1
0
dust/dust-lang/src/parser.rs

1699 lines
54 KiB
Rust

use std::{
fmt::{self, Display, Formatter},
mem::{replace, take},
num::{ParseFloatError, ParseIntError},
};
use colored::Colorize;
use serde::{Deserialize, Serialize};
use crate::{
AnnotatedError, Chunk, ChunkError, DustError, FunctionType, Identifier, Instruction, LexError,
Lexer, Operation, Span, Token, TokenKind, TokenOwned, Type, Value,
};
pub fn parse(source: &str) -> Result<Chunk, DustError> {
let lexer = Lexer::new(source);
let mut parser = Parser::new(lexer).map_err(|error| DustError::Parse { error, source })?;
while !parser.is_eof() {
parser
.parse_statement(
Allowed {
assignment: true,
explicit_return: false,
implicit_return: true,
},
Context::None,
)
.map_err(|error| DustError::Parse { error, source })?;
}
Ok(parser.take_chunk())
}
#[derive(Debug, Clone, Eq, PartialEq, PartialOrd, Ord, Serialize)]
pub struct Parser<'src> {
chunk: Chunk,
lexer: Lexer<'src>,
current_register: u8,
current_token: Token<'src>,
current_position: Span,
previous_token: Token<'src>,
previous_position: Span,
parsed_expression: bool,
latest_value_type: Option<Type>,
}
impl<'src> Parser<'src> {
pub fn new(mut lexer: Lexer<'src>) -> Result<Self, ParseError> {
let (current_token, current_position) = lexer.next_token()?;
log::info!(
"Begin chunk with {} at {}",
current_token.to_string().bold(),
current_position.to_string()
);
Ok(Parser {
lexer,
chunk: Chunk::new(),
current_register: 0,
current_token,
current_position,
previous_token: Token::Eof,
previous_position: Span(0, 0),
parsed_expression: false,
latest_value_type: None,
})
}
pub fn take_chunk(self) -> Chunk {
log::info!("End chunk");
self.chunk
}
fn is_eof(&self) -> bool {
matches!(self.current_token, Token::Eof)
}
fn increment_register(&mut self) -> Result<(), ParseError> {
let current = self.current_register;
if current == u8::MAX {
Err(ParseError::RegisterOverflow {
position: self.current_position,
})
} else {
self.current_register += 1;
Ok(())
}
}
fn advance(&mut self) -> Result<(), ParseError> {
if self.is_eof() {
return Ok(());
}
let (new_token, position) = self.lexer.next_token()?;
log::info!(
"Parsing {} at {}",
new_token.to_string().bold(),
position.to_string()
);
self.previous_token = replace(&mut self.current_token, new_token);
self.previous_position = replace(&mut self.current_position, position);
Ok(())
}
fn allow(&mut self, allowed: Token) -> Result<bool, ParseError> {
if self.current_token == allowed {
self.advance()?;
Ok(true)
} else {
Ok(false)
}
}
fn expect(&mut self, expected: Token) -> Result<(), ParseError> {
if self.current_token == expected {
self.advance()
} else {
Err(ParseError::ExpectedToken {
expected: expected.kind(),
found: self.current_token.to_owned(),
position: self.current_position,
})
}
}
fn emit_instruction(&mut self, instruction: Instruction, position: Span) {
log::debug!(
"Emitting {} at {}",
instruction.operation().to_string().bold(),
position.to_string()
);
self.chunk.push_instruction(instruction, position);
}
fn emit_constant(&mut self, value: Value, position: Span) -> Result<(), ParseError> {
self.latest_value_type = Some(value.r#type());
let constant_index = self.chunk.push_constant(value, position)?;
self.emit_instruction(
Instruction::load_constant(self.current_register, constant_index, false),
position,
);
Ok(())
}
fn parse_boolean(&mut self, _: Allowed) -> Result<(), ParseError> {
let position = self.current_position;
if let Token::Boolean(text) = self.current_token {
self.advance()?;
let boolean = text.parse::<bool>().unwrap();
self.emit_instruction(
Instruction::load_boolean(self.current_register, boolean, false),
position,
);
self.latest_value_type = Some(Type::Boolean);
self.parsed_expression = true;
Ok(())
} else {
Err(ParseError::ExpectedToken {
expected: TokenKind::Boolean,
found: self.current_token.to_owned(),
position,
})
}
}
fn parse_byte(&mut self, _: Allowed) -> Result<(), ParseError> {
let position = self.current_position;
if let Token::Byte(text) = self.current_token {
self.advance()?;
let byte = u8::from_str_radix(&text[2..], 16)
.map_err(|error| ParseError::ParseIntError { error, position })?;
let value = Value::byte(byte);
self.emit_constant(value, position)?;
self.parsed_expression = true;
Ok(())
} else {
Err(ParseError::ExpectedToken {
expected: TokenKind::Byte,
found: self.current_token.to_owned(),
position,
})
}
}
fn parse_character(&mut self, _: Allowed) -> Result<(), ParseError> {
let position = self.current_position;
if let Token::Character(character) = self.current_token {
self.advance()?;
let value = Value::character(character);
self.emit_constant(value, position)?;
self.parsed_expression = true;
Ok(())
} else {
Err(ParseError::ExpectedToken {
expected: TokenKind::Character,
found: self.current_token.to_owned(),
position,
})
}
}
fn parse_float(&mut self, _: Allowed) -> Result<(), ParseError> {
let position = self.current_position;
if let Token::Float(text) = self.current_token {
self.advance()?;
let float = text
.parse::<f64>()
.map_err(|error| ParseError::ParseFloatError {
error,
position: self.previous_position,
})?;
let value = Value::float(float);
self.emit_constant(value, position)?;
self.parsed_expression = true;
Ok(())
} else {
Err(ParseError::ExpectedToken {
expected: TokenKind::Float,
found: self.current_token.to_owned(),
position,
})
}
}
fn parse_integer(&mut self, _: Allowed) -> Result<(), ParseError> {
let position = self.current_position;
if let Token::Integer(text) = self.current_token {
self.advance()?;
let integer = text
.parse::<i64>()
.map_err(|error| ParseError::ParseIntError {
error,
position: self.previous_position,
})?;
let value = Value::integer(integer);
self.emit_constant(value, position)?;
self.parsed_expression = true;
Ok(())
} else {
Err(ParseError::ExpectedToken {
expected: TokenKind::Integer,
found: self.current_token.to_owned(),
position,
})
}
}
fn parse_string(&mut self, _: Allowed) -> Result<(), ParseError> {
let position = self.current_position;
if let Token::String(text) = self.current_token {
self.advance()?;
let value = Value::string(text);
self.emit_constant(value, position)?;
self.parsed_expression = true;
Ok(())
} else {
Err(ParseError::ExpectedToken {
expected: TokenKind::String,
found: self.current_token.to_owned(),
position,
})
}
}
fn parse_grouped(&mut self, _: Allowed) -> Result<(), ParseError> {
self.allow(Token::LeftParenthesis)?;
self.parse_expression()?;
self.expect(Token::RightParenthesis)?;
self.parsed_expression = true;
Ok(())
}
fn parse_unary(&mut self, _: Allowed) -> Result<(), ParseError> {
let operator = self.current_token;
let operator_position = self.current_position;
self.advance()?;
self.parse_expression()?;
let (previous_instruction, previous_position) =
self.chunk.pop_instruction(self.current_position)?;
let (push_back, is_constant, argument) = {
match previous_instruction.operation() {
Operation::GetLocal => (false, false, previous_instruction.a()),
Operation::LoadConstant => (false, true, previous_instruction.a()),
Operation::LoadBoolean => (true, false, previous_instruction.a()),
Operation::Close => {
return Err(ParseError::ExpectedExpression {
found: self.previous_token.to_owned(),
position: self.previous_position,
});
}
_ => (true, false, previous_instruction.a()),
}
};
if push_back {
self.increment_register()?;
}
let mut instruction = match operator.kind() {
TokenKind::Bang => Instruction::not(self.current_register, argument),
TokenKind::Minus => Instruction::negate(self.current_register, argument),
_ => {
return Err(ParseError::ExpectedTokenMultiple {
expected: &[TokenKind::Bang, TokenKind::Minus],
found: operator.to_owned(),
position: operator_position,
})
}
};
if is_constant {
instruction.set_b_is_constant();
}
if push_back {
self.emit_instruction(previous_instruction, previous_position);
}
self.emit_instruction(instruction, operator_position);
self.parsed_expression = true;
Ok(())
}
fn handle_binary_argument(
&mut self,
instruction: &Instruction,
) -> Result<(bool, bool, bool, u8), ParseError> {
let mut push_back = false;
let mut is_constant = false;
let mut is_mutable_local = false;
let argument = match instruction.operation() {
Operation::GetLocal => {
let local_index = instruction.b();
let local = self.chunk.get_local(local_index, self.current_position)?;
is_mutable_local = local.is_mutable;
local.register_index
}
Operation::LoadConstant => {
is_constant = true;
instruction.b()
}
Operation::LoadBoolean => instruction.a(),
Operation::Close => {
return Err(ParseError::ExpectedExpression {
found: self.previous_token.to_owned(),
position: self.previous_position,
});
}
_ => {
push_back = true;
instruction.a()
}
};
Ok((push_back, is_constant, is_mutable_local, argument))
}
fn parse_math_binary(&mut self) -> Result<(), ParseError> {
let (left_instruction, left_position) =
self.chunk.pop_instruction(self.current_position)?;
let (push_back_left, left_is_constant, left_is_mutable_local, left) =
self.handle_binary_argument(&left_instruction)?;
let operator = self.current_token;
let operator_position = self.current_position;
let rule = ParseRule::from(&operator);
if let TokenKind::PlusEqual
| TokenKind::MinusEqual
| TokenKind::StarEqual
| TokenKind::SlashEqual = operator.kind()
{
if !left_is_mutable_local {
return Err(ParseError::ExpectedMutableVariable {
found: self.previous_token.to_owned(),
position: left_position,
});
}
}
self.advance()?;
self.parse(
rule.precedence.increment(),
Allowed {
assignment: false,
explicit_return: false,
implicit_return: false,
},
)?;
let (right_instruction, right_position) =
self.chunk.pop_instruction(self.current_position)?;
let (push_back_right, right_is_constant, right_is_mutable_local, right) =
self.handle_binary_argument(&right_instruction)?;
let register = if left_is_mutable_local {
left
} else if right_is_mutable_local {
right
} else {
let current = self.current_register;
self.increment_register()?;
current
};
let (mut new_instruction, is_expression) = match operator.kind() {
TokenKind::Plus => (Instruction::add(register, left, right), true),
TokenKind::PlusEqual => (Instruction::add(register, left, right), false),
TokenKind::Minus => (Instruction::subtract(register, left, right), true),
TokenKind::MinusEqual => (Instruction::subtract(register, left, right), false),
TokenKind::Star => (Instruction::multiply(register, left, right), true),
TokenKind::StarEqual => (Instruction::multiply(register, left, right), false),
TokenKind::Slash => (Instruction::divide(register, left, right), true),
TokenKind::SlashEqual => (Instruction::divide(register, left, right), false),
TokenKind::Percent => (Instruction::modulo(register, left, right), true),
_ => {
return Err(ParseError::ExpectedTokenMultiple {
expected: &[
TokenKind::Plus,
TokenKind::PlusEqual,
TokenKind::Minus,
TokenKind::MinusEqual,
TokenKind::Star,
TokenKind::StarEqual,
TokenKind::Slash,
TokenKind::SlashEqual,
TokenKind::Percent,
],
found: operator.to_owned(),
position: operator_position,
})
}
};
self.parsed_expression = is_expression;
if left_is_constant {
new_instruction.set_b_is_constant();
}
if right_is_constant {
new_instruction.set_c_is_constant();
}
let mut instructions = if !push_back_left && !push_back_right {
self.emit_instruction(new_instruction, operator_position);
return Ok(());
} else if push_back_right && !push_back_left {
vec![
(right_instruction, right_position),
(new_instruction, operator_position),
]
} else if push_back_left && !push_back_right {
vec![
(left_instruction, left_position),
(new_instruction, operator_position),
]
} else {
vec![
(new_instruction, operator_position),
(left_instruction, left_position),
(right_instruction, right_position),
]
};
while let Ok(operation) = self.chunk.get_last_operation() {
if operation.is_math() {
let (instruction, position) = self.chunk.pop_instruction(self.current_position)?;
instructions.push((instruction, position));
} else {
break;
}
}
instructions.sort_by_key(|(instruction, _)| instruction.a());
for (instruction, position) in instructions {
self.emit_instruction(instruction, position);
}
Ok(())
}
fn parse_comparison_binary(&mut self) -> Result<(), ParseError> {
if let [Some(Operation::Jump), Some(Operation::Equal) | Some(Operation::Less) | Some(Operation::LessEqual)] =
self.chunk.get_last_n_operations()
{
return Err(ParseError::CannotChainComparison {
position: self.current_position,
});
}
let (left_instruction, left_position) =
self.chunk.pop_instruction(self.current_position)?;
let (push_back_left, left_is_constant, _, left) =
self.handle_binary_argument(&left_instruction)?;
let operator = self.current_token;
let operator_position = self.current_position;
let rule = ParseRule::from(&operator);
self.advance()?;
self.parse(
rule.precedence.increment(),
Allowed {
assignment: false,
explicit_return: false,
implicit_return: false,
},
)?;
let (right_instruction, right_position) =
self.chunk.pop_instruction(self.current_position)?;
let (push_back_right, right_is_constant, _, right) =
self.handle_binary_argument(&right_instruction)?;
let mut instruction = match operator {
Token::DoubleEqual => Instruction::equal(true, left.saturating_sub(1), right),
Token::BangEqual => Instruction::equal(false, left.saturating_sub(1), right),
Token::Less => Instruction::less(true, left.saturating_sub(1), right),
Token::LessEqual => Instruction::less_equal(true, left.saturating_sub(1), right),
Token::Greater => Instruction::less_equal(false, left.saturating_sub(1), right),
Token::GreaterEqual => Instruction::less(false, left.saturating_sub(1), right),
_ => {
return Err(ParseError::ExpectedTokenMultiple {
expected: &[
TokenKind::DoubleEqual,
TokenKind::BangEqual,
TokenKind::Less,
TokenKind::LessEqual,
TokenKind::Greater,
TokenKind::GreaterEqual,
],
found: operator.to_owned(),
position: operator_position,
})
}
};
self.parsed_expression = true;
if left_is_constant {
instruction.set_b_is_constant();
}
if right_is_constant {
instruction.set_c_is_constant();
}
if push_back_left {
self.emit_instruction(left_instruction, left_position);
}
if push_back_right {
self.emit_instruction(right_instruction, right_position);
}
self.emit_instruction(instruction, operator_position);
self.emit_instruction(Instruction::jump(1, true), operator_position);
Ok(())
}
fn parse_logical_binary(&mut self) -> Result<(), ParseError> {
let (left_instruction, left_position) =
self.chunk.pop_instruction(self.current_position)?;
let operator = self.current_token;
let operator_position = self.current_position;
let rule = ParseRule::from(&operator);
let instruction = match operator {
Token::DoubleAmpersand => Instruction::test(left_instruction.a(), false),
Token::DoublePipe => Instruction::test(left_instruction.a(), true),
_ => {
return Err(ParseError::ExpectedTokenMultiple {
expected: &[TokenKind::DoubleAmpersand, TokenKind::DoublePipe],
found: operator.to_owned(),
position: operator_position,
})
}
};
self.increment_register()?;
self.advance()?;
self.parse(
rule.precedence.increment(),
Allowed {
assignment: false,
explicit_return: false,
implicit_return: false,
},
)?;
let (right_instruction, right_position) =
self.chunk.pop_instruction(self.current_position)?;
self.emit_instruction(left_instruction, left_position);
self.emit_instruction(instruction, operator_position);
self.emit_instruction(Instruction::jump(1, true), operator_position);
self.emit_instruction(right_instruction, right_position);
self.parsed_expression = true;
Ok(())
}
fn parse_variable(&mut self, allowed: Allowed) -> Result<(), ParseError> {
let token = self.current_token;
let start_position = self.current_position;
self.advance()?;
let local_index = self.parse_identifier_from(token, start_position)?;
if self.allow(Token::Equal)? {
if !allowed.assignment {
return Err(ParseError::InvalidAssignmentTarget {
found: self.current_token.to_owned(),
position: self.current_position,
});
}
let is_mutable = self
.chunk
.get_local(local_index, start_position)?
.is_mutable;
if !is_mutable {
return Err(ParseError::CannotMutateImmutableVariable {
identifier: self.chunk.get_identifier(local_index).cloned().unwrap(),
position: start_position,
});
}
self.parse_expression()?;
let (mut previous_instruction, previous_position) =
self.chunk.pop_instruction(self.current_position)?;
if previous_instruction.operation().is_math() {
let register_index = self
.chunk
.get_local(local_index, start_position)?
.register_index;
log::trace!("Condensing SET_LOCAL to binary math expression");
previous_instruction.set_a(register_index);
self.emit_instruction(previous_instruction, self.current_position);
return Ok(());
}
self.emit_instruction(previous_instruction, previous_position);
self.emit_instruction(
Instruction::set_local(self.current_register, local_index),
start_position,
);
self.parsed_expression = false;
} else {
self.emit_instruction(
Instruction::get_local(self.current_register, local_index),
self.previous_position,
);
self.parsed_expression = true;
}
Ok(())
}
fn parse_identifier_from(&mut self, token: Token, position: Span) -> Result<u8, ParseError> {
if let Token::Identifier(text) = token {
let identifier = Identifier::new(text);
if let Ok(local_index) = self.chunk.get_local_index(&identifier, position) {
Ok(local_index)
} else {
Err(ParseError::UndeclaredVariable {
identifier,
position,
})
}
} else {
Err(ParseError::ExpectedToken {
expected: TokenKind::Identifier,
found: self.current_token.to_owned(),
position,
})
}
}
fn parse_type_from(&mut self, token: Token, position: Span) -> Result<Type, ParseError> {
match token {
Token::Bool => Ok(Type::Boolean),
Token::FloatKeyword => Ok(Type::Float),
Token::Int => Ok(Type::Integer),
Token::Str => Ok(Type::String { length: None }),
_ => Err(ParseError::ExpectedTokenMultiple {
expected: &[
TokenKind::Bool,
TokenKind::FloatKeyword,
TokenKind::Int,
TokenKind::Str,
],
found: self.current_token.to_owned(),
position,
}),
}
}
fn parse_block(&mut self, allowed: Allowed) -> Result<(), ParseError> {
self.advance()?;
self.chunk.begin_scope();
while !self.allow(Token::RightCurlyBrace)? && !self.is_eof() {
self.parse_statement(allowed, Context::None)?;
}
self.chunk.end_scope();
Ok(())
}
fn parse_list(&mut self, _: Allowed) -> Result<(), ParseError> {
let start = self.current_position.0;
self.advance()?;
let start_register = self.current_register;
while !self.allow(Token::RightSquareBrace)? && !self.is_eof() {
let next_register = self.current_register;
self.parse_expression()?;
if let Operation::LoadConstant = self.chunk.get_last_operation()? {
self.increment_register()?;
}
if next_register != self.current_register.saturating_sub(1) {
self.emit_instruction(
Instruction::close(next_register, self.current_register.saturating_sub(1)),
self.current_position,
);
}
self.allow(Token::Comma)?;
}
let end_register = self.current_register - 1;
let end = self.current_position.1;
self.emit_instruction(
Instruction::load_list(self.current_register, start_register, end_register),
Span(start, end),
);
self.increment_register()?;
self.parsed_expression = true;
Ok(())
}
fn parse_if(&mut self, allowed: Allowed) -> Result<(), ParseError> {
self.advance()?;
self.parse_expression()?;
let length = self.chunk.len();
let is_explicit_boolean =
matches!(self.previous_token, Token::Boolean(_)) && length == self.chunk.len() - 1;
if is_explicit_boolean {
self.emit_instruction(
Instruction::test(self.current_register, false),
self.current_position,
);
}
let block_allowed = Allowed {
assignment: allowed.assignment,
explicit_return: allowed.explicit_return,
implicit_return: false,
};
if let Token::LeftCurlyBrace = self.current_token {
self.parse_block(block_allowed)?;
}
let last_operation = self.chunk.get_last_operation()?;
if let (Operation::LoadConstant | Operation::LoadBoolean, Token::Else) =
(last_operation, self.current_token)
{
let (mut load_constant, load_constant_position) =
self.chunk.pop_instruction(self.current_position)?;
load_constant.set_c_to_boolean(true);
self.emit_instruction(load_constant, load_constant_position);
}
if self.allow(Token::Else)? {
if let Token::If = self.current_token {
self.parse_if(allowed)?;
}
if let Token::LeftCurlyBrace = self.current_token {
self.parse_block(block_allowed)?;
self.parsed_expression = true;
}
} else {
self.parsed_expression = false;
}
Ok(())
}
fn parse_while(&mut self, allowed: Allowed) -> Result<(), ParseError> {
self.advance()?;
let jump_start = self.chunk.len();
self.parse_expression()?;
self.parse_block(Allowed {
assignment: true,
explicit_return: allowed.explicit_return,
implicit_return: false,
})?;
let jump_end = self.chunk.len();
let jump_distance = jump_end.abs_diff(jump_start) as u8;
let jump_back = Instruction::jump(jump_distance, false);
let jump_over_index = self.chunk.find_last_instruction(Operation::Jump);
if let Some(index) = jump_over_index {
let (_, jump_over_position) = self.chunk.remove_instruction(index);
let jump_over = Instruction::jump(jump_distance - 1, true);
self.chunk
.insert_instruction(index, jump_over, jump_over_position);
}
self.chunk
.insert_instruction(jump_end, jump_back, self.current_position);
self.parsed_expression = false;
Ok(())
}
fn parse_statement(&mut self, allowed: Allowed, context: Context) -> Result<(), ParseError> {
self.parse(Precedence::None, allowed)?;
let previous_instructions = self.chunk.get_last_n_instructions();
if let [Some((jump, _)), Some((comparison, comparison_position))] = previous_instructions {
if let (Operation::Jump, Operation::Equal | Operation::Less | Operation::LessEqual) =
(jump.operation(), comparison.operation())
{
if matches!(self.current_token, Token::Eof | Token::RightCurlyBrace)
|| context == Context::Assignment
{
let comparison_position = *comparison_position;
self.emit_instruction(
Instruction::load_boolean(self.current_register, true, true),
comparison_position,
);
self.emit_instruction(
Instruction::load_boolean(self.current_register, false, false),
comparison_position,
);
}
}
}
let returned = self.chunk.get_last_operation()? == Operation::Return;
let has_semicolon = self.allow(Token::Semicolon)?;
if allowed.implicit_return && self.parsed_expression && !returned && !has_semicolon {
self.emit_instruction(Instruction::r#return(true), self.current_position);
}
Ok(())
}
fn parse_expression(&mut self) -> Result<(), ParseError> {
self.parse(
Precedence::None,
Allowed {
assignment: false,
explicit_return: false,
implicit_return: false,
},
)
}
fn parse_return(&mut self, allowed: Allowed) -> Result<(), ParseError> {
if !allowed.explicit_return {
return Err(ParseError::UnexpectedReturn {
position: self.current_position,
});
}
let start = self.current_position.0;
self.advance()?;
let has_return_value = if matches!(
self.current_token,
Token::Semicolon | Token::RightCurlyBrace
) {
false
} else {
self.parse_expression()?;
true
};
let end = self.current_position.1;
self.emit_instruction(Instruction::r#return(has_return_value), Span(start, end));
self.parsed_expression = false;
Ok(())
}
fn parse_let_statement(&mut self, allowed: Allowed) -> Result<(), ParseError> {
if !allowed.assignment {
return Err(ParseError::ExpectedExpression {
found: self.current_token.to_owned(),
position: self.current_position,
});
}
self.advance()?;
let is_mutable = self.allow(Token::Mut)?;
let position = self.current_position;
let identifier = if let Token::Identifier(text) = self.current_token {
self.advance()?;
Identifier::new(text)
} else {
return Err(ParseError::ExpectedToken {
expected: TokenKind::Identifier,
found: self.current_token.to_owned(),
position,
});
};
let r#type = if self.allow(Token::Colon)? {
let r#type = self.parse_type_from(self.current_token, self.current_position)?;
self.advance()?;
Some(r#type)
} else {
None
};
let register = self.current_register;
self.expect(Token::Equal)?;
self.parse_statement(
Allowed {
assignment: false,
explicit_return: true,
implicit_return: false,
},
Context::Assignment,
)?;
if self.current_register == register {
self.increment_register()?;
}
let local_index = self
.chunk
.declare_local(identifier, r#type, is_mutable, register, position)?;
self.emit_instruction(
Instruction::define_local(register, local_index, is_mutable),
position,
);
self.parsed_expression = false;
Ok(())
}
fn parse_function(&mut self, _: Allowed) -> Result<(), ParseError> {
let function_start = self.current_position.0;
let mut function_parser = Parser::new(self.lexer)?;
function_parser.expect(Token::LeftParenthesis)?;
let mut value_parameters: Option<Vec<(Identifier, Type)>> = None;
while function_parser.current_token != Token::RightParenthesis {
let start = function_parser.current_position.0;
let is_mutable = function_parser.allow(Token::Mut)?;
let parameter = if let Token::Identifier(text) = function_parser.current_token {
function_parser.advance()?;
Identifier::new(text)
} else {
return Err(ParseError::ExpectedToken {
expected: TokenKind::Identifier,
found: function_parser.current_token.to_owned(),
position: function_parser.current_position,
});
};
function_parser.expect(Token::Colon)?;
let r#type = function_parser.parse_type_from(
function_parser.current_token,
function_parser.current_position,
)?;
function_parser.advance()?;
let end = function_parser.current_position.1;
if let Some(value_parameters) = value_parameters.as_mut() {
value_parameters.push((parameter.clone(), r#type.clone()));
} else {
value_parameters = Some(vec![(parameter.clone(), r#type.clone())]);
};
function_parser.chunk.declare_local(
parameter,
Some(r#type),
is_mutable,
function_parser.current_register,
Span(start, end),
)?;
function_parser.increment_register()?;
function_parser.allow(Token::Comma)?;
}
function_parser.advance()?;
function_parser.expect(Token::LeftCurlyBrace)?;
while function_parser.current_token != Token::RightCurlyBrace {
function_parser.parse_statement(
Allowed {
assignment: true,
explicit_return: true,
implicit_return: true,
},
Context::None,
)?;
}
function_parser.advance()?;
self.previous_token = function_parser.previous_token;
self.previous_position = function_parser.previous_position;
self.current_token = function_parser.current_token;
self.current_position = function_parser.current_position;
let return_type = take(&mut self.latest_value_type).map(Box::new);
let function_type = FunctionType {
type_parameters: None,
value_parameters,
return_type,
};
let function = Value::function(function_parser.chunk, function_type);
let function_end = self.current_position.1;
self.lexer.skip_to(function_end);
self.emit_constant(function, Span(function_start, function_end))?;
self.parsed_expression = true;
Ok(())
}
fn parse_call(&mut self) -> Result<(), ParseError> {
let last_instruction = self.chunk.get_last_instruction()?.0;
if !last_instruction.is_expression() {
return Err(ParseError::ExpectedExpression {
found: self.previous_token.to_owned(),
position: self.previous_position,
});
}
let start = self.current_position.0;
self.advance()?;
let function_register = self.current_register;
let mut argument_count = 0;
while !self.allow(Token::RightParenthesis)? {
if argument_count > 0 {
self.expect(Token::Comma)?;
}
let register = self.current_register;
self.parse_expression()?;
if self.current_register == register {
return Err(ParseError::ExpectedExpression {
found: self.previous_token.to_owned(),
position: self.previous_position,
});
}
argument_count += 1;
}
let end = self.current_position.1;
self.emit_instruction(
Instruction::call(function_register, argument_count),
Span(start, end),
);
self.parsed_expression = true;
Ok(())
}
fn parse(&mut self, precedence: Precedence, allowed: Allowed) -> Result<(), ParseError> {
if let Some(prefix_parser) = ParseRule::from(&self.current_token).prefix {
log::debug!(
"{} is {precedence} prefix",
self.current_token.to_string().bold(),
);
prefix_parser(self, allowed)?;
}
let mut infix_rule = ParseRule::from(&self.current_token);
while precedence <= infix_rule.precedence {
if let Some(infix_parser) = infix_rule.infix {
log::debug!(
"{} is {precedence} infix",
self.current_token.to_string().bold(),
);
if !allowed.assignment && self.current_token == Token::Equal {
return Err(ParseError::InvalidAssignmentTarget {
found: self.current_token.to_owned(),
position: self.current_position,
});
}
infix_parser(self)?;
} else {
break;
}
infix_rule = ParseRule::from(&self.current_token);
}
Ok(())
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub enum Precedence {
None,
Assignment,
Conditional,
LogicalOr,
LogicalAnd,
Equality,
Comparison,
Term,
Factor,
Unary,
Call,
Primary,
}
impl Precedence {
fn increment(&self) -> Self {
match self {
Precedence::None => Precedence::Assignment,
Precedence::Assignment => Precedence::Conditional,
Precedence::Conditional => Precedence::LogicalOr,
Precedence::LogicalOr => Precedence::LogicalAnd,
Precedence::LogicalAnd => Precedence::Equality,
Precedence::Equality => Precedence::Comparison,
Precedence::Comparison => Precedence::Term,
Precedence::Term => Precedence::Factor,
Precedence::Factor => Precedence::Unary,
Precedence::Unary => Precedence::Call,
Precedence::Call => Precedence::Primary,
Precedence::Primary => Precedence::Primary,
}
}
}
impl Display for Precedence {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(f, "{:?}", self)
}
}
#[derive(Debug, Clone, Copy, Eq, PartialEq, PartialOrd, Ord, Serialize, Deserialize)]
pub enum Context {
None,
Assignment,
}
#[derive(Debug, Clone, Copy)]
struct Allowed {
pub assignment: bool,
pub explicit_return: bool,
pub implicit_return: bool,
}
type PrefixFunction<'a> = fn(&mut Parser<'a>, Allowed) -> Result<(), ParseError>;
type InfixFunction<'a> = fn(&mut Parser<'a>) -> Result<(), ParseError>;
#[derive(Debug, Clone, Copy)]
struct ParseRule<'a> {
pub prefix: Option<PrefixFunction<'a>>,
pub infix: Option<InfixFunction<'a>>,
pub precedence: Precedence,
}
impl From<&Token<'_>> for ParseRule<'_> {
fn from(token: &Token) -> Self {
match token {
Token::Async => todo!(),
Token::Bang => ParseRule {
prefix: Some(Parser::parse_unary),
infix: None,
precedence: Precedence::Unary,
},
Token::BangEqual => ParseRule {
prefix: None,
infix: Some(Parser::parse_comparison_binary),
precedence: Precedence::Equality,
},
Token::Bool => todo!(),
Token::Boolean(_) => ParseRule {
prefix: Some(Parser::parse_boolean),
infix: None,
precedence: Precedence::None,
},
Token::Break => todo!(),
Token::Byte(_) => ParseRule {
prefix: Some(Parser::parse_byte),
infix: None,
precedence: Precedence::None,
},
Token::Character(_) => ParseRule {
prefix: Some(Parser::parse_character),
infix: None,
precedence: Precedence::None,
},
Token::Colon => todo!(),
Token::Comma => ParseRule {
prefix: None,
infix: None,
precedence: Precedence::None,
},
Token::Dot => todo!(),
Token::DoubleAmpersand => ParseRule {
prefix: None,
infix: Some(Parser::parse_logical_binary),
precedence: Precedence::LogicalAnd,
},
Token::DoubleEqual => ParseRule {
prefix: None,
infix: Some(Parser::parse_comparison_binary),
precedence: Precedence::Equality,
},
Token::DoublePipe => ParseRule {
prefix: None,
infix: Some(Parser::parse_logical_binary),
precedence: Precedence::LogicalOr,
},
Token::DoubleDot => todo!(),
Token::Eof => ParseRule {
prefix: None,
infix: None,
precedence: Precedence::None,
},
Token::Equal => ParseRule {
prefix: None,
infix: None,
precedence: Precedence::Assignment,
},
Token::Else => ParseRule {
prefix: None,
infix: None,
precedence: Precedence::None,
},
Token::Float(_) => ParseRule {
prefix: Some(Parser::parse_float),
infix: None,
precedence: Precedence::None,
},
Token::FloatKeyword => todo!(),
Token::Fn => ParseRule {
prefix: Some(Parser::parse_function),
infix: None,
precedence: Precedence::None,
},
Token::Greater => ParseRule {
prefix: None,
infix: Some(Parser::parse_comparison_binary),
precedence: Precedence::Comparison,
},
Token::GreaterEqual => ParseRule {
prefix: None,
infix: Some(Parser::parse_comparison_binary),
precedence: Precedence::Comparison,
},
Token::Identifier(_) => ParseRule {
prefix: Some(Parser::parse_variable),
infix: None,
precedence: Precedence::None,
},
Token::If => ParseRule {
prefix: Some(Parser::parse_if),
infix: None,
precedence: Precedence::None,
},
Token::Int => todo!(),
Token::Integer(_) => ParseRule {
prefix: Some(Parser::parse_integer),
infix: None,
precedence: Precedence::None,
},
Token::LeftCurlyBrace => ParseRule {
prefix: Some(Parser::parse_block),
infix: None,
precedence: Precedence::None,
},
Token::LeftParenthesis => ParseRule {
prefix: Some(Parser::parse_grouped),
infix: Some(Parser::parse_call),
precedence: Precedence::Call,
},
Token::LeftSquareBrace => ParseRule {
prefix: Some(Parser::parse_list),
infix: None,
precedence: Precedence::None,
},
Token::Less => ParseRule {
prefix: None,
infix: Some(Parser::parse_comparison_binary),
precedence: Precedence::Comparison,
},
Token::LessEqual => ParseRule {
prefix: None,
infix: Some(Parser::parse_comparison_binary),
precedence: Precedence::Comparison,
},
Token::Let => ParseRule {
prefix: Some(Parser::parse_let_statement),
infix: None,
precedence: Precedence::None,
},
Token::Loop => todo!(),
Token::Map => todo!(),
Token::Minus => ParseRule {
prefix: Some(Parser::parse_unary),
infix: Some(Parser::parse_math_binary),
precedence: Precedence::Term,
},
Token::MinusEqual => ParseRule {
prefix: None,
infix: Some(Parser::parse_math_binary),
precedence: Precedence::Assignment,
},
Token::Mut => ParseRule {
prefix: None,
infix: None,
precedence: Precedence::None,
},
Token::Percent => ParseRule {
prefix: None,
infix: Some(Parser::parse_math_binary),
precedence: Precedence::Factor,
},
Token::PercentEqual => ParseRule {
prefix: None,
infix: Some(Parser::parse_math_binary),
precedence: Precedence::Assignment,
},
Token::Plus => ParseRule {
prefix: None,
infix: Some(Parser::parse_math_binary),
precedence: Precedence::Term,
},
Token::PlusEqual => ParseRule {
prefix: None,
infix: Some(Parser::parse_math_binary),
precedence: Precedence::Assignment,
},
Token::Return => ParseRule {
prefix: Some(Parser::parse_return),
infix: None,
precedence: Precedence::None,
},
Token::RightCurlyBrace => ParseRule {
prefix: None,
infix: None,
precedence: Precedence::None,
},
Token::RightParenthesis => ParseRule {
prefix: None,
infix: None,
precedence: Precedence::None,
},
Token::RightSquareBrace => ParseRule {
prefix: None,
infix: None,
precedence: Precedence::None,
},
Token::Semicolon => ParseRule {
prefix: None,
infix: None,
precedence: Precedence::None,
},
Token::Slash => ParseRule {
prefix: None,
infix: Some(Parser::parse_math_binary),
precedence: Precedence::Factor,
},
Token::SlashEqual => ParseRule {
prefix: None,
infix: Some(Parser::parse_math_binary),
precedence: Precedence::Assignment,
},
Token::Star => ParseRule {
prefix: None,
infix: Some(Parser::parse_math_binary),
precedence: Precedence::Factor,
},
Token::StarEqual => ParseRule {
prefix: None,
infix: Some(Parser::parse_math_binary),
precedence: Precedence::Assignment,
},
Token::Str => todo!(),
Token::String(_) => ParseRule {
prefix: Some(Parser::parse_string),
infix: None,
precedence: Precedence::None,
},
Token::Struct => todo!(),
Token::While => ParseRule {
prefix: Some(Parser::parse_while),
infix: None,
precedence: Precedence::None,
},
}
}
}
#[derive(Debug, PartialEq)]
pub enum ParseError {
CannotChainComparison {
position: Span,
},
CannotMutateImmutableVariable {
identifier: Identifier,
position: Span,
},
ExpectedExpression {
found: TokenOwned,
position: Span,
},
ExpectedToken {
expected: TokenKind,
found: TokenOwned,
position: Span,
},
ExpectedTokenMultiple {
expected: &'static [TokenKind],
found: TokenOwned,
position: Span,
},
ExpectedMutableVariable {
found: TokenOwned,
position: Span,
},
InvalidAssignmentTarget {
found: TokenOwned,
position: Span,
},
UndeclaredVariable {
identifier: Identifier,
position: Span,
},
UnexpectedReturn {
position: Span,
},
RegisterOverflow {
position: Span,
},
RegisterUnderflow {
position: Span,
},
// Wrappers around foreign errors
Chunk(ChunkError),
Lex(LexError),
ParseFloatError {
error: ParseFloatError,
position: Span,
},
ParseIntError {
error: ParseIntError,
position: Span,
},
}
impl From<ChunkError> for ParseError {
fn from(error: ChunkError) -> Self {
Self::Chunk(error)
}
}
impl AnnotatedError for ParseError {
fn title() -> &'static str {
"Parse Error"
}
fn description(&self) -> &'static str {
match self {
Self::CannotChainComparison { .. } => "Cannot chain comparison",
Self::CannotMutateImmutableVariable { .. } => "Cannot mutate immutable variable",
Self::ExpectedExpression { .. } => "Expected an expression",
Self::ExpectedToken { .. } => "Expected a specific token",
Self::ExpectedTokenMultiple { .. } => "Expected one of multiple tokens",
Self::ExpectedMutableVariable { .. } => "Expected a mutable variable",
Self::InvalidAssignmentTarget { .. } => "Invalid assignment target",
Self::UndeclaredVariable { .. } => "Undeclared variable",
Self::UnexpectedReturn { .. } => "Unexpected return",
Self::RegisterOverflow { .. } => "Register overflow",
Self::RegisterUnderflow { .. } => "Register underflow",
Self::ParseFloatError { .. } => "Failed to parse float",
Self::ParseIntError { .. } => "Failed to parse integer",
Self::Chunk(error) => error.description(),
Self::Lex(error) => error.description(),
}
}
fn details(&self) -> Option<String> {
match self {
Self::CannotChainComparison { .. } => {
Some("Cannot chain comparison operations".to_string())
}
Self::CannotMutateImmutableVariable { identifier, .. } => {
Some(format!("Cannot mutate immutable variable {identifier}"))
}
Self::ExpectedExpression { found, .. } => Some(format!("Found {found}")),
Self::ExpectedToken {
expected, found, ..
} => Some(format!("Expected {expected} but found {found}")),
Self::ExpectedTokenMultiple {
expected, found, ..
} => {
let mut details = String::from("Expected");
for (index, token) in expected.iter().enumerate() {
details.push_str(&format!(" {token}"));
if index < expected.len() - 2 {
details.push_str(", ");
}
if index == expected.len() - 2 {
details.push_str(" or");
}
}
details.push_str(&format!(" but found {found}"));
Some(details)
}
Self::ExpectedMutableVariable { found, .. } => {
Some(format!("Expected mutable variable, found {found}"))
}
Self::InvalidAssignmentTarget { found, .. } => {
Some(format!("Invalid assignment target, found {found}"))
}
Self::UndeclaredVariable { identifier, .. } => {
Some(format!("Undeclared variable {identifier}"))
}
Self::UnexpectedReturn { .. } => None,
Self::RegisterOverflow { .. } => None,
Self::RegisterUnderflow { .. } => None,
Self::ParseFloatError { error, .. } => Some(error.to_string()),
Self::ParseIntError { error, .. } => Some(error.to_string()),
Self::Chunk(error) => error.details(),
Self::Lex(error) => error.details(),
}
}
fn position(&self) -> Span {
match self {
Self::CannotChainComparison { position } => *position,
Self::CannotMutateImmutableVariable { position, .. } => *position,
Self::ExpectedExpression { position, .. } => *position,
Self::ExpectedToken { position, .. } => *position,
Self::ExpectedTokenMultiple { position, .. } => *position,
Self::ExpectedMutableVariable { position, .. } => *position,
Self::InvalidAssignmentTarget { position, .. } => *position,
Self::UndeclaredVariable { position, .. } => *position,
Self::UnexpectedReturn { position } => *position,
Self::RegisterOverflow { position } => *position,
Self::RegisterUnderflow { position } => *position,
Self::ParseFloatError { position, .. } => *position,
Self::ParseIntError { position, .. } => *position,
Self::Chunk(error) => error.position(),
Self::Lex(error) => error.position(),
}
}
}
impl From<LexError> for ParseError {
fn from(error: LexError) -> Self {
Self::Lex(error)
}
}