try_into() {
+                        Ok(number) => number,
+                        Err(_) => return Some(ScalarCow::new(self.render().to_string())),
+                    };
+                    Some(ScalarCow::new(number))
+                }
+                Number::NegInt(number) => Some(ScalarCow::new(*number)),
+                Number::Finite(number) => Some(ScalarCow::new(*number)),
+            },
+            Value::String(s) => Some(ScalarCow::new(*s)),
+            _ => None,
+        }
+    }
+
+    fn is_scalar(&self) -> bool {
+        use raw_collections::Value;
+        match &self.value {
+            Value::Bool(_) | Value::Number(_) | Value::String(_) => true,
+            _ => false,
+        }
+    }
+
+    fn as_array(&self) -> Option<&dyn liquid::model::ArrayView> {
+        if let raw_collections::Value::Array(array) = &self.value {
+            return Some(ParseableArray::as_parseable(array) as _);
+        }
+        None
+    }
+
+    fn is_array(&self) -> bool {
+        matches!(&self.value, raw_collections::Value::Array(_))
+    }
+
+    fn as_object(&self) -> Option<&dyn ObjectView> {
+        if let raw_collections::Value::Object(object) = &self.value {
+            return Some(ParseableMap::as_parseable(object) as _);
+        }
+        None
+    }
+
+    fn is_object(&self) -> bool {
+        matches!(&self.value, raw_collections::Value::Object(_))
+    }
+
+    fn is_nil(&self) -> bool {
+        matches!(&self.value, raw_collections::Value::Null)
+    }
+}
+
+struct ArraySource<'s, 'doc> {
+    s: &'s RawVec<'doc>,
+}
+
+impl<'s, 'doc> fmt::Display for ArraySource<'s, 'doc> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "[")?;
+        for item in self.s {
+            let v = ParseableValue::new(item, self.s.bump());
+            write!(f, "{}, ", v.render())?;
+        }
+        write!(f, "]")?;
+        Ok(())
+    }
+}
+
+struct ArrayRender<'s, 'doc> {
+    s: &'s RawVec<'doc>,
+}
+
+impl<'s, 'doc> fmt::Display for ArrayRender<'s, 'doc> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for item in self.s {
+            let v = ParseableValue::new(item, self.s.bump());
+
+            write!(f, "{}", v.render())?;
+        }
+        Ok(())
+    }
+}
+
+fn convert_index(index: i64, max_size: i64) -> i64 {
+    if 0 <= index {
+        index
+    } else {
+        max_size + index
+    }
 }

milli/src/prompt/fields.rs

@@ -1,36 +1,23 @@
+use std::cell::RefCell;
+use std::fmt;
+
+use bumpalo::Bump;
 use liquid::model::{
     ArrayView, DisplayCow, KStringCow, ObjectRender, ObjectSource, State, Value as LiquidValue,
 };
 use liquid::{ObjectView, ValueView};
 
-use super::document::Document;
 use super::{FieldMetadata, FieldsIdsMapWithMetadata};
-#[derive(Debug, Clone)]
+use crate::GlobalFieldsIdsMap;
-pub struct Fields<'a>(Vec<FieldValue<'a>>);
-
-impl<'a> Fields<'a> {
-    pub fn new(document: &'a Document<'a>, field_id_map: &'a FieldsIdsMapWithMetadata<'a>) -> Self {
-        Self(
-            std::iter::repeat(document)
-                .zip(field_id_map.iter())
-                .map(|(document, (fid, name))| FieldValue {
-                    document,
-                    name,
-                    metadata: field_id_map.metadata(fid).unwrap_or_default(),
-                })
-                .collect(),
-        )
-    }
-}
 
 #[derive(Debug, Clone, Copy)]
-pub struct FieldValue<'a> {
+pub struct FieldValue<'a, D: ObjectView> {
     name: &'a str,
-    document: &'a Document<'a>,
+    document: &'a D,
     metadata: FieldMetadata,
 }
 
-impl<'a> ValueView for FieldValue<'a> {
+impl<'a, D: ObjectView> ValueView for FieldValue<'a, D> {
     fn as_debug(&self) -> &dyn std::fmt::Debug {
         self
     }
@@ -70,7 +57,7 @@ impl<'a> ValueView for FieldValue<'a> {
     }
 }
 
-impl<'a> FieldValue<'a> {
+impl<'a, D: ObjectView> FieldValue<'a, D> {
     pub fn name(&self) -> &&'a str {
         &self.name
     }
@@ -88,7 +75,7 @@ impl<'a> FieldValue<'a> {
     }
 }
 
-impl<'a> ObjectView for FieldValue<'a> {
+impl<'a, D: ObjectView> ObjectView for FieldValue<'a, D> {
     fn as_value(&self) -> &dyn ValueView {
         self
     }
@@ -127,7 +114,42 @@ impl<'a> ObjectView for FieldValue<'a> {
     }
 }
 
-impl<'a> ArrayView for Fields<'a> {
+#[derive(Debug, Clone)]
+pub struct OwnedFields<'a, D: ObjectView>(Vec<FieldValue<'a, D>>);
+
+#[derive(Debug)]
+pub struct BorrowedFields<'a, 'map, D: ObjectView> {
+    document: &'a D,
+    field_id_map: &'a RefCell<GlobalFieldsIdsMap<'map>>,
+    doc_alloc: &'a Bump,
+}
+
+impl<'a, D: ObjectView> OwnedFields<'a, D> {
+    pub fn new(document: &'a D, field_id_map: &'a FieldsIdsMapWithMetadata<'a>) -> Self {
+        Self(
+            std::iter::repeat(document)
+                .zip(field_id_map.iter())
+                .map(|(document, (fid, name))| FieldValue {
+                    document,
+                    name,
+                    metadata: field_id_map.metadata(fid).unwrap_or_default(),
+                })
+                .collect(),
+        )
+    }
+}
+
+impl<'a, 'map, D: ObjectView> BorrowedFields<'a, 'map, D> {
+    pub fn new(
+        document: &'a D,
+        field_id_map: &'a RefCell<GlobalFieldsIdsMap<'map>>,
+        doc_alloc: &'a Bump,
+    ) -> Self {
+        Self { document, field_id_map, doc_alloc }
+    }
+}
+
+impl<'a, D: ObjectView> ArrayView for OwnedFields<'a, D> {
     fn as_value(&self) -> &dyn ValueView {
         self.0.as_value()
     }
@@ -149,7 +171,91 @@ impl<'a> ArrayView for Fields<'a> {
     }
 }
 
-impl<'a> ValueView for Fields<'a> {
+impl<'a, 'map, D: ObjectView> ArrayView for BorrowedFields<'a, 'map, D> {
+    fn as_value(&self) -> &dyn ValueView {
+        self
+    }
+
+    fn size(&self) -> i64 {
+        self.document.size()
+    }
+
+    fn values<'k>(&'k self) -> Box<dyn Iterator<Item = &'k dyn ValueView> + 'k> {
+        Box::new(self.document.keys().map(|k| {
+            let mut field_id_map = self.field_id_map.borrow_mut();
+            let (_, metadata) = field_id_map.id_with_metadata_or_insert(&k).unwrap();
+            let fv = self.doc_alloc.alloc(FieldValue {
+                name: self.doc_alloc.alloc_str(&k),
+                document: self.document,
+                metadata: FieldMetadata { searchable: metadata.searchable },
+            });
+            fv as _
+        }))
+    }
+
+    fn contains_key(&self, index: i64) -> bool {
+        let index = if index >= 0 { index } else { self.size() + index };
+        index >= 0 && index < self.size()
+    }
+
+    fn get(&self, index: i64) -> Option<&dyn ValueView> {
+        let index = if index >= 0 { index } else { self.size() + index };
+        let index: usize = index.try_into().ok()?;
+        let key = self.document.keys().nth(index)?;
+        let mut field_id_map = self.field_id_map.borrow_mut();
+        let (_, metadata) = field_id_map.id_with_metadata_or_insert(&key)?;
+        let fv = self.doc_alloc.alloc(FieldValue {
+            name: self.doc_alloc.alloc_str(&key),
+            document: self.document,
+            metadata: FieldMetadata { searchable: metadata.searchable },
+        });
+        Some(fv as _)
+    }
+}
+
+impl<'a, 'map, D: ObjectView> ValueView for BorrowedFields<'a, 'map, D> {
+    fn as_debug(&self) -> &dyn std::fmt::Debug {
+        self
+    }
+
+    fn render(&self) -> liquid::model::DisplayCow<'_> {
+        DisplayCow::Owned(Box::new(ArrayRender { s: self }))
+    }
+
+    fn source(&self) -> liquid::model::DisplayCow<'_> {
+        DisplayCow::Owned(Box::new(ArraySource { s: self }))
+    }
+
+    fn type_name(&self) -> &'static str {
+        "array"
+    }
+
+    fn query_state(&self, state: liquid::model::State) -> bool {
+        match state {
+            State::Truthy => true,
+            State::DefaultValue | State::Empty | State::Blank => self.document.size() == 0,
+        }
+    }
+
+    fn to_kstr(&self) -> liquid::model::KStringCow<'_> {
+        let s = ArrayRender { s: self }.to_string();
+        KStringCow::from_string(s)
+    }
+
+    fn to_value(&self) -> LiquidValue {
+        LiquidValue::Array(self.values().map(|v| v.to_value()).collect())
+    }
+
+    fn as_array(&self) -> Option<&dyn ArrayView> {
+        Some(self)
+    }
+
+    fn is_array(&self) -> bool {
+        true
+    }
+}
+
+impl<'a, D: ObjectView> ValueView for OwnedFields<'a, D> {
     fn as_debug(&self) -> &dyn std::fmt::Debug {
         self
     }
@@ -182,3 +288,39 @@ impl<'a> ValueView for Fields<'a> {
         Some(self)
     }
 }
+
+struct ArraySource<'a, 'map, D: ObjectView> {
+    s: &'a BorrowedFields<'a, 'map, D>,
+}
+
+impl<'a, 'map, D: ObjectView> fmt::Display for ArraySource<'a, 'map, D> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "[")?;
+        for item in self.s.values() {
+            write!(f, "{}, ", item.render())?;
+        }
+        write!(f, "]")?;
+        Ok(())
+    }
+}
+
+struct ArrayRender<'a, 'map, D: ObjectView> {
+    s: &'a BorrowedFields<'a, 'map, D>,
+}
+
+impl<'a, 'map, D: ObjectView> fmt::Display for ArrayRender<'a, 'map, D> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for item in self.s.values() {
+            write!(f, "{}", item.render())?;
+        }
+        Ok(())
+    }
+}
+
+fn convert_index(index: i64, max_size: i64) -> i64 {
+    if 0 <= index {
+        index
+    } else {
+        max_size + index
+    }
+}

milli/src/prompt/mod.rs

@@ -4,17 +4,22 @@ pub(crate) mod error;
 mod fields;
 mod template_checker;
 
+use std::cell::RefCell;
 use std::collections::BTreeMap;
 use std::convert::TryFrom;
+use std::fmt::Debug;
 use std::num::NonZeroUsize;
 use std::ops::Deref;
 
+use bumpalo::Bump;
+use document::ParseableDocument;
 use error::{NewPromptError, RenderPromptError};
+use fields::{BorrowedFields, OwnedFields};
 
 use self::context::Context;
 use self::document::Document;
 use crate::update::del_add::DelAdd;
-use crate::{FieldId, FieldsIdsMap};
+use crate::{FieldId, FieldsIdsMap, GlobalFieldsIdsMap};
 
 pub struct Prompt {
     template: liquid::Template,
@@ -109,14 +114,38 @@ impl Prompt {
         Ok(this)
     }
 
-    pub fn render(
+    pub fn render_document<
+        'a,       // lifetime of the borrow of the document
+        'doc: 'a, // lifetime of the allocator, will live for an entire chunk of documents
+    >(
+        &self,
+        document: impl crate::update::new::document::Document<'a> + Debug,
+        field_id_map: &RefCell<GlobalFieldsIdsMap>,
+        doc_alloc: &'doc Bump,
+    ) -> Result<&'doc str, RenderPromptError> {
+        let document = ParseableDocument::new(document, doc_alloc);
+        let fields = BorrowedFields::new(&document, field_id_map, doc_alloc);
+        let context = Context::new(&document, &fields);
+        let mut rendered = bumpalo::collections::Vec::with_capacity_in(
+            self.max_bytes.unwrap_or_else(default_max_bytes).get(),
+            &doc_alloc,
+        );
+        self.template
+            .render_to(&mut rendered, &context)
+            .map_err(RenderPromptError::missing_context)?;
+        Ok(std::str::from_utf8(rendered.into_bump_slice())
+            .expect("render can only write UTF-8 because all inputs and processing preserve utf-8"))
+    }
+
+    pub fn render_kvdeladd(
         &self,
         document: &obkv::KvReaderU16,
         side: DelAdd,
         field_id_map: &FieldsIdsMapWithMetadata,
     ) -> Result<String, RenderPromptError> {
         let document = Document::new(document, side, field_id_map);
-        let context = Context::new(&document, field_id_map);
+        let fields = OwnedFields::new(&document, field_id_map);
+        let context = Context::new(&document, &fields);
 
         let mut rendered =
             self.template.render(&context).map_err(RenderPromptError::missing_context)?;