Refactoring

This commit is contained in:
Andy Grove 2018-09-03 09:13:43 -06:00
parent 375671e208
commit a86bd30515
6 changed files with 101 additions and 338 deletions

View file

@ -1,6 +1,5 @@
use std::cmp::PartialEq;
use std::fmt::Debug;
use std::sync::{Arc, Mutex};
use super::tokenizer::*;
@ -8,7 +7,7 @@ use super::tokenizer::*;
/// ANSI SQL:2011 Data Types
#[derive(Debug)]
pub enum SQLDataType<T> {
pub enum SQLDataType {
/// BOOLEAN
Boolean,
/// NUMERIC, DECIMAL, DEC
@ -49,14 +48,12 @@ pub enum SQLDataType<T> {
Time { precision: usize, tz: bool },
/// Time: `TIMESTAMP [(precision)] [WITH TIME ZONE | WITHOUT TIME ZONE]`
Timestamp { precision: usize, tz: bool },
/// Custom data type
Custom(T)
}
#[derive(Debug)]
pub enum SQLOperator<T> {
pub enum SQLOperator {
Plus,
Minus,
Mult,
@ -66,217 +63,44 @@ pub enum SQLOperator<T> {
GtEq,
Lt,
LtEq,
Custom(T) // extension point for vendor-specific operators
}
/// SQL Expressions
#[derive(Debug)]
pub enum SQLExpr<ExprType> {
pub enum SQLExpr{
/// Identifier e.g. table name or column name
Identifier(String),
/// Literal value
Literal(String),
/// Binary expression e.g. `1 + 2` or `fname LIKE "A%"`
Binary(Box<SQLExpr<ExprType>>, SQLOperator<ExprType>, Box<SQLExpr<ExprType>>),
Binary(Box<SQLExpr>, SQLOperator, Box<SQLExpr>),
/// Function invocation with function name and list of argument expressions
FunctionCall(String, Vec<SQLExpr<ExprType>>),
FunctionCall(String, Vec<SQLExpr>),
Insert,
Update,
Delete,
Select,
CreateTable,
/// Custom expression (vendor-specific)
Custom(ExprType)
}
#[derive(Debug)]
pub enum ParserError<TokenType>
where TokenType: Debug + PartialEq {
WrongToken { expected: Vec<SQLToken<TokenType>>, actual: SQLToken<TokenType>, line: usize, col: usize },
pub enum ParserError {
WrongToken { expected: Vec<SQLToken>, actual: SQLToken, line: usize, col: usize },
Custom(String)
}
impl<TokenType> From<TokenizerError> for ParserError<TokenType>
where TokenType: Debug + PartialEq {
fn from(_: TokenizerError) -> Self {
unimplemented!()
impl From<TokenizerError> for ParserError {
fn from(e: TokenizerError) -> Self {
ParserError::Custom(format!("{:?}", e))
}
}
pub trait SQLParser<TokenType, ExprType>
where TokenType: Debug + PartialEq, ExprType: Debug {
pub trait SQLParser {
fn parse_expr(&mut self) -> Result<Option<Box<SQLExpr>>, ParserError>;
/// parse the prefix and stop once an infix operator is reached
fn parse_prefix(&mut self, chars: &mut CharSeq) -> Result<Option<Box<SQLExpr<ExprType>>>, ParserError<TokenType>> ;
fn parse_prefix(&mut self) -> Result<Option<Box<SQLExpr>>, ParserError> ;
/// parse the next infix expression, returning None if the precedence has changed
fn parse_infix(&mut self, chars: &mut CharSeq, left: &SQLExpr<ExprType>, precedence: usize) -> Result<Option<Box<SQLExpr<ExprType>>>, ParserError<TokenType>>;
fn parse_infix(&mut self, left: &SQLExpr, precedence: usize) -> Result<Option<Box<SQLExpr>>, ParserError>;
}
pub struct PrattParser<TokenType, ExprType> {
pub chars: CharSeq,
pub parsers: Vec<Arc<Mutex<SQLParser<TokenType, ExprType>>>>
}
impl<TokenType, ExprType> PrattParser<TokenType, ExprType> where TokenType: Debug + PartialEq, ExprType: Debug {
pub fn parse_expr(&mut self) -> Result<Option<Box<SQLExpr<ExprType>>>, ParserError<TokenType>> {
for i in 0..self.parsers.len() {
let mut p = self.parsers[i].lock().unwrap();
let expr = p.parse_prefix(&mut self.chars)?;
// return as soon as we have a match
match expr {
Some(_) => return Ok(expr),
_ => {}
}
}
// found no valid token
Ok(None)
}
}
//
//pub fn parse_expr<'a, TokenType, ExprType>(parser: Arc<Mutex<SQLParser<TokenType, ExprType>>>)
// -> Result<Box<SQLExpr<ExprType>>, ParserError<TokenType>> where TokenType: Debug + PartialEq, ExprType: Debug {
// let mut guard = parser.lock().unwrap();
//
// //Result<Box<SQLExpr<ExprType>>, ParserError<TokenType>>
// let x = guard.parse_prefix();
// x
//}
//impl<'a, TokenType, ExprType> PrattParser<'a, TokenType, ExprType>
// where TokenType: Debug + PartialEq, ExprType: Debug {
//
// pub fn parse_expr(&mut self) -> Result<Box<SQLExpr<ExprType>>, ParserError<TokenType>> {
//
// let precedence: usize = 0;
// let parser_ref = self.parser.as_ref();
//
// let mut expr = parser_ref.parse_prefix()?;
//
// while let Some(token) = self.tokenizer.peek_token(&mut self.chars)? {
//
// let next_precedence = self.tokenizer.precedence(&token);
//
// if precedence >= next_precedence {
// break;
// }
//
// expr = parser_ref.parse_infix(&expr, next_precedence)?.unwrap(); //TODO: fix me
// }
//
// Ok(expr)
// }
//
//}
// fn parse_prefix(&mut self) -> Result<Box<SQLExpr>, ParserError> {
//
// match self.tokenizer.peek_token()? {
// Some(SQLToken::Keyword(ref k)) => match k.to_uppercase().as_ref() {
// "INSERT" => unimplemented!(),
// "UPDATE" => unimplemented!(),
// "DELETE" => unimplemented!(),
// "SELECT" => unimplemented!(),
// "CREATE" => unimplemented!(),
// _ => unimplemented!()
// },
// _ => unimplemented!()
// }
// unimplemented!()
// }
//
// fn parse_infix(&mut self, expr: Box<SQLExpr>, precedence: u8) -> Result<Box<SQLExpr>, ParserError> {
//
// match self.tokenizer.next_token()? {
// Some(tok) => {
// match tok {
// SQLToken::Eq | SQLToken::Gt | SQLToken::GtEq |
// SQLToken::Lt | SQLToken::LtEq => Ok(Box::new(SQLExpr::Binary(
// expr,
// self.to_sql_operator(&tok),
// self.parse_expr(precedence)?
// ))),
// _ => Err(ParserError::WrongToken {
// expected: vec![SQLToken::Eq, SQLToken::Gt], //TODO: complete
// actual: tok,
// line: 0,
// col: 0
// })
// }
// },
// None => Err(ParserError::TBD)
// }
// }
//
// fn to_sql_operator(&self, token: &SQLToken) -> SQLOperator {
// unimplemented!()
// }
//
// fn get_precedence(&self, token: &SQLToken) -> u8 {
// unimplemented!()
// }
//
// /// parse a list of SQL expressions separated by a comma
// fn parse_expr_list(&mut self, precedence: u8) -> Result<Vec<SQLExpr>, ParserError> {
// unimplemented!()
// }
//
//}
//
////impl GenericParser {
////
//// fn tokenizer(&mut self) -> &mut SQLTokenizer {
//// &mut self.tokenizer
//// }
////
//// fn parse_keywords(&mut self, keywords: Vec<&str>) -> Result<bool, ParserError> {
//// unimplemented!()
//// }
////
////// fn parse_identifier(&mut self) -> Result<String, ParserError>;
////
////}
//
//
//
//#[cfg(test)]
//mod tests {
//
// use super::SQLToken::*;
// use super::*;
// #[test]
// fn parse_Acme_create_table() {
//
// // CREATE TABLE test (col1 int8) HASH (col1)
// let tokens = vec![
// k("CREATE"), k("TABLE"), i("test"), LParen,
// i("col1"), k("int8"),
// RParen,
// k("HASH"), LParen, i("col1"), RParen
// ];
//
// //let parser = AcmeParser { generic_parser: }
// }
// }
//
// fn k(s: &str) -> SQLToken {
// Keyword(s.to_string())
// }
//
// fn i(s: &str) -> SQLToken {
// Identifier(s.to_string())
// }
//
//
//}