From 60390fe4f0870fb228f06124eaee58dcda1f0db4 Mon Sep 17 00:00:00 2001
From: KtorZ <matthias.benkort@gmail.com>
Date: Thu, 16 Feb 2023 13:50:50 +0100
Subject: [PATCH] Add TraceIfFalse untyped expression

  The goal is to handle this without bothering the code generation down the line. That is, we can handle it when transforming from the untyped AST to the typed one. That's why there's no 'TraceIfFalse' constructor in the typed AST. It has disappeared during type-check.
---
 crates/aiken-lang/src/expr.rs      | 8 +++++++-
 crates/aiken-lang/src/format.rs    | 6 ++++++
 crates/aiken-lang/src/tipo/expr.rs | 5 +++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/crates/aiken-lang/src/expr.rs b/crates/aiken-lang/src/expr.rs
index b5dab82f..36cfb1f0 100644
--- a/crates/aiken-lang/src/expr.rs
+++ b/crates/aiken-lang/src/expr.rs
@@ -382,6 +382,11 @@ pub enum UntypedExpr {
         text: Box<Self>,
     },
 
+    TraceIfFalse {
+        location: Span,
+        value: Box<Self>,
+    },
+
     When {
         location: Span,
         subjects: Vec<Self>,
@@ -510,7 +515,8 @@ impl UntypedExpr {
         match self {
             Self::PipeLine { expressions, .. } => expressions.last().location(),
             Self::Trace { then, .. } => then.location(),
-            Self::Fn { location, .. }
+            Self::TraceIfFalse { location, .. }
+            | Self::Fn { location, .. }
             | Self::Var { location, .. }
             | Self::Int { location, .. }
             | Self::ErrorTerm { location, .. }
diff --git a/crates/aiken-lang/src/format.rs b/crates/aiken-lang/src/format.rs
index a6e71b00..9b8cd0d3 100644
--- a/crates/aiken-lang/src/format.rs
+++ b/crates/aiken-lang/src/format.rs
@@ -800,6 +800,8 @@ impl<'comments> Formatter<'comments> {
             }
 
             UntypedExpr::ErrorTerm { .. } => "error".to_doc(),
+
+            UntypedExpr::TraceIfFalse { value, .. } => self.trace_if_false(value),
         };
 
         commented(document, comments)
@@ -814,6 +816,10 @@ impl<'comments> Formatter<'comments> {
         }
     }
 
+    pub fn trace_if_false<'a>(&mut self, value: &'a UntypedExpr) -> Document<'a> {
+        docvec![self.wrap_unary_op(value), "?"]
+    }
+
     pub fn trace<'a>(
         &mut self,
         kind: &'a TraceKind,
diff --git a/crates/aiken-lang/src/tipo/expr.rs b/crates/aiken-lang/src/tipo/expr.rs
index ac5686e4..52019b78 100644
--- a/crates/aiken-lang/src/tipo/expr.rs
+++ b/crates/aiken-lang/src/tipo/expr.rs
@@ -225,6 +225,7 @@ impl<'a, 'b> ExprTyper<'a, 'b> {
             | UntypedExpr::TupleIndex { .. }
             | UntypedExpr::UnOp { .. }
             | UntypedExpr::Var { .. }
+            | UntypedExpr::TraceIfFalse { .. }
             | UntypedExpr::When { .. } => Ok(()),
         }
     }
@@ -361,6 +362,10 @@ impl<'a, 'b> ExprTyper<'a, 'b> {
                 value,
                 op,
             } => self.infer_un_op(location, value, op),
+
+            UntypedExpr::TraceIfFalse { value, location } => {
+                self.infer_trace_if_false(*value, location)
+            }
         }
     }