function things

src/ast.rs

@@ -7,7 +7,7 @@ use crate::errors::Span;
 use crate::gc::Symbol;
 use bumpalo::collections::Vec;
 
-#[derive(Debug, PartialEq, Eq, Hash)]
+#[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
 pub struct Ident {
     pub sym: Symbol,
     pub span: Span,

src/bytecode.rs

@@ -20,7 +20,7 @@
 //! to the length before the call. This means the interpreter has to do some bookkeeping, but it has
 //! to do that anyways.
 //!
-//! It is the compilers job to generate the correct loading of the arguments and assure that the aritiy
+//! It is the compilers job to generate the correct loading of the arguments and assure that the arity
 //! is correct before the `Call` instruction.
 //!
 //!
@@ -31,7 +31,7 @@
 //!
 //! When a call happens, the current stack offset is pushed onto the stack as a `Value::Native` and
 //! the element before it is stored as the new offset.
-//! Then all parameters are pushed onto the stack, from last to first.
+//! Then all parameters are pushed onto the stack, from first to last
 //! Afterwards, execution of the code is started. A function always has to return, and compiler
 //! inserts `return null` at the end of every function implicitly.
 //!
@@ -41,12 +41,12 @@
 //! returned value.
 //!
 //! ```text
-//!                 old stack offset─╮
-//!         ╭─Parameters─╮           │       old FnBlock index─╮     local─╮
-//!         v            v           v                         v           v  
-//! ───────┬─────────┬──────────┬─────────────┬────────────┬────────────┬─────────╮
-//! Num(6) │ Num(5)  │  Num(6)  │ NativeU(20) │ NativeU(4) │ NativeU(1) │  Num(5) │
-//! ───────┴─────────┴──────────┴─────────────┴────────────┴────────────┴─────────╯
+//!                   old stack offset─╮
+//!         ╭─Parameters─╮             │           old Function─╮     local─╮
+//!         v            v             v                        v           v  
+//! ───────┬─────────┬──────────┬─────────────┬────────────┬──────────┬─────────╮
+//! Num(6) │ Num(5)  │  Num(6)  │ NativeU(20) │ NativeU(4) │ Function │  Num(5) │
+//! ───────┴─────────┴──────────┴─────────────┴────────────┴──────────┴─────────╯
 //!  ^     ╰────────────────────────────────────────────────────────────────── current stack frame
 //!  │                                             ^
 //!  ╰─ old local                                  ╰─old PC
@@ -67,7 +67,7 @@ use debug2::Formatter;
 #[derive(Debug)]
 pub struct FnBlock<'bc> {
     /// The bytecode of the function
-    pub code: Vec<'bc, Instr<'bc>>,
+    pub code: Vec<'bc, Instr>,
     /// The sizes of the stack required by the function after the instruction at the same index. This is only used
     /// during compilation to calculate local variable offsets.
     pub stack_sizes: Vec<'bc, usize>,
@@ -90,10 +90,12 @@ impl debug2::Debug for FnBlock<'_> {
     }
 }
 
+pub type Function = usize;
+
 /// A bytecode instruction. For more details on the structure of the bytecode, read the module level docs [`bytecode`](`self`)
 #[derive(Debug, Clone, Copy)]
 #[cfg_attr(feature = "pretty", derive(debug2::Debug))]
-pub enum Instr<'bc> {
+pub enum Instr {
     /// An operation that does nothing.
     Nop,
 
@@ -129,7 +131,8 @@ pub enum Instr<'bc> {
     /// Same as `JmpFalse`, but unconditional
     Jmp(isize),
 
-    Call(&'bc FnBlock<'bc>),
+    /// Calls the function at the top of the stack, after the parameters
+    Call,
 
     Return,
 

src/compile.rs

@@ -1,8 +1,8 @@
 //! The compiler that compiles the AST down to bytecode
 
 use crate::ast::{
-    Assignment, BinaryOp, BinaryOpKind, Block, Call, Declaration, ElsePart, Expr, FnDecl, Ident,
-    IfStmt, Literal, Program, Stmt, UnaryOp, WhileStmt,
+    Assignment, BinaryOp, BinaryOpKind, Block, Call, CallKind, Declaration, ElsePart, Expr, FnDecl,
+    Ident, IfStmt, Literal, Program, Stmt, UnaryOp, WhileStmt,
 };
 use crate::bytecode::{FnBlock, Instr};
 use crate::errors::{CompilerError, Span};
@@ -11,6 +11,7 @@ use crate::vm::Value;
 use crate::{HashMap, RtAlloc};
 use bumpalo::collections::Vec;
 use bumpalo::Bump;
+use std::borrow::BorrowMut;
 use std::cell::RefCell;
 use std::rc::Rc;
 
@@ -152,8 +153,25 @@ impl<'bc, 'gc> Compiler<'bc, 'gc> {
         Ok(())
     }
 
-    fn compile_fn_decl(&mut self, _: &FnDecl) -> CResult {
-        todo!()
+    fn compile_fn_decl(&mut self, decl: &FnDecl) -> CResult {
+        let block = FnBlock {
+            code: Vec::new_in(self.bump),
+            stack_sizes: Vec::new_in(self.bump),
+            spans: Vec::new_in(self.bump),
+            arity: decl.params.len().try_into().map_err(|_| {
+                CompilerError::new(
+                    decl.params[u8::MAX as usize]
+                        .span
+                        .extend(decl.params.last().unwrap().span),
+                    "Too many parameters".to_string(),
+                )
+            })?,
+        };
+
+        self.blocks.push(block);
+        self.current_block = self.blocks.len() - 1;
+
+        Ok(())
     }
 
     fn compile_if(&mut self, if_stmt: &IfStmt) -> CResult {
@@ -214,7 +232,6 @@ impl<'bc, 'gc> Compiler<'bc, 'gc> {
         self.compile_block(ast_block)?;
 
         self.shrink_stack(pre_loop_stack_size, span);
-
         let jmp_offset = self.back_jmp_offset(first_stmt_idx);
         self.push_instr(Instr::Jmp(jmp_offset), StackChange::None, span);
 
@@ -358,8 +375,27 @@ impl<'bc, 'gc> Compiler<'bc, 'gc> {
         Ok(())
     }
 
-    fn compile_expr_call(&mut self, _: &Call) -> CResult {
-        todo!()
+    fn compile_expr_call(&mut self, call: &Call) -> CResult {
+        let params = match &call.kind {
+            CallKind::Fn(params) => params,
+            _ => todo!(),
+        };
+
+        let name = match &call.callee {
+            Expr::Ident(ident) => ident,
+            _ => todo!(),
+        };
+
+        let offset = self.env.borrow().lookup_local(name)?;
+
+        for param in params {
+            self.compile_expr(param)?;
+        }
+
+        self.push_instr(Instr::Load(offset), StackChange::Grow, call.span);
+        self.push_instr(Instr::Call, StackChange::Grow, call.span);
+
+        Ok(())
     }
 
     fn shrink_stack(&mut self, jmp_target_stack_size: usize, span: Span) {
@@ -415,13 +451,13 @@ impl<'bc, 'gc> Compiler<'bc, 'gc> {
         block.stack_sizes.last().copied().unwrap_or(0)
     }
 
-    fn change_instr(&mut self, index: usize, instr: Instr<'bc>) {
+    fn change_instr(&mut self, index: usize, instr: Instr) {
         let block = &mut self.blocks[self.current_block];
         block.code[index] = instr;
     }
 
     /// Pushes an instruction and returns the index of the new instruction
-    fn push_instr(&mut self, instr: Instr<'bc>, stack_change: StackChange, span: Span) -> usize {
+    fn push_instr(&mut self, instr: Instr, stack_change: StackChange, span: Span) -> usize {
         let block = &mut self.blocks[self.current_block];
         let stack_top = block.stack_sizes.last().copied().unwrap_or(0);
         let new_stack_top = stack_top as isize + stack_change.as_isize();

src/vm.rs

@@ -1,4 +1,4 @@
-use crate::bytecode::{FnBlock, Instr};
+use crate::bytecode::{FnBlock, Function, Instr};
 use crate::gc::{Object, RtAlloc, Symbol};
 use crate::Config;
 use std::fmt::{Debug, Display, Formatter};
@@ -16,6 +16,8 @@ pub fn execute<'bc>(
     let mut vm = Vm {
         blocks: bytecode,
         current: bytecode.first().ok_or("no bytecode found")?,
+        current_block_index: 0,
+        stack_offset: 0,
         pc: 0,
         stack: Vec::with_capacity(1024 << 5),
         _alloc: alloc,
@@ -41,20 +43,18 @@ pub enum Value {
     Array,
     /// A map from string to value
     Object(Object),
+    /// A first-class function object
+    Function(Function),
     /// A value that is stored by the vm for bookkeeping and should never be accessed for anything else
     NativeU(usize),
 }
 
+#[cfg(target_pointer_width = "64")]
+const _: [(); 24] = [(); std::mem::size_of::<Value>()];
+
 #[derive(Debug, Clone, Copy)]
 pub struct Ptr(NonNull<()>);
 
-const _: () = _check_val_size();
-const fn _check_val_size() {
-    if std::mem::size_of::<Value>() != 24 {
-        panic!("value got bigger!");
-    }
-}
-
 const TRUE: Value = Value::Bool(true);
 const FALSE: Value = Value::Bool(false);
 
@@ -67,7 +67,11 @@ struct Vm<'bc, 'io> {
     step: bool,
 
     // -- local to the current function
+    /// The current function
     current: &'bc FnBlock<'bc>,
+    current_block_index: usize,
+    /// The offset of the first parameter of the current function
+    stack_offset: usize,
     /// Index of the instruction currently being executed
     pc: usize,
 }
@@ -96,9 +100,9 @@ impl<'bc> Vm<'bc, '_> {
             Instr::Nop => {}
             Instr::Store(index) => {
                 let val = self.stack.pop().unwrap();
-                self.stack[index] = val;
+                self.stack[self.stack_offset + index] = val;
             }
-            Instr::Load(index) => self.stack.push(self.stack[index]),
+            Instr::Load(index) => self.stack.push(self.stack[self.stack_offset + index]),
             Instr::PushVal(value) => self.stack.push(value),
             Instr::Neg => {
                 let val = self.stack.pop().unwrap();
@@ -185,7 +189,7 @@ impl<'bc> Vm<'bc, '_> {
                 }
             }
             Instr::Jmp(pos) => self.pc = (self.pc as isize + pos) as usize,
-            Instr::Call(_) => todo!(),
+            Instr::Call => self.call()?,
             Instr::Return => todo!(),
             Instr::ShrinkStack(size) => {
                 assert!(self.stack.len() >= size);
@@ -210,6 +214,34 @@ impl<'bc> Vm<'bc, '_> {
         Ok(())
     }
 
+    fn call(&mut self) -> VmResult {
+        let old_offset = self.stack_offset;
+        let old_idx = self.current_block_index;
+        let function = self.stack.pop().unwrap();
+        if let Value::Function(func) = function {
+            let fn_block = &self.blocks[func];
+
+            let new_stack_frame_start = self.stack.len() - fn_block.arity as usize;
+            self.stack_offset = new_stack_frame_start;
+
+            self.stack.push(Value::NativeU(old_offset));
+            self.stack.push(Value::NativeU(self.pc));
+            self.stack.push(Value::Function(old_idx));
+
+            self.current_block_index = func;
+            self.current = fn_block;
+
+            self.pc = 0;
+
+            // TODO don't be recursive like this
+            self.execute_function()?;
+        } else {
+            return Err("not a function");
+        }
+
+        Ok(())
+    }
+
     fn type_error(&self) -> VmError {
         "bad type"
     }
@@ -240,6 +272,7 @@ impl Display for Value {
             Value::String(str) => f.write_str(str.as_str()),
             Value::Array => todo!(),
             Value::Object(_) => todo!(),
+            Value::Function(_) => f.write_str("[function]"),
             Value::NativeU(_) => panic!("Called display on native value!"),
         }
     }

test.dil

@@ -1,5 +1,14 @@
-let i = 0;
+let x = 5;
 
-while i < 1000 {
-    i = i + 1;
-}
+x(5, 6, 7);
+
+fn hi(a, b,c,ds,gds,fdsa,fds,fd,sf,ds,fd,fd,fd,d,fd,fd,f,df,df,d,fd
+,fd,f,fd,fd,fd,fd,fd,f,a, b,c,ds,gds,fdsa,fds,fd,sf,ds,fd,fd,fd,d,fd,
+fd,f,df,df,d,fd,fd,f,fd,fd,fd,fd,fd,f,a, b,c,ds,gds,fdsa,fds,fd,sf,ds,
+fd,fd,fd,d,fd,fd,f,df,df,d,fd,fd,f,fd,fd,fd,fd,fd,f,a, b,c,ds,gds,fdsa,
+fds,fd,sf,ds,fd,fd,fd,d,fd,fd,f,df,df,d,fd,fd,f,fd,fd,fd,fd,fd,f,a, b,c,ds,
+gds,fdsa,fds,fd,sf,ds,fd,fd,fd,d,fd,fd,f,df,df,d,fd,fd,f,fd,fd,fd,fd,fd,f,df,
+df,d,fd,fd,f,fd,fd,fd,fd,fd,f,df,df,d,fd,fd,f,fd,fd,fd,fd,f,df,df,d,fd,fd,f,
+fd,fd,fd,fd,fd,f,df,df,d,fd,fd,f,fd,fd,fd,fd,f,df,df,d,fd,fd,f,fd,fd,fd,fd,
+fd,f,df,df,d,fd,fd,f,fd,fd,fd,fd,f,df,df,d,fd,fd,f,fd,fd,fd,fd,fd,f,df,df,d,
+fd,fd,f,fd,fd,fd,fd,f,df,df,d,fd,fd,f,fd,fd,fd,fd,fd,f,df,df,d,fd,fd,f,fd,fd,fd) {}