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Interpreter - Refactored internals out of the node implemntations

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Emmanuel BENOîT 2023-01-17 07:23:17 +01:00
parent b01ae10d09
commit 18d9bfb74c
1 changed files with 371 additions and 402 deletions
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315
src/interpreter/interpretable.rs
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@ -1,7 +1,10 @@
use std::{cell::RefCell, collections::HashMap, rc::Rc}; use std::{cell::RefCell, collections::HashMap, rc::Rc};
use crate::{ use crate::{
ast::{ClassDecl, ExprNode, FunDecl, GetExpr, ProgramNode, SetExpr, StmtNode, VariableExpr}, ast::{
ClassDecl, ExprNode, FunDecl, GetExpr, ProgramNode, SetExpr, StmtNode, SuperExpr,
VariableExpr,
},
errors::{ErrorKind, SloxError, SloxResult}, errors::{ErrorKind, SloxError, SloxResult},
resolver::ResolvedVariables, resolver::ResolvedVariables,
tokens::{Token, TokenType}, tokens::{Token, TokenType},
@ -128,9 +131,9 @@ fn error<T>(token: &Token, message: &str) -> SloxResult<T> {
)) ))
} }
/* ----------------------------- * /* -------------------------- *
* INTERPRETER FOR PROGRAM NODES * * ENTRY POINTS FOR AST NODES *
* ----------------------------- */ * -------------------------- */
impl Interpretable for ProgramNode { impl Interpretable for ProgramNode {
fn interpret(&self, es: &mut InterpreterState) -> InterpreterResult { fn interpret(&self, es: &mut InterpreterState) -> InterpreterResult {
@ -141,39 +144,85 @@ impl Interpretable for ProgramNode {
} }
} }
/* ------------------------------- *
* INTERPRETER FOR STATEMENT NODES *
* ------------------------------- */
impl Interpretable for StmtNode { impl Interpretable for StmtNode {
fn interpret(&self, es: &mut InterpreterState) -> InterpreterResult { fn interpret(&self, es: &mut InterpreterState) -> InterpreterResult {
match self { match self {
StmtNode::VarDecl(name, expr) => self.on_var_decl(es, name, expr), StmtNode::VarDecl(name, expr) => on_var_decl(es, name, expr),
StmtNode::FunDecl(decl) => self.on_fun_decl(es, decl), StmtNode::FunDecl(decl) => on_fun_decl(es, decl),
StmtNode::ClassDecl(decl) => self.on_class_decl(es, decl), StmtNode::ClassDecl(decl) => on_class_decl(es, decl),
StmtNode::Expression(expr) => expr.interpret(es), StmtNode::Expression(expr) => expr.interpret(es),
StmtNode::Print(expr) => self.on_print(es, expr), StmtNode::Print(expr) => on_print(es, expr),
StmtNode::Block(statements) => self.on_block(es, statements), StmtNode::Block(statements) => on_block(es, statements),
StmtNode::If { StmtNode::If {
condition, condition,
then_branch, then_branch,
else_branch, else_branch,
} => self.on_if_statement(es, condition, then_branch, else_branch), } => on_if_statement(es, condition, then_branch, else_branch),
StmtNode::Loop { StmtNode::Loop {
label, label,
condition, condition,
body, body,
after_body, after_body,
} => self.on_loop_statement(es, label, condition, body, after_body), } => on_loop_statement(es, label, condition, body, after_body),
StmtNode::LoopControl { StmtNode::LoopControl {
is_break, is_break,
loop_name, loop_name,
} => self.on_loop_control_statemement(*is_break, loop_name), } => on_loop_control_statemement(*is_break, loop_name),
StmtNode::Return { token: _, value } => self.on_return_statement(es, value), StmtNode::Return { token: _, value } => on_return_statement(es, value),
} }
} }
} }
impl Interpretable for ExprNode {
fn interpret(&self, es: &mut InterpreterState) -> InterpreterResult {
match self {
ExprNode::Assignment { name, value, id } => {
let value = value.interpret(es)?.result();
es.assign_var(name, id, value)?;
Ok(InterpreterFlowControl::default())
}
ExprNode::Logical(binary_expr) => on_logic(
es,
&binary_expr.left,
&binary_expr.operator,
&binary_expr.right,
),
ExprNode::Binary(binary_expr) => on_binary(
es,
&binary_expr.left,
&binary_expr.operator,
&binary_expr.right,
),
ExprNode::Unary { operator, right } => on_unary(es, operator, right),
ExprNode::Grouping { expression } => expression.interpret(es),
ExprNode::Litteral { value } => on_litteral(value),
ExprNode::Variable(var_expr) | ExprNode::This(var_expr) => var_expr.interpret(es),
ExprNode::Call {
callee,
right_paren,
arguments,
} => on_call(es, callee, right_paren, arguments),
ExprNode::Lambda { params, body } => {
let lambda = Function::new(None, params, body, es.environment.clone(), false);
Ok(Value::from(lambda).into())
}
ExprNode::Get(get_expr) => on_get_expression(es, get_expr),
ExprNode::Set(set_expr) => on_set_expression(es, set_expr),
ExprNode::Super(super_expr) => on_super(es, super_expr),
}
}
}
impl Interpretable for VariableExpr {
fn interpret(&self, es: &mut InterpreterState) -> InterpreterResult {
Ok(es.lookup_var(self)?.into())
}
}
/* --------------------- *
* INTERPRETER INTERNALS *
* --------------------- */
/// Extract members from a class declaration, generating a map of /// Extract members from a class declaration, generating a map of
/// functions. /// functions.
fn extract_members( fn extract_members(
@ -198,32 +247,30 @@ fn extract_members(
.collect() .collect()
} }
impl StmtNode { /// Handle the `print` statement.
/// Handle the `print` statement. fn on_print(es: &mut InterpreterState, expr: &ExprNode) -> InterpreterResult {
fn on_print(&self, es: &mut InterpreterState, expr: &ExprNode) -> InterpreterResult {
let value = expr.interpret(es)?.result(); let value = expr.interpret(es)?.result();
let output = value.to_string(); let output = value.to_string();
println!("{}", output); println!("{}", output);
Ok(InterpreterFlowControl::default()) Ok(InterpreterFlowControl::default())
} }
/// Handle a variable declaration. /// Handle a variable declaration.
fn on_var_decl( fn on_var_decl(
&self,
es: &mut InterpreterState, es: &mut InterpreterState,
name: &Token, name: &Token,
initializer: &Option<ExprNode>, initializer: &Option<ExprNode>,
) -> InterpreterResult { ) -> InterpreterResult {
let variable = match initializer { let variable = match initializer {
Some(expr) => Some(expr.interpret(es)?.result()), Some(expr) => Some(expr.interpret(es)?.result()),
None => None, None => None,
}; };
es.environment.borrow_mut().define(name, variable)?; es.environment.borrow_mut().define(name, variable)?;
Ok(InterpreterFlowControl::default()) Ok(InterpreterFlowControl::default())
} }
/// Handle a class declaration /// Handle a class declaration
fn on_class_decl(&self, es: &mut InterpreterState, decl: &ClassDecl) -> InterpreterResult { fn on_class_decl(es: &mut InterpreterState, decl: &ClassDecl) -> InterpreterResult {
es.environment.borrow_mut().define(&decl.name, None)?; es.environment.borrow_mut().define(&decl.name, None)?;
let class = match &decl.superclass { let class = match &decl.superclass {
None => Class::new(decl.name.lexeme.clone(), None, extract_members(es, decl)), None => Class::new(decl.name.lexeme.clone(), None, extract_members(es, decl)),
@ -250,10 +297,10 @@ impl StmtNode {
.borrow_mut() .borrow_mut()
.assign(&decl.name, class.into())?; .assign(&decl.name, class.into())?;
Ok(InterpreterFlowControl::default()) Ok(InterpreterFlowControl::default())
} }
/// Handle a function declaration. /// Handle a function declaration.
fn on_fun_decl(&self, es: &mut InterpreterState, decl: &FunDecl) -> InterpreterResult { fn on_fun_decl(es: &mut InterpreterState, decl: &FunDecl) -> InterpreterResult {
let fun = Function::new( let fun = Function::new(
Some(&decl.name), Some(&decl.name),
&decl.params, &decl.params,
@ -265,10 +312,10 @@ impl StmtNode {
.borrow_mut() .borrow_mut()
.define(&decl.name, Some(fun.into()))?; .define(&decl.name, Some(fun.into()))?;
Ok(InterpreterFlowControl::default()) Ok(InterpreterFlowControl::default())
} }
/// Execute the contents of a block. /// Execute the contents of a block.
fn on_block(&self, es: &mut InterpreterState, stmts: &[StmtNode]) -> InterpreterResult { fn on_block(es: &mut InterpreterState, stmts: &[StmtNode]) -> InterpreterResult {
let mut child = InterpreterState::create_child(es); let mut child = InterpreterState::create_child(es);
for stmt in stmts.iter() { for stmt in stmts.iter() {
let result = stmt.interpret(&mut child)?; let result = stmt.interpret(&mut child)?;
@ -277,16 +324,15 @@ impl StmtNode {
} }
} }
Ok(InterpreterFlowControl::default()) Ok(InterpreterFlowControl::default())
} }
/// Execute an if statement. /// Execute an if statement.
fn on_if_statement( fn on_if_statement(
&self,
es: &mut InterpreterState, es: &mut InterpreterState,
condition: &ExprNode, condition: &ExprNode,
then_branch: &StmtNode, then_branch: &StmtNode,
else_branch: &Option<Box<StmtNode>>, else_branch: &Option<Box<StmtNode>>,
) -> InterpreterResult { ) -> InterpreterResult {
if condition.interpret(es)?.result().is_truthy() { if condition.interpret(es)?.result().is_truthy() {
then_branch.interpret(es) then_branch.interpret(es)
} else if let Some(else_stmt) = else_branch { } else if let Some(else_stmt) = else_branch {
@ -294,17 +340,16 @@ impl StmtNode {
} else { } else {
Ok(InterpreterFlowControl::default()) Ok(InterpreterFlowControl::default())
} }
} }
/// Execute a while statement. /// Execute a while statement.
fn on_loop_statement( fn on_loop_statement(
&self,
es: &mut InterpreterState, es: &mut InterpreterState,
label: &Option<Token>, label: &Option<Token>,
condition: &ExprNode, condition: &ExprNode,
body: &StmtNode, body: &StmtNode,
after_body: &Option<Box<StmtNode>>, after_body: &Option<Box<StmtNode>>,
) -> InterpreterResult { ) -> InterpreterResult {
let ln = label.as_ref().map(|token| token.lexeme.clone()); let ln = label.as_ref().map(|token| token.lexeme.clone());
while condition.interpret(es)?.result().is_truthy() { while condition.interpret(es)?.result().is_truthy() {
let result = body.interpret(es)?; let result = body.interpret(es)?;
@ -325,115 +370,34 @@ impl StmtNode {
} }
} }
Ok(InterpreterFlowControl::default()) Ok(InterpreterFlowControl::default())
} }
/// Execute a loop control statement. /// Execute a loop control statement.
fn on_loop_control_statemement( fn on_loop_control_statemement(is_break: bool, label: &Option<Token>) -> InterpreterResult {
&self,
is_break: bool,
label: &Option<Token>,
) -> InterpreterResult {
let name = label.as_ref().map(|token| token.lexeme.clone()); let name = label.as_ref().map(|token| token.lexeme.clone());
if is_break { if is_break {
Ok(InterpreterFlowControl::Break(name)) Ok(InterpreterFlowControl::Break(name))
} else { } else {
Ok(InterpreterFlowControl::Continue(name)) Ok(InterpreterFlowControl::Continue(name))
} }
} }
/// Execute a return statement. /// Execute a return statement.
fn on_return_statement( fn on_return_statement(es: &mut InterpreterState, value: &Option<ExprNode>) -> InterpreterResult {
&self,
es: &mut InterpreterState,
value: &Option<ExprNode>,
) -> InterpreterResult {
let rv = match value { let rv = match value {
None => Value::Nil, None => Value::Nil,
Some(expr) => expr.interpret(es)?.result(), Some(expr) => expr.interpret(es)?.result(),
}; };
Ok(InterpreterFlowControl::Return(rv)) Ok(InterpreterFlowControl::Return(rv))
}
} }
/* -------------------------------- * /// Evaluate a logical operator.
* INTERPRETER FOR EXPRESSION NODES * fn on_logic(
* -------------------------------- */
impl Interpretable for ExprNode {
fn interpret(&self, es: &mut InterpreterState) -> InterpreterResult {
match self {
ExprNode::Assignment { name, value, id } => {
let value = value.interpret(es)?.result();
es.assign_var(name, id, value)?;
Ok(InterpreterFlowControl::default())
}
ExprNode::Logical(binary_expr) => self.on_logic(
es,
&binary_expr.left,
&binary_expr.operator,
&binary_expr.right,
),
ExprNode::Binary(binary_expr) => self.on_binary(
es,
&binary_expr.left,
&binary_expr.operator,
&binary_expr.right,
),
ExprNode::Unary { operator, right } => self.on_unary(es, operator, right),
ExprNode::Grouping { expression } => expression.interpret(es),
ExprNode::Litteral { value } => self.on_litteral(value),
ExprNode::Variable(var_expr) | ExprNode::This(var_expr) => var_expr.interpret(es),
ExprNode::Call {
callee,
right_paren,
arguments,
} => self.on_call(es, callee, right_paren, arguments),
ExprNode::Lambda { params, body } => {
let lambda = Function::new(None, params, body, es.environment.clone(), false);
Ok(Value::from(lambda).into())
}
ExprNode::Get(get_expr) => self.on_get_expression(es, get_expr),
ExprNode::Set(set_expr) => self.on_set_expression(es, set_expr),
ExprNode::Super(super_expr) => {
let distance = match es.locals.get(&super_expr.keyword.id) {
Some(distance) => *distance,
None => panic!("super environment not found"),
};
assert!(distance > 0);
let obj_ref = es.environment.borrow().get_at(
distance - 1,
&Token {
token_type: TokenType::This,
lexeme: "this".to_owned(),
line: 0,
},
)?;
Ok(obj_ref
.with_property_carrier(
|inst| inst.get_super(es, &super_expr, distance),
|| panic!("'this' didn't contain an instance"),
)?
.into())
}
}
}
}
impl Interpretable for VariableExpr {
fn interpret(&self, es: &mut InterpreterState) -> InterpreterResult {
Ok(es.lookup_var(self)?.into())
}
}
impl ExprNode {
/// Evaluate a logical operator.
fn on_logic(
&self,
es: &mut InterpreterState, es: &mut InterpreterState,
left: &ExprNode, left: &ExprNode,
operator: &Token, operator: &Token,
right: &ExprNode, right: &ExprNode,
) -> InterpreterResult { ) -> InterpreterResult {
let left_value = left.interpret(es)?.result(); let left_value = left.interpret(es)?.result();
if operator.token_type == TokenType::Or && left_value.is_truthy() if operator.token_type == TokenType::Or && left_value.is_truthy()
|| operator.token_type == TokenType::And && !left_value.is_truthy() || operator.token_type == TokenType::And && !left_value.is_truthy()
@ -442,16 +406,15 @@ impl ExprNode {
} else { } else {
right.interpret(es) right.interpret(es)
} }
} }
/// Evaluate a binary operator. /// Evaluate a binary operator.
fn on_binary( fn on_binary(
&self,
es: &mut InterpreterState, es: &mut InterpreterState,
left: &ExprNode, left: &ExprNode,
operator: &Token, operator: &Token,
right: &ExprNode, right: &ExprNode,
) -> InterpreterResult { ) -> InterpreterResult {
let left_value = left.interpret(es)?.result(); let left_value = left.interpret(es)?.result();
let right_value = right.interpret(es)?.result(); let right_value = right.interpret(es)?.result();
match operator.token_type { match operator.token_type {
@ -468,9 +431,7 @@ impl ExprNode {
TokenType::Star => match (left_value, right_value) { TokenType::Star => match (left_value, right_value) {
(Value::Number(a), Value::Number(b)) => Ok(Value::Number(a * b).into()), (Value::Number(a), Value::Number(b)) => Ok(Value::Number(a * b).into()),
(Value::String(a), Value::Number(b)) => { (Value::String(a), Value::Number(b)) => Ok(Value::String(a.repeat(b as usize)).into()),
Ok(Value::String(a.repeat(b as usize)).into())
}
_ => error(operator, "type error"), _ => error(operator, "type error"),
}, },
@ -513,15 +474,10 @@ impl ExprNode {
operator operator
), ),
} }
} }
/// Evaluate an unary operator. /// Evaluate an unary operator.
fn on_unary( fn on_unary(es: &mut InterpreterState, operator: &Token, right: &ExprNode) -> InterpreterResult {
&self,
es: &mut InterpreterState,
operator: &Token,
right: &ExprNode,
) -> InterpreterResult {
let right_value = right.interpret(es)?.result(); let right_value = right.interpret(es)?.result();
match operator.token_type { match operator.token_type {
TokenType::Minus => { TokenType::Minus => {
@ -539,10 +495,10 @@ impl ExprNode {
operator operator
), ),
} }
} }
/// Evaluate a litteral. /// Evaluate a litteral.
fn on_litteral(&self, value: &Token) -> InterpreterResult { fn on_litteral(value: &Token) -> InterpreterResult {
let out_value = match &value.token_type { let out_value = match &value.token_type {
TokenType::Nil => Value::Nil, TokenType::Nil => Value::Nil,
TokenType::True => Value::Boolean(true), TokenType::True => Value::Boolean(true),
@ -552,16 +508,15 @@ impl ExprNode {
_ => panic!("Unsupported token type for litteral (token {:?})", value), _ => panic!("Unsupported token type for litteral (token {:?})", value),
}; };
Ok(out_value.into()) Ok(out_value.into())
} }
/// Evaluate a function call. /// Evaluate a function call.
fn on_call( fn on_call(
&self,
es: &mut InterpreterState, es: &mut InterpreterState,
callee: &ExprNode, callee: &ExprNode,
right_paren: &Token, right_paren: &Token,
arguments: &Vec<ExprNode>, arguments: &Vec<ExprNode>,
) -> InterpreterResult { ) -> InterpreterResult {
let callee = callee.interpret(es)?.result(); let callee = callee.interpret(es)?.result();
let arg_values = { let arg_values = {
let mut v = Vec::with_capacity(arguments.len()); let mut v = Vec::with_capacity(arguments.len());
@ -588,27 +543,19 @@ impl ExprNode {
}, },
|| error(right_paren, "expression result is not callable"), || error(right_paren, "expression result is not callable"),
) )
} }
/// Evaluate a get expression. /// Evaluate a get expression.
fn on_get_expression( fn on_get_expression(itpr_state: &mut InterpreterState, get_expr: &GetExpr) -> InterpreterResult {
&self,
itpr_state: &mut InterpreterState,
get_expr: &GetExpr,
) -> InterpreterResult {
let instance = get_expr.instance.interpret(itpr_state)?.result(); let instance = get_expr.instance.interpret(itpr_state)?.result();
instance.with_property_carrier( instance.with_property_carrier(
|inst| inst.get(itpr_state, &get_expr.name).map(|v| v.into()), |inst| inst.get(itpr_state, &get_expr.name).map(|v| v.into()),
|| error(&get_expr.name, "this object doesn't have properties"), || error(&get_expr.name, "this object doesn't have properties"),
) )
} }
/// Evaluate a set expression. /// Evaluate a set expression.
fn on_set_expression( fn on_set_expression(itpr_state: &mut InterpreterState, set_expr: &SetExpr) -> InterpreterResult {
&self,
itpr_state: &mut InterpreterState,
set_expr: &SetExpr,
) -> InterpreterResult {
let instance = set_expr.instance.interpret(itpr_state)?.result(); let instance = set_expr.instance.interpret(itpr_state)?.result();
instance.with_property_carrier( instance.with_property_carrier(
|instance| { |instance| {
@ -618,5 +565,27 @@ impl ExprNode {
}, },
|| error(&set_expr.name, "this object doesn't have properties"), || error(&set_expr.name, "this object doesn't have properties"),
) )
} }
/// Evaluate a reference to a superclass method.
fn on_super(itpr_state: &mut InterpreterState, super_expr: &SuperExpr) -> InterpreterResult {
let distance = match itpr_state.locals.get(&super_expr.keyword.id) {
Some(distance) => *distance,
None => panic!("super environment not found"),
};
assert!(distance > 0);
let obj_ref = itpr_state.environment.borrow().get_at(
distance - 1,
&Token {
token_type: TokenType::This,
lexeme: "this".to_owned(),
line: 0,
},
)?;
Ok(obj_ref
.with_property_carrier(
|inst| inst.get_super(itpr_state, &super_expr, distance),
|| panic!("'this' didn't contain an instance"),
)?
.into())
} }