Cargo.toml

@@ -9,15 +9,15 @@ name = "ngr"
 path = "src/lib.rs"
 
 [dependencies]
-clap = { version = "4.4.11", features = ["derive"] }
+clap = { version = "4.4.18", features = ["derive"] }
 codespan = "0.11.1"
 codespan-reporting = "0.11.1"
-cranelift-codegen = "0.103.0"
+cranelift-codegen = "0.104.0"
-cranelift-jit = "0.103.0"
+cranelift-jit = "0.104.0"
-cranelift-frontend = "0.103.0"
+cranelift-frontend = "0.104.0"
-cranelift-module = "0.103.0"
+cranelift-module = "0.104.0"
-cranelift-native = "0.103.0"
+cranelift-native = "0.104.0"
-cranelift-object = "0.103.0"
+cranelift-object = "0.104.0"
 internment = { version = "0.7.4", default-features = false, features = ["arc"] }
 lalrpop-util = "0.20.0"
 lazy_static = "1.4.0"
@@ -26,10 +26,10 @@ pretty = { version = "0.12.3", features = ["termcolor"] }
 proptest = "1.4.0"
 rand = "0.8.5"
 rustyline = "13.0.0"
-target-lexicon = "0.12.12"
+target-lexicon = "0.12.13"
-tempfile = "3.8.1"
+tempfile = "3.9.0"
-thiserror = "1.0.52"
+thiserror = "1.0.56"
-anyhow = "1.0.77"
+anyhow = "1.0.79"
 
 [build-dependencies]
 lalrpop = "0.20.0"

examples/basic/generated0001.ngr

@@ -0,0 +1,3 @@
+x = 4u64;
+function f(y) (x + y)
+print x;

examples/basic/generated0002.ngr

@@ -0,0 +1,7 @@
+b = -7662558304906888395i64;
+z = 1030390794u32;
+v = z;
+q = <i64>z;
+s = -2115098981i32;
+t = <i32>s;
+print t;

examples/basic/generated0003.ngr

@@ -0,0 +1,4 @@
+n = (49u8 + 155u8);
+q = n;
+function u (b) n + b
+v = n;

runtime/rts.c

@@ -28,6 +28,11 @@ void print(char *_ignore, char *variable_name, int64_t vtype, int64_t value) {
     case /* I64 = */ 23:
         printf("%s = %" PRIi64 "i64\n", variable_name, value);
         break;
+    case /* void = */ 255:
+        printf("%s = <void>\n", variable_name);
+        break;
+    default:
+        printf("%s = UNKNOWN VTYPE %d\n", variable_name, vtype);
     }
 }
 

src/backend.rs

@@ -60,6 +60,7 @@ pub struct Backend<M: Module> {
     data_ctx: DataDescription,
     runtime_functions: RuntimeFunctions,
     defined_strings: HashMap<String, DataId>,
+    defined_functions: HashMap<ArcIntern<String>, FuncId>,
     defined_symbols: HashMap<ArcIntern<String>, (DataId, ConstantType)>,
     output_buffer: Option<String>,
     platform: Triple,
@@ -92,6 +93,7 @@ impl Backend<JITModule> {
             data_ctx: DataDescription::new(),
             runtime_functions,
             defined_strings: HashMap::new(),
+            defined_functions: HashMap::new(),
             defined_symbols: HashMap::new(),
             output_buffer,
             platform: Triple::host(),
@@ -132,6 +134,7 @@ impl Backend<ObjectModule> {
             data_ctx: DataDescription::new(),
             runtime_functions,
             defined_strings: HashMap::new(),
+            defined_functions: HashMap::new(),
             defined_symbols: HashMap::new(),
             output_buffer: None,
             platform,

src/backend/error.rs

@@ -55,6 +55,7 @@ impl From<BackendError> for Diagnostic<usize> {
         match value {
             BackendError::Cranelift(me) => {
                 Diagnostic::error().with_message(format!("Internal cranelift error: {}", me))
+                    .with_notes(vec![format!("{:?}", me)])
             }
             BackendError::BuiltinError(me) => {
                 Diagnostic::error().with_message(format!("Internal runtime function error: {}", me))

src/backend/eval.rs

@@ -26,34 +26,7 @@ impl Backend<JITModule> {
     /// of the built-in test systems.)
     pub fn eval(program: Program<Type>) -> Result<String, EvalError<Expression<Type>>> {
         let mut jitter = Backend::jit(Some(String::new()))?;
-        let mut function_map = HashMap::new();
+        let function_id = jitter.compile_program("___test_jit_eval___", program)?;
-        let mut main_function_body = vec![];
-
-        for item in program.items {
-            match item {
-                TopLevel::Function(name, args, rettype, body) => {
-                    let function_id =
-                        jitter.compile_function(name.as_str(), args.as_slice(), rettype, body)?;
-                    function_map.insert(name, function_id);
-                }
-
-                TopLevel::Statement(stmt) => {
-                    main_function_body.push(stmt);
-                }
-            }
-        }
-
-        let main_function_body = Expression::Block(
-            Location::manufactured(),
-            Type::Primitive(crate::eval::PrimitiveType::Void),
-            main_function_body,
-        );
-        let function_id = jitter.compile_function(
-            "___test_jit_eval___",
-            &[],
-            Type::Primitive(crate::eval::PrimitiveType::Void),
-            main_function_body,
-        )?;
         jitter.module.finalize_definitions()?;
         let compiled_bytes = jitter.bytes(function_id);
         let compiled_function = unsafe { std::mem::transmute::<_, fn() -> ()>(compiled_bytes) };
@@ -89,8 +62,13 @@ impl Backend<ObjectModule> {
         for item in program.items {
             match item {
                 TopLevel::Function(name, args, rettype, body) => {
-                    let function_id =
+                    let function_id = backend.compile_function(
-                        backend.compile_function(name.as_str(), args.as_slice(), rettype, body)?;
+                        &mut HashMap::new(),
+                        name.as_str(),
+                        args.as_slice(),
+                        rettype,
+                        body,
+                    )?;
                     function_map.insert(name, function_id);
                 }
 
@@ -111,6 +89,7 @@ impl Backend<ObjectModule> {
         let executable_path = my_directory.path().join("test_executable");
 
         backend.compile_function(
+            &mut HashMap::new(),
             "gogogo",
             &[],
             Type::Primitive(crate::eval::PrimitiveType::Void),
@@ -154,6 +133,7 @@ impl Backend<ObjectModule> {
                     .join("runtime")
                     .join("rts.c"),
             )
+            .arg("-Wl,-ld_classic")
             .arg(object_file)
             .arg("-o")
             .arg(executable_path)
@@ -206,16 +186,15 @@ proptest::proptest! {
     #[test]
     fn jit_backend(program in Program::arbitrary()) {
         use crate::eval::PrimOpError;
-            use pretty::{DocAllocator, Pretty};
+        //    use pretty::{DocAllocator, Pretty};
-            let allocator = pretty::BoxAllocator;
+        //    let allocator = pretty::BoxAllocator;
-            allocator
+        //    allocator
-              .text("---------------")
+        //      .text("---------------")
-              .append(allocator.hardline())
+        //      .append(allocator.hardline())
-              .append(program.pretty(&allocator))
+        //      .append(program.pretty(&allocator))
-              .1
+        //      .1
-              .render_colored(70, pretty::termcolor::StandardStream::stdout(pretty::termcolor::ColorChoice::Auto))
+        //      .render_colored(70, pretty::termcolor::StandardStream::stdout(pretty::termcolor::ColorChoice::Auto))
-              .expect("rendering works");
+        //      .expect("rendering works");
-
 
         let basic_result = program.eval().map(|(_,x)| x);
 

src/backend/into_crane.rs

@@ -1,24 +1,23 @@
+use crate::backend::error::BackendError;
+use crate::backend::Backend;
 use crate::eval::PrimitiveType;
 use crate::ir::{Expression, Primitive, Program, TopLevel, Type, Value, ValueOrRef, Variable};
 use crate::syntax::{ConstantType, Location};
-use crate::util::scoped_map::ScopedMap;
 use cranelift_codegen::ir::{
-    self, entities, types, AbiParam, Function, GlobalValue, InstBuilder, Signature, UserFuncName,
+    self, entities, types, AbiParam, Function, GlobalValue, InstBuilder, MemFlags, Signature, UserFuncName
 };
 use cranelift_codegen::isa::CallConv;
 use cranelift_codegen::Context;
 use cranelift_frontend::{FunctionBuilder, FunctionBuilderContext};
-use cranelift_module::{FuncId, Linkage, Module};
+use cranelift_module::{DataDescription, FuncId, Linkage, Module};
 use internment::ArcIntern;
-
+use std::collections::{hash_map, HashMap};
-use crate::backend::error::BackendError;
-use crate::backend::Backend;
 
 /// When we're talking about variables, it's handy to just have a table that points
 /// from a variable to "what to do if you want to reference this variable", which is
 /// agnostic about whether the variable is local, global, an argument, etc. Since
 /// the type of that function is a little bit annoying, we summarize it here.
-enum ReferenceBuilder {
+pub enum ReferenceBuilder {
     Global(ConstantType, GlobalValue),
     Local(ConstantType, cranelift_frontend::Variable),
     Argument(ConstantType, entities::Value),
@@ -29,7 +28,8 @@ impl ReferenceBuilder {
         match self {
             ReferenceBuilder::Global(ty, gv) => {
                 let cranelift_type = ir::Type::from(*ty);
-                let value = builder.ins().symbol_value(cranelift_type, *gv);
+                let ptr_value = builder.ins().symbol_value(types::I64, *gv);
+                let value = builder.ins().load(cranelift_type, MemFlags::new(), ptr_value, 0);
                 (value, *ty)
             }
 
@@ -81,11 +81,44 @@ impl<M: Module> Backend<M> {
         program: Program<Type>,
     ) -> Result<FuncId, BackendError> {
         let mut generated_body = vec![];
+        let mut variables = HashMap::new();
+
+        for (top_level_name, top_level_type) in program.get_top_level_variables() {
+            match top_level_type {
+                Type::Function(argument_types, return_type) => {
+                    let func_id = self.declare_function(
+                        top_level_name.as_str(),
+                        Linkage::Export,
+                        argument_types,
+                        *return_type,
+                    )?;
+                    self.defined_functions.insert(top_level_name, func_id);
+                }
+
+                Type::Primitive(pt) => {
+                    let data_id = self.module.declare_data(
+                        top_level_name.as_str(),
+                        Linkage::Export,
+                        true,
+                        false,
+                    )?;
+                    self.module.define_data(data_id, &pt.blank_data())?;
+                    self.defined_symbols
+                        .insert(top_level_name, (data_id, pt.into()));
+                }
+            }
+        }
+
+        let void = Type::Primitive(PrimitiveType::Void);
+        let main_func_id =
+            self.declare_function(function_name, Linkage::Export, vec![], void.clone())?;
+        self.defined_functions
+            .insert(ArcIntern::new(function_name.to_string()), main_func_id);
 
         for item in program.items {
             match item {
                 TopLevel::Function(name, args, rettype, body) => {
-                    self.compile_function(name.as_str(), &args, rettype, body)?;
+                    self.compile_function(&mut variables, name.as_str(), &args, rettype, body)?;
                 }
 
                 TopLevel::Statement(stmt) => {
@@ -94,8 +127,8 @@ impl<M: Module> Backend<M> {
             }
         }
 
-        let void = Type::Primitive(PrimitiveType::Void);
         self.compile_function(
+            &mut variables,
             function_name,
             &[],
             void.clone(),
@@ -103,14 +136,47 @@ impl<M: Module> Backend<M> {
         )
     }
 
+    fn declare_function(
+        &mut self,
+        name: &str,
+        linkage: Linkage,
+        argument_types: Vec<Type>,
+        return_type: Type,
+    ) -> Result<FuncId, cranelift_module::ModuleError> {
+        let basic_signature = Signature {
+            params: argument_types
+                .iter()
+                .map(|t| self.translate_type(t))
+                .collect(),
+            returns: if return_type == Type::Primitive(PrimitiveType::Void) {
+                vec![]
+            } else {
+                vec![self.translate_type(&return_type)]
+            },
+            call_conv: CallConv::triple_default(&self.platform),
+        };
+
+        // this generates the handle for the function that we'll eventually want to
+        // return to the user. For now, we declare all functions defined by this
+        // function as public/global/exported, although we may want to reconsider
+        // this decision later.
+        self.module
+            .declare_function(name, linkage, &basic_signature)
+    }
+
     /// Compile the given function.
     pub fn compile_function(
         &mut self,
+        variables: &mut HashMap<Variable, ReferenceBuilder>,
         function_name: &str,
         arguments: &[(Variable, Type)],
         return_type: Type,
         body: Expression<Type>,
     ) -> Result<FuncId, BackendError> {
+        // reset the next variable counter. this value shouldn't matter; hopefully
+        // we won't be using close to 2^32 variables!
+        self.reset_local_variable_tracker();
+
         let basic_signature = Signature {
             params: arguments
                 .iter()
@@ -124,17 +190,23 @@ impl<M: Module> Backend<M> {
             call_conv: CallConv::triple_default(&self.platform),
         };
 
-        // reset the next variable counter. this value shouldn't matter; hopefully
-        // we won't be using close to 2^32 variables!
-        self.reset_local_variable_tracker();
-
         // this generates the handle for the function that we'll eventually want to
         // return to the user. For now, we declare all functions defined by this
         // function as public/global/exported, although we may want to reconsider
         // this decision later.
-        let func_id =
+        let interned_name = ArcIntern::new(function_name.to_string());
-            self.module
+        let func_id = match self.defined_functions.entry(interned_name) {
-                .declare_function(function_name, Linkage::Export, &basic_signature)?;
+            hash_map::Entry::Occupied(entry) => *entry.get(),
+            hash_map::Entry::Vacant(vac) => {
+                let func_id = self.module.declare_function(
+                    function_name,
+                    Linkage::Export,
+                    &basic_signature,
+                )?;
+                vac.insert(func_id);
+                func_id
+            }
+        };
 
         // Next we have to generate the compilation context for the rest of this
         // function. Currently, we generate a fresh context for every function.
@@ -145,14 +217,6 @@ impl<M: Module> Backend<M> {
         let user_func_name = UserFuncName::user(0, func_id.as_u32());
         ctx.func = Function::with_name_signature(user_func_name, basic_signature);
 
-        // Let's start creating the variable table we'll use when we're dereferencing
-        // them later. This table is a little interesting because instead of pointing
-        // from data to data, we're going to point from data (the variable) to an
-        // action to take if we encounter that variable at some later point. This
-        // makes it nice and easy to have many different ways to access data, such
-        // as globals, function arguments, etc.
-        let mut variables: ScopedMap<ArcIntern<String>, ReferenceBuilder> = ScopedMap::new();
-
         // At the outer-most scope of things, we'll put global variables we've defined
         // elsewhere in the program.
         for (name, (data_id, ty)) in self.defined_symbols.iter() {
@@ -160,12 +224,6 @@ impl<M: Module> Backend<M> {
             variables.insert(name.clone(), ReferenceBuilder::Global(*ty, local_data));
         }
 
-        // Once we have these, we're going to actually push a level of scope and
-        // add our arguments. We push scope because if there happen to be any with
-        // the same name (their shouldn't be, but just in case), we want the arguments
-        // to win.
-        variables.new_scope();
-
         // Finally (!), we generate the function builder that we're going to use to
         // make this function!
         let mut fctx = FunctionBuilderContext::new();
@@ -192,7 +250,7 @@ impl<M: Module> Backend<M> {
 
         builder.switch_to_block(main_block);
 
-        let (value, _) = self.compile_expression(body, &mut variables, &mut builder)?;
+        let (value, _) = self.compile_expression(body, variables, &mut builder)?;
 
         // Now that we're done, inject a return function (one with no actual value; basically
         // the equivalent of Rust's `return;`). We then seal the block (which lets Cranelift
@@ -221,7 +279,7 @@ impl<M: Module> Backend<M> {
     fn compile_expression(
         &mut self,
         expr: Expression<Type>,
-        variables: &mut ScopedMap<Variable, ReferenceBuilder>,
+        variables: &mut HashMap<Variable, ReferenceBuilder>,
         builder: &mut FunctionBuilder,
     ) -> Result<(entities::Value, ConstantType), BackendError> {
         match expr {
@@ -282,6 +340,29 @@ impl<M: Module> Backend<M> {
 
                     (ConstantType::U64, Type::Primitive(PrimitiveType::U64)) => Ok((val, val_type)),
 
+                    (ConstantType::Void, Type::Primitive(PrimitiveType::Void)) => {
+                        Ok((val, val_type))
+                    }
+
+                    (ConstantType::U8, Type::Primitive(PrimitiveType::I16)) => {
+                        Ok((builder.ins().uextend(types::I16, val), ConstantType::I16))
+                    }
+                    (ConstantType::U8, Type::Primitive(PrimitiveType::I32)) => {
+                        Ok((builder.ins().uextend(types::I32, val), ConstantType::I32))
+                    }
+                    (ConstantType::U8, Type::Primitive(PrimitiveType::I64)) => {
+                        Ok((builder.ins().uextend(types::I64, val), ConstantType::I64))
+                    }
+                    (ConstantType::U16, Type::Primitive(PrimitiveType::I32)) => {
+                        Ok((builder.ins().uextend(types::I32, val), ConstantType::I32))
+                    }
+                    (ConstantType::U16, Type::Primitive(PrimitiveType::I64)) => {
+                        Ok((builder.ins().uextend(types::I64, val), ConstantType::I64))
+                    }
+                    (ConstantType::U32, Type::Primitive(PrimitiveType::I64)) => {
+                        Ok((builder.ins().uextend(types::I64, val), ConstantType::I64))
+                    }
+
                     _ => Err(BackendError::InvalidTypeCast {
                         from: val_type.into(),
                         to: target_type,
@@ -327,7 +408,7 @@ impl<M: Module> Backend<M> {
             }
 
             Expression::Block(_, _, mut exprs) => match exprs.pop() {
-                None => Ok((builder.ins().iconst(types::I8, 0), ConstantType::I8)),
+                None => Ok((builder.ins().iconst(types::I64, 0), ConstantType::Void)),
                 Some(last) => {
                     for inner in exprs {
                         // we can ignore all of these return values and such, because we
@@ -354,7 +435,7 @@ impl<M: Module> Backend<M> {
                 // Look up the value for the variable. Because this might be a
                 // global variable (and that requires special logic), we just turn
                 // this into an `Expression` and re-use the logic in that implementation.
-                let fake_ref = ValueOrRef::Ref(ann, Type::Primitive(PrimitiveType::U8), var);
+                let fake_ref = ValueOrRef::Ref(ann, Type::Primitive(PrimitiveType::U8), var.clone());
                 let (val, vtype) = self.compile_value_or_ref(fake_ref, variables, builder)?;
 
                 let vtype_repr = builder.ins().iconst(types::I64, vtype as i64);
@@ -379,7 +460,7 @@ impl<M: Module> Backend<M> {
                     print_func_ref,
                     &[buffer_ptr, name_ptr, vtype_repr, casted_val],
                 );
-                Ok((builder.ins().iconst(types::I8, 0), ConstantType::I8))
+                Ok((builder.ins().iconst(types::I64, 0), ConstantType::Void))
             }
 
             Expression::Bind(_, name, _, expr) => {
@@ -390,7 +471,7 @@ impl<M: Module> Backend<M> {
                 builder.declare_var(variable, ir_type);
                 builder.def_var(variable, value);
                 variables.insert(name, ReferenceBuilder::Local(value_type, variable));
-                Ok((builder.ins().iconst(types::I8, 0), ConstantType::I8))
+                Ok((builder.ins().iconst(types::I64, 0), ConstantType::Void))
             }
         }
     }
@@ -400,7 +481,7 @@ impl<M: Module> Backend<M> {
     fn compile_value_or_ref(
         &self,
         valref: ValueOrRef<Type>,
-        variables: &ScopedMap<Variable, ReferenceBuilder>,
+        variables: &HashMap<Variable, ReferenceBuilder>,
         builder: &mut FunctionBuilder,
     ) -> Result<(entities::Value, ConstantType), BackendError> {
         match valref {
@@ -453,3 +534,23 @@ impl<M: Module> Backend<M> {
         }
     }
 }
+
+impl PrimitiveType {
+    fn blank_data(&self) -> DataDescription {
+        let (size, alignment) = match self {
+            PrimitiveType::Void => (8, 8),
+            PrimitiveType::U8 => (1, 1),
+            PrimitiveType::U16 => (2, 2),
+            PrimitiveType::U32 => (4, 4),
+            PrimitiveType::U64 => (4, 4),
+            PrimitiveType::I8 => (1, 1),
+            PrimitiveType::I16 => (2, 2),
+            PrimitiveType::I32 => (4, 4),
+            PrimitiveType::I64 => (4, 4),
+        };
+        let mut result = DataDescription::new();
+        result.define_zeroinit(size);
+        result.set_align(alignment);
+        result
+    }
+}

src/backend/runtime.rs

@@ -119,7 +119,7 @@ extern "C" fn runtime_print(
         Ok(ConstantType::U16) => format!("{} = {}u16", reconstituted, value as u16),
         Ok(ConstantType::U32) => format!("{} = {}u32", reconstituted, value as u32),
         Ok(ConstantType::U64) => format!("{} = {}u64", reconstituted, value as u64),
-        Err(_) => format!("{} = {}<unknown type>", reconstituted, value),
+        Err(_) => format!("{} = {}<unknown type {}>", reconstituted, value, vtype_repr),
     };
 
     if let Some(output_buffer) = unsafe { output_buffer.as_mut() } {

src/eval/primtype.rs

@@ -191,6 +191,13 @@ impl PrimitiveType {
             (PrimitiveType::I64, Value::I32(x)) => Ok(Value::I64(*x as i64)),
             (PrimitiveType::I64, Value::I64(x)) => Ok(Value::I64(*x)),
 
+            (PrimitiveType::I16, Value::U8(x)) => Ok(Value::I16(*x as i16)),
+            (PrimitiveType::I32, Value::U8(x)) => Ok(Value::I32(*x as i32)),
+            (PrimitiveType::I64, Value::U8(x)) => Ok(Value::I64(*x as i64)),
+            (PrimitiveType::I32, Value::U16(x)) => Ok(Value::I32(*x as i32)),
+            (PrimitiveType::I64, Value::U16(x)) => Ok(Value::I64(*x as i64)),
+            (PrimitiveType::I64, Value::U32(x)) => Ok(Value::I64(*x as i64)),
+
             (PrimitiveType::Void, Value::Void) => Ok(Value::Void),
 
             _ => Err(PrimOpError::UnsafeCast {

src/ir.rs

@@ -16,5 +16,6 @@ mod arbitrary;
 pub mod ast;
 mod eval;
 mod strings;
+mod top_level;
 
 pub use ast::*;

src/ir/arbitrary.rs

@@ -1,5 +1,5 @@
 use crate::eval::PrimitiveType;
-use crate::ir::{Expression, Primitive, Program, TopLevel, Type, Value, ValueOrRef, Variable};
+use crate::ir::{Expression, Primitive, Program, TopLevel, Type, TypeWithVoid, Value, ValueOrRef, Variable};
 use crate::syntax::Location;
 use crate::util::scoped_map::ScopedMap;
 use proptest::strategy::{NewTree, Strategy, ValueTree};
@@ -288,14 +288,25 @@ fn generate_random_expression(
         ExpressionType::Block => {
             let num_stmts = BLOCK_LENGTH_DISTRIBUTION.sample(rng);
             let mut stmts = Vec::new();
-            let mut last_type = Type::Primitive(PrimitiveType::Void);
+
+            if num_stmts == 0 {
+                return Expression::Block(Location::manufactured(), Type::void(), stmts);
+            }
 
             env.new_scope();
-            for _ in 0..num_stmts {
+            for _ in 1..num_stmts {
-                let next = generate_random_expression(rng, env);
+                let mut next = generate_random_expression(rng, env);
-                last_type = next.type_of();
+                let next_type = next.type_of();
+                if !next_type.is_void() {
+                    let name = generate_random_name(rng);
+                    env.insert(name.clone(), next_type.clone());
+                    next = Expression::Bind(Location::manufactured(), name, next_type, Box::new(next));
+                }
                 stmts.push(next);
             }
+            let last_expr = generate_random_expression(rng, env);
+            let last_type = last_expr.type_of();
+            stmts.push(last_expr);
             env.release_scope();
 
             Expression::Block(Location::manufactured(), last_type, stmts)

src/ir/ast.rs

@@ -6,7 +6,10 @@ use crate::{
 use internment::ArcIntern;
 use pretty::{BoxAllocator, DocAllocator, Pretty};
 use proptest::arbitrary::Arbitrary;
-use std::{fmt, str::FromStr, sync::atomic::AtomicUsize};
+use std::convert::TryFrom;
+use std::fmt;
+use std::str::FromStr;
+use std::sync::atomic::AtomicUsize;
 
 use super::arbitrary::ProgramGenerator;
 
@@ -97,6 +100,19 @@ pub enum TopLevel<Type> {
     Function(Variable, Vec<(Variable, Type)>, Type, Expression<Type>),
 }
 
+impl<T: Clone + TypeWithVoid + TypeWithFunction> TopLevel<T> {
+    /// Return the type of the item, as inferred or recently
+    /// computed.
+    pub fn type_of(&self) -> T {
+        match self {
+            TopLevel::Statement(expr) => expr.type_of(),
+            TopLevel::Function(_, args, ret, _) => {
+                T::build_function_type(args.iter().map(|(_, t)| t.clone()).collect(), ret.clone())
+            }
+        }
+    }
+}
+
 impl<'a, 'b, D, A, Type> Pretty<'a, D, A> for &'b TopLevel<Type>
 where
     A: 'a,
@@ -148,7 +164,7 @@ pub enum Expression<Type> {
 }
 
 impl<Type: Clone + TypeWithVoid> Expression<Type> {
-    /// Return a reference to the type of the expression, as inferred or recently
+    /// Return the type of the expression, as inferred or recently
     /// computed.
     pub fn type_of(&self) -> Type {
         match self {
@@ -242,6 +258,16 @@ where
     }
 }
 
+impl Expression<Type> {
+    pub fn to_pretty(&self) -> String {
+        let arena = pretty::Arena::<()>::new();
+        let doc = self.pretty(&arena);
+        let mut output_bytes = Vec::new();
+        doc.render(72, &mut output_bytes).unwrap();
+        String::from_utf8(output_bytes).expect("pretty generates valid utf-8")
+    }
+}
+
 /// A type representing the primitives allowed in the language.
 ///
 /// Having this as an enumeration avoids a lot of "this should not happen"
@@ -565,27 +591,56 @@ impl TypeOrVar {
     }
 }
 
+impl PartialEq<Type> for TypeOrVar {
+    fn eq(&self, other: &Type) -> bool {
+        match other {
+            Type::Function(a, b) => match self {
+                TypeOrVar::Function(x, y) => x == a && y.as_ref() == b.as_ref(),
+                _ => false,
+            },
+
+            Type::Primitive(a) => match self {
+                TypeOrVar::Primitive(x) => a == x,
+                _ => false,
+            },
+        }
+    }
+}
+
 pub trait TypeWithVoid {
     fn void() -> Self;
+    fn is_void(&self) -> bool;
 }
 
 impl TypeWithVoid for Type {
     fn void() -> Self {
         Type::Primitive(PrimitiveType::Void)
     }
+
+    fn is_void(&self) -> bool {
+        self == &Type::Primitive(PrimitiveType::Void)
+    }
 }
 
 impl TypeWithVoid for TypeOrVar {
     fn void() -> Self {
         TypeOrVar::Primitive(PrimitiveType::Void)
     }
+
+    fn is_void(&self) -> bool {
+        self == &TypeOrVar::Primitive(PrimitiveType::Void)
+    }
 }
 
-//impl From<Type> for TypeOrVar {
+pub trait TypeWithFunction: Sized {
-//    fn from(value: Type) -> Self {
+    fn build_function_type(arg_types: Vec<Self>, ret_type: Self) -> Self;
-//        TypeOrVar::Type(value)
+}
-//    }
+
-//}
+impl TypeWithFunction for Type {
+    fn build_function_type(arg_types: Vec<Self>, ret_type: Self) -> Self {
+        Type::Function(arg_types, Box::new(ret_type))
+    }
+}
 
 impl<T: Into<Type>> From<T> for TypeOrVar {
     fn from(value: T) -> Self {
@@ -598,3 +653,24 @@ impl<T: Into<Type>> From<T> for TypeOrVar {
         }
     }
 }
+
+impl TryFrom<TypeOrVar> for Type {
+    type Error = TypeOrVar;
+
+    fn try_from(value: TypeOrVar) -> Result<Self, Self::Error> {
+        match value {
+            TypeOrVar::Function(args, ret) => {
+                let args = args
+                    .into_iter()
+                    .map(Type::try_from)
+                    .collect::<Result<_, _>>()?;
+                let ret = Type::try_from(*ret)?;
+
+                Ok(Type::Function(args, Box::new(ret)))
+            }
+
+            TypeOrVar::Primitive(t) => Ok(Type::Primitive(t)),
+            _ => Err(value),
+        }
+    }
+}

src/ir/top_level.rs

@@ -0,0 +1,45 @@
+use crate::ir::{Expression, Program, TopLevel, TypeWithFunction, TypeWithVoid, Variable};
+use std::collections::HashMap;
+
+impl<T: Clone + TypeWithVoid + TypeWithFunction> Program<T> {
+    /// Retrieve the complete set of variables that are defined at the top level of
+    /// this program.
+    pub fn get_top_level_variables(&self) -> HashMap<Variable, T> {
+        let mut result = HashMap::new();
+
+        for item in self.items.iter() {
+            result.extend(item.get_top_level_variables());
+        }
+
+        result
+    }
+}
+
+impl<T: Clone + TypeWithVoid + TypeWithFunction> TopLevel<T> {
+    /// Retrieve the complete set of variables that are defined at the top level of
+    /// this top-level item.
+    ///
+    /// For functions, this is the function name. For expressions this can be a little
+    /// bit more complicated, as it sort of depends on the block structuring.
+    pub fn get_top_level_variables(&self) -> HashMap<Variable, T> {
+        match self {
+            TopLevel::Function(name, _, _, _) => HashMap::from([(name.clone(), self.type_of())]),
+            TopLevel::Statement(expr) => expr.get_top_level_variables(),
+        }
+    }
+}
+
+impl<T: Clone> Expression<T> {
+    /// Retrieve the complete set of variables that are defined at the top level of
+    /// this expression. Basically, returns the variable named in bind.
+    pub fn get_top_level_variables(&self) -> HashMap<Variable, T> {
+        match self {
+            Expression::Bind(_, name, ty, expr) => {
+                let mut tlvs = expr.get_top_level_variables();
+                tlvs.insert(name.clone(), ty.clone());
+                tlvs
+            },
+            _ => HashMap::new(),
+        }
+    }
+}

src/syntax/ast.rs

@@ -154,6 +154,19 @@ impl PartialEq for Expression {
     }
 }
 
+impl Expression {
+    /// Get the location of the expression in the source file (if there is one).
+    pub fn location(&self) -> &Location {
+        match self {
+            Expression::Value(loc, _) => loc,
+            Expression::Reference(loc, _) => loc,
+            Expression::Cast(loc, _, _) => loc,
+            Expression::Primitive(loc, _, _) => loc,
+            Expression::Block(loc, _) => loc,
+        }
+    }
+}
+
 /// A value from the source syntax
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub enum Value {

src/syntax/tokens.rs

@@ -270,6 +270,7 @@ impl TryFrom<i64> for ConstantType {
             21 => Ok(ConstantType::I16),
             22 => Ok(ConstantType::I32),
             23 => Ok(ConstantType::I64),
+            255 => Ok(ConstantType::Void),
             _ => Err(InvalidConstantType::Value(value)),
         }
     }

src/type_infer/convert.rs

@@ -4,6 +4,7 @@ use crate::syntax::{self, ConstantType};
 use crate::type_infer::solve::Constraint;
 use crate::util::scoped_map::ScopedMap;
 use internment::ArcIntern;
+use std::collections::HashMap;
 use std::str::FromStr;
 
 /// This function takes a syntactic program and converts it into the IR version of the
@@ -19,7 +20,7 @@ pub fn convert_program(
     let mut constraint_db = Vec::new();
     let mut items = Vec::new();
     let mut renames = ScopedMap::new();
-    let mut bindings = ScopedMap::new();
+    let mut bindings = HashMap::new();
 
     for item in program.items.drain(..) {
         items.push(convert_top_level(
@@ -40,43 +41,68 @@ pub fn convert_top_level(
     top_level: syntax::TopLevel,
     constraint_db: &mut Vec<Constraint>,
     renames: &mut ScopedMap<ArcIntern<String>, ArcIntern<String>>,
-    bindings: &mut ScopedMap<ArcIntern<String>, ir::TypeOrVar>,
+    bindings: &mut HashMap<ArcIntern<String>, ir::TypeOrVar>,
 ) -> ir::TopLevel<ir::TypeOrVar> {
     match top_level {
         syntax::TopLevel::Function(name, args, expr) => {
-            // First, let us figure out what we're going to name this function. If the user
+            // First, at some point we're going to want to know a location for this function,
+            // which should either be the name if we have one, or the body if we don't.
+            let function_location = match name {
+                None => expr.location().clone(),
+                Some(ref name) => name.location.clone(),
+            };
+            // Next, let us figure out what we're going to name this function. If the user
             // didn't provide one, we'll just call it "function:<something>" for them. (We'll
             // want a name for this function, eventually, so we might as well do it now.)
             //
             // If they did provide a name, see if we're shadowed. IF we are, then we'll have
             // to specialize the name a bit. Otherwise we'll stick with their name.
-            let funname = match name {
+            let function_name = match name {
                 None => ir::gensym("function"),
                 Some(unbound) => finalize_name(bindings, renames, unbound),
             };
 
-            // Now we manufacture types for the inputs and outputs, and then a type for the
+            // This function is going to have a type. We don't know what it is, but it'll have
-            // function itself. We're not going to make any claims on these types, yet; they're
+            // one.
-            // all just unknown type variables we need to work out.
+            let function_type = ir::TypeOrVar::new();
-            let argtypes: Vec<ir::TypeOrVar> = args.iter().map(|_| ir::TypeOrVar::new()).collect();
+            bindings.insert(function_name.clone(), function_type.clone());
+
+            // Then, let's figure out what to do with the argument names, which similarly
+            // may need to be renamed. We'll also generate some new type variables to associate
+            // with all of them.
+            //
+            // Note that we want to do all this in a new renaming scope, so that we shadow
+            // appropriately.
+            renames.new_scope();
+            let arginfo = args
+                .iter()
+                .map(|name| {
+                    let new_type = ir::TypeOrVar::new();
+                    constraint_db.push(Constraint::IsSomething(
+                        name.location.clone(),
+                        new_type.clone(),
+                    ));
+                    let new_name = finalize_name(bindings, renames, name.clone());
+                    bindings.insert(new_name.clone(), new_type.clone());
+                    (new_name, new_type)
+                })
+                .collect::<Vec<_>>();
+
+            // Now we manufacture types for the outputs and then a type for the function itself.
+            // We're not going to make any claims on these types, yet; they're all just unknown
+            // type variables we need to work out.
             let rettype = ir::TypeOrVar::new();
-            let funtype = ir::TypeOrVar::Function(argtypes.clone(), Box::new(rettype.clone()));
+            let actual_function_type = ir::TypeOrVar::Function(
-
+                arginfo.iter().map(|x| x.1.clone()).collect(),
-            // Now let's bind these types into the environment. First, we bind our function
+                Box::new(rettype.clone()),
-            // namae to the function type we just generated.
+            );
-            bindings.insert(funname.clone(), funtype);
+            constraint_db.push(Constraint::Equivalent(
-            // And then we attach the argument names to the argument types. (We have to go
+                function_location,
-            // convert all the names, first.)
+                function_type,
-            let iargs: Vec<ArcIntern<String>> =
+                actual_function_type,
-                args.iter().map(|x| ArcIntern::new(x.to_string())).collect();
+            ));
-            assert_eq!(argtypes.len(), iargs.len());
-            let mut function_args = vec![];
-            for ((arg_name, arg_type), orig_name) in iargs.iter().zip(argtypes).zip(args) {
-                bindings.insert(arg_name.clone(), arg_type.clone());
-                function_args.push((arg_name.clone(), arg_type.clone()));
-                constraint_db.push(Constraint::IsSomething(orig_name.location, arg_type));
-            }
 
+            // Now let's convert the body over to the new IR.
             let (expr, ty) = convert_expression(expr, constraint_db, renames, bindings);
             constraint_db.push(Constraint::Equivalent(
                 expr.location().clone(),
@@ -84,7 +110,10 @@ pub fn convert_top_level(
                 ty,
             ));
 
-            ir::TopLevel::Function(funname, function_args, rettype, expr)
+            // Remember to exit this scoping level!
+            renames.release_scope();
+
+            ir::TopLevel::Function(function_name, arginfo, rettype, expr)
         }
 
         syntax::TopLevel::Statement(stmt) => {
@@ -108,7 +137,7 @@ fn convert_statement(
     statement: syntax::Statement,
     constraint_db: &mut Vec<Constraint>,
     renames: &mut ScopedMap<ArcIntern<String>, ArcIntern<String>>,
-    bindings: &mut ScopedMap<ArcIntern<String>, ir::TypeOrVar>,
+    bindings: &mut HashMap<ArcIntern<String>, ir::TypeOrVar>,
 ) -> ir::Expression<ir::TypeOrVar> {
     match statement {
         syntax::Statement::Print(loc, name) => {
@@ -152,7 +181,7 @@ fn convert_expression(
     expression: syntax::Expression,
     constraint_db: &mut Vec<Constraint>,
     renames: &mut ScopedMap<ArcIntern<String>, ArcIntern<String>>,
-    bindings: &mut ScopedMap<ArcIntern<String>, ir::TypeOrVar>,
+    bindings: &mut HashMap<ArcIntern<String>, ir::TypeOrVar>,
 ) -> (ir::Expression<ir::TypeOrVar>, ir::TypeOrVar) {
     match expression {
         // converting values is mostly tedious, because there's so many cases
@@ -339,7 +368,7 @@ fn finalize_expression(
 }
 
 fn finalize_name(
-    bindings: &ScopedMap<ArcIntern<String>, ir::TypeOrVar>,
+    bindings: &HashMap<ArcIntern<String>, ir::TypeOrVar>,
     renames: &mut ScopedMap<ArcIntern<String>, ArcIntern<String>>,
     name: syntax::Name,
 ) -> ArcIntern<String> {

src/type_infer/finalize.rs

@@ -105,7 +105,7 @@ fn finalize_type(ty: TypeOrVar, resolutions: &TypeResolutions) -> Type {
         TypeOrVar::Primitive(x) => Type::Primitive(x),
         TypeOrVar::Variable(_, tvar) => match resolutions.get(&tvar) {
             None => panic!("Did not resolve type for type variable {}", tvar),
-            Some(pt) => Type::Primitive(*pt),
+            Some(pt) => pt.clone(),
         },
         TypeOrVar::Function(mut args, ret) => Type::Function(
             args.drain(..)

src/type_infer/solve.rs

@@ -1,5 +1,5 @@
 use crate::eval::PrimitiveType;
-use crate::ir::{Primitive, TypeOrVar};
+use crate::ir::{Primitive, Type, TypeOrVar};
 use crate::syntax::Location;
 use codespan_reporting::diagnostic::Diagnostic;
 use internment::ArcIntern;
@@ -50,7 +50,7 @@ impl fmt::Display for Constraint {
     }
 }
 
-pub type TypeResolutions = HashMap<ArcIntern<String>, PrimitiveType>;
+pub type TypeResolutions = HashMap<ArcIntern<String>, Type>;
 
 /// The results of type inference; like [`Result`], but with a bit more information.
 ///
@@ -257,18 +257,21 @@ pub fn solve_constraints(
 ) -> TypeInferenceResult<TypeResolutions> {
     let mut errors = vec![];
     let mut warnings = vec![];
-    let mut resolutions = HashMap::new();
+    let mut resolutions: HashMap<ArcIntern<String>, Type> = HashMap::new();
     let mut changed_something = true;
 
-    println!("CONSTRAINTS:");
-    for constraint in constraint_db.iter() {
-        println!("{}", constraint);
-    }
-
     // We want to run this inference endlessly, until either we have solved all of our
     // constraints. Internal to the loop, we have a check that will make sure that we
     // do (eventually) stop.
     while changed_something && !constraint_db.is_empty() {
+        println!("CONSTRAINT:");
+        for constraint in constraint_db.iter() {
+            println!("  {}", constraint);
+        }
+        println!("RESOLUTIONS:");
+        for (name, ty) in resolutions.iter() {
+            println!("  {} = {}", name, ty);
+        }
         // Set this to false at the top of the loop. We'll set this to true if we make
         // progress in any way further down, but having this here prevents us from going
         // into an infinite look when we can't figure stuff out.
@@ -292,9 +295,13 @@ pub fn solve_constraints(
                 Constraint::IsSomething(_, TypeOrVar::Function(_, _))
                 | Constraint::IsSomething(_, TypeOrVar::Primitive(_)) => changed_something = true,
 
-                // Otherwise, we'll keep looking for it.
+                // Otherwise, see if we've resolved this variable to anything. If not, add it
-                Constraint::IsSomething(_, TypeOrVar::Variable(_, _)) => {
+                // back.
-                    constraint_db.push(constraint);
+                Constraint::IsSomething(_, TypeOrVar::Variable(_, ref name)) => {
+                    if resolutions.get(name).is_none() {
+                        constraint_db.push(constraint);
+                    }
+                    changed_something = true;
                 }
 
                 // Case #1a: We have two primitive types. If they're equal, we've discharged this
@@ -311,35 +318,7 @@ pub fn solve_constraints(
                     changed_something = true;
                 }
 
-                // Case #2: One of the two constraints is a primitive, and the other is a variable.
+                // Case #2: They're both variables. In which case, we'll have to do much the same
-                // In this case, we'll check to see if we've resolved the variable, and check for
-                // equivalence if we have. If we haven't, we'll set that variable to be primitive
-                // type.
-                Constraint::Equivalent(
-                    loc,
-                    TypeOrVar::Primitive(t),
-                    TypeOrVar::Variable(_, name),
-                )
-                | Constraint::Equivalent(
-                    loc,
-                    TypeOrVar::Variable(_, name),
-                    TypeOrVar::Primitive(t),
-                ) => {
-                    match resolutions.get(&name) {
-                        None => {
-                            resolutions.insert(name, t);
-                        }
-                        Some(t2) if &t == t2 => {}
-                        Some(t2) => errors.push(TypeInferenceError::NotEquivalent(
-                            loc,
-                            TypeOrVar::Primitive(t),
-                            TypeOrVar::Primitive(*t2),
-                        )),
-                    }
-                    changed_something = true;
-                }
-
-                // Case #3: They're both variables. In which case, we'll have to do much the same
                 // check, but now on their resolutions.
                 Constraint::Equivalent(
                     ref loc,
@@ -350,11 +329,11 @@ pub fn solve_constraints(
                         constraint_db.push(constraint);
                     }
                     (Some(pt), None) => {
-                        resolutions.insert(name2.clone(), *pt);
+                        resolutions.insert(name2.clone(), pt.clone());
                         changed_something = true;
                     }
                     (None, Some(pt)) => {
-                        resolutions.insert(name1.clone(), *pt);
+                        resolutions.insert(name1.clone(), pt.clone());
                         changed_something = true;
                     }
                     (Some(pt1), Some(pt2)) if pt1 == pt2 => {
@@ -363,13 +342,43 @@ pub fn solve_constraints(
                     (Some(pt1), Some(pt2)) => {
                         errors.push(TypeInferenceError::NotEquivalent(
                             loc.clone(),
-                            TypeOrVar::Primitive(*pt1),
+                            pt1.clone().into(),
-                            TypeOrVar::Primitive(*pt2),
+                            pt2.clone().into(),
                         ));
                         changed_something = true;
                     }
                 },
 
+                // Case #3: One of the two constraints is a primitive, and the other is a variable.
+                // In this case, we'll check to see if we've resolved the variable, and check for
+                // equivalence if we have. If we haven't, we'll set that variable to be primitive
+                // type.
+                Constraint::Equivalent(loc, t, TypeOrVar::Variable(vloc, name))
+                | Constraint::Equivalent(loc, TypeOrVar::Variable(vloc, name), t) => {
+                    match resolutions.get(&name) {
+                        None => match t.try_into() {
+                            Ok(real_type) => {
+                                resolutions.insert(name, real_type);
+                            }
+                            Err(variable_type) => {
+                                constraint_db.push(Constraint::Equivalent(
+                                    loc,
+                                    variable_type,
+                                    TypeOrVar::Variable(vloc, name),
+                                ));
+                                continue;
+                            }
+                        },
+                        Some(t2) if &t == t2 => {}
+                        Some(t2) => errors.push(TypeInferenceError::NotEquivalent(
+                            loc,
+                            t,
+                            t2.clone().into(),
+                        )),
+                    }
+                    changed_something = true;
+                }
+
                 // Case #4: Like primitives, but for function types. This is a little complicated, because
                 // we first want to resolve all the type variables in the two types, and then see if they're
                 // equivalent. Fortunately, though, we can cheat a bit. What we're going to do is first see
@@ -445,7 +454,7 @@ pub fn solve_constraints(
                         Some(nt) => {
                             constraint_db.push(Constraint::FitsInNumType(
                                 loc,
-                                TypeOrVar::Primitive(*nt),
+                                nt.clone().into(),
                                 val,
                             ));
                             changed_something = true;
@@ -474,7 +483,7 @@ pub fn solve_constraints(
                         Some(nt) => {
                             constraint_db.push(Constraint::CanCastTo(
                                 loc,
-                                TypeOrVar::Primitive(*nt),
+                                nt.clone().into(),
                                 to_type,
                             ));
                             changed_something = true;
@@ -494,7 +503,7 @@ pub fn solve_constraints(
                             constraint_db.push(Constraint::CanCastTo(
                                 loc,
                                 from_type,
-                                TypeOrVar::Primitive(*nt),
+                                nt.clone().into(),
                             ));
                             changed_something = true;
                         }
@@ -560,8 +569,7 @@ pub fn solve_constraints(
                         None => constraint_db
                             .push(Constraint::NumericType(loc, TypeOrVar::Variable(vloc, var))),
                         Some(nt) => {
-                            constraint_db
+                            constraint_db.push(Constraint::NumericType(loc, nt.clone().into()));
-                                .push(Constraint::NumericType(loc, TypeOrVar::Primitive(*nt)));
                             changed_something = true;
                         }
                     }
@@ -592,10 +600,8 @@ pub fn solve_constraints(
                             TypeOrVar::Variable(vloc, var),
                         )),
                         Some(nt) => {
-                            constraint_db.push(Constraint::ConstantNumericType(
+                            constraint_db
-                                loc,
+                                .push(Constraint::ConstantNumericType(loc, nt.clone().into()));
-                                TypeOrVar::Primitive(*nt),
-                            ));
                             changed_something = true;
                         }
                     }