From 7aeb9d525d79924bb52e6b1f86139412e153ce1e Mon Sep 17 00:00:00 2001
From: Erin <erin@erindesu.cz>
Date: Thu, 9 Dec 2021 17:18:37 +0100
Subject: [PATCH] Implemented coercions when subtracting able functios

---
 ablescript/src/variables.rs | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/ablescript/src/variables.rs b/ablescript/src/variables.rs
index 96c963dc..f16f94c4 100644
--- a/ablescript/src/variables.rs
+++ b/ablescript/src/variables.rs
@@ -472,7 +472,35 @@ impl ops::Sub for Value {
                         tape_len: lhs_tl,
                     },
                 },
-                Functio::Able { params, body } => todo!(),
+                Functio::Able {
+                    params: lhs_params,
+                    body: lhs_body,
+                } => match rhs.into_functio() {
+                    Functio::Able {
+                        params: rhs_params,
+                        body: rhs_body,
+                    } => Functio::Able {
+                        params: lhs_params
+                            .into_iter()
+                            .zip(rhs_params.into_iter())
+                            .filter_map(|(l, r)| if l != r { Some(l) } else { None })
+                            .collect(),
+                        body: lhs_body
+                            .into_iter()
+                            .zip(rhs_body.into_iter())
+                            .filter_map(|(l, r)| if l != r { Some(l) } else { None })
+                            .collect(),
+                    },
+                    rhs => Value::Int(
+                        Value::Functio(Functio::Able {
+                            params: lhs_params,
+                            body: lhs_body,
+                        })
+                        .into_i32()
+                            - Value::Functio(rhs).into_i32(),
+                    )
+                    .into_functio(),
+                },
                 Functio::Chain { functios, kind } => todo!(),
                 Functio::Eval(lhs_code) => Functio::Eval(lhs_code.replace(
                     &match rhs.into_functio() {