examples/basic/function0001.ngr

@@ -0,0 +1,5 @@
+x = 1;
+function add_x(y) x + y
+a = 3;
+result = add_x(a);
+print result;

src/backend/error.rs

@@ -53,10 +53,9 @@ pub enum BackendError {
 impl From<BackendError> for Diagnostic<usize> {
     fn from(value: BackendError) -> Self {
         match value {
-            BackendError::Cranelift(me) => {
+            BackendError::Cranelift(me) => Diagnostic::error()
-                Diagnostic::error().with_message(format!("Internal cranelift error: {}", me))
+                .with_message(format!("Internal cranelift error: {}", me))
-                    .with_notes(vec![format!("{:?}", me)])
+                .with_notes(vec![format!("{:?}", me)]),
-            }
             BackendError::BuiltinError(me) => {
                 Diagnostic::error().with_message(format!("Internal runtime function error: {}", me))
             }

src/backend/into_crane.rs

@@ -4,7 +4,8 @@ use crate::eval::PrimitiveType;
 use crate::ir::{Expression, Primitive, Program, TopLevel, Type, Value, ValueOrRef, Variable};
 use crate::syntax::{ConstantType, Location};
 use cranelift_codegen::ir::{
-    self, entities, types, AbiParam, Function, GlobalValue, InstBuilder, MemFlags, Signature, UserFuncName
+    self, entities, types, AbiParam, Function, GlobalValue, InstBuilder, MemFlags, Signature,
+    UserFuncName,
 };
 use cranelift_codegen::isa::CallConv;
 use cranelift_codegen::Context;
@@ -29,7 +30,9 @@ impl ReferenceBuilder {
             ReferenceBuilder::Global(ty, gv) => {
                 let cranelift_type = ir::Type::from(*ty);
                 let ptr_value = builder.ins().symbol_value(types::I64, *gv);
-                let value = builder.ins().load(cranelift_type, MemFlags::new(), ptr_value, 0);
+                let value = builder
+                    .ins()
+                    .load(cranelift_type, MemFlags::new(), ptr_value, 0);
                 (value, *ty)
             }
 
@@ -435,7 +438,8 @@ 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.clone());
+                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);
@@ -473,6 +477,39 @@ impl<M: Module> Backend<M> {
                 variables.insert(name, ReferenceBuilder::Local(value_type, variable));
                 Ok((builder.ins().iconst(types::I64, 0), ConstantType::Void))
             }
+
+            Expression::Call(_, _, function, args) => {
+                let (arguments, _argument_types): (Vec<_>, Vec<_>) = args
+                    .into_iter()
+                    .map(|x| self.compile_value_or_ref(x, variables, builder))
+                    .collect::<Result<Vec<(_,_)>,BackendError>>()?
+                    .into_iter()
+                    .unzip();
+
+                match *function {
+                    ValueOrRef::Value(_, _, _) => {
+                        panic!("Can't use a value for a function")
+                    }
+
+                    ValueOrRef::Ref(_, result_type, name) => match self.defined_functions.get(&name) {
+                        None => panic!("Couldn't find function {} to call", name),
+                        Some(function) => {
+                            let func_ref = self.module.declare_func_in_func(*function, builder.func);
+                            let call = builder.ins().call(func_ref, &arguments);
+                            let results = builder.inst_results(call);
+                            
+                            match results {
+                                [] => Ok((builder.ins().iconst(types::I64, 0), ConstantType::Void)),
+                                [result] => match result_type {
+                                    Type::Primitive(ct) => Ok((*result, ct.into())),
+                                    Type::Function(_, _) => panic!("return value is a function?"),
+                                }
+                                _ => panic!("don't support multi-value returns yet"),
+                            }
+                        }
+                    }
+                }
+            }
         }
     }
 

src/eval.rs

@@ -39,6 +39,7 @@ mod primtype;
 mod value;
 
 use cranelift_module::ModuleError;
+use internment::ArcIntern;
 pub use primop::PrimOpError;
 pub use primtype::PrimitiveType;
 pub use value::Value;
@@ -76,6 +77,15 @@ pub enum EvalError<IR> {
     UnknownPrimType(#[from] UnknownPrimType),
     #[error("Variable lookup failed for {1} at {0:?}")]
     LookupFailed(crate::syntax::Location, String),
+    #[error("Attempted to call something that wasn't a function at {0:?} (it was a {1})")]
+    NotAFunction(crate::syntax::Location, Value<IR>),
+    #[error("Wrong argument call for function ({1:?}) at {0:?}; expected {2}, saw {3}")]
+    WrongArgCount(
+        crate::syntax::Location,
+        Option<ArcIntern<String>>,
+        usize,
+        usize,
+    ),
 }
 
 impl<IR1: Clone, IR2: Clone> PartialEq<EvalError<IR1>> for EvalError<IR2> {
@@ -129,6 +139,16 @@ impl<IR1: Clone, IR2: Clone> PartialEq<EvalError<IR1>> for EvalError<IR2> {
                 EvalError::UnknownPrimType(b) => a == b,
                 _ => false,
             },
+
+            EvalError::NotAFunction(a, b) => match other {
+                EvalError::NotAFunction(x, y) => a == x && b == y,
+                _ => false,
+            },
+
+            EvalError::WrongArgCount(a, b, c, d) => match other {
+                EvalError::WrongArgCount(w, x, y, z) => a == w && b == x && c == y && d == z,
+                _ => false,
+            },
         }
     }
 }

src/ir/arbitrary.rs

@@ -1,5 +1,7 @@
 use crate::eval::PrimitiveType;
-use crate::ir::{Expression, Primitive, Program, TopLevel, Type, TypeWithVoid, 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};
@@ -300,7 +302,8 @@ fn generate_random_expression(
                 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));
+                    next =
+                        Expression::Bind(Location::manufactured(), name, next_type, Box::new(next));
                 }
                 stmts.push(next);
             }

src/ir/ast.rs

@@ -160,6 +160,7 @@ pub enum Expression<Type> {
     Primitive(Location, Type, Primitive, Vec<ValueOrRef<Type>>),
     Block(Location, Type, Vec<Expression<Type>>),
     Print(Location, Variable),
+    Call(Location, Type, Box<ValueOrRef<Type>>, Vec<ValueOrRef<Type>>),
     Bind(Location, Variable, Type, Box<Expression<Type>>),
 }
 
@@ -173,6 +174,7 @@ impl<Type: Clone + TypeWithVoid> Expression<Type> {
             Expression::Primitive(_, t, _, _) => t.clone(),
             Expression::Block(_, t, _) => t.clone(),
             Expression::Print(_, _) => Type::void(),
+            Expression::Call(_, t, _, _) => t.clone(),
             Expression::Bind(_, _, _, _) => Type::void(),
         }
     }
@@ -186,6 +188,7 @@ impl<Type: Clone + TypeWithVoid> Expression<Type> {
             Expression::Primitive(l, _, _, _) => l,
             Expression::Block(l, _, _) => l,
             Expression::Print(l, _) => l,
+            Expression::Call(l, _, _, _) => l,
             Expression::Bind(l, _, _, _) => l,
         }
     }
@@ -221,6 +224,12 @@ where
             Expression::Primitive(_, _, op, exprs) => {
                 allocator.text(format!("!!{:?} with {} arguments!!", op, exprs.len()))
             }
+            Expression::Call(_, _, fun, args) => {
+                let args = args.iter().map(|x| x.pretty(allocator));
+                let comma_sepped_args =
+                    allocator.intersperse(args, crate::syntax::pretty::CommaSep {});
+                fun.pretty(allocator).append(comma_sepped_args.parens())
+            }
             Expression::Block(_, _, exprs) => match exprs.split_last() {
                 None => allocator.text("()"),
                 Some((last, &[])) => last.pretty(allocator),
@@ -660,13 +669,20 @@ impl TryFrom<TypeOrVar> for Type {
     fn try_from(value: TypeOrVar) -> Result<Self, Self::Error> {
         match value {
             TypeOrVar::Function(args, ret) => {
-                let args = args
+                let converted_args = args
-                    .into_iter()
+                    .iter()
+                    .cloned()
                     .map(Type::try_from)
-                    .collect::<Result<_, _>>()?;
+                    .collect::<Result<_, _>>();
-                let ret = Type::try_from(*ret)?;
+                let converted_ret = Type::try_from((*ret).clone());
+            
+                if let Ok(args) = converted_args {
+                    if let Ok(ret) = converted_ret {
+                        return Ok(Type::Function(args, Box::new(ret)));
+                    }
+                }
 
-                Ok(Type::Function(args, Box::new(ret)))
+                Err(TypeOrVar::Function(args, ret))
             }
 
             TypeOrVar::Primitive(t) => Ok(Type::Primitive(t)),

src/ir/eval.rs

@@ -103,6 +103,33 @@ where
                 env.insert(name.clone(), value);
                 Ok(Value::Void)
             }
+
+            Expression::Call(loc, _, fun, args) => {
+                let function = fun.eval(env)?;
+
+                match function {
+                    Value::Closure(name, mut env, arguments, body) => {
+                        if args.len() != arguments.len() {
+                            return Err(EvalError::WrongArgCount(
+                                loc.clone(),
+                                name,
+                                arguments.len(),
+                                args.len(),
+                            ));
+                        }
+
+                        env.new_scope();
+                        for (name, value) in arguments.into_iter().zip(args.into_iter()) {
+                            let value = value.eval(&mut env)?;
+                            env.insert(name, value);
+                        }
+                        let result = body.eval(&mut env, stdout)?;
+                        env.release_scope();
+                        Ok(result)
+                    }
+                    _ => Err(EvalError::NotAFunction(loc.clone(), function)),
+                }
+            }
         }
     }
 }

src/ir/top_level.rs

@@ -38,7 +38,7 @@ impl<T: Clone> Expression<T> {
                 let mut tlvs = expr.get_top_level_variables();
                 tlvs.insert(name.clone(), ty.clone());
                 tlvs
-            },
+            }
             _ => HashMap::new(),
         }
     }

src/syntax.rs

@@ -37,7 +37,7 @@ lalrpop_mod!(
     parser,
     "/syntax/parser.rs"
 );
-mod pretty;
+pub mod pretty;
 mod validate;
 
 #[cfg(test)]

src/syntax/ast.rs

@@ -124,6 +124,7 @@ pub enum Expression {
     Reference(Location, String),
     Cast(Location, String, Box<Expression>),
     Primitive(Location, String, Vec<Expression>),
+    Call(Location, Box<Expression>, Vec<Expression>),
     Block(Location, Vec<Statement>),
 }
 
@@ -146,6 +147,10 @@ impl PartialEq for Expression {
                 Expression::Primitive(_, prim2, args2) => prim1 == prim2 && args1 == args2,
                 _ => false,
             },
+            Expression::Call(_, f1, a1) => match other {
+                Expression::Call(_, f2, a2) => f1 == f2 && a1 == a2,
+                _ => false,
+            },
             Expression::Block(_, stmts1) => match other {
                 Expression::Block(_, stmts2) => stmts1 == stmts2,
                 _ => false,
@@ -162,6 +167,7 @@ impl Expression {
             Expression::Reference(loc, _) => loc,
             Expression::Cast(loc, _, _) => loc,
             Expression::Primitive(loc, _, _) => loc,
+            Expression::Call(loc, _, _) => loc,
             Expression::Block(loc, _) => loc,
         }
     }

src/syntax/eval.rs

@@ -118,6 +118,33 @@ impl Expression {
                 Ok(Value::calculate(op, arg_values)?)
             }
 
+            Expression::Call(loc, fun, args) => {
+                let function = fun.eval(stdout, env)?;
+
+                match function {
+                    Value::Closure(name, mut closure_env, arguments, body) => {
+                        if args.len() != arguments.len() {
+                            return Err(EvalError::WrongArgCount(
+                                loc.clone(),
+                                name,
+                                arguments.len(),
+                                args.len(),
+                            ));
+                        }
+
+                        closure_env.new_scope();
+                        for (name, value) in arguments.into_iter().zip(args.iter()) {
+                            let value = value.eval(stdout, env)?;
+                            closure_env.insert(name, value);
+                        }
+                        let result = body.eval(stdout, &mut closure_env)?;
+                        closure_env.release_scope();
+                        Ok(result)
+                    }
+                    _ => Err(EvalError::NotAFunction(loc.clone(), function)),
+                }
+            }
+
             Expression::Block(_, stmts) => {
                 let mut result = Value::Void;
 

src/syntax/parser.lalrpop

@@ -205,9 +205,24 @@ UnaryExpression: Expression = {
        Expression::Primitive(Location::new(file_idx, l..le), "-".to_string(), vec![e]),
     <l: @L> "<" <v:"<var>"> ">" <e:UnaryExpression> <le: @L> =>
        Expression::Cast(Location::new(file_idx, l..le), v.to_string(), Box::new(e)),
+    CallExpression,
+}
+
+CallExpression: Expression = {
+    <s: @L> <f:CallExpression> "(" <args: CallArguments> ")" <e: @L> =>
+       Expression::Call(Location::new(file_idx, s..e), Box::new(f), args),
     AtomicExpression,
 }
 
+CallArguments: Vec<Expression> = {
+    => vec![],
+    <e:Expression> => vec![e],
+    <mut args:CallArguments> "," <e:Expression> => {
+        args.push(e);
+        args
+    }
+}
+
 // finally, we describe our lowest-level expressions as "atomic", because
 // they cannot be further divided into parts
 AtomicExpression: Expression = {

src/syntax/pretty.rs

@@ -105,6 +105,11 @@ where
                 let comma_sepped_args = allocator.intersperse(args, CommaSep {});
                 call.append(comma_sepped_args.parens())
             }
+            Expression::Call(_, fun, args) => {
+                let args = args.iter().map(|x| x.pretty(allocator));
+                let comma_sepped_args = allocator.intersperse(args, CommaSep {});
+                fun.pretty(allocator).append(comma_sepped_args.parens())
+            }
             Expression::Block(_, stmts) => match stmts.split_last() {
                 None => allocator.text("()"),
                 Some((last, &[])) => last.pretty(allocator),
@@ -167,7 +172,7 @@ fn type_suffix(x: &Option<ConstantType>) -> &'static str {
 }
 
 #[derive(Clone, Copy)]
-struct CommaSep {}
+pub struct CommaSep {}
 
 impl<'a, D, A> Pretty<'a, D, A> for CommaSep
 where

src/syntax/validate.rs

@@ -212,6 +212,17 @@ impl Expression {
 
                 (errors, warnings)
             }
+            Expression::Call(_, func, args) => {
+                let (mut errors, mut warnings) = func.validate(variable_map);
+
+                for arg in args.iter() {
+                    let (mut e, mut w) = arg.validate(variable_map);
+                    errors.append(&mut e);
+                    warnings.append(&mut w);
+                }
+
+                (errors, warnings)
+            }
             Expression::Block(_, stmts) => {
                 let mut errors = vec![];
                 let mut warnings = vec![];

src/type_infer/convert.rs

@@ -286,9 +286,7 @@ fn convert_expression(
                 let (aexp, atype) = convert_expression(arg, constraint_db, renames, bindings);
                 let (aprereqs, asimple) = simplify_expr(aexp);
 
-                if let Some(prereq) = aprereqs {
+                merge_prereq(&mut prereqs, aprereqs);
-                    prereqs.push(prereq);
-                }
                 nargs.push(asimple);
                 atypes.push(atype);
             }
@@ -313,6 +311,59 @@ fn convert_expression(
             }
         }
 
+        syntax::Expression::Call(loc, fun, args) => {
+            let return_type = ir::TypeOrVar::new();
+            let arg_types = args
+                .iter()
+                .map(|_| ir::TypeOrVar::new())
+                .collect::<Vec<_>>();
+
+            let (new_fun, new_fun_type) =
+                convert_expression(*fun, constraint_db, renames, bindings);
+            let target_fun_type =
+                ir::TypeOrVar::Function(arg_types.clone(), Box::new(return_type.clone()));
+            constraint_db.push(Constraint::Equivalent(
+                loc.clone(),
+                new_fun_type,
+                target_fun_type,
+            ));
+            let mut prereqs = vec![];
+
+            let (fun_prereqs, fun) = simplify_expr(new_fun);
+            merge_prereq(&mut prereqs, fun_prereqs);
+
+            let new_args = args
+                .into_iter()
+                .zip(arg_types.into_iter())
+                .map(|(arg, target_type)| {
+                    let (new_arg, inferred_type) =
+                        convert_expression(arg, constraint_db, renames, bindings);
+                    let location = new_arg.location().clone();
+                    let (arg_prereq, new_valref) = simplify_expr(new_arg);
+                    merge_prereq(&mut prereqs, arg_prereq);
+                    constraint_db.push(Constraint::Equivalent(
+                        location,
+                        inferred_type,
+                        target_type,
+                    ));
+                    new_valref
+                })
+                .collect();
+
+            let last_call =
+                ir::Expression::Call(loc.clone(), return_type.clone(), Box::new(fun), new_args);
+
+            if prereqs.is_empty() {
+                (last_call, return_type)
+            } else {
+                prereqs.push(last_call);
+                (
+                    ir::Expression::Block(loc, return_type.clone(), prereqs),
+                    return_type,
+                )
+            }
+        }
+
         syntax::Expression::Block(loc, stmts) => {
             let mut ret_type = ir::TypeOrVar::Primitive(PrimitiveType::Void);
             let mut exprs = vec![];
@@ -381,6 +432,12 @@ fn finalize_name(
     }
 }
 
+fn merge_prereq<T>(left: &mut Vec<T>, prereq: Option<T>) {
+    if let Some(item) = prereq {
+        left.push(item)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     //    use super::*;

src/type_infer/finalize.rs

@@ -91,6 +91,15 @@ fn finalize_expression(
 
         Expression::Print(loc, var) => Expression::Print(loc, var),
 
+        Expression::Call(loc, ty, fun, args) => Expression::Call(
+            loc,
+            finalize_type(ty, resolutions),
+            Box::new(finalize_val_or_ref(*fun, resolutions)),
+            args.into_iter()
+                .map(|x| finalize_val_or_ref(x, resolutions))
+                .collect(),
+        ),
+
         Expression::Bind(loc, var, ty, subexp) => Expression::Bind(
             loc,
             var,

src/type_infer/solve.rs

@@ -192,7 +192,7 @@ impl From<TypeInferenceError> for Diagnostic<usize> {
             }
             TypeInferenceError::CouldNotSolve(Constraint::Equivalent(loc, a, b)) => {
                 loc.labelled_error("internal error").with_message(format!(
-                    "could not determine if {} and {:#?} were equivalent",
+                    "could not determine if {} and {} were equivalent",
                     a, b
                 ))
             }
@@ -264,7 +264,7 @@ pub fn solve_constraints(
     // 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:");
+        println!("\n\n\nCONSTRAINT:");
         for constraint in constraint_db.iter() {
             println!("  {}", constraint);
         }
@@ -300,8 +300,9 @@ pub fn solve_constraints(
                 Constraint::IsSomething(_, TypeOrVar::Variable(_, ref name)) => {
                     if resolutions.get(name).is_none() {
                         constraint_db.push(constraint);
+                    } else {
+                        changed_something = true;
                     }
-                    changed_something = true;
                 }
 
                 // Case #1a: We have two primitive types. If they're equal, we've discharged this
@@ -355,12 +356,15 @@ pub fn solve_constraints(
                 // type.
                 Constraint::Equivalent(loc, t, TypeOrVar::Variable(vloc, name))
                 | Constraint::Equivalent(loc, TypeOrVar::Variable(vloc, name), t) => {
+                    println!("IN THIS CASE with {}", name);
                     match resolutions.get(&name) {
                         None => match t.try_into() {
                             Ok(real_type) => {
+                                println!("  HERE with {} and {}", name, real_type);
                                 resolutions.insert(name, real_type);
                             }
                             Err(variable_type) => {
+                                println!("  REJECTED INTO RETURN with {} and {}", name, variable_type);
                                 constraint_db.push(Constraint::Equivalent(
                                     loc,
                                     variable_type,
@@ -369,7 +373,9 @@ pub fn solve_constraints(
                                 continue;
                             }
                         },
-                        Some(t2) if &t == t2 => {}
+                        Some(t2) if &t == t2 => {
+                            println!("  MATCHED at {} == {}", t, t2);
+                        }
                         Some(t2) => errors.push(TypeInferenceError::NotEquivalent(
                             loc,
                             t,