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138 lines
4.4 KiB
138 lines
4.4 KiB
use crate::lexer::Keyword; |
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/** |
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* Copyright 2020 Garrit Franke |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* https://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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use crate::lexer::Position; |
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use crate::lexer::{Token, TokenKind}; |
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use crate::parser::infer::infer; |
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use crate::parser::node_type::*; |
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use crate::util::string_util::highlight_position_in_file; |
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use std::convert::TryFrom; |
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use std::iter::Peekable; |
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use std::vec::IntoIter; |
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pub struct Parser { |
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tokens: Peekable<IntoIter<Token>>, |
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peeked: Vec<Token>, |
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current: Option<Token>, |
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prev: Option<Token>, |
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raw: Option<String>, |
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} |
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impl Parser { |
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pub fn new(tokens: Vec<Token>, raw: Option<String>) -> Parser { |
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let tokens_without_whitespace: Vec<Token> = tokens |
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.into_iter() |
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.filter(|token| token.kind != TokenKind::Whitespace && token.kind != TokenKind::Comment) |
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.collect(); |
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Parser { |
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tokens: tokens_without_whitespace.into_iter().peekable(), |
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peeked: vec![], |
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current: None, |
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prev: None, |
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raw, |
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} |
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} |
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pub fn parse(&mut self) -> Result<Program, String> { |
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let mut program = self.parse_program()?; |
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// infer types |
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infer(&mut program); |
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Ok(program) |
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} |
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pub(super) fn next(&mut self) -> Result<Token, String> { |
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self.prev = self.current.to_owned(); |
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let item = if self.peeked.is_empty() { |
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self.tokens.next() |
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} else { |
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self.peeked.pop() |
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}; |
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self.current = item.to_owned(); |
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item.ok_or_else(|| "Expected token".into()) |
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} |
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pub(super) fn peek(&mut self) -> Result<Token, String> { |
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let token = self.next()?; |
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self.push(token.to_owned()); |
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Ok(token) |
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} |
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pub(super) fn push(&mut self, token: Token) { |
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self.peeked.push(token); |
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} |
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pub(super) fn has_more(&mut self) -> bool { |
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!self.peeked.is_empty() || self.tokens.peek().is_some() |
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} |
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pub(super) fn match_token(&mut self, token_kind: TokenKind) -> Result<Token, String> { |
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match self.next()? { |
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token if token.kind == token_kind => Ok(token), |
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other => Err(self.make_error(token_kind, other)), |
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} |
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} |
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pub(super) fn peek_token(&mut self, token_kind: TokenKind) -> Result<Token, String> { |
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match self.peek()? { |
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token if token.kind == token_kind => Ok(token), |
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other => Err(format!( |
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"Token {:?} not found, found {:?}", |
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token_kind, other |
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)), |
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} |
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} |
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pub(super) fn match_keyword(&mut self, keyword: Keyword) -> Result<(), String> { |
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let token = self.next()?; |
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match &token.kind { |
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TokenKind::Keyword(ref k) if k == &keyword => Ok(()), |
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_ => Err(self.make_error(TokenKind::SemiColon, token)), |
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} |
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} |
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pub(super) fn match_operator(&mut self) -> Result<BinOp, String> { |
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BinOp::try_from(self.next()?.kind) |
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} |
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pub(super) fn match_identifier(&mut self) -> Result<String, String> { |
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match self.next()?.kind { |
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TokenKind::Identifier(n) => Ok(n), |
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other => Err(format!("Expected Identifier, found {:?}", other)), |
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} |
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} |
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pub(super) fn make_error(&mut self, token_kind: TokenKind, other: Token) -> String { |
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match &self.raw { |
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Some(raw_file) => format!( |
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"Token {:?} not found, found {:?}\n{:?}", |
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token_kind, |
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other, |
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highlight_position_in_file(raw_file.to_string(), other.to_owned().pos) |
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), |
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None => format!("Token {:?} not found, found {:?}", token_kind, other), |
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} |
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} |
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pub(super) fn make_error_msg(&mut self, pos: Position, msg: String) -> String { |
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let pos_string = format!("{}:{}", pos.line, pos.offset); |
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format!("ERROR: {}\nAt {}", msg, pos_string) |
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} |
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pub(super) fn prev(&mut self) -> Option<Token> { |
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self.prev.clone() |
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} |
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}
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