schala/src/schala_lang/parsing.rs
2018-02-12 00:25:48 -08:00

1338 lines
42 KiB
Rust

use itertools::Itertools;
use std::collections::HashMap;
use std::rc::Rc;
use std::iter::{Enumerate, Peekable};
use std::vec::IntoIter;
use std::str::Chars;
#[derive(Debug, PartialEq, Clone)]
pub enum TokenType {
Newline, Semicolon,
LParen, RParen,
LSquareBracket, RSquareBracket,
LAngleBracket, RAngleBracket,
LCurlyBrace, RCurlyBrace,
Pipe,
Comma, Period, Colon, Underscore,
Operator(Rc<String>),
DigitGroup(Rc<String>), HexLiteral(Rc<String>), BinNumberSigil,
StrLiteral(Rc<String>),
Identifier(Rc<String>),
Keyword(Kw),
EOF,
Error(String),
}
use self::TokenType::*;
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum Kw {
If, Else,
Func,
For,
Match,
Var, Const, Let, In,
Return,
Alias, Type, SelfType, SelfIdent,
Trait, Impl,
True, False,
Module
}
use self::Kw::*;
lazy_static! {
static ref KEYWORDS: HashMap<&'static str, Kw> =
hashmap! {
"if" => Kw::If,
"else" => Kw::Else,
"fn" => Kw::Func,
"for" => Kw::For,
"match" => Kw::Match,
"var" => Kw::Var,
"const" => Kw::Const,
"let" => Kw::Let,
"in" => Kw::In,
"return" => Kw::Return,
"alias" => Kw::Alias,
"type" => Kw::Type,
"Self" => Kw::SelfType,
"self" => Kw::SelfIdent,
"trait" => Kw::Trait,
"impl" => Kw::Impl,
"true" => Kw::True,
"false" => Kw::False,
"module" => Kw::Module,
};
}
#[derive(Debug)]
pub struct Token {
pub token_type: TokenType,
pub offset: usize,
}
impl Token {
pub fn get_error(&self) -> Option<&String> {
match self.token_type {
TokenType::Error(ref s) => Some(s),
_ => None,
}
}
}
const OPERATOR_CHARS: [char; 19] = ['!', '$', '%', '&', '*', '+', '-', '.', '/', ':', '<', '>', '=', '?', '@', '^', '|', '~', '`'];
fn is_operator(c: &char) -> bool {
OPERATOR_CHARS.iter().any(|x| x == c)
}
type CharIter<'a> = Peekable<Enumerate<Chars<'a>>>;
pub fn tokenize(input: &str) -> Vec<Token> {
let mut tokens: Vec<Token> = Vec::new();
let mut input: CharIter = input.chars().enumerate().peekable();
while let Some((idx, c)) = input.next() {
let cur_tok_type = match c {
'#' => {
if let Some(&(_, '{')) = input.peek() {
} else {
while let Some((_, c)) = input.next() {
if c == '\n' {
break;
}
}
}
continue;
},
c if c.is_whitespace() && c != '\n' => continue,
'\n' => Newline, ';' => Semicolon,
':' => Colon, ',' => Comma,
'(' => LParen, ')' => RParen,
'{' => LCurlyBrace, '}' => RCurlyBrace,
'[' => LSquareBracket, ']' => RSquareBracket,
'"' => handle_quote(&mut input),
c if c.is_digit(10) => handle_digit(c, &mut input),
c if c.is_alphabetic() || c == '_' => handle_alphabetic(c, &mut input), //TODO I'll probably have to rewrite this if I care about types being uppercase, also type parameterization
c if is_operator(&c) => handle_operator(c, &mut input),
unknown => Error(format!("Unexpected character: {}", unknown)),
};
tokens.push(Token { token_type: cur_tok_type, offset: idx });
}
tokens
}
fn handle_digit(c: char, input: &mut CharIter) -> TokenType {
if c == '0' && input.peek().map_or(false, |&(_, c)| { c == 'x' }) {
input.next();
let rest: String = input.peeking_take_while(|&(_, ref c)| c.is_digit(16) || *c == '_').map(|(_, c)| { c }).collect();
HexLiteral(Rc::new(rest))
} else if c == '0' && input.peek().map_or(false, |&(_, c)| { c == 'b' }) {
input.next();
BinNumberSigil
} else {
let mut buf = c.to_string();
buf.extend(input.peeking_take_while(|&(_, ref c)| c.is_digit(10)).map(|(_, c)| { c }));
DigitGroup(Rc::new(buf))
}
}
fn handle_quote(input: &mut CharIter) -> TokenType {
let mut buf = String::new();
loop {
match input.next().map(|(_, c)| { c }) {
Some('"') => break,
Some('\\') => {
let next = input.peek().map(|&(_, c)| { c });
if next == Some('n') {
input.next();
buf.push('\n')
} else if next == Some('"') {
input.next();
buf.push('"');
} else if next == Some('t') {
input.next();
buf.push('\t');
}
},
Some(c) => buf.push(c),
None => return TokenType::Error(format!("Unclosed string")),
}
}
TokenType::StrLiteral(Rc::new(buf))
}
fn handle_alphabetic(c: char, input: &mut CharIter) -> TokenType {
let mut buf = String::new();
buf.push(c);
if c == '_' && input.peek().map(|&(_, c)| { !c.is_alphabetic() }).unwrap_or(true) {
return TokenType::Underscore
}
loop {
match input.peek().map(|&(_, c)| { c }) {
Some(c) if c.is_alphanumeric() => {
input.next();
buf.push(c);
},
_ => break,
}
}
match KEYWORDS.get(buf.as_str()) {
Some(kw) => TokenType::Keyword(*kw),
None => TokenType::Identifier(Rc::new(buf)),
}
}
fn handle_operator(c: char, input: &mut CharIter) -> TokenType {
match c {
'<' | '>' | '|' | '.' => {
let ref next = input.peek().map(|&(_, c)| { c });
if !next.map(|n| { is_operator(&n) }).unwrap_or(false) {
return match c {
'<' => LAngleBracket,
'>' => RAngleBracket,
'|' => Pipe,
'.' => Period,
_ => unreachable!(),
}
}
},
_ => (),
};
let mut buf = String::new();
buf.push(c);
loop {
match input.peek().map(|&(_, c)| { c }) {
Some(c) if is_operator(&c) => {
input.next();
buf.push(c);
},
_ => break
}
}
TokenType::Operator(Rc::new(buf))
}
#[cfg(test)]
mod schala_tokenizer_tests {
use super::*;
macro_rules! digit { ($ident:expr) => { DigitGroup(Rc::new($ident.to_string())) } }
macro_rules! ident { ($ident:expr) => { Identifier(Rc::new($ident.to_string())) } }
macro_rules! op { ($ident:expr) => { Operator(Rc::new($ident.to_string())) } }
#[test]
fn tokens() {
let a = tokenize("let a: A<B> = c ++ d");
let token_types: Vec<TokenType> = a.into_iter().map(move |t| t.token_type).collect();
assert_eq!(token_types, vec![Keyword(Let), ident!("a"), Colon, ident!("A"),
LAngleBracket, ident!("B"), RAngleBracket, op!("="), ident!("c"), op!("++"), ident!("d")]);
}
#[test]
fn underscores() {
let token_types: Vec<TokenType> = tokenize("4_8").into_iter().map(move |t| t.token_type).collect();
assert_eq!(token_types, vec![digit!("4"), Underscore, digit!("8")]);
}
}
/* Schala EBNF Grammar */
/* Terminal productions are in 'single quotes' or UPPERCASE if they are a class
* or not representable in ASCII
program := (statement delimiter)* EOF
delimiter := NEWLINE | ';'
statement := expression | declaration
declaration := type_declaration | func_declaration | binding_declaration | impl_declaration
type_declaration := 'type' type_declaration_body
type_declaration_body := 'alias' type_alias | IDENTIFIER '=' type_body
type_alias := IDENTIFIER '=' type_name
type_body := variant_specifier ('|' variant_specifier)*
variant_specifier := IDENTIFIER | IDENTIFIER '{' typed_identifier_list '}' | IDENTIFIER '(' type_name* ')'
typed_identifier_list := typed_identifier*
typed_identifier := IDENTIFIER type_anno
func_declaration := func_signature func_body
func_body := ε | '{' (statement delimiter)* '}'
func_signature := 'fn' IDENTIFIER formal_param_list func_body
formal_param_list := '(' (formal_param ',')* ')'
formal_param := IDENTIFIER type_anno+
binding_declaration: 'var' IDENTIFIER '=' expression
| 'const' IDENTIFIER '=' expression
trait_declaration := 'trait' trait_name decl_block
impl_declaration := 'impl' IDENTIFIER decl_block | 'impl' trait_name 'for' IDENTIFIER decl_block
decl_block := '{' (func_declaration)* '}'
trait_name := IDENTIFIER
type_anno := (':' type_name)+
type_name := IDENTIFIER (type_params)* | '(' type_names ')'
type_names := ε | type_name (, type_name)*
type_params := '<' type_name (, type_name)* '>'
expression := precedence_expr type_anno+
precedence_expr := prefix_expr
prefix_expr := prefix_op primary
prefix_op := '+' | '-' | '!' | '~'
primary := literal | paren_expr | if_expr | match_expr | for_expr | identifier_expr
paren_expr := LParen paren_inner RParen
paren_inner := (expression ',')*
identifier_expr := named_struct | call_expr | index_expr | IDENTIFIER
literal := 'true' | 'false' | number_literal | STR_LITERAL
named_struct := IDENTIFIER record_block
record_block := '{' (record_entry, ',')* | '}' //TODO support anonymus structs, update syntax
record_entry := IDENTIFIER ':' expression
if_expr := 'if' expression block else_clause
else_clause := ε | 'else' block
match_expr := 'match' expression match_body
match_body := '{' (match_arm)* '}'
match_arm := pattern '=>' expression
pattern := identifier //TODO NOT DONE
block := '{' (statement)* '}'
call_expr := IDENTIFIER '(' expr_list ')' //TODO maybe make this optional? or no, have a bare identifier meant to be used as method taken care of in eval
index_expr := '[' (expression (',' (expression)* | ε) ']'
expr_list := expression (',' expression)* | ε
for_expr := 'for' ... ????
// a float_literal can still be assigned to an int in type-checking
number_literal := int_literal | float_literal
int_literal = ('0x' | '0b') digits
float_literal := digits ('.' digits)
digits := (DIGIT_GROUP underscore)+
*/
type TokenIter = Peekable<IntoIter<Token>>;
#[derive(Debug, PartialEq)]
pub struct ParseError {
pub msg: String,
}
impl ParseError {
fn new<T>(msg: &str) -> ParseResult<T> {
Err(ParseError { msg: msg.to_string() })
}
}
pub type ParseResult<T> = Result<T, ParseError>;
#[derive(Debug)]
pub struct ParseRecord {
production_name: String,
next_token: String,
level: u32,
}
struct Parser {
tokens: TokenIter,
parse_record: Vec<ParseRecord>,
parse_level: u32,
restrictions: ParserRestrictions,
}
struct ParserRestrictions {
no_struct_literal: bool
}
impl Parser {
fn new(input: Vec<Token>) -> Parser {
Parser {
tokens: input.into_iter().peekable(),
parse_record: vec![],
parse_level: 0,
restrictions: ParserRestrictions { no_struct_literal: false }
}
}
fn peek(&mut self) -> TokenType {
self.tokens.peek().map(|ref t| { t.token_type.clone() }).unwrap_or(TokenType::EOF)
}
fn next(&mut self) -> TokenType {
self.tokens.next().map(|ref t| { t.token_type.clone() }).unwrap_or(TokenType::EOF)
}
}
macro_rules! expect {
($self:expr, $token_type:pat, $expected_item:expr) => { expect!($self, $token_type if true, $expected_item) };
($self:expr, $token_type:pat if $cond:expr, $expected_item:expr) => {
match $self.peek() {
$token_type if $cond => $self.next(),
tok => {
let msg = format!("Expected {}, got {:?}", $expected_item, tok);
return Err(ParseError { msg })
}
}
}
}
#[derive(Debug, PartialEq)]
pub struct AST(pub Vec<Statement>);
#[derive(Debug, PartialEq, Clone)]
pub enum Statement {
ExpressionStatement(Expression),
Declaration(Declaration),
}
type ParamName = Rc<String>;
type TraitName = Rc<String>; //should be a singleton I think??
type FormalParam = (ParamName, Option<TypeName>);
#[derive(Debug, PartialEq, Clone)]
pub enum Declaration {
FuncSig(Signature),
FuncDecl(Signature, Vec<Statement>),
TypeDecl(Rc<String>, TypeBody), //should have TypeSingletonName in it
TypeAlias(Rc<String>, Rc<String>), //should have TypeSingletonName in it, or maybe just String, not sure
Binding {
name: Rc<String>,
constant: bool,
expr: Expression,
},
Impl {
type_name: TypeName,
trait_name: Option<TraitName>,
block: Vec<Declaration>,
},
}
#[derive(Debug, PartialEq, Clone)]
pub struct Signature {
pub name: Rc<String>,
pub params: Vec<FormalParam>,
pub type_anno: Option<TypeName>,
}
#[derive(Debug, PartialEq, Clone)]
pub struct TypeBody(pub Vec<Variant>);
#[derive(Debug, PartialEq, Clone)]
pub enum Variant {
UnitStruct(Rc<String>),
TupleStruct(Rc<String>, Vec<TypeName>),
Record(Rc<String>, Vec<(Rc<String>, TypeName)>),
}
#[derive(Debug, PartialEq, Clone)]
pub struct Expression(pub ExpressionType, pub Option<TypeName>);
#[derive(Debug, PartialEq, Clone)]
pub enum TypeName {
Tuple(Vec<TypeName>),
Singleton(TypeSingletonName)
}
#[derive(Debug, PartialEq, Clone)]
pub struct TypeSingletonName {
pub name: Rc<String>,
pub params: Vec<TypeName>,
}
#[derive(Debug, PartialEq, Clone)]
pub enum ExpressionType {
IntLiteral(u64),
FloatLiteral(f64),
StringLiteral(Rc<String>),
BoolLiteral(bool),
BinExp(Operation, Box<Expression>, Box<Expression>),
PrefixExp(Operation, Box<Expression>),
TupleLiteral(Vec<Expression>),
Value(Rc<String>, Vec<(Rc<String>, Expression)>),
Call {
f: Box<Expression>,
arguments: Vec<Expression>,
},
Index {
indexee: Box<Expression>,
indexers: Vec<Expression>,
},
IfExpression(Box<Expression>, Vec<Statement>, Option<Vec<Statement>>),
MatchExpression(Box<Expression>, Vec<MatchArm>),
ForExpression
}
#[derive(Debug, PartialEq, Clone)]
pub struct MatchArm {
pat: Pattern,
expr: Expression,
}
#[derive(Debug, PartialEq, Clone)]
pub struct Pattern(Rc<String>);
#[derive(Debug, PartialEq, Clone)]
pub struct Operation(pub Rc<String>);
impl Operation {
fn min_precedence() -> i32 {
i32::min_value()
}
fn get_precedence(op: &str) -> i32 {
match op {
"+" | "-" => 10,
"*" | "/" | "%" => 20,
_ => 30,
}
}
fn is_prefix(op: &str) -> bool {
match op {
"+" | "-" | "!" | "~" => true,
_ => false,
}
}
}
macro_rules! parse_method {
($name:ident(&mut $self:ident) -> $type:ty $body:block) => {
fn $name(&mut $self) -> $type {
let next_token = $self.peek();
let record = ParseRecord {
production_name: stringify!($name).to_string(),
next_token: format!("{:?}", next_token),
level: $self.parse_level,
};
$self.parse_level += 1;
$self.parse_record.push(record);
let result = { $body };
if $self.parse_level != 0 {
$self.parse_level -= 1;
}
result
}
};
}
macro_rules! delimited {
($self:expr, $start:pat, $start_str:expr, $parse_fn:ident, $( $delim:pat )|+, $end:pat, $end_str:expr, nonstrict) => {
delimited!($self, $start, $start_str, $parse_fn, $( $delim )|*, $end, $end_str, false)
};
($self:expr, $start:pat, $start_str:expr, $parse_fn:ident, $( $delim:pat )|+, $end:pat, $end_str:expr) => {
delimited!($self, $start, $start_str, $parse_fn, $( $delim )|*, $end, $end_str, true)
};
($self:expr, $start:pat, $start_str:expr, $parse_fn:ident, $( $delim:pat )|+, $end:pat, $end_str:expr, $strictness:expr) => {
{
expect!($self, $start, $start_str);
let mut acc = vec![];
loop {
let peek = $self.peek();
match peek {
$end | EOF => break,
_ => (),
}
if !$strictness {
match peek {
$( $delim )|* => { $self.next(); continue },
_ => ()
}
}
acc.push($self.$parse_fn()?);
match $self.peek() {
$( $delim )|* => { $self.next(); continue },
_ => break
};
}
expect!($self, $end, $end_str);
acc
}
};
}
impl Parser {
parse_method!(program(&mut self) -> ParseResult<AST> {
let mut statements = Vec::new();
loop {
match self.peek() {
EOF => break,
Newline | Semicolon => {
self.next();
continue;
},
_ => statements.push(self.statement()?),
}
}
Ok(AST(statements))
});
parse_method!(statement(&mut self) -> ParseResult<Statement> {
//TODO handle error recovery here
match self.peek() {
Keyword(Type) => self.type_declaration().map(|decl| { Statement::Declaration(decl) }),
Keyword(Func)=> self.func_declaration().map(|func| { Statement::Declaration(func) }),
Keyword(Var) | Keyword(Const) => self.binding_declaration().map(|decl| Statement::Declaration(decl)),
Keyword(Trait) => self.trait_declaration().map(|decl| Statement::Declaration(decl)),
Keyword(Impl) => self.impl_declaration().map(|decl| Statement::Declaration(decl)),
_ => self.expression().map(|expr| { Statement::ExpressionStatement(expr) } ),
}
});
parse_method!(type_declaration(&mut self) -> ParseResult<Declaration> {
expect!(self, Keyword(Type), "'type'");
self.type_declaration_body()
});
parse_method!(type_declaration_body(&mut self) -> ParseResult<Declaration> {
if let Keyword(Alias) = self.peek() {
self.type_alias()
} else {
let name = self.identifier()?;
expect!(self, Operator(ref c) if **c == "=", "'='");
let body = self.type_body()?;
Ok(Declaration::TypeDecl(name, body))
}
});
parse_method!(type_alias(&mut self) -> ParseResult<Declaration> {
expect!(self, Keyword(Alias), "'alias'");
let alias = self.identifier()?;
expect!(self, Operator(ref c) if **c == "=", "'='");
let original = self.identifier()?;
Ok(Declaration::TypeAlias(alias, original))
});
parse_method!(type_body(&mut self) -> ParseResult<TypeBody> {
let mut variants = Vec::new();
variants.push(self.variant_specifier()?);
loop {
if let Pipe = self.peek() {
self.next();
variants.push(self.variant_specifier()?);
} else {
break;
}
}
Ok(TypeBody(variants))
});
parse_method!(variant_specifier(&mut self) -> ParseResult<Variant> {
use self::Variant::*;
let name = self.identifier()?;
match self.peek() {
LParen => {
let tuple_members = delimited!(self, LParen, '(', type_name, Comma, RParen, ')');
Ok(TupleStruct(name, tuple_members))
},
LCurlyBrace => {
let typed_identifier_list = delimited!(self, LCurlyBrace, '{', typed_identifier, Comma, RCurlyBrace, '}');
Ok(Record(name, typed_identifier_list))
},
_ => Ok(UnitStruct(name))
}
});
parse_method!(typed_identifier(&mut self) -> ParseResult<(Rc<String>, TypeName)> {
let identifier = self.identifier()?;
expect!(self, Colon, "':'");
let type_name = self.type_name()?;
Ok((identifier, type_name))
});
parse_method!(func_declaration(&mut self) -> ParseResult<Declaration> {
let signature = self.signature()?;
if let LCurlyBrace = self.peek() {
let statements = delimited!(self, LCurlyBrace, '{', statement, Newline | Semicolon, RCurlyBrace, '}');
Ok(Declaration::FuncDecl(signature, statements))
} else {
Ok(Declaration::FuncSig(signature))
}
});
parse_method!(signature(&mut self) -> ParseResult<Signature> {
expect!(self, Keyword(Func), "'fn'");
let name = self.identifier()?;
let params = delimited!(self, LParen, '(', formal_param, Comma, RParen, ')');
let type_anno = match self.peek() {
Colon => Some(self.type_anno()?),
_ => None,
};
Ok(Signature { name, params, type_anno })
});
parse_method!(formal_param(&mut self) -> ParseResult<FormalParam> {
let name = self.identifier()?;
let ty = match self.peek() {
Colon => Some(self.type_anno()?),
_ => None
};
Ok((name, ty))
});
parse_method!(binding_declaration(&mut self) -> ParseResult<Declaration> {
let constant = match self.next() {
Keyword(Var) => false,
Keyword(Const) => true,
_ => return ParseError::new("Expected 'var' or 'const'"),
};
let name = self.identifier()?;
expect!(self, Operator(ref o) if **o == "=", "'='");
let expr = self.expression()?;
Ok(Declaration::Binding { name, constant, expr })
});
parse_method!(trait_declaration(&mut self) -> ParseResult<Declaration> {
unimplemented!()
});
parse_method!(impl_declaration(&mut self) -> ParseResult<Declaration> {
expect!(self, Keyword(Impl), "'impl'");
let first = self.type_name()?;
let second = if let Keyword(For) = self.peek() {
self.next();
Some(self.type_name()?)
} else {
None
};
let block = self.decl_block()?;
let result = match (first, second) {
(first, Some(second)) => {
match first {
TypeName::Singleton(TypeSingletonName { ref name, ref params }) if params.len() == 0 =>
Declaration::Impl { type_name: second, trait_name: Some(name.clone()), block },
_ => return ParseError::new(&format!("Invalid name for a trait")),
}
},
(first, None) => Declaration::Impl { type_name: first, trait_name: None, block }
};
Ok(result)
});
parse_method!(decl_block(&mut self) -> ParseResult<Vec<Declaration>> {
Ok(delimited!(self, LCurlyBrace, '{', func_declaration, Newline | Semicolon, RCurlyBrace, '}', nonstrict))
});
parse_method!(expression(&mut self) -> ParseResult<Expression> {
let mut expr_body = self.precedence_expr(Operation::min_precedence())?;
let type_anno = match self.peek() {
Colon => Some(self.type_anno()?),
_ => None
};
if let Some(_) = expr_body.1 {
return ParseError::new("Bad parse state");
}
expr_body.1 = type_anno;
Ok(expr_body)
});
parse_method!(type_anno(&mut self) -> ParseResult<TypeName> {
expect!(self, Colon, "':'");
self.type_name()
});
parse_method!(type_name(&mut self) -> ParseResult<TypeName> {
use self::TypeName::*;
Ok(match self.peek() {
LParen => Tuple(delimited!(self, LParen, '(', type_name, Comma, RParen, ')')),
_ => Singleton(TypeSingletonName {
name: self.identifier()?,
params: match self.peek() {
LAngleBracket => delimited!(self, LAngleBracket, '<', type_name, Comma, RAngleBracket, '>'),
_ => vec![],
}
})
})
});
// this implements Pratt parsing, see http://journal.stuffwithstuff.com/2011/03/19/pratt-parsers-expression-parsing-made-easy/
fn precedence_expr(&mut self, precedence: i32) -> ParseResult<Expression> {
let next_token = self.peek();
let record = ParseRecord {
production_name: "precedence_expr".to_string(),
next_token: format!("{:?}", next_token),
level: self.parse_level,
};
self.parse_level += 1;
self.parse_record.push(record);
let mut lhs = self.prefix_expr()?;
loop {
let new_precedence = match self.peek() {
Operator(op) => Operation::get_precedence(&*op),
Period => Operation::get_precedence("."),
_ => break,
};
if precedence >= new_precedence {
break;
}
let op_str = match self.next() {
Operator(op) => op,
Period => Rc::new(".".to_string()),
_ => unreachable!(),
};
let rhs = self.precedence_expr(new_precedence)?;
let operation = Operation(op_str);
lhs = Expression(ExpressionType::BinExp(operation, Box::new(lhs), Box::new(rhs)), None);
}
self.parse_level -= 1;
Ok(lhs)
}
parse_method!(prefix_expr(&mut self) -> ParseResult<Expression> {
match self.peek() {
Operator(ref op) if Operation::is_prefix(&*op) => {
let op_str = match self.next() {
Operator(op) => op,
_ => unreachable!(),
};
let expr = self.primary()?;
Ok(Expression(
ExpressionType::PrefixExp(Operation(op_str), Box::new(expr)),
None))
},
_ => self.primary()
}
});
parse_method!(primary(&mut self) -> ParseResult<Expression> {
match self.peek() {
LParen => self.paren_expr(),
Keyword(Kw::If) => self.if_expr(),
Keyword(Kw::Match) => self.match_expr(),
Keyword(Kw::For) => self.for_expr(),
Identifier(_) => self.identifier_expr(),
_ => self.literal(),
}
});
parse_method!(paren_expr(&mut self) -> ParseResult<Expression> {
use self::ExpressionType::*;
let old_struct_value = self.restrictions.no_struct_literal;
self.restrictions.no_struct_literal = false;
let output = (|| {
let mut inner = delimited!(self, LParen, '(', expression, Comma, RParen, ')');
match inner.len() {
0 => Ok(Expression(TupleLiteral(vec![]), None)),
1 => Ok(inner.pop().unwrap()),
_ => Ok(Expression(TupleLiteral(inner), None)),
}
})();
self.restrictions.no_struct_literal = old_struct_value;
output
});
parse_method!(identifier_expr(&mut self) -> ParseResult<Expression> {
use self::ExpressionType::*;
let identifier = self.identifier()?;
Ok(match self.peek() {
LCurlyBrace if !self.restrictions.no_struct_literal => {
let fields = self.record_block()?;
Expression(Value(identifier, fields), None)
},
LParen => {
let arguments = self.call_expr()?;
//TODO make this be more general
let f = Box::new(Expression(Value(identifier, vec![]), None));
Expression(Call { f, arguments }, None)
},
LSquareBracket => {
let indexers = self.index_expr()?;
Expression(Index {
indexee: Box::new(Expression(Value(identifier, vec![]), None)),
indexers,
}, None)
}
_ => Expression(Value(identifier, vec![]), None)
})
});
parse_method!(record_block(&mut self) -> ParseResult<Vec<(Rc<String>, Expression)>> {
Ok(delimited!(self, LCurlyBrace, '{', record_entry, Comma, RCurlyBrace, '}'))
});
parse_method!(record_entry(&mut self) -> ParseResult<(Rc<String>, Expression)> {
let field_name = self.identifier()?;
expect!(self, Colon, ":");
let value = self.expression()?;
Ok((field_name, value))
});
parse_method!(call_expr(&mut self) -> ParseResult<Vec<Expression>> {
Ok(delimited!(self, LParen, ')', expression, Comma, RParen, '('))
});
parse_method!(index_expr(&mut self) -> ParseResult<Vec<Expression>> {
Ok(delimited!(self, LSquareBracket, '[', expression, Comma, RSquareBracket, ']'))
});
parse_method!(if_expr(&mut self) -> ParseResult<Expression> {
expect!(self, Keyword(Kw::If), "'if'");
let condition = (|| {
self.restrictions.no_struct_literal = true;
let x = self.expression();
self.restrictions.no_struct_literal = false;
x
})()?;
let then_clause = self.block()?;
let else_clause = self.else_clause()?;
Ok(Expression(ExpressionType::IfExpression(Box::new(condition), then_clause, else_clause), None))
});
parse_method!(else_clause(&mut self) -> ParseResult<Option<Vec<Statement>>> {
Ok(if let Keyword(Kw::Else) = self.peek() {
self.next();
Some(self.block()?)
} else {
None
})
});
parse_method!(block(&mut self) -> ParseResult<Vec<Statement>> {
Ok(delimited!(self, LCurlyBrace, '{', statement, Newline | Semicolon, RCurlyBrace, '}', nonstrict))
});
parse_method!(match_expr(&mut self) -> ParseResult<Expression> {
expect!(self, Keyword(Kw::Match), "'match'");
let expr = self.expression()?;
//TODO abstract these errors into the delimited macro
//expect!(self, LCurlyBrace, "Expected '{'");
let body = self.match_body()?;
//expect!(self, RCurlyBrace, "Expected '}'");
Ok(Expression(ExpressionType::MatchExpression(Box::new(expr), body), None))
});
parse_method!(match_body(&mut self) -> ParseResult<Vec<MatchArm>> {
Ok(delimited!(self, LCurlyBrace, '{', match_arm, Comma, RCurlyBrace, '}'))
});
parse_method!(match_arm(&mut self) -> ParseResult<MatchArm> {
let pat = self.pattern()?;
expect!(self, Operator(ref c) if **c == "=>", "'=>'");
let expr = self.expression()?;
Ok(MatchArm { pat, expr })
});
parse_method!(pattern(&mut self) -> ParseResult<Pattern> {
let identifier = self.identifier()?;
Ok(Pattern(identifier))
});
parse_method!(for_expr(&mut self) -> ParseResult<Expression> {
expect!(self, Keyword(Kw::For), "'for'");
Ok(Expression(ExpressionType::ForExpression, None))
});
parse_method!(identifier(&mut self) -> ParseResult<Rc<String>> {
match self.next() {
Identifier(s) => Ok(s),
p => ParseError::new(&format!("Expected an identifier, got {:?}", p)),
}
});
parse_method!(literal(&mut self) -> ParseResult<Expression> {
use self::ExpressionType::*;
match self.peek() {
DigitGroup(_) | HexLiteral(_) | BinNumberSigil | Period => self.number_literal(),
Keyword(Kw::True) => {
self.next();
Ok(Expression(BoolLiteral(true), None))
},
Keyword(Kw::False) => {
self.next();
Ok(Expression(BoolLiteral(false), None))
},
StrLiteral(s) => {
self.next();
Ok(Expression(StringLiteral(s), None))
}
e => ParseError::new(&format!("Expected a literal expression, got {:?}", e)),
}
});
parse_method!(number_literal(&mut self) -> ParseResult<Expression> {
match self.peek() {
HexLiteral(_) | BinNumberSigil => self.int_literal(),
_ => self.float_literal(),
}
});
parse_method!(int_literal(&mut self) -> ParseResult<Expression> {
use self::ExpressionType::*;
match self.next() {
BinNumberSigil => {
let digits = self.digits()?;
let n = parse_binary(digits)?;
Ok(Expression(IntLiteral(n), None))
},
HexLiteral(text) => {
let digits: String = text.chars().filter(|c| c.is_digit(16)).collect();
let n = parse_hex(digits)?;
Ok(Expression(IntLiteral(n), None))
},
_ => return ParseError::new("Expected '0x' or '0b'"),
}
});
parse_method!(float_literal(&mut self) -> ParseResult<Expression> {
use self::ExpressionType::*;
let mut digits = self.digits()?;
if let TokenType::Period = self.peek() {
self.next();
digits.push_str(".");
digits.push_str(&self.digits()?);
match digits.parse::<f64>() {
Ok(f) => Ok(Expression(FloatLiteral(f), None)),
Err(e) => ParseError::new(&format!("Float failed to parse with error: {}", e)),
}
} else {
match digits.parse::<u64>() {
Ok(d) => Ok(Expression(IntLiteral(d), None)),
Err(e) => ParseError::new(&format!("Integer failed to parse with error: {}", e)),
}
}
});
parse_method!(digits(&mut self) -> ParseResult<String> {
let mut ds = String::new();
loop {
match self.peek() {
Underscore => { self.next(); continue; },
DigitGroup(ref s) => { self.next(); ds.push_str(s)},
_ => break,
}
}
Ok(ds)
});
}
fn parse_binary(digits: String) -> ParseResult<u64> {
let mut result: u64 = 0;
let mut multiplier = 1;
for d in digits.chars().rev() {
match d {
'1' => result += multiplier,
'0' => (),
_ => return ParseError::new("Encountered a character not '1' or '0 while parsing a binary literal"),
}
multiplier *= 2;
}
Ok(result)
}
fn parse_hex(digits: String) -> ParseResult<u64> {
let mut result: u64 = 0;
let mut multiplier: u64 = 1;
for d in digits.chars().rev() {
match d.to_digit(16) {
Some(n) => result += n as u64 * multiplier,
None => return ParseError::new("Encountered a non-hex digit in a hex literal"),
}
multiplier *= 16;
}
Ok(result)
}
pub fn parse(input: Vec<Token>) -> (Result<AST, ParseError>, Vec<String>) {
let mut parser = Parser::new(input);
let ast = parser.program();
let trace = parser.parse_record.into_iter().map(|r| {
let mut indent = String::new();
for i in 0..r.level {
indent.push(' ');
}
format!("{}Production `{}`, token: {:?}", indent, r.production_name, r.next_token)
}).collect();
(ast, trace)
}
#[cfg(test)]
mod parse_tests {
use ::std::rc::Rc;
use super::{AST, Expression, Statement, Operation, TypeBody, Variant, parse, tokenize};
use super::Statement::*;
use super::Declaration::*;
use super::Signature;
use super::TypeName::*;
use super::ExpressionType::*;
use super::Variant::*;
macro_rules! rc {
($string:tt) => { Rc::new(stringify!($string).to_string()) }
}
macro_rules! parse_test {
($string:expr, $correct:expr) => { assert_eq!(parse(tokenize($string)).0.unwrap(), $correct) }
}
macro_rules! parse_error {
($string:expr) => { assert!(parse(tokenize($string)).0.is_err()) }
}
macro_rules! binexp {
($op:expr, $lhs:expr, $rhs:expr) => { BinExp(op!($op), Box::new(Expression($lhs, None)), Box::new(Expression($rhs, None))) }
}
macro_rules! prefexp {
($op:expr, $lhs:expr) => { PrefixExp(op!($op), Box::new(Expression($lhs, None))) }
}
macro_rules! op {
($op:expr) => { Operation(Rc::new($op.to_string())) }
}
macro_rules! val {
($var:expr) => { Value(Rc::new($var.to_string()), vec![]) }
}
macro_rules! exprstatement {
($expr_type:expr) => { Statement::ExpressionStatement(Expression($expr_type, None)) };
($expr_type:expr, $type_anno:expr) => { Statement::ExpressionStatement(Expression($expr_type, Some($type_anno))) };
}
macro_rules! ex {
($expr_type:expr) => { Expression($expr_type, None) }
}
macro_rules! ty {
($name:expr) => { Singleton { name: Rc::new($name.to_string()), params: vec![] } };
}
#[test]
fn parsing_number_literals_and_binexps() {
parse_test!(".2", AST(vec![exprstatement!(FloatLiteral(0.2))]));
parse_test!("8.1", AST(vec![exprstatement!(FloatLiteral(8.1))]));
parse_test!("0b010", AST(vec![exprstatement!(IntLiteral(2))]));
parse_test!("0b0_1_0_", AST(vec![exprstatement!(IntLiteral(2))]));
parse_test!("0xff", AST(vec![exprstatement!(IntLiteral(255))]));
parse_test!("0xf_f_", AST(vec![exprstatement!(IntLiteral(255))]));
parse_test!("0xf_f_+1", AST(vec![exprstatement!(binexp!("+", IntLiteral(255), IntLiteral(1)))]));
parse_test!("3; 4; 4.3", AST(
vec![exprstatement!(IntLiteral(3)), exprstatement!(IntLiteral(4)),
exprstatement!(FloatLiteral(4.3))]));
parse_test!("1 + 2 * 3", AST(vec!
[
exprstatement!(binexp!("+", IntLiteral(1), binexp!("*", IntLiteral(2), IntLiteral(3))))
]));
parse_test!("1 * 2 + 3", AST(vec!
[
exprstatement!(binexp!("+", binexp!("*", IntLiteral(1), IntLiteral(2)), IntLiteral(3)))
]));
parse_test!("1 && 2", AST(vec![exprstatement!(binexp!("&&", IntLiteral(1), IntLiteral(2)))]));
parse_test!("1 + 2 * 3 + 4", AST(vec![exprstatement!(
binexp!("+",
binexp!("+", IntLiteral(1), binexp!("*", IntLiteral(2), IntLiteral(3))),
IntLiteral(4)))]));
parse_test!("(1 + 2) * 3", AST(vec!
[exprstatement!(binexp!("*", binexp!("+", IntLiteral(1), IntLiteral(2)), IntLiteral(3)))]));
parse_test!(".1 + .2", AST(vec![exprstatement!(binexp!("+", FloatLiteral(0.1), FloatLiteral(0.2)))]));
}
#[test]
fn parsing_tuples() {
parse_test!("()", AST(vec![exprstatement!(TupleLiteral(vec![]))]));
parse_test!("(\"hella\", 34)", AST(vec![exprstatement!(
TupleLiteral(
vec![ex!(StringLiteral(rc!(hella))), ex!(IntLiteral(34))]
)
)]));
parse_test!("((1+2), \"slough\")", AST(vec![exprstatement!(TupleLiteral(vec![
ex!(binexp!("+", IntLiteral(1), IntLiteral(2))),
ex!(StringLiteral(rc!(slough))),
]))]))
}
#[test]
fn parsing_identifiers() {
parse_test!("a", AST(vec![exprstatement!(val!("a"))]));
parse_test!("a + b", AST(vec![exprstatement!(binexp!("+", val!("a"), val!("b")))]));
//parse_test!("a[b]", AST(vec![Expression(
//parse_test!("a[]", <- TODO THIS NEEDS TO FAIL
//parse_test!(damn()[a] ,<- TODO needs to succeed
parse_test!("a[b,c]", AST(vec![exprstatement!(Index { indexee: Box::new(ex!(val!("a"))), indexers: vec![ex!(val!("b")), ex!(val!("c"))]} )]));
parse_test!("None", AST(vec![exprstatement!(val!("None"))]));
parse_test!("Pandas { a: x + y }", AST(vec![
exprstatement!(Value(rc!(Pandas), vec![(rc!(a), ex!(binexp!("+", val!("x"), val!("y"))))]))]));
}
#[test]
fn parsing_complicated_operators() {
parse_test!("a <- b", AST(vec![exprstatement!(binexp!("<-", val!("a"), val!("b")))]));
parse_test!("a || b", AST(vec![exprstatement!(binexp!("||", val!("a"), val!("b")))]));
parse_test!("a<>b", AST(vec![exprstatement!(binexp!("<>", val!("a"), val!("b")))]));
parse_test!("a.b.c.d", AST(vec![exprstatement!(binexp!(".",
binexp!(".",
binexp!(".", val!("a"), val!("b")),
val!("c")),
val!("d")))]));
parse_test!("-3", AST(vec![exprstatement!(prefexp!("-", IntLiteral(3)))]));
parse_test!("-0.2", AST(vec![exprstatement!(prefexp!("-", FloatLiteral(0.2)))]));
parse_test!("!3", AST(vec![exprstatement!(prefexp!("!", IntLiteral(3)))]));
parse_test!("a <- -b", AST(vec![exprstatement!(binexp!("<-", val!("a"), prefexp!("-", val!("b"))))]));
parse_test!("a <--b", AST(vec![exprstatement!(binexp!("<--", val!("a"), val!("b")))]));
}
#[test]
fn parsing_functions() {
parse_test!("fn oi()", AST(vec![Declaration(FuncSig(Signature { name: rc!(oi), params: vec![], type_anno: None }))]));
parse_test!("oi()", AST(vec![exprstatement!(Call { f: Box::new(ex!(val!("oi"))), arguments: vec![] })]));
parse_test!("oi(a, 2 + 2)", AST(vec![exprstatement!(Call
{ f: Box::new(ex!(val!("oi"))),
arguments: vec![ex!(val!("a")), ex!(binexp!("+", IntLiteral(2), IntLiteral(2)))]
})]));
parse_error!("a(b,,c)");
parse_test!("fn a(b, c: Int): Int", AST(vec![Declaration(
FuncSig(Signature { name: rc!(a), params: vec![
(rc!(b), None), (rc!(c), Some(ty!("Int")))
], type_anno: Some(ty!("Int")) }))]));
parse_test!("fn a(x) { x() }", AST(vec![Declaration(
FuncDecl(Signature { name: rc!(a), params: vec![(rc!(x),None)], type_anno: None },
vec![exprstatement!(Call { f: Box::new(ex!(val!("x"))), arguments: vec![] })]))]));
}
#[test]
fn parsing_bools() {
parse_test!("false", AST(vec![exprstatement!(BoolLiteral(false))]));
parse_test!("true", AST(vec![exprstatement!(BoolLiteral(true))]));
}
#[test]
fn parsing_strings() {
parse_test!(r#""hello""#, AST(vec![exprstatement!(StringLiteral(rc!(hello)))]));
}
#[test]
fn parsing_types() {
parse_test!("type Yolo = Yolo", AST(vec![Declaration(TypeDecl(rc!(Yolo), TypeBody(vec![UnitStruct(rc!(Yolo))])))]));
parse_test!("type alias Sex = Drugs", AST(vec![Declaration(TypeAlias(rc!(Sex), rc!(Drugs)))]));
parse_test!("type Sanchez = Miguel | Alejandro(Int, Option<a>) | Esparanza { a: Int, b: String }",
AST(vec![Declaration(TypeDecl(rc!(Sanchez), TypeBody(vec![
UnitStruct(rc!(Miguel)),
TupleStruct(rc!(Alejandro), vec![
Singleton { name: rc!(Int), params: vec![] },
Singleton { name: rc!(Option), params: vec![Singleton { name: rc!(a), params: vec![] }] },
]),
Record(rc!(Esparanza), vec![
(rc!(a), Singleton { name: rc!(Int), params: vec![] }),
(rc!(b), Singleton { name: rc!(String), params: vec![] }),
])])))]));
}
#[test]
fn parsing_bindings() {
parse_test!("var a = 10", AST(vec![Declaration(Binding { name: rc!(a), constant: false, expr: ex!(IntLiteral(10)) } )]));
parse_test!("const a = 2 + 2", AST(vec![Declaration(Binding { name: rc!(a), constant: true, expr: ex!(binexp!("+", IntLiteral(2), IntLiteral(2))) }) ]));
}
#[test]
fn parsing_block_expressions() {
parse_test!("if a() { b(); c() }", AST(vec![exprstatement!(
IfExpression(Box::new(ex!(Call { f: Box::new(ex!(val!("a"))), arguments: vec![]})),
vec![exprstatement!(Call { f: Box::new(ex!(val!("b"))), arguments: vec![]}), exprstatement!(Call { f: Box::new(ex!(val!("c"))), arguments: vec![] })],
None)
)]));
parse_test!(r#"
if true {
const a = 10
b
} else {
c
}"#,
AST(vec![exprstatement!(IfExpression(Box::new(ex!(BoolLiteral(true))),
vec![Declaration(Binding { name: rc!(a), constant: true, expr: ex!(IntLiteral(10)) }),
exprstatement!(Value(rc!(b), vec![]))],
Some(vec![exprstatement!(Value(rc!(c), vec![]))])))])
);
parse_test!("if a { b } else { c }", AST(vec![exprstatement!(
IfExpression(Box::new(ex!(val!("a"))),
vec![exprstatement!(val!("b"))],
Some(vec![exprstatement!(val!("c"))])))]));
parse_test!("if (A {a: 1}) { b } else { c }", AST(vec![exprstatement!(
IfExpression(Box::new(ex!(Value(rc!(A), vec![(rc!(a), ex!(IntLiteral(1)))]))),
vec![exprstatement!(val!("b"))],
Some(vec![exprstatement!(val!("c"))])))]));
parse_error!("if A {a: 1} { b } else { c }");
}
#[test]
fn parsing_impls() {
parse_test!("impl Heh { fn yolo(); fn swagg(); }", AST(vec![
Declaration(Impl {
type_name: ty!("Heh"),
trait_name: None,
block: vec![
FuncSig(Signature { name: rc!(yolo), params: vec![], type_anno: None }),
FuncSig(Signature { name: rc!(swagg), params: vec![], type_anno: None })
] })]));
parse_test!("impl Mondai for Lollerino { fn yolo(); fn swagg(); }", AST(vec![
Declaration(Impl {
type_name: ty!("Lollerino"),
trait_name: Some(rc!(Mondai)),
block: vec![
FuncSig(Signature { name: rc!(yolo), params: vec![], type_anno: None}),
FuncSig(Signature { name: rc!(swagg), params: vec![], type_anno: None })
] })]));
parse_test!("impl Option<WTFMate> { fn oi() }", AST(vec![
Declaration(Impl {
type_name: Singleton { name: rc!(Option), params: vec![ty!("WTFMate")]},
trait_name: None,
block: vec![
FuncSig(Signature { name: rc!(oi), params: vec![], type_anno: None }),
]
})]));
}
#[test]
fn parsing_type_annotations() {
parse_test!("const a = b : Int", AST(vec![
Declaration(Binding { name: rc!(a), constant: true, expr:
Expression(val!("b"), Some(ty!("Int"))) })]));
parse_test!("a : Int", AST(vec![
exprstatement!(val!("a"), ty!("Int"))
]));
parse_test!("a : Option<Int>", AST(vec![
exprstatement!(val!("a"), Singleton { name: rc!(Option), params: vec![ty!("Int")] })
]));
parse_test!("a : KoreanBBQSpecifier<Kimchi, Option<Bulgogi> >", AST(vec![
exprstatement!(val!("a"), Singleton { name: rc!(KoreanBBQSpecifier), params: vec![
ty!("Kimchi"), Singleton { name: rc!(Option), params: vec![ty!("Bulgogi")] }
] })
]));
parse_test!("a : (Int, Yolo<a>)", AST(vec![
exprstatement!(val!("a"), Tuple(
vec![ty!("Int"), Singleton {
name: rc!(Yolo), params: vec![ty!("a")]
}]))]));
}
}