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|
use std::{mem, fmt};
use std::error::Error;
use std::collections::HashMap;
use super::*;
use synth::*;
#[derive(Debug)]
pub enum ErrorKind {
Unexpected(TokType, TokType),
ExpectedOp(char, TokType),
UnknownGen(String),
}
#[derive(Debug)]
pub struct ErrorType {
pub kind: ErrorKind,
desc: String,
}
impl ErrorType {
pub fn new(kind: ErrorKind) -> ErrorType {
let mut ret = ErrorType {
kind: kind,
desc: "".to_string(),
};
ret.desc = match &ret.kind {
&ErrorKind::Unexpected(found, expected) => format!("Found {:?}, expected {:?}", found, expected),
&ErrorKind::ExpectedOp(c, found) => format!("Expected {:?}, found {:?}", c, found),
&ErrorKind::UnknownGen(ref s) => format!("Unknown generator name {}", s),
};
ret
}
pub fn with_description(kind: ErrorKind, desc: String) -> ErrorType {
ErrorType {
kind: kind,
desc: desc,
}
}
}
impl Error for ErrorType {
fn description<'a>(&'a self) -> &'a str {
&self.desc
}
}
impl fmt::Display for ErrorType {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
write!(f, "{}", self.description())
}
}
pub struct Parser<T: Iterator<Item=char>> {
tzr: Tokenizer<T>,
token: Token,
pushback: Option<Token>,
factories: HashMap<String, &'static GeneratorFactory>,
}
impl<T: Iterator<Item=char>> Parser<T> {
pub fn new(mut tzr: Tokenizer<T>) -> Result<Parser<T>, Box<Error>> {
let token = tzr.next_token()?;
Ok(Parser {
tzr: tzr,
token: token,
pushback: None,
factories: all_factories(),
})
}
pub fn push_back(&mut self, tok: Token) {
match self.pushback {
None => {
self.pushback = Some(mem::replace(&mut self.token, tok));
},
Some(_) => panic!("too many pushbacks on Parser"),
}
}
pub fn expect(&mut self, ty: TokType) -> Result<Token, Box<Error>> {
if ty == self.token.to_type() {
Ok(mem::replace(&mut self.token, match self.pushback {
Some(_) => mem::replace(&mut self.pushback, None).unwrap(),
None => self.tzr.next_token()?,
}))
} else {
Err(ErrorType::new(ErrorKind::Unexpected(self.token.to_type(), ty)).into())
}
}
pub fn expect_ident(&mut self) -> Result<String, Box<Error>> {
match self.expect(TokType::Ident)? {
Token::Ident(s) => Ok(s),
_ => unreachable!(),
}
}
pub fn expect_op(&mut self, oper: char) -> Result<(), Box<Error>> {
match self.token {
Token::Oper(c) if c == oper => { self.expect(TokType::Oper)?; Ok(()) },
_ => Err(ErrorType::new(ErrorKind::ExpectedOp(oper, self.token.to_type())).into()),
}
}
pub fn parse(&mut self) -> Result<GenBox, Box<Error>> {
self.parse_gen()
}
pub fn parse_gen(&mut self) -> Result<GenBox, Box<Error>> {
let name = self.expect_ident()?;
self.expect_op('(')?;
let mut params: FactoryParameters = Default::default();
let mut ctr = 0;
loop {
if self.expect_op(')').is_ok() {
break;
}
let (nm, vl, new_ctr) = self.parse_param(ctr)?;
params.vars.insert(nm, vl);
ctr = new_ctr;
if self.expect_op(',').is_err() {
eprintln!("No comma: {:?}", self.token);
self.expect_op(')')?;
break;
}
}
let factory = match self.factories.get(&name) {
Some(fac) => fac,
None => return Err(ErrorType::new(ErrorKind::UnknownGen(name)).into()),
};
factory.new(&mut params).map_err(Into::into)
}
pub fn parse_param(&mut self, pos: usize) -> Result<(String, ParamValue, usize), Box<Error>> {
let mut ctr = pos;
let name = match self.expect_ident() {
Ok(nm) => {
if self.expect_op('=').is_ok() {
nm
} else {
match &self.token {
&Token::Oper(c) if c == '(' => {
self.push_back(Token::Ident(nm));
ctr += 1;
(ctr - 1).to_string()
},
_ => return Err(ErrorType::new(ErrorKind::Unexpected(self.token.to_type(), TokType::Ident)).into()),
}
}
},
Err(_) => {
ctr += 1;
(ctr - 1).to_string()
},
};
let ret = match self.token {
Token::Integer(v) => Ok((name, ParamValue::Integer(v), ctr)),
Token::Float(v) => Ok((name, ParamValue::Float(v), ctr)),
Token::String(ref v) => Ok((name, ParamValue::String(v.clone()), ctr)),
Token::Ident(_) => return Ok((name, ParamValue::Generator(self.parse_gen()?), ctr)),
_ => return Err(ErrorType::new(ErrorKind::Unexpected(self.token.to_type(), TokType::Ident)).into()),
};
let tp = self.token.to_type();
self.expect(tp)?;
ret
}
}
|
