feat(hql): Object creations (#416)

## Description
<!-- Provide a brief description of the changes in this PR -->

## Related Issues
<!-- Link to any related issues using #issue_number -->

Closes #

## Checklist when merging to main
<!-- Mark items with "x" when completed -->

- [ ] No compiler warnings (if applicable)
- [ ] Code is formatted with `rustfmt`
- [ ] No useless or dead code (if applicable)
- [ ] Code is easy to understand
- [ ] Doc comments are used for all functions, enums, structs, and
fields (where appropriate)
- [ ] All tests pass
- [ ] Performance has not regressed (assuming change was not to fix a
bug)
- [ ] Version number has been updated in `helix-cli/Cargo.toml` and
`helixdb/Cargo.toml`

## Additional Notes
<!-- Add any additional information that would be helpful for reviewers
-->

Author: xav-db

helix-db/src/grammar.pest

@@ -127,7 +127,7 @@ evaluates_to_number = {
 // ---------------------------------------------------------------------
 // Return statement
 // ---------------------------------------------------------------------
-return_stmt = { "RETURN" ~ evaluates_to_anything ~ ("," ~ evaluates_to_anything)* }
+return_stmt = { "RETURN" ~ (evaluates_to_anything ~ ("," ~ evaluates_to_anything)* | array_creation | object_creation) }
 
 // ---------------------------------------------------------------------
 // Creation steps
@@ -229,6 +229,10 @@ exclude_field = { "!" ~ "{" ~ identifier ~ ("," ~ identifier)* ~ "}" }
 closure_step  = { "|" ~ identifier ~ "|" ~ object_step }
 spread_object = { ".." ~ ","?}
 mapping_field = { (identifier ~ (":" ~ (anonymous_traversal | evaluates_to_anything | object_step))) | identifier }
+array_creation = { "[" ~ (identifier | object_creation ) ~ ("," ~ (identifier | object_creation))* ~ ","? ~ "]" }
+object_creation = {  "{" ~ object_inner ~ ("," ~ object_inner)* ~ ","? ~ "}" }
+object_inner = { identifier ~ ":" ~ object_field }
+object_field = { (object_creation | array_creation | evaluates_to_anything) }
 
 // ---------------------------------------------------------------------
 // Macros

helix-db/src/helixc/analyzer/analyzer.rs

@@ -5,12 +5,12 @@ use crate::helixc::{
         methods::{
             migration_validation::validate_migration,
             query_validation::validate_query,
-            schema_methods::{SchemaVersionMap, build_field_lookups, check_schema},
+            schema_methods::{build_field_lookups, check_schema, SchemaVersionMap},
         },
         types::Type,
     },
     generator::Source as GeneratedSource,
-    parser::helix_parser::{EdgeSchema, ExpressionType, Field, Query, Source},
+    parser::helix_parser::{EdgeSchema, ExpressionType, Field, Query, ReturnType, Source},
 };
 use itertools::Itertools;
 use serde::Serialize;
@@ -250,8 +250,12 @@ impl QueryData {
             .return_values
             .iter()
             .flat_map(|e| {
-                if let ExpressionType::Identifier(ident) = &e.expr {
-                    Some(ident.clone())
+                if let ReturnType::Expression(expr) = e {
+                    if let ExpressionType::Identifier(ident) = &expr.expr {
+                        Some(ident.clone())
+                    } else {
+                        None
+                    }
                 } else {
                     None
                 }

helix-db/src/helixc/analyzer/methods/query_validation.rs

@@ -84,8 +84,10 @@ impl Query {
 
     fn print_query(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // prints the function signature
-        self.print_input_struct(f)?;
-        self.print_parameters(f)?;
+        if !self.parameters.is_empty() {
+            self.print_input_struct(f)?;
+            self.print_parameters(f)?;
+        }
         self.print_handler(f)?;
         writeln!(
             f,
@@ -95,17 +97,19 @@ impl Query {
 
         // print the db boilerplate
         writeln!(f, "let db = Arc::clone(&input.graph.storage);")?;
-        match self.hoisted_embedding_calls.is_empty() {
-            true => writeln!(
-                f,
-                "let data = input.request.in_fmt.deserialize::<{}Input>(&input.request.body)?;",
-                self.name
-            )?,
-            false => writeln!(
-                f,
-                "let data = input.request.in_fmt.deserialize::<{}Input>(&input.request.body)?.into_owned();",
-                self.name
-            )?,
+        if !self.parameters.is_empty() {
+            match self.hoisted_embedding_calls.is_empty() {
+                true => writeln!(
+                    f,
+                    "let data = input.request.in_fmt.deserialize::<{}Input>(&input.request.body)?;",
+                    self.name
+                )?,
+                false => writeln!(
+                    f,
+                    "let data = input.request.in_fmt.deserialize::<{}Input>(&input.request.body)?.into_owned();",
+                    self.name
+                )?,
+            }
         }
 
         // print embedding calls
@@ -221,10 +225,7 @@ impl Query {
         )?;
 
         writeln!(f, "connection.iter = result.into_iter();")?;
-        writeln!(
-            f,
-            "let mut connections = connections.lock().unwrap();"
-        )?;
+        writeln!(f, "let mut connections = connections.lock().unwrap();")?;
         writeln!(f, "connections.add_connection(connection);")?;
         writeln!(f, "drop(connections);")?;
         writeln!(

helix-db/src/helixc/generator/queries.rs

@@ -1,9 +1,8 @@
 use core::fmt;
-use std::fmt::Display;
+use std::{collections::HashMap, fmt::Display};
 
 use crate::helixc::generator::{traversal_steps::Traversal, utils::GeneratedValue};
 
-
 pub struct ReturnValue {
     pub value: ReturnValueExpr,
     pub return_type: ReturnType,
@@ -40,8 +39,25 @@ impl Display for ReturnValue {
                 )
             }
             ReturnType::UnnamedExpr => {
-                write!(f, "// need to implement unnamed return value\n todo!()")?;
-                panic!("Unnamed return value is not supported");
+                writeln!(
+                    f,
+                    "    return_vals.insert(\"data\".to_string(), ReturnValue::from_traversal_value_array_with_mixin({}.clone(), remapping_vals.borrow_mut()));",
+                    self.value
+                )
+            }
+            ReturnType::HashMap => {
+                writeln!(
+                    f,
+                    "    return_vals.insert(\"data\".to_string(), ReturnValue::from({}));",
+                    self.value
+                )
+            }
+            ReturnType::Array => {
+                writeln!(
+                    f,
+                    "    return_vals.insert(\"data\".to_string(), ReturnValue::from({}));",
+                    self.value
+                )
             }
         }
     }
@@ -55,6 +71,8 @@ impl ReturnValue {
             ReturnType::NamedExpr(name) => name.inner().inner().to_string(),
             ReturnType::SingleExpr(name) => name.inner().inner().to_string(),
             ReturnType::UnnamedExpr => todo!(),
+            ReturnType::HashMap => todo!(),
+            ReturnType::Array => todo!(),
         }
     }
 
@@ -88,6 +106,18 @@ impl ReturnValue {
             return_type: ReturnType::UnnamedExpr,
         }
     }
+    pub fn new_array(values: Vec<ReturnValueExpr>) -> Self {
+        Self {
+            value: ReturnValueExpr::Array(values),
+            return_type: ReturnType::Array,
+        }
+    }
+    pub fn new_object(values: HashMap<String, ReturnValueExpr>) -> Self {
+        Self {
+            value: ReturnValueExpr::Object(values),
+            return_type: ReturnType::HashMap,
+        }
+    }
 }
 
 #[derive(Clone)]
@@ -97,19 +127,39 @@ pub enum ReturnType {
     NamedExpr(GeneratedValue),
     SingleExpr(GeneratedValue),
     UnnamedExpr,
+    HashMap,
+    Array,
 }
 #[derive(Clone)]
 pub enum ReturnValueExpr {
     Traversal(Traversal),
     Identifier(GeneratedValue),
     Value(GeneratedValue),
+    Array(Vec<ReturnValueExpr>),
+    Object(HashMap<String, ReturnValueExpr>),
 }
 impl Display for ReturnValueExpr {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             ReturnValueExpr::Traversal(traversal) => write!(f, "{traversal}"),
             ReturnValueExpr::Identifier(identifier) => write!(f, "{identifier}"),
             ReturnValueExpr::Value(value) => write!(f, "{value}"),
+            ReturnValueExpr::Array(values) => {
+                write!(f, "vec![")?;
+                // if traversal then use the other from functions
+                for value in values {
+                    write!(f, "ReturnValue::from({value}),")?;
+                }
+                write!(f, "]")
+            }
+            ReturnValueExpr::Object(values) => {
+                write!(f, "HashMap::from([")?;
+                // if traversal then use the other from functions
+                for (key, value) in values {
+                    write!(f, "(String::from(\"{key}\"), ReturnValue::from({value})),")?;
+                }
+                write!(f, "])")
+            }
         }
     }
 }

helix-db/src/helixc/generator/return_values.rs

@@ -411,7 +411,7 @@ pub struct Query {
     pub name: String,
     pub parameters: Vec<Parameter>,
     pub statements: Vec<Statement>,
-    pub return_values: Vec<Expression>,
+    pub return_values: Vec<ReturnType>,
     pub loc: Loc,
 }
 
@@ -502,6 +502,15 @@ pub enum ExpressionType {
     BM25Search(BM25Search),
     Empty,
 }
+
+#[derive(Debug, Clone)]
+pub enum ReturnType {
+    Array(Vec<ReturnType>),
+    Object(HashMap<String, ReturnType>),
+    Expression(Expression),
+    Empty,
+}
+
 impl Debug for ExpressionType {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
@@ -2217,11 +2226,91 @@ impl HelixParser {
         })
     }
 
-    fn parse_return_statement(&self, pair: Pair<Rule>) -> Result<Vec<Expression>, ParserError> {
+    fn parse_return_statement(&self, pair: Pair<Rule>) -> Result<Vec<ReturnType>, ParserError> {
         // println!("pair: {:?}", pair.clone().into_inner());
+        let inner = pair.into_inner();
+        let mut return_types = Vec::new();
+        for pair in inner {
+            match pair.as_rule() {
+                Rule::array_creation => {
+                    return_types.push(ReturnType::Array(self.parse_array_creation(pair)?));
+                }
+                Rule::object_creation => {
+                    return_types.push(ReturnType::Object(self.parse_object_creation(pair)?));
+                }
+                Rule::evaluates_to_anything => {
+                    return_types.push(ReturnType::Expression(self.parse_expression(pair)?));
+                }
+                _ => {
+                    return Err(ParserError::from(format!(
+                        "Unexpected rule in return statement: {:?}",
+                        pair.as_rule()
+                    )));
+                }
+            }
+        }
+        Ok(return_types)
+    }
+
+    fn parse_array_creation(&self, pair: Pair<Rule>) -> Result<Vec<ReturnType>, ParserError> {
+        let pairs = pair.into_inner();
+        let mut objects = Vec::new();
+        for p in pairs {
+            match p.as_rule() {
+                Rule::identifier => {
+                    objects.push(ReturnType::Expression(Expression {
+                        loc: p.loc(),
+                        expr: ExpressionType::Identifier(p.as_str().to_string()),
+                    }));
+                }
+                _ => {
+                    objects.push(ReturnType::Object(self.parse_object_creation(p)?));
+                }
+            }
+        }
+        Ok(objects)
+    }
+
+    fn parse_object_creation(
+        &self,
+        pair: Pair<Rule>,
+    ) -> Result<HashMap<String, ReturnType>, ParserError> {
         pair.into_inner()
-            .map(|p| self.parse_expression(p))
-            .collect()
+            .map(|p| {
+                let mut object_inner = p.into_inner();
+                let key = object_inner
+                    .next()
+                    .ok_or_else(|| ParserError::from("Missing object inner"))?;
+                let value = object_inner
+                    .next()
+                    .ok_or_else(|| ParserError::from("Missing object inner"))?;
+                let value = self.parse_object_inner(value)?;
+                Ok((key.as_str().to_string(), value))
+            })
+            .collect::<Result<HashMap<String, ReturnType>, _>>()
+    }
+
+    fn parse_object_inner(&self, object_field: Pair<Rule>) -> Result<ReturnType, ParserError> {
+        let object_field_inner = object_field
+            .into_inner()
+            .next()
+            .ok_or_else(|| ParserError::from("Missing object inner"))?;
+
+        match object_field_inner.as_rule() {
+            Rule::evaluates_to_anything => Ok(ReturnType::Expression(
+                self.parse_expression(object_field_inner)?,
+            )),
+            Rule::object_creation => Ok(ReturnType::Object(
+                self.parse_object_creation(object_field_inner)?,
+            )),
+            Rule::array_creation => Ok(ReturnType::Array(
+                self.parse_array_creation(object_field_inner)?,
+            )),
+            _ => Err(ParserError::from(format!(
+                "Unexpected rule in parse_object_inner: {:?}",
+                object_field_inner.as_rule()
+            ))),
+        }
     }
 
     fn parse_expression_vec(&self, pairs: Pairs<Rule>) -> Result<Vec<Expression>, ParserError> {