From 422b8e640f00977177a5a7250a3c56009eed10c4 Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Sat, 26 Jun 2021 18:07:05 +0200
Subject: With expressions

---
 src/syntax/expr.rs  | 18 +++++++++++++++++-
 src/syntax/token.rs |  3 +++
 src/syntax/visit.rs |  6 ++++++
 3 files changed, 26 insertions(+), 1 deletion(-)

(limited to 'src/syntax')

diff --git a/src/syntax/expr.rs b/src/syntax/expr.rs
index 24850d65..62f02399 100644
--- a/src/syntax/expr.rs
+++ b/src/syntax/expr.rs
@@ -52,6 +52,8 @@ pub enum Expr {
     Call(CallExpr),
     /// A closure expression: `(x, y) => z`.
     Closure(ClosureExpr),
+    /// A with expression: `f with (x, y: 1)`.
+    With(WithExpr),
     /// A let expression: `let x = 1`.
     Let(LetExpr),
     /// An if-else expression: `if x { y } else { z }`.
@@ -91,6 +93,7 @@ impl Expr {
             Self::Binary(ref v) => v.span,
             Self::Call(ref v) => v.span,
             Self::Closure(ref v) => v.span,
+            Self::With(ref v) => v.span,
             Self::Let(ref v) => v.span,
             Self::If(ref v) => v.span,
             Self::While(ref v) => v.span,
@@ -383,7 +386,7 @@ pub enum Associativity {
 pub struct CallExpr {
     /// The source code location.
     pub span: Span,
-    /// The callee of the function.
+    /// The function to call.
     pub callee: Box<Expr>,
     /// The arguments to the function.
     pub args: CallArgs,
@@ -435,6 +438,19 @@ pub struct ClosureExpr {
     pub body: Rc<Expr>,
 }
 
+/// A with expression: `f with (x, y: 1)`.
+///
+/// Applies arguments to a function.
+#[derive(Debug, Clone, PartialEq)]
+pub struct WithExpr {
+    /// The source code location.
+    pub span: Span,
+    /// The function to apply the arguments to.
+    pub callee: Box<Expr>,
+    /// The arguments to apply to the function.
+    pub args: CallArgs,
+}
+
 /// A let expression: `let x = 1`.
 #[derive(Debug, Clone, PartialEq)]
 pub struct LetExpr {
diff --git a/src/syntax/token.rs b/src/syntax/token.rs
index 254a56a2..3f07bb33 100644
--- a/src/syntax/token.rs
+++ b/src/syntax/token.rs
@@ -74,6 +74,8 @@ pub enum Token<'s> {
     And,
     /// The `or` operator.
     Or,
+    /// The `with` operator.
+    With,
     /// The none literal: `none`.
     None,
     /// The auto literal: `auto`.
@@ -241,6 +243,7 @@ impl<'s> Token<'s> {
             Self::Not => "operator `not`",
             Self::And => "operator `and`",
             Self::Or => "operator `or`",
+            Self::With => "operator `with`",
             Self::None => "`none`",
             Self::Auto => "`auto`",
             Self::Let => "keyword `let`",
diff --git a/src/syntax/visit.rs b/src/syntax/visit.rs
index a1a848ef..cf819ef0 100644
--- a/src/syntax/visit.rs
+++ b/src/syntax/visit.rs
@@ -99,6 +99,7 @@ visit! {
             Expr::Binary(e) => v.visit_binary(e),
             Expr::Call(e) => v.visit_call(e),
             Expr::Closure(e) => v.visit_closure(e),
+            Expr::With(e) => v.visit_with(e),
             Expr::Let(e) => v.visit_let(e),
             Expr::If(e) => v.visit_if(e),
             Expr::While(e) => v.visit_while(e),
@@ -176,6 +177,11 @@ visit! {
         }
     }
 
+    fn visit_with(v, node: &WithExpr) {
+        v.visit_expr(&node.callee);
+        v.visit_args(&node.args);
+    }
+
     fn visit_let(v, node: &LetExpr) {
         v.visit_binding(&node.binding);
         if let Some(init) = &node.init {
-- 
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