490 lines
22 KiB
Rust
490 lines
22 KiB
Rust
use std::rc::Rc;
|
|
|
|
use super::{EvalResult, Memory, MemoryValue, Primitive, State};
|
|
use crate::{
|
|
builtin::Builtin,
|
|
reduced_ir::{
|
|
Alternative, Callable, Expression, FunctionDefinition, Literal, Lookup, Pattern, ReducedIR, Statement,
|
|
},
|
|
type_inference::TypeContext,
|
|
util::ScopeStack,
|
|
};
|
|
|
|
#[derive(Debug)]
|
|
enum StatementOutput {
|
|
Primitive(Primitive),
|
|
Nothing,
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy)]
|
|
enum LoopControlFlow {
|
|
Break,
|
|
Continue,
|
|
}
|
|
|
|
pub struct Evaluator<'a, 'b> {
|
|
type_context: &'b TypeContext,
|
|
state: &'b mut State<'a>,
|
|
early_returning: bool,
|
|
loop_control: Option<LoopControlFlow>,
|
|
}
|
|
|
|
impl<'a, 'b> Evaluator<'a, 'b> {
|
|
pub(crate) fn new(state: &'b mut State<'a>, type_context: &'b TypeContext) -> Self {
|
|
Self { state, type_context, early_returning: false, loop_control: None }
|
|
}
|
|
|
|
pub fn evaluate(&mut self, reduced: ReducedIR, repl: bool) -> Vec<Result<String, String>> {
|
|
let mut acc = vec![];
|
|
for (def_id, function) in reduced.functions.into_iter() {
|
|
let mem = (&def_id).into();
|
|
self.state.environments.insert(mem, MemoryValue::Function(function));
|
|
}
|
|
|
|
for statement in reduced.entrypoint.into_iter() {
|
|
match self.statement(statement) {
|
|
Ok(StatementOutput::Primitive(output)) if repl =>
|
|
acc.push(Ok(output.to_repl(self.type_context))),
|
|
Ok(_) => (),
|
|
Err(error) => {
|
|
acc.push(Err(error.msg));
|
|
return acc;
|
|
}
|
|
}
|
|
}
|
|
acc
|
|
}
|
|
|
|
fn block(&mut self, statements: Vec<Statement>) -> EvalResult<Primitive> {
|
|
let mut retval = None;
|
|
for stmt in statements.into_iter() {
|
|
match self.statement(stmt)? {
|
|
StatementOutput::Nothing => (),
|
|
StatementOutput::Primitive(prim) => {
|
|
retval = Some(prim);
|
|
}
|
|
};
|
|
if self.early_returning {
|
|
break;
|
|
}
|
|
if self.loop_control.is_some() {
|
|
break;
|
|
}
|
|
}
|
|
Ok(if let Some(ret) = retval { ret } else { self.expression(Expression::unit())? })
|
|
}
|
|
|
|
fn statement(&mut self, stmt: Statement) -> EvalResult<StatementOutput> {
|
|
match stmt {
|
|
Statement::Binding { ref id, expr, constant: _ } => {
|
|
let evaluated = self.expression(expr)?;
|
|
self.state.environments.insert(id.into(), evaluated.into());
|
|
Ok(StatementOutput::Nothing)
|
|
}
|
|
Statement::Expression(expr) => {
|
|
let evaluated = self.expression(expr)?;
|
|
Ok(StatementOutput::Primitive(evaluated))
|
|
}
|
|
Statement::Return(expr) => {
|
|
let evaluated = self.expression(expr)?;
|
|
self.early_returning = true;
|
|
Ok(StatementOutput::Primitive(evaluated))
|
|
}
|
|
Statement::Break => {
|
|
self.loop_control = Some(LoopControlFlow::Break);
|
|
Ok(StatementOutput::Nothing)
|
|
}
|
|
Statement::Continue => {
|
|
self.loop_control = Some(LoopControlFlow::Continue);
|
|
Ok(StatementOutput::Nothing)
|
|
}
|
|
}
|
|
}
|
|
|
|
fn expression(&mut self, expression: Expression) -> EvalResult<Primitive> {
|
|
Ok(match expression {
|
|
Expression::Literal(lit) => Primitive::Literal(lit),
|
|
Expression::Tuple(items) => Primitive::Tuple(
|
|
items
|
|
.into_iter()
|
|
.map(|expr| self.expression(expr))
|
|
.collect::<EvalResult<Vec<Primitive>>>()?,
|
|
),
|
|
Expression::List(items) => Primitive::List(
|
|
items
|
|
.into_iter()
|
|
.map(|expr| self.expression(expr))
|
|
.collect::<EvalResult<Vec<Primitive>>>()?,
|
|
),
|
|
Expression::Lookup(kind) => match kind {
|
|
Lookup::Function(ref id) => {
|
|
let mem = id.into();
|
|
match self.state.environments.lookup(&mem) {
|
|
// This just checks that the function exists in "memory" by ID, we don't
|
|
// actually retrieve it until `apply_function()`
|
|
Some(MemoryValue::Function(_)) => Primitive::Callable(Callable::UserDefined(*id)),
|
|
x => return Err(format!("Function not found for id: {} : {:?}", id, x).into()),
|
|
}
|
|
}
|
|
Lookup::Param(n) => {
|
|
let mem = n.into();
|
|
match self.state.environments.lookup(&mem) {
|
|
Some(MemoryValue::Primitive(prim)) => prim.clone(),
|
|
e => return Err(format!("Param lookup error, got {:?}", e).into()),
|
|
}
|
|
}
|
|
Lookup::LocalVar(ref id) | Lookup::GlobalVar(ref id) => {
|
|
let mem = id.into();
|
|
match self.state.environments.lookup(&mem) {
|
|
Some(MemoryValue::Primitive(expr)) => expr.clone(),
|
|
_ =>
|
|
return Err(
|
|
format!("Nothing found for local/gloval variable lookup {}", id).into()
|
|
),
|
|
}
|
|
}
|
|
},
|
|
Expression::Assign { ref lval, box rval } => {
|
|
let mem = lval.into();
|
|
let evaluated = self.expression(rval)?;
|
|
println!("Inserting {:?} into {:?}", evaluated, mem);
|
|
self.state.environments.insert(mem, MemoryValue::Primitive(evaluated));
|
|
Primitive::unit()
|
|
}
|
|
Expression::Call { box f, args } => self.call_expression(f, args)?,
|
|
Expression::Callable(Callable::DataConstructor { type_id, tag }) => {
|
|
let arity = self.type_context.lookup_variant_arity(&type_id, tag).unwrap();
|
|
if arity == 0 {
|
|
Primitive::Object { type_id, tag, items: vec![], ordered_fields: None }
|
|
} else {
|
|
Primitive::Callable(Callable::DataConstructor { type_id, tag })
|
|
}
|
|
}
|
|
Expression::Callable(func) => Primitive::Callable(func),
|
|
Expression::Conditional { box cond, then_clause, else_clause } => {
|
|
let cond = self.expression(cond)?;
|
|
match cond {
|
|
Primitive::Literal(Literal::Bool(true)) => self.block(then_clause)?,
|
|
Primitive::Literal(Literal::Bool(false)) => self.block(else_clause)?,
|
|
v => return Err(format!("Non-boolean value {:?} in if-statement", v).into()),
|
|
}
|
|
}
|
|
Expression::CaseMatch { box cond, alternatives } =>
|
|
self.case_match_expression(cond, alternatives)?,
|
|
Expression::Index { box indexee, box indexer } => {
|
|
let indexee = self.expression(indexee)?;
|
|
let indexer = self.expression(indexer)?;
|
|
match (indexee, indexer) {
|
|
(Primitive::List(items), Primitive::Literal(Literal::Nat(n))) =>
|
|
match items.get(n as usize) {
|
|
Some(item) => item.clone(),
|
|
None => return Err(format!("Invalid index {} for this value", n).into()),
|
|
},
|
|
_ => return Err("Invalid index type".to_string().into()),
|
|
}
|
|
}
|
|
Expression::Loop { box cond, statements } => self.loop_expression(cond, statements)?,
|
|
Expression::ReductionError(e) => return Err(e.into()),
|
|
Expression::Access { name, box expr } => {
|
|
let expr = self.expression(expr)?;
|
|
match expr {
|
|
Primitive::Object { items, ordered_fields: Some(ordered_fields), .. } => {
|
|
let idx = match ordered_fields.iter().position(|s| s == &name) {
|
|
Some(idx) => idx,
|
|
None => return Err(format!("Field `{}` not found", name).into()),
|
|
};
|
|
|
|
let item = match items.get(idx) {
|
|
Some(item) => item,
|
|
None => return Err(format!("Field lookup `{}` failed", name).into()),
|
|
};
|
|
|
|
item.clone()
|
|
}
|
|
e =>
|
|
return Err(
|
|
format!("Trying to do a field lookup on a non-object value: {:?}", e).into()
|
|
),
|
|
}
|
|
}
|
|
})
|
|
}
|
|
|
|
fn loop_expression(&mut self, cond: Expression, statements: Vec<Statement>) -> EvalResult<Primitive> {
|
|
let existing = self.loop_control;
|
|
let output = self.loop_expression_inner(cond, statements);
|
|
self.loop_control = existing;
|
|
output
|
|
}
|
|
|
|
fn loop_expression_inner(
|
|
&mut self,
|
|
cond: Expression,
|
|
statements: Vec<Statement>,
|
|
) -> EvalResult<Primitive> {
|
|
loop {
|
|
let cond = self.expression(cond.clone())?;
|
|
println!("COND: {:?}", cond);
|
|
match cond {
|
|
Primitive::Literal(Literal::Bool(true)) => (),
|
|
Primitive::Literal(Literal::Bool(false)) => break,
|
|
e => return Err(format!("Loop condition evaluates to non-boolean: {:?}", e).into()),
|
|
};
|
|
//TODO eventually loops shoudl be able to return something
|
|
let _output = self.block(statements.clone())?;
|
|
match self.loop_control {
|
|
None => (),
|
|
Some(LoopControlFlow::Continue) => {
|
|
self.loop_control = None;
|
|
}
|
|
Some(LoopControlFlow::Break) => {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
Ok(Primitive::unit())
|
|
}
|
|
|
|
fn case_match_expression(
|
|
&mut self,
|
|
cond: Expression,
|
|
alternatives: Vec<Alternative>,
|
|
) -> EvalResult<Primitive> {
|
|
fn matches(scrut: &Primitive, pat: &Pattern, scope: &mut ScopeStack<Memory, MemoryValue>) -> bool {
|
|
match pat {
|
|
Pattern::Ignored => true,
|
|
Pattern::Binding(ref def_id) => {
|
|
let mem = def_id.into();
|
|
scope.insert(mem, MemoryValue::Primitive(scrut.clone())); //TODO make sure this doesn't cause problems with nesting
|
|
true
|
|
}
|
|
Pattern::Literal(pat_literal) =>
|
|
if let Primitive::Literal(scrut_literal) = scrut {
|
|
pat_literal == scrut_literal
|
|
} else {
|
|
false
|
|
},
|
|
Pattern::Tuple { subpatterns, tag } => match tag {
|
|
None => match scrut {
|
|
Primitive::Tuple(items) if items.len() == subpatterns.len() => items
|
|
.iter()
|
|
.zip(subpatterns.iter())
|
|
.all(|(item, subpat)| matches(item, subpat, scope)),
|
|
_ => false, //TODO should be a type error
|
|
},
|
|
Some(pattern_tag) => match scrut {
|
|
//TODO should test type_ids for runtime type checking, once those work
|
|
Primitive::Object { tag, items, .. }
|
|
if tag == pattern_tag && items.len() == subpatterns.len() =>
|
|
items
|
|
.iter()
|
|
.zip(subpatterns.iter())
|
|
.all(|(item, subpat)| matches(item, subpat, scope)),
|
|
_ => false,
|
|
},
|
|
},
|
|
Pattern::Record { tag: pattern_tag, subpatterns } => match scrut {
|
|
//TODO several types of possible error here
|
|
Primitive::Object { tag, items, ordered_fields: Some(ordered_fields), .. }
|
|
if tag == pattern_tag =>
|
|
subpatterns.iter().all(|(field_name, subpat)| {
|
|
let idx = ordered_fields
|
|
.iter()
|
|
.position(|field| field.as_str() == field_name.as_ref())
|
|
.unwrap();
|
|
let item = &items[idx];
|
|
matches(item, subpat, scope)
|
|
}),
|
|
_ => false,
|
|
},
|
|
}
|
|
}
|
|
let cond = self.expression(cond)?;
|
|
|
|
for alt in alternatives.into_iter() {
|
|
let mut new_scope = self.state.environments.new_scope(None);
|
|
if matches(&cond, &alt.pattern, &mut new_scope) {
|
|
let mut new_state = State { environments: new_scope };
|
|
let mut evaluator = Evaluator::new(&mut new_state, self.type_context);
|
|
let output = evaluator.block(alt.item);
|
|
self.early_returning = evaluator.early_returning;
|
|
return output;
|
|
}
|
|
}
|
|
Err("No valid match in match expression".into())
|
|
}
|
|
|
|
fn call_expression(&mut self, f: Expression, args: Vec<Expression>) -> EvalResult<Primitive> {
|
|
let func = match self.expression(f)? {
|
|
Primitive::Callable(func) => func,
|
|
other => return Err(format!("Trying to call non-function value: {:?}", other).into()),
|
|
};
|
|
match func {
|
|
Callable::Builtin(builtin) => self.apply_builtin(builtin, args),
|
|
Callable::UserDefined(def_id) => {
|
|
let mem = (&def_id).into();
|
|
match self.state.environments.lookup(&mem) {
|
|
Some(MemoryValue::Function(FunctionDefinition { body })) => {
|
|
let body = body.clone(); //TODO ideally this clone would not happen
|
|
self.apply_function(body, args)
|
|
}
|
|
e => Err(format!("Error looking up function with id {}: {:?}", def_id, e).into()),
|
|
}
|
|
}
|
|
Callable::Lambda { arity, body } => {
|
|
if arity as usize != args.len() {
|
|
return Err(format!(
|
|
"Lambda expression requries {} arguments, only {} provided",
|
|
arity,
|
|
args.len()
|
|
)
|
|
.into());
|
|
}
|
|
self.apply_function(body, args)
|
|
}
|
|
Callable::DataConstructor { type_id, tag } => {
|
|
let arity = self.type_context.lookup_variant_arity(&type_id, tag).unwrap();
|
|
if arity as usize != args.len() {
|
|
return Err(format!(
|
|
"Constructor expression requries {} arguments, only {} provided",
|
|
arity,
|
|
args.len()
|
|
)
|
|
.into());
|
|
}
|
|
|
|
let mut items: Vec<Primitive> = vec![];
|
|
for arg in args.into_iter() {
|
|
items.push(self.expression(arg)?);
|
|
}
|
|
Ok(Primitive::Object { type_id, tag, items, ordered_fields: None })
|
|
}
|
|
Callable::RecordConstructor { type_id, tag, field_order } => {
|
|
//TODO maybe I'll want to do a runtime check of the evaluated fields
|
|
/*
|
|
let record_members = self.type_context.lookup_record_members(type_id, tag)
|
|
.ok_or(format!("Runtime record lookup for: {} {} not found", type_id, tag).into())?;
|
|
*/
|
|
|
|
let mut items: Vec<Primitive> = vec![];
|
|
for arg in args.into_iter() {
|
|
items.push(self.expression(arg)?);
|
|
}
|
|
Ok(Primitive::Object { type_id, tag, items, ordered_fields: Some(field_order) })
|
|
}
|
|
}
|
|
}
|
|
|
|
fn apply_builtin(&mut self, builtin: Builtin, args: Vec<Expression>) -> EvalResult<Primitive> {
|
|
use Builtin::*;
|
|
use Literal::*;
|
|
use Primitive::Literal as Lit;
|
|
|
|
let evaled_args: EvalResult<Vec<Primitive>> =
|
|
args.into_iter().map(|arg| self.expression(arg)).collect();
|
|
let evaled_args = evaled_args?;
|
|
|
|
Ok(match (builtin, evaled_args.as_slice()) {
|
|
/* builtin functions */
|
|
(IOPrint, &[ref anything]) => {
|
|
print!("{}", anything.to_repl(self.type_context));
|
|
Primitive::Tuple(vec![])
|
|
}
|
|
(IOPrintLn, &[ref anything]) => {
|
|
println!("{}", anything.to_repl(self.type_context));
|
|
Primitive::Tuple(vec![])
|
|
}
|
|
(IOGetLine, &[]) => {
|
|
let mut buf = String::new();
|
|
std::io::stdin().read_line(&mut buf).expect("Error readling line in 'getline'");
|
|
StringLit(Rc::new(buf.trim().to_string())).into()
|
|
}
|
|
/* Binops */
|
|
(binop, &[ref lhs, ref rhs]) => match (binop, lhs, rhs) {
|
|
// TODO need a better way of handling these literals
|
|
(Add, Lit(Nat(l)), Lit(Nat(r))) => Nat(l + r).into(),
|
|
(Add, Lit(Int(l)), Lit(Int(r))) => Int(l + r).into(),
|
|
(Add, Lit(Nat(l)), Lit(Int(r))) => Int((*l as i64) + (*r as i64)).into(),
|
|
(Add, Lit(Int(l)), Lit(Nat(r))) => Int((*l as i64) + (*r as i64)).into(),
|
|
(Concatenate, Lit(StringLit(ref s1)), Lit(StringLit(ref s2))) =>
|
|
StringLit(Rc::new(format!("{}{}", s1, s2))).into(),
|
|
(Subtract, Lit(Nat(l)), Lit(Nat(r))) => Nat(l - r).into(),
|
|
(Multiply, Lit(Nat(l)), Lit(Nat(r))) => Nat(l * r).into(),
|
|
(Divide, Lit(Nat(l)), Lit(Nat(r))) => Float((*l as f64) / (*r as f64)).into(),
|
|
(Quotient, Lit(Nat(l)), Lit(Nat(r))) =>
|
|
if *r == 0 {
|
|
return Err("Divide-by-zero error".into());
|
|
} else {
|
|
Nat(l / r).into()
|
|
},
|
|
(Modulo, Lit(Nat(l)), Lit(Nat(r))) => Nat(l % r).into(),
|
|
(Exponentiation, Lit(Nat(l)), Lit(Nat(r))) => Nat(l ^ r).into(),
|
|
(BitwiseAnd, Lit(Nat(l)), Lit(Nat(r))) => Nat(l & r).into(),
|
|
(BitwiseOr, Lit(Nat(l)), Lit(Nat(r))) => Nat(l | r).into(),
|
|
|
|
/* comparisons */
|
|
(Equality, Lit(Nat(l)), Lit(Nat(r))) => Bool(l == r).into(),
|
|
(Equality, Lit(Int(l)), Lit(Int(r))) => Bool(l == r).into(),
|
|
(Equality, Lit(Float(l)), Lit(Float(r))) => Bool(l == r).into(),
|
|
(Equality, Lit(Bool(l)), Lit(Bool(r))) => Bool(l == r).into(),
|
|
(Equality, Lit(StringLit(ref l)), Lit(StringLit(ref r))) => Bool(l == r).into(),
|
|
|
|
(NotEqual, Lit(Nat(l)), Lit(Nat(r))) => Bool(l != r).into(),
|
|
(NotEqual, Lit(Int(l)), Lit(Int(r))) => Bool(l != r).into(),
|
|
(NotEqual, Lit(Float(l)), Lit(Float(r))) => Bool(l != r).into(),
|
|
(NotEqual, Lit(Bool(l)), Lit(Bool(r))) => Bool(l != r).into(),
|
|
(NotEqual, Lit(StringLit(ref l)), Lit(StringLit(ref r))) => Bool(l != r).into(),
|
|
|
|
(LessThan, Lit(Nat(l)), Lit(Nat(r))) => Bool(l < r).into(),
|
|
(LessThan, Lit(Int(l)), Lit(Int(r))) => Bool(l < r).into(),
|
|
(LessThan, Lit(Float(l)), Lit(Float(r))) => Bool(l < r).into(),
|
|
|
|
(LessThanOrEqual, Lit(Nat(l)), Lit(Nat(r))) => Bool(l <= r).into(),
|
|
(LessThanOrEqual, Lit(Int(l)), Lit(Int(r))) => Bool(l <= r).into(),
|
|
(LessThanOrEqual, Lit(Float(l)), Lit(Float(r))) => Bool(l <= r).into(),
|
|
|
|
(GreaterThan, Lit(Nat(l)), Lit(Nat(r))) => Bool(l > r).into(),
|
|
(GreaterThan, Lit(Int(l)), Lit(Int(r))) => Bool(l > r).into(),
|
|
(GreaterThan, Lit(Float(l)), Lit(Float(r))) => Bool(l > r).into(),
|
|
|
|
(GreaterThanOrEqual, Lit(Nat(l)), Lit(Nat(r))) => Bool(l >= r).into(),
|
|
(GreaterThanOrEqual, Lit(Int(l)), Lit(Int(r))) => Bool(l >= r).into(),
|
|
(GreaterThanOrEqual, Lit(Float(l)), Lit(Float(r))) => Bool(l >= r).into(),
|
|
|
|
(binop, lhs, rhs) =>
|
|
return Err(format!("Invalid binop expression {:?} {:?} {:?}", lhs, binop, rhs).into()),
|
|
},
|
|
(prefix, &[ref arg]) => match (prefix, arg) {
|
|
(BooleanNot, Lit(Bool(true))) => Bool(false),
|
|
(BooleanNot, Lit(Bool(false))) => Bool(true),
|
|
(Negate, Lit(Nat(n))) => Int(-(*n as i64)),
|
|
(Negate, Lit(Int(n))) => Int(-(*n as i64)),
|
|
(Negate, Lit(Float(f))) => Float(-(*f as f64)),
|
|
(Increment, Lit(Int(n))) => Int(*n),
|
|
(Increment, Lit(Nat(n))) => Nat(*n),
|
|
_ => return Err("No valid prefix op".into()),
|
|
}
|
|
.into(),
|
|
(x, args) => return Err(format!("bad or unimplemented builtin {:?} | {:?}", x, args).into()),
|
|
})
|
|
}
|
|
|
|
fn apply_function(&mut self, body: Vec<Statement>, args: Vec<Expression>) -> EvalResult<Primitive> {
|
|
let mut evaluated_args: Vec<Primitive> = vec![];
|
|
for arg in args.into_iter() {
|
|
evaluated_args.push(self.expression(arg)?);
|
|
}
|
|
|
|
let mut frame_state = State { environments: self.state.environments.new_scope(None) };
|
|
let mut evaluator = Evaluator::new(&mut frame_state, self.type_context);
|
|
|
|
for (n, evaled) in evaluated_args.into_iter().enumerate() {
|
|
let n = n as u8;
|
|
let mem = n.into();
|
|
evaluator.state.environments.insert(mem, MemoryValue::Primitive(evaled));
|
|
}
|
|
|
|
evaluator.block(body)
|
|
}
|
|
}
|