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// Copyright (C) 2024 Ethan Uppal.
//
// This Source Code Form is subject to the terms of the Mozilla Public License,
// v. 2.0. If a copy of the MPL was not distributed with this file, You can
// obtain one at https://mozilla.org/MPL/2.0/.
use std::{
cell::RefCell,
collections::{BTreeMap, HashMap},
};
use crate::{
ast::{self, Type},
loc::Loc,
parser::Diagnostic,
};
pub fn create_function_context<'ast, 'source: 'ast>(
functions: impl Iterator<Item = &'ast Loc<ast::Function<'source>>>,
) -> HashMap<String, (Vec<Type>, Option<Type>)> {
let mut context = HashMap::new();
for function in functions {
let mut parameter_types = vec![];
let mut return_type = None;
for (_, type_annotation) in &function.parameters {
parameter_types.push(type_annotation.ty.inner.clone());
}
if let Some(return_type_annotation) = &function.return_type {
return_type = Some(return_type_annotation.ty.inner.clone());
}
context.insert(function.name.to_string(), (parameter_types, return_type));
}
context
}
pub fn type_infer_function(
context: &HashMap<String, (Vec<Type>, Option<Type>)>,
function: &ast::Function,
) -> Result<BTreeMap<String, Type>, Diagnostic> {
let symbols = RefCell::new(HashMap::new());
let env = RefCell::new(BTreeMap::new());
let mut return_type = None;
for (parameter, type_annotation) in &function.parameters {
if env.borrow().contains_key(¶meter.to_string()) {
let symbols = symbols.borrow();
let previous = symbols
.get(¶meter.to_string())
.expect("Should be in symbols map");
return Err(Diagnostic::new("Duplicate parameter name", parameter)
.label("Previous definition here", previous));
}
symbols
.borrow_mut()
.insert(parameter.to_string(), parameter.clone());
env.borrow_mut()
.insert(parameter.to_string(), type_annotation.ty.inner.clone());
}
if let Some(return_type_annotation) = &function.return_type {
return_type = Some(return_type_annotation.ty.inner.clone());
}
let get_signature = |name: &Loc<&str>| -> Result<(Vec<Type>, Option<Type>), Diagnostic> {
if let Some(signature) = context.get(&name.to_string()) {
Ok(signature.clone())
} else {
Err(Diagnostic::new("Called undefined function", name))
}
};
let ensure = |op: &str, arg: &Loc<&str>, ty: Type| -> Result<(), Diagnostic> {
if let Some(arg_type) = env.borrow().get(&arg.to_string()) {
if arg_type.is_same_type_as(&ty) {
Ok(())
} else {
let symbols = symbols.borrow();
let original = symbols
.get(&arg.to_string())
.expect("type exists so symbol does too");
Err(Diagnostic::new(
format!("Expected argument of type {} in {} instruction", ty, op),
arg,
)
.label(format!("Type inferred here to be {}", arg_type), original))
}
} else {
Err(Diagnostic::new(
format!("Undefined variable in this {} instruction", op),
arg,
))
}
};
for code in &function.body {
if let ast::FunctionCode::Instruction {
inner: instruction, ..
} = &**code
{
match &**instruction {
ast::Instruction::Constant(constant) => {
let mut inferred_type = match &*constant.value {
ast::ConstantValue::IntegerLiteral(_) => ast::Type::Int,
ast::ConstantValue::BooleanLiteral(_) => ast::Type::Bool,
ast::ConstantValue::FloatLiteral(_) => ast::Type::Float,
ast::ConstantValue::CharacterLiteral(_) => ast::Type::Char,
};
if let Some(annotation) = &constant.type_annotation {
if !annotation.ty.inner.is_same_type_as(&inferred_type) {
if annotation.ty.is_same_type_as(&Type::Float)
&& inferred_type.is_same_type_as(&Type::Int)
{
// don't think this should be valid but some
// programs rely on it
inferred_type = Type::Float;
} else {
return Err(Diagnostic::new(format!("Inferred type {inferred_type} did not match type annotation"), annotation).label("Type inferred here", &constant.value));
}
}
}
symbols
.borrow_mut()
.insert(constant.name.to_string(), constant.name.clone());
env.borrow_mut()
.insert(constant.name.to_string(), inferred_type);
}
ast::Instruction::ValueOperation(value_operation) => {
let inferred_type = match &*value_operation.op {
ast::ValueOperationOp::Add(lhs, rhs) => {
ensure("add", lhs, Type::Int)?;
ensure("add", rhs, Type::Int)?;
Type::Int
}
ast::ValueOperationOp::Mul(lhs, rhs) => {
ensure("mul", lhs, Type::Int)?;
ensure("mul", rhs, Type::Int)?;
Type::Int
}
ast::ValueOperationOp::Sub(lhs, rhs) => {
ensure("sub", lhs, Type::Int)?;
ensure("sub", rhs, Type::Int)?;
Type::Int
}
ast::ValueOperationOp::Div(lhs, rhs) => {
ensure("div", lhs, Type::Int)?;
ensure("div", rhs, Type::Int)?;
Type::Int
}
ast::ValueOperationOp::Eq(lhs, rhs) => {
ensure("eq", lhs, Type::Int)?;
ensure("eq", rhs, Type::Int)?;
Type::Bool
}
ast::ValueOperationOp::Lt(lhs, rhs) => {
ensure("lt", lhs, Type::Int)?;
ensure("lt", rhs, Type::Int)?;
Type::Bool
}
ast::ValueOperationOp::Gt(lhs, rhs) => {
ensure("gt", lhs, Type::Int)?;
ensure("gt", rhs, Type::Int)?;
Type::Bool
}
ast::ValueOperationOp::Le(lhs, rhs) => {
ensure("le", lhs, Type::Int)?;
ensure("le", rhs, Type::Int)?;
Type::Bool
}
ast::ValueOperationOp::Ge(lhs, rhs) => {
ensure("ge", lhs, Type::Int)?;
ensure("ge", rhs, Type::Int)?;
Type::Bool
}
ast::ValueOperationOp::Not(value) => {
ensure("not", value, Type::Bool)?;
Type::Bool
}
ast::ValueOperationOp::And(lhs, rhs) => {
ensure("and", lhs, Type::Bool)?;
ensure("and", rhs, Type::Bool)?;
Type::Bool
}
ast::ValueOperationOp::Or(lhs, rhs) => {
ensure("or", lhs, Type::Bool)?;
ensure("or", rhs, Type::Bool)?;
Type::Bool
}
ast::ValueOperationOp::Call(name, args) => {
let signature = get_signature(name)?;
if args.len() != signature.0.len() {
return Err(Diagnostic::new(
format!(
"Called function takes {} argument(s) but was passed {}",
signature.0.len(),
args.len()
),
name,
));
}
for (i, parameter_type) in signature.0.iter().enumerate() {
ensure("call", &args[i], parameter_type.clone())?;
}
signature.1.clone().ok_or(Diagnostic::new("Called function has no return type, but call used as value operation", name))?
}
ast::ValueOperationOp::Id(value) => {
let Some(ty) = env.borrow().get(&value.to_string()).cloned() else {
return Err(Diagnostic::new(
"Undefined variable in id instruction",
value,
));
};
ty
}
ast::ValueOperationOp::Fadd(lhs, rhs) => {
ensure("fadd", lhs, Type::Float)?;
ensure("fadd", rhs, Type::Float)?;
Type::Float
}
ast::ValueOperationOp::Fmul(lhs, rhs) => {
ensure("fmul", lhs, Type::Float)?;
ensure("fmul", rhs, Type::Float)?;
Type::Float
}
ast::ValueOperationOp::Fsub(lhs, rhs) => {
ensure("fsub", lhs, Type::Float)?;
ensure("fsub", rhs, Type::Float)?;
Type::Float
}
ast::ValueOperationOp::Fdiv(lhs, rhs) => {
ensure("fdiv", lhs, Type::Float)?;
ensure("fdiv", rhs, Type::Float)?;
Type::Float
}
ast::ValueOperationOp::Feq(lhs, rhs) => {
ensure("feq", lhs, Type::Float)?;
ensure("feq", rhs, Type::Float)?;
Type::Bool
}
ast::ValueOperationOp::Flt(lhs, rhs) => {
ensure("flt", lhs, Type::Float)?;
ensure("flt", rhs, Type::Float)?;
Type::Bool
}
ast::ValueOperationOp::Fle(lhs, rhs) => {
ensure("fle", lhs, Type::Float)?;
ensure("fle", rhs, Type::Float)?;
Type::Bool
}
ast::ValueOperationOp::Fgt(lhs, rhs) => {
ensure("fgt", lhs, Type::Float)?;
ensure("fgt", rhs, Type::Float)?;
Type::Bool
}
ast::ValueOperationOp::Fge(lhs, rhs) => {
ensure("fge", lhs, Type::Float)?;
ensure("fge", rhs, Type::Float)?;
Type::Bool
}
ast::ValueOperationOp::Alloc(_loc) => todo!("implement hindley-milner"),
ast::ValueOperationOp::Load(_loc) => todo!("implement hindley-milner"),
ast::ValueOperationOp::PtrAdd(_loc, _loc1) => {
todo!("implement hindley-milner")
}
ast::ValueOperationOp::Ceq(lhs, rhs) => {
ensure("ceq", lhs, Type::Char)?;
ensure("ceq", rhs, Type::Char)?;
Type::Bool
}
ast::ValueOperationOp::Clt(lhs, rhs) => {
ensure("clt", lhs, Type::Char)?;
ensure("clt", rhs, Type::Char)?;
Type::Bool
}
ast::ValueOperationOp::Cle(lhs, rhs) => {
ensure("cle", lhs, Type::Char)?;
ensure("cle", rhs, Type::Char)?;
Type::Bool
}
ast::ValueOperationOp::Cgt(lhs, rhs) => {
ensure("cgt", lhs, Type::Char)?;
ensure("cgt", rhs, Type::Char)?;
Type::Bool
}
ast::ValueOperationOp::Cge(lhs, rhs) => {
ensure("cge", lhs, Type::Char)?;
ensure("cge", rhs, Type::Char)?;
Type::Bool
}
ast::ValueOperationOp::Char2Int(value) => {
ensure("char2int", value, Type::Char)?;
Type::Int
}
ast::ValueOperationOp::Int2Char(value) => {
ensure("char2int", value, Type::Int)?;
Type::Char
}
};
if let Some(annotation) = &value_operation.type_annotation {
if !annotation.ty.inner.is_same_type_as(&inferred_type) {
return Err(Diagnostic::new(
format!(
"Inferred type {inferred_type} did not match type annotation"
),
annotation,
)
.label("Type inferred here", &value_operation.op));
}
}
symbols.borrow_mut().insert(
value_operation.name.to_string(),
value_operation.name.clone(),
);
env.borrow_mut()
.insert(value_operation.name.to_string(), inferred_type);
}
ast::Instruction::EffectOperation(effect_operation) => {
match &*effect_operation.op {
ast::EffectOperationOp::Jmp(_) => {}
ast::EffectOperationOp::Br(condition, _, _) => {
ensure("br", condition, Type::Bool)?;
}
ast::EffectOperationOp::Call(name, args) => {
let signature = get_signature(name)?;
if args.len() != signature.0.len() {
return Err(Diagnostic::new(
format!(
"Called function takes {} argument(s) but was passed {}",
signature.0.len(),
args.len()
),
name,
));
}
for (i, parameter_type) in signature.0.iter().enumerate() {
ensure("call", &args[i], parameter_type.clone())?;
}
if let Some(return_type) = &signature.1 {
return Err(Diagnostic::new(format!("Called function returns {}, but call used as effect operation", return_type), name));
}
}
ast::EffectOperationOp::Ret(value) => {
if let Some(value) = value {
if let Some(return_type) = return_type.clone() {
ensure("ret", value, return_type)?;
} else {
return Err(Diagnostic::new(
"Tried to return value, but function has no return type",
value,
));
}
} else if let Some(return_type) = return_type {
return Err(Diagnostic::new(
format!(
"Tried to return nothing, but function has return type {}",
return_type
),
effect_operation,
));
}
}
ast::EffectOperationOp::Print(_) => {}
ast::EffectOperationOp::Nop => {}
ast::EffectOperationOp::Store(_loc, _loc1) => {
todo!("implement hindley-milner")
}
ast::EffectOperationOp::Free(_value) => todo!("implement hindley-milner"),
}
}
}
}
}
Ok(env.take())
}