Merge pull request #104 from AleoHQ/feature/return-tuple

Feature/return tuple

README.md

@@ -279,7 +279,7 @@ function main() -> field {
 Functions can return tuples whose types are specified in the function signature.
 ```js
 function test() -> (u32, u32[2]) {
-    return 1, [2, 3]
+    return (1, [2, 3])
 }
 
 function main() -> u32[3] {

ast/src/common/mod.rs

@@ -22,6 +22,12 @@ pub use range::*;
 pub mod range_or_expression;
 pub use range_or_expression::*;
 
+pub mod return_;
+pub use return_::*;
+
+pub mod return_tuple;
+pub use return_tuple::*;
+
 pub mod spread;
 pub use spread::*;
 

ast/src/common/return_.rs

@@ -0,0 +1,20 @@
+use crate::{ast::Rule, common::ReturnTuple, expressions::Expression};
+
+use pest_ast::FromPest;
+use std::fmt;
+
+#[derive(Clone, Debug, FromPest, PartialEq)]
+#[pest_ast(rule(Rule::return_))]
+pub enum Return<'ast> {
+    Single(Expression<'ast>),
+    Tuple(ReturnTuple<'ast>),
+}
+
+impl<'ast> fmt::Display for Return<'ast> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Return::Single(ref expression) => write!(f, "{}", expression),
+            Return::Tuple(ref expressions) => write!(f, "{}", expressions),
+        }
+    }
+}

ast/src/common/return_tuple.rs

@@ -0,0 +1,25 @@
+use crate::{ast::Rule, expressions::Expression};
+
+use pest::Span;
+use pest_ast::FromPest;
+use std::fmt;
+
+#[derive(Clone, Debug, FromPest, PartialEq)]
+#[pest_ast(rule(Rule::return_tuple))]
+pub struct ReturnTuple<'ast> {
+    pub expressions: Vec<Expression<'ast>>,
+    #[pest_ast(outer())]
+    pub span: Span<'ast>,
+}
+
+impl<'ast> fmt::Display for ReturnTuple<'ast> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        for (i, expression) in self.expressions.iter().enumerate() {
+            write!(f, "{}", expression)?;
+            if i < self.expressions.len() - 1 {
+                write!(f, ", ")?;
+            }
+        }
+        write!(f, "")
+    }
+}

ast/src/leo.pest

@@ -32,6 +32,12 @@ spread = { "..." ~ expression }
 // Declared in common/spread_or_expression.rs
 spread_or_expression = { spread | expression }
 
+// Declared in common/return_.rs
+return_ = { return_tuple | expression }
+
+// Declared in common/return_tuple.rs
+return_tuple = {"(" ~ expression ~ ("," ~ expression)+ ~ ")"}
+
 // Declared in common/static_.rs
 static_ = { "static " }
 
@@ -291,7 +297,7 @@ statement_multiple_assignment = { declare ~ "(" ~ variable_tuple ~ ")" ~ "=" ~
 variable_tuple = _{ variable ~ ("," ~ variable)* }
 
 // Declared in statements/return_statement.rs
-statement_return = { "return " ~ expression_tuple }
+statement_return = { "return " ~ return_}
 
 /// Functions
 

ast/src/statements/return_statement.rs

@@ -1,4 +1,4 @@
-use crate::{ast::Rule, expressions::Expression};
+use crate::{ast::Rule, common::Return};
 
 use pest::Span;
 use pest_ast::FromPest;
@@ -7,19 +7,13 @@ use std::fmt;
 #[derive(Clone, Debug, FromPest, PartialEq)]
 #[pest_ast(rule(Rule::statement_return))]
 pub struct ReturnStatement<'ast> {
-    pub expressions: Vec<Expression<'ast>>,
+    pub return_: Return<'ast>,
     #[pest_ast(outer())]
     pub span: Span<'ast>,
 }
 
 impl<'ast> fmt::Display for ReturnStatement<'ast> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        for (i, expression) in self.expressions.iter().enumerate() {
+        write!(f, "{}", self.return_)
-            write!(f, "{}", expression)?;
-            if i < self.expressions.len() - 1 {
-                write!(f, ", ")?;
-            }
-        }
-        write!(f, "")
     }
 }

compiler/tests/function/multiple.leo

@@ -1,8 +1,8 @@
 function test() -> (bool, bool) {
-  return true, false
+  return (true, false)
 }
 
 function main() -> (bool, bool) {
   let (a, b) = test();
-  return a, b
+  return (a, b)
 }

compiler/tests/function/multiple_main.leo

@@ -1,3 +1,3 @@
 function main() -> (bool, bool) {
-  return true, false
+  return (true, false)
 }

compiler/tests/group/point.leo

@@ -1,3 +1,5 @@
 function main() -> group {
-  return (7374112779530666882856915975292384652154477718021969292781165691637980424078, 3435195339177955418892975564890903138308061187980579490487898366607011481796)group
+    const point = (7374112779530666882856915975292384652154477718021969292781165691637980424078, 3435195339177955418892975564890903138308061187980579490487898366607011481796)group;
+
+    return point
 }

types/src/statements/statement.rs

@@ -1,5 +1,6 @@
 use crate::{Assignee, ConditionalStatement, Declare, Expression, Identifier, Span, Variable};
 use leo_ast::{
+    common::Return,
     operations::AssignOperation,
     statements::{
         AssertStatement,
@@ -32,8 +33,10 @@ pub enum Statement {
 impl<'ast> From<ReturnStatement<'ast>> for Statement {
     fn from(statement: ReturnStatement<'ast>) -> Self {
         let span = Span::from(statement.span);
-        Statement::Return(
+
-            statement
+        let expressions = match statement.return_ {
+            Return::Single(expression) => vec![Expression::from(expression)],
+            Return::Tuple(tuple) => tuple
                 .expressions
                 .into_iter()
                 .map(|expression| {
@@ -43,8 +46,9 @@ impl<'ast> From<ReturnStatement<'ast>> for Statement {
                     expression
                 })
                 .collect(),
-            span,
+        };
-        )
+
+        Statement::Return(expressions, span)
     }
 }