From 749b11adfa3397c8644e555c27b07684b1e70515 Mon Sep 17 00:00:00 2001
From: Ross Andrews <ross.andrews@gmail.com>
Date: Mon, 13 Nov 2023 00:44:26 -0600
Subject: [PATCH] A bunch of prerequisites before we can do arrays, part 3.1,
 using the pool pointer in calls (removes the cursed test case)

---
 forge_core/src/compiler/ast_nodes/call.rs | 14 +++++---------
 forge_core/src/compiler/mod.rs            |  2 +-
 vtest/src/forge_tests.rs                  | 21 ++++++++++++++++++++-
 3 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/forge_core/src/compiler/ast_nodes/call.rs b/forge_core/src/compiler/ast_nodes/call.rs
index 18ff5ac..9c9bf5d 100644
--- a/forge_core/src/compiler/ast_nodes/call.rs
+++ b/forge_core/src/compiler/ast_nodes/call.rs
@@ -16,13 +16,10 @@ impl Compilable for Call {
             arg.process(state, Some(sig), loc)?;
         }
 
-        // Now we increment the frame ptr to right after the current frame:
-        // see cursed test case in vtest/forge_tests.rs
-        sig.emit("peekr");
-        let frame_size = sig.frame_size();
-        if frame_size > 0 {
-            sig.emit_arg("add", frame_size);
-        }
+        // Whatever shall we send as a frame pointer to the new fn? Our pool pointer, because we
+        // know that's free, even if we've alloced anything, it'll increment it:
+        sig.emit("popr"); sig.emit("peekr"); // take the frame ptr off and copy the pool off
+        sig.emit("swap"); sig.emit("pushr"); // swap the pool under the frame and put the frame back on
 
         // Eval the target
         self.target.0.process(state, Some(sig), loc)?;
@@ -51,8 +48,7 @@ mod test {
             vec![
                 "push 2", // evaluating args, in order
                 "push 3",
-                "peekr", // The new fn's frame ptr:
-                "add 6",
+                "popr", "peekr", "swap", "pushr", // Pool ptr to send to the new call
                 "push _forge_gensym_1", // evaluating target (this fn)
                 "call", // Actually make the call
                 "pop", // expr-as-statement drops the evaluated value
diff --git a/forge_core/src/compiler/mod.rs b/forge_core/src/compiler/mod.rs
index 67631d9..524bd99 100644
--- a/forge_core/src/compiler/mod.rs
+++ b/forge_core/src/compiler/mod.rs
@@ -140,7 +140,7 @@ mod test {
             "_forge_gensym_3:", // fn main()
             "dup", "pushr", // capture pool ptr
             "pushr", // capture frame ptr
-            "peekr", // prep frame ptr to send to foo
+            "popr", "peekr", "swap", "pushr", // Grab pool ptr to send to foo
             "push _forge_gensym_1", // load foo
             "call", // call it
             "pop", // Throw away its return value
diff --git a/vtest/src/forge_tests.rs b/vtest/src/forge_tests.rs
index c55deb9..a0dc8b7 100644
--- a/vtest/src/forge_tests.rs
+++ b/vtest/src/forge_tests.rs
@@ -86,7 +86,26 @@ fn scope_test() {
 }
 
 #[test]
-fn cursed_call_test() {
+fn recursion_test() {
+    // Recursive call with some stuff in it
+    assert_eq!(
+        main_return(
+            "fn sum(n) {
+                    if (n > 0) {
+                        return n + sum(n - 1);
+                    } else {
+                        return 0;
+                    }
+                }
+                 fn main() { return sum(5); }"),
+        15
+    )
+}
+
+//#[test]
+// This is no longer cursed, or a test. The revised calling convention with the pool pointer makes
+// it now perfectly sane. Left here for posterity.
+fn _cursed_call_test() {
     // This is a cursed subtlety of block scoping and the way calls are compiled. It's not actually
     // a bug. It's explained below:
     let src = "