From 0290bb3bf2f86a5dbd1dac6f7369ad12f1d2042c Mon Sep 17 00:00:00 2001
From: Scott Richmond <kredati@users.noreply.github.com>
Date: Mon, 23 Jun 2025 21:22:28 -0400
Subject: [PATCH] update (fix?) partial function application stack discipline

---
 sandbox.ld      | 76 ++++++++++++++++++++++++++-----------------------
 src/compiler.rs |  2 +-
 src/main.rs     |  2 +-
 src/vm.rs       |  4 +--
 4 files changed, 44 insertions(+), 40 deletions(-)

diff --git a/sandbox.ld b/sandbox.ld
index b99e3d0..9e65145 100644
--- a/sandbox.ld
+++ b/sandbox.ld
@@ -1,37 +1,41 @@
-fn apply_command {
-	"Takes a turtle state and a command and calculates a new state."
-	(state, command) -> match command with {
-		(:goto, (x, y)) -> assoc (state, :position, (x, y))
-		(:home) -> do state > 
-			assoc (_, :position, (0, 0)) >
-			assoc (_, :heading, 0)
-		(:clear) -> do state >
-			assoc (state, :position, (0, 0)) >
-			assoc (_, :heading, 0)
-		(:right, turns) -> update (state, :heading, add (_, turns))
-		(:left, turns) -> update (state, :heading, sub (_, turns))
-		(:forward, steps) -> {
-			let #{heading, position, ...} = state
-			let unit = heading/vector (heading)
-			let vect = mult (steps, unit)
-			update (state, :position, add (vect, _))
-		}
-		(:back, steps) -> {
-			let #{heading, position, ...} = state
-			let unit = heading/vector (heading)
-			let vect = mult (steps, unit)
-			update (state, :position, sub (_, vect))
-		}
-		(:penup) -> assoc (state, :pendown?, false)
-		(:pendown) -> assoc (state, :pendown?, true)
-		(:penwidth, pixels) -> assoc (state, :penwidth, pixels)
-		(:pencolor, color) -> assoc (state, :pencolor, color)
-		(:setheading, heading) -> assoc (state, :heading, heading)
-		(:loadstate, position, heading, visible?, pendown?, penwidth, pencolor) -> #{position, heading, visible?, pendown?, penwidth, pencolor}
-		(:show) -> assoc (state, :visible?, true)
-		(:hide) -> assoc (state, :visible?, false)
-		(:background, _) -> state
-	}
-}
+& fn apply_command {
+& 	"Takes a turtle state and a command and calculates a new state."
+& 	(state, command) -> match command with {
+& 		(:goto, (x, y)) -> assoc (state, :position, (x, y))
+& 		(:home) -> do state > 
+& 			assoc (_, :position, (0, 0)) >
+& 			assoc (_, :heading, 0)
+& 		(:clear) -> do state >
+& 			assoc (state, :position, (0, 0)) >
+& 			assoc (_, :heading, 0)
+& 		(:right, turns) -> update (state, :heading, add (_, turns))
+& 		(:left, turns) -> update (state, :heading, sub (_, turns))
+& 		(:forward, steps) -> {
+& 			let #{heading, position, ...} = state
+& 			let unit = heading/vector (heading)
+& 			let vect = mult (steps, unit)
+& 			update (state, :position, add (vect, _))
+& 		}
+& 		(:back, steps) -> {
+& 			let #{heading, position, ...} = state
+& 			let unit = heading/vector (heading)
+& 			let vect = mult (steps, unit)
+& 			update (state, :position, sub (_, vect))
+& 		}
+& 		(:penup) -> assoc (state, :pendown?, false)
+& 		(:pendown) -> assoc (state, :pendown?, true)
+& 		(:penwidth, pixels) -> assoc (state, :penwidth, pixels)
+& 		(:pencolor, color) -> assoc (state, :pencolor, color)
+& 		(:setheading, heading) -> assoc (state, :heading, heading)
+& 		(:loadstate, position, heading, visible?, pendown?, penwidth, pencolor) -> #{position, heading, visible?, pendown?, penwidth, pencolor}
+& 		(:show) -> assoc (state, :visible?, true)
+& 		(:hide) -> assoc (state, :visible?, false)
+& 		(:background, _) -> state
+& 	}
+& }
 
-apply_command (turtle_init, (:penup))
+fn many_args (_, _, x, _) -> x
+
+let fewer_args = many_args (:foo, :bar, _, :baz)
+
+fewer_args(:quux)
diff --git a/src/compiler.rs b/src/compiler.rs
index 5134627..7cd0595 100644
--- a/src/compiler.rs
+++ b/src/compiler.rs
@@ -917,7 +917,7 @@ impl Compiler {
                             self.resolve_binding(fn_name);
                             self.emit_op(Op::Partial);
                             self.emit_byte(arity);
-                            self.stack_depth -= 1;
+                            self.stack_depth -= args.len() - 1;
                         } else {
                             match get_builtin(fn_name, args.len()) {
                                 Some(code) => {
diff --git a/src/main.rs b/src/main.rs
index 3b26244..b9674ef 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,7 +4,7 @@ use std::env;
 use std::fs;
 
 const DEBUG_SCRIPT_COMPILE: bool = false;
-const DEBUG_SCRIPT_RUN: bool = false;
+const DEBUG_SCRIPT_RUN: bool = true;
 const DEBUG_PRELUDE_COMPILE: bool = false;
 const DEBUG_PRELUDE_RUN: bool = false;
 
diff --git a/src/vm.rs b/src/vm.rs
index badc4a0..589f32e 100644
--- a/src/vm.rs
+++ b/src/vm.rs
@@ -1000,7 +1000,7 @@ impl Vm {
                             let mut frame = CallFrame {
                                 function: the_fn,
                                 arity: args.len() as u8,
-                                stack_base: self.stack.len() - arity as usize - 1,
+                                stack_base: self.stack.len() - args.len(),
                                 ip: 0,
                             };
 
@@ -1090,7 +1090,7 @@ impl Vm {
                             let mut frame = CallFrame {
                                 function: the_fn,
                                 arity: args.len() as u8,
-                                stack_base: self.stack.len() - arity as usize - 1,
+                                stack_base: self.stack.len() - args.len(),
                                 ip: 0,
                             };