From 615fef6ebc5823a2b3031eddb023eb877712b122 Mon Sep 17 00:00:00 2001
From: Scott Richmond <kredati@users.noreply.github.com>
Date: Tue, 3 Jun 2025 17:30:00 -0400
Subject: [PATCH] function calls: first draft, worked out the obvious bugs

---
 src/compiler.rs | 36 +++++++++++++++++++++---------------
 src/main.rs     | 11 +++++++++--
 src/vm.rs       |  2 +-
 3 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/src/compiler.rs b/src/compiler.rs
index 4539827..0c83131 100644
--- a/src/compiler.rs
+++ b/src/compiler.rs
@@ -27,10 +27,10 @@ pub enum Op {
     Stash,
     Load,
     ResetMatch,
+    Match,
     MatchNil,
     MatchTrue,
     MatchFalse,
-    MatchWord,
     PanicIfNoMatch,
     MatchConstant,
     MatchType,
@@ -135,10 +135,10 @@ impl std::fmt::Display for Op {
             StoreAt => "store_at",
             Stash => "stash",
             Load => "load",
+            Match => "match",
             MatchNil => "match_nil",
             MatchTrue => "match_true",
             MatchFalse => "match_false",
-            MatchWord => "match_word",
             ResetMatch => "reset_match",
             PanicIfNoMatch => "panic_if_no_match",
             MatchConstant => "match_constant",
@@ -211,10 +211,10 @@ impl Chunk {
         use Op::*;
         match op {
             Pop | Store | Stash | Load | Nil | True | False | MatchNil | MatchTrue | MatchFalse
-            | PanicIfNoMatch | MatchWord | ResetMatch | GetKey | PanicNoWhen | PanicNoMatch
-            | TypeOf | Duplicate | Decrement | Truncate | Noop | LoadTuple | LoadList | Eq
-            | Add | Sub | Mult | Div | Unbox | BoxStore | Assert | Get | At | Not | Panic
-            | EmptyString | ConcatStrings | Stringify | MatchType | Return => {
+            | PanicIfNoMatch | ResetMatch | GetKey | PanicNoWhen | PanicNoMatch | TypeOf
+            | Duplicate | Decrement | Truncate | Noop | LoadTuple | LoadList | Eq | Add | Sub
+            | Mult | Div | Unbox | BoxStore | Assert | Get | At | Not | Panic | EmptyString
+            | ConcatStrings | Stringify | MatchType | Return | Match => {
                 println!("{i:04}: {op}")
             }
             Constant | MatchConstant => {
@@ -551,7 +551,7 @@ impl Compiler {
                 self.emit_op(Op::PanicIfNoMatch);
             }
             WordPattern(name) => {
-                self.emit_op(Op::MatchWord);
+                self.emit_op(Op::Match);
                 self.bind(name);
             }
             Word(name) => {
@@ -566,7 +566,7 @@ impl Compiler {
                 }
             }
             PlaceholderPattern => {
-                self.emit_op(Op::MatchWord);
+                self.emit_op(Op::Match);
             }
             NilPattern => {
                 self.emit_op(Op::MatchNil);
@@ -838,6 +838,7 @@ impl Compiler {
                             // visit all the args
                             // then store them
                             // then call the function
+                            let arity = args.len();
                             for arg in args {
                                 self.visit(arg);
                             }
@@ -852,7 +853,8 @@ impl Compiler {
                                 }
                             }
                             self.emit_op(Op::Call);
-                            self.emit_byte(args.len());
+                            self.emit_byte(arity);
+                            self.stack_depth -= arity;
                         }
                     },
                     _ => unreachable!(),
@@ -982,15 +984,16 @@ impl Compiler {
                         None => {
                             let mut compiler = Compiler::new(clause, self.name, self.src);
                             // compiler.emit_op(Op::Load);
-                            compiler.stack_depth += arity;
-                            compiler.scope_depth += 1;
                             compiler.emit_op(Op::ResetMatch);
-                            compiler.match_depth = arity;
                             compilers.insert(arity, compiler);
                             compilers.get_mut(&arity).unwrap()
                         }
                     };
 
+                    compiler.stack_depth += arity;
+                    compiler.scope_depth += 1;
+                    compiler.match_depth = arity;
+
                     let mut tup_jump_idxes = vec![];
                     for member in pattern {
                         compiler.match_depth -= 1;
@@ -1001,6 +1004,9 @@ impl Compiler {
                         tup_jump_idxes.push(compiler.len());
                         compiler.emit_byte(0xff);
                     }
+                    if pattern.is_empty() {
+                        compiler.emit_op(Op::Match);
+                    }
                     compiler.emit_op(Op::Jump);
                     let jump_idx = compiler.len();
                     compiler.emit_byte(0xff);
@@ -1024,12 +1030,12 @@ impl Compiler {
                             break;
                         }
                     }
-                    while compiler.stack_depth > arity {
+                    while compiler.stack_depth > 0 {
                         compiler.pop();
                     }
                     compiler.stack_depth = 0;
                     compiler.emit_op(Op::Return);
-                    compiler.chunk.bytecode[jnm_idx] = compiler.len() as u8 - jnm_idx as u8;
+                    compiler.chunk.bytecode[jnm_idx] = compiler.len() as u8 - jnm_idx as u8 - 1;
                     compiler.scope_depth -= 1;
                 }
 
@@ -1054,7 +1060,7 @@ impl Compiler {
 
                 for (arity, mut compiler) in compilers.into_iter() {
                     compiler.emit_op(Op::PanicNoMatch);
-                    let mut chunk = compiler.chunk;
+                    let chunk = compiler.chunk;
                     if crate::DEBUG_COMPILE {
                         println!("=== function chuncktion: {name}/{arity} ===");
                         chunk.dissasemble();
diff --git a/src/main.rs b/src/main.rs
index 11573f0..59e3c08 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -76,9 +76,16 @@ pub fn run(src: &'static str) {
 pub fn main() {
     env::set_var("RUST_BACKTRACE", "1");
     let src = "
-fn foo (_) -> :foo
+fn foo () -> {
+    let x = :foo
+    let y = :bar
+    (x, y)
+}
 
-foo (nil)
+let x = foo ()
+let y = foo ()
+
+(x, y)
     ";
     run(src);
 }
diff --git a/src/vm.rs b/src/vm.rs
index f8a697f..688c61d 100644
--- a/src/vm.rs
+++ b/src/vm.rs
@@ -294,7 +294,7 @@ impl Vm {
                     self.match_depth = 0;
                     self.ip += 1;
                 }
-                MatchWord => {
+                Match => {
                     self.matches = true;
                     self.ip += 1;
                 }