From 4fc233a02e8dc07619a969400c445ec47c2b1a9d Mon Sep 17 00:00:00 2001
From: Marcus Klaas de Vries <mail@marcusklaas.nl>
Date: Sat, 5 Jan 2019 21:28:30 +0100
Subject: Implement type inference for boolean operators

---
 crates/ra_syntax/src/ast.rs           | 39 +++++++++++++++++++++++++++++++++++
 crates/ra_syntax/src/ast/generated.rs | 10 ++++++++-
 crates/ra_syntax/src/grammar.ron      |  7 ++++++-
 3 files changed, 54 insertions(+), 2 deletions(-)

(limited to 'crates/ra_syntax/src')

diff --git a/crates/ra_syntax/src/ast.rs b/crates/ra_syntax/src/ast.rs
index c10169d90..1bce6fa40 100644
--- a/crates/ra_syntax/src/ast.rs
+++ b/crates/ra_syntax/src/ast.rs
@@ -488,6 +488,45 @@ impl<'a> PrefixExpr<'a> {
     }
 }
 
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub enum BinOp {
+    /// The `||` operator for boolean OR
+    BooleanOr,
+    /// The `&&` operator for boolean AND
+    BooleanAnd,
+    /// The `==` operator for equality testing
+    EqualityTest,
+    /// The `<=` operator for lesser-equal testing
+    LesserEqualTest,
+    /// The `>=` operator for greater-equal testing
+    GreaterEqualTest,
+    /// The `<` operator for comparison
+    LesserTest,
+    /// The `>` operator for comparison
+    GreaterTest,
+    // TODO: lots of others
+}
+
+impl<'a> BinExpr<'a> {
+    pub fn op(&self) -> Option<BinOp> {
+        self.syntax()
+            .children()
+            .filter_map(|c| {
+                match c.kind() {
+                    PIPEPIPE => Some(BinOp::BooleanOr),
+                    AMPAMP => Some(BinOp::BooleanAnd),
+                    EQEQ => Some(BinOp::EqualityTest),
+                    LTEQ => Some(BinOp::LesserEqualTest),
+                    GTEQ => Some(BinOp::GreaterEqualTest),
+                    L_ANGLE => Some(BinOp::LesserTest),
+                    R_ANGLE => Some(BinOp::GreaterTest),
+                    _ => None,
+                }
+            })
+            .next()
+    }
+}
+
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 pub enum SelfParamFlavor {
     /// self
diff --git a/crates/ra_syntax/src/ast/generated.rs b/crates/ra_syntax/src/ast/generated.rs
index 7df6a9c46..ac320606d 100644
--- a/crates/ra_syntax/src/ast/generated.rs
+++ b/crates/ra_syntax/src/ast/generated.rs
@@ -217,7 +217,15 @@ impl<R: TreeRoot<RaTypes>> BinExprNode<R> {
 }
 
 
-impl<'a> BinExpr<'a> {}
+impl<'a> BinExpr<'a> {
+    pub fn lhs(self) -> Option<Expr<'a>> {
+        super::child_opt(self)
+    }
+
+    pub fn rhs(self) -> Option<Expr<'a>> {
+        super::child_opt(self)
+    }
+}
 
 // BindPat
 #[derive(Debug, Clone, Copy,)]
diff --git a/crates/ra_syntax/src/grammar.ron b/crates/ra_syntax/src/grammar.ron
index c55e9e07a..e59961da3 100644
--- a/crates/ra_syntax/src/grammar.ron
+++ b/crates/ra_syntax/src/grammar.ron
@@ -422,7 +422,12 @@ Grammar(
         "RefExpr": (options: ["Expr"]),
         "PrefixExpr": (options: ["Expr"]),
         "RangeExpr": (),
-        "BinExpr": (),
+        "BinExpr": (
+            options: [
+                ["lhs", "Expr"],
+                ["rhs", "Expr"]
+            ]
+        ),
         "String": (),
         "Byte": (),
         "ByteString": (),
-- 
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