schala/schala-lang/language/src/parsing.rs

1310 lines
42 KiB
Rust
Raw Normal View History

//! # Parsing
//! This module is where the recursive-descent parsing methods live.
//!
//!
2019-06-16 16:07:27 -07:00
//! # Schala EBNF Grammar
2019-06-09 01:08:32 -07:00
//! This document is the authoritative grammar of Schala, represented in something approximating
//! Extended Backus-Naur form. Terminal productions are in "double quotes", or UPPERCASE
//! if they represent a class of tokens rather than an specific string, or are otherwise
//! unreprsentable in ASCII.
//!
//! ## Top level structure
//!
//! ```text
//! program := (statement delimiter)* EOF
//! delimiter := NEWLINE | ";"
2019-10-22 03:15:14 -07:00
//! statement := expression | declaration | import | module
//! block := "{" (statement delimiter)* "}"
//! declaration := type_declaration | func_declaration | binding_declaration | impl_declaration
//! ```
2019-06-09 01:08:32 -07:00
//! ## Declarations
//!
//! ### Types
//! ```text
//! type_declaration := "type" type_declaration_body
//! type_declaration_body := "alias" type_alias | "mut"? type_singleton_name "=" 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
//! ```
2019-06-09 01:08:32 -07:00
//! ### Functions
//!
//! ```text
//! func_declaration := func_signature func_body
//! func_body := ε | nonempty_func_body
//! nonempty_func_body := "{" (statement delimiter)* "}"
//! func_signature := "fn" func_name formal_param_list type_anno+
//! func_name := IDENTIFIER | operator
//! formal_param_list := "(" (formal_param ",")* ")"
//! formal_param := IDENTIFIER type_anno+
//! ```
2019-06-09 01:08:32 -07:00
//!
//! ### Variable bindings
//! ```text binding_declaration := "let" "mut"? IDENTIFIER "=" expresion```
2019-06-09 01:08:32 -07:00
//!
//! ### Interfaces
//!
//! ```text
//! interface_declaration := "interface" type_singleton_name signature_block
//! impl_declaration := "impl" type_singleton_name decl_block | "impl" type_singleton_name "for" type_name decl_block
//! decl_block := "{" (func_declaration)* "}"
//! signature_block := "{" (func_signature)* "}"
//! ```
2019-06-09 01:08:32 -07:00
//!
//! ### Type Annotations
//!
//! ```text
2019-06-09 01:08:32 -07:00
//! type_anno := ":" type_name
//! type_name := type_singleton_name | "(" type_names ")"
//! type_names := ε | type_name (, type_name)*
//! type_singleton_name = IDENTIFIER (type_params)*
//! type_params := "<" type_name (, type_name)* ">"
//! ```
2019-06-09 01:08:32 -07:00
//!
//! ## Expressions
//! ```text
//! expression := precedence_expr type_anno+
//! precedence_expr := prefix_expr
//! prefix_expr := prefix_op call_expr
//! prefix_op := "+" | "-" | "!" | "~"
//! call_expr := index_expr ( "(" invocation_list ")" )* | ε
//! invocation_list := invocation_argument ("," invocation_argument)* | ε
//! invocation_argument := expression | IDENTIFIER "=" expression | "_"
//! index_expr := primary ( "[" (expression ("," (expression)* | ε) "]" )*
//! primary := literal | paren_expr | if_expr | for_expr | while_expr | identifier_expr | lambda_expr | anonymous_struct | list_expr
2019-06-09 01:08:32 -07:00
//! expr_or_block := "{" (statement delimiter)* "}" | expr
//! ```
2019-06-09 01:08:32 -07:00
//!
//! ### Primary expressions
//!
//! ```text
//! list_expr := "[" (expression, ",")* "]"
2019-06-09 01:12:19 -07:00
//! lambda_expr := "\\" lambda_param_list type_anno+ nonempty_func_body
//! lambda_param_list := formal_param_list | formal_param
2019-06-09 01:12:19 -07:00
//! paren_expr := "(" paren_inner ")"
//! paren_inner := (expression ",")*
2019-08-31 23:39:01 -07:00
//! identifier_expr := qualified_identifier | named_struct
//! qualified_identifier := IDENTIFIER ("::" IDENTIFIER)*
//! ```
2019-06-09 01:08:32 -07:00
//!
//! ## Literals
//! ```text
//! literal := "true" | "false" | number_literal | STR_LITERAL
2019-08-31 23:39:01 -07:00
//! named_struct := qualified_identifier record_block
//! record_block := "{" (record_entry, ",")* | "}" //TODO support anonymus structs, update syntax
//! record_entry := IDENTIFIER ":" expression
//! anonymous_struct := TODO
//! number_literal := int_literal | float_literal
//! int_literal = ("0x" | "0b") digits
//! float_literal := digits ("." digits)
2019-06-09 01:12:19 -07:00
//! digits := (digit_group underscore*)+
//! digit_group := DIGIT+
//! ```
2019-06-09 01:08:32 -07:00
//!
//! ### Patterns
//! ```text
//! pattern := "(" (pattern, ",")* ")" | simple_pattern
//! simple_pattern := pattern_literal | record_pattern | tuple_struct_pattern
2019-09-03 21:14:12 -07:00
//! pattern_literal := "true" | "false" | signed_number_literal | STR_LITERAL | qualified_identifier
//! signed_number_literal := "-"? number_literal
2019-09-03 21:14:12 -07:00
//! record_pattern := qualified_identifier "{" (record_pattern_entry, ",")* "}"
//! record_pattern_entry := IDENTIFIER | IDENTIFIER ":" Pattern
2019-09-03 21:14:12 -07:00
//! tuple_struct_pattern := qualified_identifier "(" (pattern, ",")* ")"
//! ```
2019-10-10 02:34:56 -07:00
//! ### If expressions
//!
//! TODO: it would be nice if the grammar could capture an incomplete precedence expr in the
//! discriminator
2019-06-09 01:08:32 -07:00
//!
//! ```text
//! if_expr := "if" discriminator if_expr_body
//! if_expr_body := ("then" simple_conditional | "is" simple_pattern_match | cond_block)
2019-10-10 02:34:56 -07:00
//! discriminator := ε | expression
//! simple_conditional := expr_or_block else_case
2019-10-10 02:34:56 -07:00
//! simple_pattern_match := pattern "then" simple_conditional
//! else_case := "else" expr_or_block
2019-10-10 02:34:56 -07:00
//!
//! cond_block := "{" (cond_arm comma_or_delimiter)* "}"
//! cond_arm := condition guard "then" expr_or_block | "else" expr_or_block
2019-10-10 02:34:56 -07:00
//! condition := "is" pattern | operator precedence_expr | expression
//! guard := "if" expression
//! comma_or_delimiter := "," | delimiter
//! ```
2019-06-09 01:08:32 -07:00
//!
2019-10-10 02:34:56 -07:00
//!
2019-06-09 01:08:32 -07:00
//! ### While expressions
//! ```text
//! while_expr := "while" while_cond "{" (statement delimiter)* "}"
//! while_cond := ε | expression | expression "is" pattern //TODO maybe is-expresions should be primary
//! ```
2019-06-09 01:08:32 -07:00
//!
//! //TODO this implies there must be at least one enumerator, which the parser doesn"t support right
//! //this second, and maybe should fail later anyway
2019-06-09 01:08:32 -07:00
//! ### For-expressions
//! ```text
//! for_expr := "for" (enumerator | "{" enumerators "}") for_expr_body
//! for_expr_body := "return" expression | "{" (statement delimiter)* "}"
//! enumerators := enumerator ("," enumerators)*
//! enumerator := identifier "<-" expression | identifier "=" expression //TODO add guards, etc.
//! ```
2019-09-20 18:19:29 -07:00
//! ## Imports
//! ```text
2019-09-21 02:30:28 -07:00
//! import := 'import' IDENTIFIER (:: IDENTIFIER)* import_suffix
//! import_suffix := ε | '::{' IDENTIFIER (, IDENTIFIER)* '}' | '*' //TODO add qualified, exclusions, etc.
2019-10-22 03:15:14 -07:00
//!
//! ## Modules
//!
//! module := 'module' IDENTIFIER '{' statement* '}'
2019-09-20 18:19:29 -07:00
//! ```
mod test;
2017-08-29 05:08:09 -07:00
use std::rc::Rc;
use std::str::FromStr;
2017-08-29 04:27:07 -07:00
2019-01-07 13:00:37 -08:00
use crate::tokenizing::*;
use crate::tokenizing::Kw::*;
use crate::tokenizing::TokenKind::*;
2017-09-06 09:42:29 -07:00
use crate::source_map::{SourceMap, Location};
2019-01-07 13:00:37 -08:00
use crate::ast::*;
2018-06-04 19:25:40 -07:00
/// Represents a parsing error
#[derive(Debug)]
2017-09-11 02:07:17 -07:00
pub struct ParseError {
pub production_name: Option<String>,
2017-09-11 02:07:17 -07:00
pub msg: String,
2019-01-08 01:04:46 -08:00
pub token: Token
2017-09-11 02:07:17 -07:00
}
impl ParseError {
fn new_with_token<T, M>(msg: M, token: Token) -> ParseResult<T> where M: Into<String> {
Err(ParseError { msg: msg.into(), token, production_name: None })
}
2017-09-11 02:07:17 -07:00
}
/// Represents either a successful parsing result or a ParseError
2017-09-11 02:07:17 -07:00
pub type ParseResult<T> = Result<T, ParseError>;
#[derive(Debug)]
2017-09-17 05:06:58 -07:00
pub struct ParseRecord {
production_name: String,
next_token: String,
2018-02-10 15:10:06 -08:00
level: u32,
2017-09-17 05:06:58 -07:00
}
/// Main data structure for doing parsing.
2019-10-23 09:53:18 -07:00
pub struct Parser<'a> {
token_handler: TokenHandler,
parse_record: Vec<ParseRecord>,
parse_level: u32,
restrictions: ParserRestrictions,
2019-09-18 09:56:11 -07:00
id_store: ItemIdStore,
2019-10-23 09:53:18 -07:00
source_map: &'a mut SourceMap,
2019-10-22 19:07:42 -07:00
}
struct ParserRestrictions {
no_struct_literal: bool
2017-09-09 01:25:11 -07:00
}
struct TokenHandler {
tokens: Vec<Token>,
idx: usize,
end_of_file: Location
}
impl TokenHandler {
fn new(tokens: Vec<Token>) -> TokenHandler {
let end_of_file = match tokens.last() {
None => Location { line_num: 0, char_num : 0 },
Some(t) => t.location,
};
TokenHandler { idx: 0, tokens, end_of_file }
}
fn peek_kind(&mut self) -> TokenKind {
self.peek().kind
}
2019-06-14 01:30:53 -07:00
fn peek_kind_n(&mut self, n: usize) -> TokenKind {
self.peek_n(n).kind
}
fn peek(&mut self) -> Token {
self.tokens.get(self.idx).map(|t: &Token| { t.clone()}).unwrap_or(Token { kind: TokenKind::EOF, location: self.end_of_file })
}
2019-08-31 23:39:01 -07:00
/// calling peek_n(0) is the same thing as peek()
2019-06-14 01:30:53 -07:00
fn peek_n(&mut self, n: usize) -> Token {
self.tokens.get(self.idx + n).map(|t: &Token| { t.clone()}).unwrap_or(Token { kind: TokenKind::EOF, location: self.end_of_file })
2019-06-14 01:30:53 -07:00
}
2019-01-05 17:50:54 -08:00
fn next(&mut self) -> Token {
self.idx += 1;
self.tokens.get(self.idx - 1).map(|t: &Token| { t.clone() }).unwrap_or(Token { kind: TokenKind::EOF, location: self.end_of_file })
}
}
2019-10-23 09:53:18 -07:00
impl<'a> Parser<'a> {
/// Create a new parser initialized with some tokens.
pub fn new(initial_input: Vec<Token>, source_map: &mut SourceMap) -> Parser {
Parser {
token_handler: TokenHandler::new(initial_input),
parse_record: vec![],
parse_level: 0,
2019-09-18 09:56:11 -07:00
restrictions: ParserRestrictions { no_struct_literal: false },
id_store: ItemIdStore::new(),
source_map,
}
2017-09-09 01:25:11 -07:00
}
/// Parse all loaded tokens up to this point.
pub fn parse(&mut self) -> ParseResult<AST> {
self.program()
}
/*
pub fn parse_with_new_tokens(&mut self, new_tokens: Vec<Token>) -> ParseResult<AST> {
}
*/
2019-08-12 09:32:04 -07:00
pub fn format_parse_trace(&self) -> String {
let mut buf = String::new();
buf.push_str("Parse productions:\n");
2019-10-22 02:11:49 -07:00
let mut next_token = None;
2019-08-12 09:32:04 -07:00
for r in self.parse_record.iter() {
2018-10-20 14:27:00 -07:00
let mut indent = String::new();
for _ in 0..r.level {
indent.push('.');
2018-10-20 14:27:00 -07:00
}
2019-10-22 02:11:49 -07:00
let effective_token = if next_token == Some(&r.next_token) {
"".to_string()
} else {
next_token = Some(&r.next_token);
format!(", next token: {}", r.next_token)
};
buf.push_str(&format!("{}`{}`{}\n", indent, r.production_name, effective_token));
2019-08-12 09:32:04 -07:00
}
buf
2018-10-20 14:27:00 -07:00
}
2017-09-08 16:42:42 -07:00
}
macro_rules! print_token_pattern {
($tokenpattern:pat) => { stringify!($tokenpattern) }
}
2017-09-11 02:07:17 -07:00
macro_rules! expect {
2019-01-05 17:40:05 -08:00
($self:expr, $token_kind:pat) => { expect!($self, $token_kind if true) };
($self:expr, $expected_kind:pat if $cond:expr) => {
{
let tok = $self.token_handler.peek();
2019-01-05 17:40:05 -08:00
match tok.get_kind() {
2019-01-05 18:29:24 -08:00
$expected_kind if $cond => $self.token_handler.next(),
2019-01-05 17:40:05 -08:00
actual_kind => {
let msg = format!("Expected {}, got {:?}", print_token_pattern!($expected_kind), actual_kind);
return ParseError::new_with_token(msg, tok);
2019-01-05 17:40:05 -08:00
}
2017-09-30 14:41:37 -07:00
}
2017-09-13 22:40:05 -07:00
}
2017-09-11 02:07:17 -07:00
}
2017-09-09 00:31:15 -07:00
}
2017-09-28 23:55:10 -07:00
macro_rules! delimited {
2018-05-13 02:50:43 -07:00
($self:expr, $start:pat, $parse_fn:ident, $( $delim:pat )|+, $end:pat, nonstrict) => {
delimited!($self, $start, $parse_fn, $( $delim )|*, $end, false)
};
2018-05-13 02:50:43 -07:00
($self:expr, $start:pat, $parse_fn:ident, $( $delim:pat )|+, $end:pat) => {
delimited!($self, $start, $parse_fn, $( $delim )|*, $end, true)
};
2018-05-13 02:50:43 -07:00
($self:expr, $start:pat, $parse_fn:ident, $( $delim:pat )|+, $end:pat, $strictness:expr) => {
2017-09-28 23:55:10 -07:00
{
expect!($self, $start);
let mut acc = vec![];
loop {
let peek = $self.token_handler.peek();
match peek.get_kind() {
2017-09-30 13:46:50 -07:00
$end | EOF => break,
_ => (),
}
if !$strictness {
match peek.get_kind() {
2019-01-05 18:29:24 -08:00
$( $delim )|* => { $self.token_handler.next(); continue },
2017-09-30 13:46:50 -07:00
_ => ()
}
}
acc.push($self.$parse_fn()?);
match $self.token_handler.peek().get_kind() {
2019-01-05 18:29:24 -08:00
$( $delim )|* => { $self.token_handler.next(); continue },
_ if $strictness => break,
_ => continue,
};
}
expect!($self, $end);
acc
2017-09-28 23:55:10 -07:00
}
};
2017-09-28 23:55:10 -07:00
}
2018-07-14 00:47:16 -07:00
2019-10-23 09:53:18 -07:00
impl<'a> Parser<'a> {
/// `program := (statement delimiter)* EOF`
/// `delimiter := NEWLINE | ';'`
#[recursive_descent_method]
fn program(&mut self) -> ParseResult<AST> {
let mut statements = Vec::new();
loop {
match self.token_handler.peek().get_kind() {
EOF => break,
Newline | Semicolon => {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
continue;
},
2019-01-04 22:58:25 -08:00
_ => statements.push(
self.statement()?
2019-01-04 22:58:25 -08:00
),
}
}
2019-09-18 09:56:11 -07:00
Ok(AST { id: self.id_store.fresh(), statements })
}
2017-09-11 02:07:17 -07:00
/// `statement := expression | declaration`
#[recursive_descent_method]
fn statement(&mut self) -> ParseResult<Statement> {
2017-09-11 02:07:17 -07:00
//TODO handle error recovery here
2019-10-23 02:37:42 -07:00
let tok = self.token_handler.peek();
let kind = match tok.get_kind() {
2019-09-17 02:25:11 -07:00
Keyword(Type) => self.type_declaration().map(|decl| { StatementKind::Declaration(decl) }),
Keyword(Func)=> self.func_declaration().map(|func| { StatementKind::Declaration(func) }),
Keyword(Let) => self.binding_declaration().map(|decl| StatementKind::Declaration(decl)),
Keyword(Interface) => self.interface_declaration().map(|decl| StatementKind::Declaration(decl)),
Keyword(Impl) => self.impl_declaration().map(|decl| StatementKind::Declaration(decl)),
2019-09-21 02:30:28 -07:00
Keyword(Import) => self.import_declaration().map(|spec| StatementKind::Import(spec)),
2019-10-22 03:15:14 -07:00
Keyword(Module) => self.module_declaration().map(|spec| StatementKind::Module(spec)),
2019-10-01 02:19:12 -07:00
_ => self.expression().map(|expr| { StatementKind::Expression(expr) } ),
2019-09-17 02:25:11 -07:00
}?;
2019-10-23 02:37:42 -07:00
let id = self.id_store.fresh();
self.source_map.add_location(&id, tok.location);
Ok(Statement { kind, id })
}
2017-09-11 02:07:17 -07:00
#[recursive_descent_method]
fn type_declaration(&mut self) -> ParseResult<Declaration> {
expect!(self, Keyword(Type));
2017-10-04 22:02:31 -07:00
self.type_declaration_body()
}
2017-10-04 22:02:31 -07:00
#[recursive_descent_method]
fn type_declaration_body(&mut self) -> ParseResult<Declaration> {
if let Keyword(Alias) = self.token_handler.peek_kind() {
2017-10-04 22:02:31 -07:00
self.type_alias()
} else {
let mutable = if let Keyword(Mut) = self.token_handler.peek_kind() {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
2018-07-12 02:07:52 -07:00
true
} else {
false
};
2018-02-12 00:51:53 -08:00
let name = self.type_singleton_name()?;
2019-06-16 16:07:27 -07:00
expect!(self, Equals);
2017-10-04 22:02:31 -07:00
let body = self.type_body()?;
2018-07-12 02:07:52 -07:00
Ok(Declaration::TypeDecl { name, body, mutable})
2017-10-04 22:02:31 -07:00
}
}
2017-10-04 22:02:31 -07:00
#[recursive_descent_method]
fn type_alias(&mut self) -> ParseResult<Declaration> {
expect!(self, Keyword(Alias));
2017-09-13 22:40:05 -07:00
let alias = self.identifier()?;
2019-06-16 16:07:27 -07:00
expect!(self, Equals);
2017-09-13 22:40:05 -07:00
let original = self.identifier()?;
2019-09-28 02:42:18 -07:00
Ok(Declaration::TypeAlias { alias, original })
}
2017-09-13 22:40:05 -07:00
#[recursive_descent_method]
fn type_body(&mut self) -> ParseResult<TypeBody> {
2017-10-08 18:47:57 -07:00
let mut variants = Vec::new();
variants.push(self.variant_specifier()?);
loop {
if let Pipe = self.token_handler.peek_kind() {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
2017-10-08 18:47:57 -07:00
variants.push(self.variant_specifier()?);
} else {
break;
}
}
Ok(TypeBody(variants))
}
2017-10-08 18:47:57 -07:00
#[recursive_descent_method]
fn variant_specifier(&mut self) -> ParseResult<Variant> {
2017-10-08 19:02:52 -07:00
use self::Variant::*;
let name = self.identifier()?;
match self.token_handler.peek_kind() {
2017-10-08 19:02:52 -07:00
LParen => {
2018-05-13 02:50:43 -07:00
let tuple_members = delimited!(self, LParen, type_name, Comma, RParen);
2017-10-08 19:02:52 -07:00
Ok(TupleStruct(name, tuple_members))
},
LCurlyBrace => {
2018-05-13 02:50:43 -07:00
let typed_identifier_list = delimited!(self, LCurlyBrace, typed_identifier, Comma, RCurlyBrace);
2019-01-24 20:47:20 -08:00
Ok(Record {name, members: typed_identifier_list })
2017-10-08 19:02:52 -07:00
},
_ => Ok(UnitStruct(name))
2017-10-08 19:02:52 -07:00
}
}
2017-10-08 19:02:52 -07:00
#[recursive_descent_method]
fn typed_identifier(&mut self) -> ParseResult<(Rc<String>, TypeIdentifier)> {
2017-10-08 19:02:52 -07:00
let identifier = self.identifier()?;
expect!(self, Colon);
2017-10-08 19:02:52 -07:00
let type_name = self.type_name()?;
Ok((identifier, type_name))
}
2017-09-11 02:07:17 -07:00
#[recursive_descent_method]
fn func_declaration(&mut self) -> ParseResult<Declaration> {
let signature = self.func_signature()?;
if let LCurlyBrace = self.token_handler.peek_kind() {
2018-11-05 18:50:45 -08:00
let statements = self.nonempty_func_body()?;
Ok(Declaration::FuncDecl(signature, statements))
} else {
Ok(Declaration::FuncSig(signature))
}
}
#[recursive_descent_method]
fn func_signature(&mut self) -> ParseResult<Signature> {
expect!(self, Keyword(Func));
let (name, operator) = match self.token_handler.peek_kind() {
Operator(s) => {
let name = s.clone();
2019-01-05 18:29:24 -08:00
self.token_handler.next();
(name, true)
},
_ => (self.identifier()?, false)
};
2018-11-05 18:50:45 -08:00
let params = self.formal_param_list()?;
let type_anno = match self.token_handler.peek_kind() {
Colon => Some(self.type_anno()?),
_ => None,
};
Ok(Signature { name, operator, params, type_anno })
}
2017-09-11 20:37:19 -07:00
2018-11-05 18:50:45 -08:00
#[recursive_descent_method]
fn nonempty_func_body(&mut self) -> ParseResult<Vec<Statement>> {
2019-01-04 22:58:25 -08:00
let statements = delimited!(self, LCurlyBrace, statement, Newline | Semicolon, RCurlyBrace, nonstrict);
Ok(statements)
2018-11-05 18:50:45 -08:00
}
#[recursive_descent_method]
fn formal_param_list(&mut self) -> ParseResult<Vec<FormalParam>> {
Ok(delimited!(self, LParen, formal_param, Comma, RParen))
}
#[recursive_descent_method]
fn formal_param(&mut self) -> ParseResult<FormalParam> {
2017-10-08 20:55:05 -07:00
let name = self.identifier()?;
2019-06-16 14:56:52 -07:00
let anno = match self.token_handler.peek_kind() {
2017-10-08 20:55:05 -07:00
Colon => Some(self.type_anno()?),
_ => None
};
2019-06-16 16:07:27 -07:00
let default = match self.token_handler.peek_kind() {
2019-06-16 21:36:59 -07:00
Equals => {
self.token_handler.next();
2019-10-01 02:19:12 -07:00
Some(self.expression()?)
2019-06-16 21:36:59 -07:00
},
2019-06-16 16:07:27 -07:00
_ => None
};
2019-06-16 14:56:52 -07:00
Ok(FormalParam { name, anno, default })
}
2018-07-11 16:44:15 -07:00
#[recursive_descent_method]
fn binding_declaration(&mut self) -> ParseResult<Declaration> {
2018-07-11 16:44:15 -07:00
expect!(self, Keyword(Kw::Let));
let constant = match self.token_handler.peek_kind() {
2018-07-11 16:44:15 -07:00
Keyword(Kw::Mut) => {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
2018-07-11 16:44:15 -07:00
false
}
_ => true
2017-09-17 06:04:24 -07:00
};
let name = self.identifier()?;
let type_anno = if let Colon = self.token_handler.peek_kind() {
Some(self.type_anno()?)
} else {
None
};
2019-06-16 16:07:27 -07:00
expect!(self, Equals);
2019-10-01 02:19:12 -07:00
let expr = self.expression()?;
2017-09-17 06:04:24 -07:00
Ok(Declaration::Binding { name, constant, type_anno, expr })
}
2017-09-17 06:04:24 -07:00
#[recursive_descent_method]
fn interface_declaration(&mut self) -> ParseResult<Declaration> {
expect!(self, Keyword(Interface));
2018-02-21 22:06:56 -08:00
let name = self.identifier()?;
let signatures = self.signature_block()?;
2018-04-24 16:30:17 -07:00
Ok(Declaration::Interface { name, signatures })
}
2018-02-21 22:06:56 -08:00
#[recursive_descent_method]
fn signature_block(&mut self) -> ParseResult<Vec<Signature>> {
Ok(delimited!(self, LCurlyBrace, func_signature, Newline | Semicolon, RCurlyBrace, nonstrict))
}
2017-10-03 03:49:07 -07:00
#[recursive_descent_method]
fn impl_declaration(&mut self) -> ParseResult<Declaration> {
expect!(self, Keyword(Impl));
let first = self.type_singleton_name()?;
let second = if let Keyword(For) = self.token_handler.peek_kind() {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
2017-10-08 19:30:52 -07:00
Some(self.type_name()?)
2017-10-03 03:49:07 -07:00
} else {
None
};
2017-10-08 14:24:02 -07:00
let block = self.decl_block()?;
Ok(match (first, second) {
(interface_name, Some(type_name)) =>
Declaration::Impl { type_name, interface_name: Some(interface_name), block },
(type_singleton_name, None) =>
Declaration::Impl { type_name: TypeIdentifier::Singleton(type_singleton_name), interface_name: None, block }
})
}
2017-10-08 14:24:02 -07:00
#[recursive_descent_method]
fn decl_block(&mut self) -> ParseResult<Vec<Declaration>> {
2018-05-13 02:50:43 -07:00
Ok(delimited!(self, LCurlyBrace, func_declaration, Newline | Semicolon, RCurlyBrace, nonstrict))
}
2017-10-03 03:49:07 -07:00
#[recursive_descent_method]
fn expression(&mut self) -> ParseResult<Expression> {
let mut expr_body = self.precedence_expr(BinOp::min_precedence())?;
let type_anno = match self.token_handler.peek_kind() {
2017-09-28 23:55:10 -07:00
Colon => Some(self.type_anno()?),
_ => None
};
if let Some(_) = expr_body.type_anno {
return ParseError::new_with_token("Bad parse state encountered", self.token_handler.peek());
2017-09-27 22:27:50 -07:00
}
expr_body.type_anno = type_anno;
2017-09-27 22:27:50 -07:00
Ok(expr_body)
}
#[recursive_descent_method]
fn type_anno(&mut self) -> ParseResult<TypeIdentifier> {
expect!(self, Colon);
self.type_name()
}
#[recursive_descent_method]
fn type_name(&mut self) -> ParseResult<TypeIdentifier> {
2018-10-18 13:27:09 -07:00
use self::TypeIdentifier::*;
Ok(match self.token_handler.peek_kind() {
2018-05-13 02:50:43 -07:00
LParen => Tuple(delimited!(self, LParen, type_name, Comma, RParen)),
2018-02-12 00:51:53 -08:00
_ => Singleton(self.type_singleton_name()?),
})
}
2018-02-12 00:51:53 -08:00
#[recursive_descent_method]
fn type_singleton_name(&mut self) -> ParseResult<TypeSingletonName> {
2018-02-12 00:51:53 -08:00
Ok(TypeSingletonName {
name: self.identifier()?,
params: match self.token_handler.peek_kind() {
2018-05-13 02:50:43 -07:00
LAngleBracket => delimited!(self, LAngleBracket, type_name, Comma, RAngleBracket),
2018-02-12 00:51:53 -08:00
_ => vec![],
}
2017-09-28 23:55:10 -07:00
})
}
// 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> {
2017-09-17 05:06:58 -07:00
let record = ParseRecord {
production_name: "precedence_expr".to_string(),
next_token: format!("{}", self.token_handler.peek().to_string_with_metadata()),
2018-02-10 15:10:06 -08:00
level: self.parse_level,
2017-09-17 05:06:58 -07:00
};
2018-02-10 17:45:00 -08:00
self.parse_level += 1;
2017-09-17 05:06:58 -07:00
self.parse_record.push(record);
2017-09-17 17:44:06 -07:00
let mut lhs = self.prefix_expr()?;
loop {
let new_precedence = match BinOp::get_precedence_from_token(&self.token_handler.peek_kind()) {
2018-08-19 20:33:50 -07:00
Some(p) => p,
None => break,
};
2017-09-17 05:12:20 -07:00
if precedence >= new_precedence {
break;
}
2019-01-05 18:29:24 -08:00
let next_tok = self.token_handler.next();
2019-01-05 17:50:54 -08:00
let operation = match BinOp::from_sigil_token(&next_tok.kind) {
2018-08-19 20:33:50 -07:00
Some(sigil) => sigil,
//TODO I think I can fix this unreachable
2018-08-19 20:33:50 -07:00
None => unreachable!()
};
let rhs = self.precedence_expr(new_precedence)?;
2019-10-01 02:19:12 -07:00
lhs = Expression::new(self.id_store.fresh(), ExpressionKind::BinExp(operation, bx!(lhs), bx!(rhs)));
}
2018-02-10 17:45:00 -08:00
self.parse_level -= 1;
2017-09-12 02:30:27 -07:00
Ok(lhs)
2017-09-11 02:07:17 -07:00
}
#[recursive_descent_method]
fn prefix_expr(&mut self) -> ParseResult<Expression> {
match self.token_handler.peek_kind() {
Operator(ref op) if PrefixOp::is_prefix(&*op) => {
2019-01-05 18:29:24 -08:00
let sigil = match self.token_handler.next().kind {
2017-09-17 17:44:06 -07:00
Operator(op) => op,
_ => unreachable!(),
};
let expr = self.primary()?;
let prefix_op = PrefixOp::from_str(sigil.as_str()).unwrap();
Ok(Expression::new(
2019-09-18 14:15:05 -07:00
self.id_store.fresh(),
2019-10-01 02:19:12 -07:00
ExpressionKind::PrefixExp(prefix_op, bx!(expr))
2019-01-05 16:02:30 -08:00
))
2017-09-17 17:44:06 -07:00
},
_ => self.call_expr()
2017-09-17 17:44:06 -07:00
}
}
2017-09-17 17:44:06 -07:00
#[recursive_descent_method]
fn call_expr(&mut self) -> ParseResult<Expression> {
2018-11-06 02:40:10 -08:00
let mut expr = self.index_expr()?;
while let LParen = self.token_handler.peek_kind() {
2019-06-12 03:28:46 -07:00
let arguments = delimited!(self, LParen, invocation_argument, Comma, RParen);
2019-10-01 02:19:12 -07:00
expr = Expression::new(self.id_store.fresh(), ExpressionKind::Call { f: bx!(expr), arguments }); //TODO no type anno is incorrect
2018-11-06 02:40:10 -08:00
}
Ok(expr)
}
2018-03-06 02:51:45 -08:00
#[recursive_descent_method]
2019-06-12 03:28:46 -07:00
fn invocation_argument(&mut self) -> ParseResult<InvocationArgument> {
Ok(match self.token_handler.peek_kind() {
Underscore => {
self.token_handler.next();
InvocationArgument::Ignored
},
Identifier(s) => {
match self.token_handler.peek_kind_n(1) {
2019-06-16 16:07:27 -07:00
Equals => {
self.token_handler.next();
2019-06-12 03:28:46 -07:00
self.token_handler.next();
2019-10-01 02:19:12 -07:00
let expr = self.expression()?;
2019-06-12 03:28:46 -07:00
InvocationArgument::Keyword { name: s.clone(), expr }
},
_ => {
let expr = self.expression()?;
2019-10-01 02:19:12 -07:00
InvocationArgument::Positional(expr)
2019-06-12 03:28:46 -07:00
}
}
},
2019-10-01 02:19:12 -07:00
_ => InvocationArgument::Positional(self.expression()?)
2019-06-12 03:28:46 -07:00
})
}
#[recursive_descent_method]
fn index_expr(&mut self) -> ParseResult<Expression> {
2018-03-06 02:51:45 -08:00
let primary = self.primary()?;
Ok(if let LSquareBracket = self.token_handler.peek_kind() {
2019-10-01 02:19:12 -07:00
let indexers = delimited!(self, LSquareBracket, expression, Comma, RSquareBracket);
2019-09-18 14:15:05 -07:00
Expression::new(self.id_store.fresh(), ExpressionKind::Index {
2019-10-01 02:19:12 -07:00
indexee: bx!(Expression::new(self.id_store.fresh(), primary.kind)),
2018-03-06 02:51:45 -08:00
indexers,
})
} else {
primary
})
}
#[recursive_descent_method]
fn primary(&mut self) -> ParseResult<Expression> {
match self.token_handler.peek_kind() {
2018-03-04 02:11:22 -08:00
LCurlyBrace => self.curly_brace_expr(),
2018-11-05 18:50:45 -08:00
Backslash => self.lambda_expr(),
2017-09-13 03:46:16 -07:00
LParen => self.paren_expr(),
2018-03-08 12:01:24 -08:00
LSquareBracket => self.list_expr(),
2017-09-18 23:22:28 -07:00
Keyword(Kw::If) => self.if_expr(),
2017-10-08 22:02:58 -07:00
Keyword(Kw::For) => self.for_expr(),
Keyword(Kw::While) => self.while_expr(),
Identifier(_) => self.identifier_expr(),
2017-09-13 03:46:16 -07:00
_ => self.literal(),
}
}
2017-09-13 03:46:16 -07:00
#[recursive_descent_method]
fn list_expr(&mut self) -> ParseResult<Expression> {
2019-10-01 02:19:12 -07:00
let exprs = delimited!(self, LSquareBracket, expression, Comma, RSquareBracket);
2019-09-18 14:15:05 -07:00
Ok(Expression::new(self.id_store.fresh(), ExpressionKind::ListLiteral(exprs)))
}
2018-03-08 12:01:24 -08:00
#[recursive_descent_method]
fn curly_brace_expr(&mut self) -> ParseResult<Expression> {
ParseError::new_with_token("Not implemented", self.token_handler.peek())
}
2018-03-04 02:11:22 -08:00
#[recursive_descent_method]
fn lambda_expr(&mut self) -> ParseResult<Expression> {
2018-11-05 18:50:45 -08:00
expect!(self, Backslash);
let params = self.lambda_param_list()?;
let type_anno = match self.token_handler.peek_kind() {
2018-11-05 19:10:34 -08:00
Colon => Some(self.type_anno()?),
_ => None,
};
2018-11-05 18:50:45 -08:00
let body = self.nonempty_func_body()?;
2019-09-18 14:15:05 -07:00
Ok(Expression::new(self.id_store.fresh(), ExpressionKind::Lambda { params, type_anno, body })) //TODO need to handle types somehow
}
2018-03-04 02:11:22 -08:00
#[recursive_descent_method]
fn lambda_param_list(&mut self) -> ParseResult<Vec<FormalParam>> {
if let LParen = self.token_handler.peek_kind() {
self.formal_param_list()
} else {
let single_param = self.formal_param()?;
Ok(vec![single_param])
}
}
#[recursive_descent_method]
fn paren_expr(&mut self) -> ParseResult<Expression> {
use self::ExpressionKind::*;
let old_struct_value = self.restrictions.no_struct_literal;
self.restrictions.no_struct_literal = false;
2018-05-13 01:43:29 -07:00
let output = {
2018-05-13 02:50:43 -07:00
let mut inner = delimited!(self, LParen, expression, Comma, RParen);
match inner.len() {
2019-09-18 14:15:05 -07:00
0 => Ok(Expression::new(self.id_store.fresh(), TupleLiteral(vec![]))),
1 => Ok(inner.pop().unwrap()),
2019-10-01 02:19:12 -07:00
_ => Ok(Expression::new(self.id_store.fresh(), TupleLiteral(inner)))
}
2018-05-13 01:43:29 -07:00
};
self.restrictions.no_struct_literal = old_struct_value;
output
}
2017-09-11 15:42:49 -07:00
#[recursive_descent_method]
fn identifier_expr(&mut self) -> ParseResult<Expression> {
use self::ExpressionKind::*;
2019-09-21 02:30:28 -07:00
let components = self.qualified_identifier()?;
let qualified_identifier = QualifiedName { id: self.id_store.fresh(), components };
Ok(match self.token_handler.peek_kind() {
LCurlyBrace if !self.restrictions.no_struct_literal => {
2017-10-14 13:54:17 -07:00
let fields = self.record_block()?;
Expression::new(self.id_store.fresh(), NamedStruct { name: qualified_identifier, fields })
},
2019-09-20 01:57:48 -07:00
_ => Expression::new(self.id_store.fresh(), Value(qualified_identifier))
2017-10-08 22:52:05 -07:00
})
}
2019-08-31 23:39:01 -07:00
#[recursive_descent_method]
2019-09-21 02:30:28 -07:00
fn qualified_identifier(&mut self) -> ParseResult<Vec<Rc<String>>> {
2019-09-19 01:34:21 -07:00
let mut components = vec![self.identifier()?];
2019-08-31 23:39:01 -07:00
loop {
match (self.token_handler.peek_kind(), self.token_handler.peek_kind_n(1)) {
(Colon, Colon) => {
self.token_handler.next(); self.token_handler.next();
2019-09-19 01:34:21 -07:00
components.push(self.identifier()?);
2019-08-31 23:39:01 -07:00
},
_ => break,
}
}
2019-09-21 02:30:28 -07:00
Ok(components)
2019-08-31 23:39:01 -07:00
}
#[recursive_descent_method]
fn record_block(&mut self) -> ParseResult<Vec<(Rc<String>, Expression)>> {
2019-10-01 02:19:12 -07:00
Ok(delimited!(self, LCurlyBrace, record_entry, Comma, RCurlyBrace))
}
2017-10-14 13:54:17 -07:00
#[recursive_descent_method]
fn record_entry(&mut self) -> ParseResult<(Rc<String>, Expression)> {
2017-10-14 13:54:17 -07:00
let field_name = self.identifier()?;
expect!(self, Colon);
2017-10-14 13:54:17 -07:00
let value = self.expression()?;
Ok((field_name, value))
}
2017-10-14 13:54:17 -07:00
#[recursive_descent_method]
fn if_expr(&mut self) -> ParseResult<Expression> {
expect!(self, Keyword(Kw::If));
2019-10-11 09:11:14 -07:00
let old_struct_value = self.restrictions.no_struct_literal;
self.restrictions.no_struct_literal = true;
let discriminator = if let LCurlyBrace = self.token_handler.peek_kind() {
None
2019-10-10 17:50:20 -07:00
} else {
Some(Box::new(self.expression()?))
};
2019-10-10 10:34:54 -07:00
let body = Box::new(self.if_expr_body()?);
2019-10-11 09:11:14 -07:00
self.restrictions.no_struct_literal = old_struct_value;
2019-09-18 14:15:05 -07:00
Ok(Expression::new(self.id_store.fresh(), ExpressionKind::IfExpression { discriminator, body }))
}
#[recursive_descent_method]
fn if_expr_body(&mut self) -> ParseResult<IfExpressionBody> {
match self.token_handler.peek_kind() {
Keyword(Kw::Then) => self.simple_conditional(),
Keyword(Kw::Is) => self.simple_pattern_match(),
_ => self.cond_block(),
}
}
#[recursive_descent_method]
fn simple_conditional(&mut self) -> ParseResult<IfExpressionBody> {
expect!(self, Keyword(Kw::Then));
let then_case = self.expr_or_block()?;
let else_case = self.else_case()?;
Ok(IfExpressionBody::SimpleConditional {then_case, else_case })
}
#[recursive_descent_method]
fn simple_pattern_match(&mut self) -> ParseResult<IfExpressionBody> {
2018-06-20 02:07:11 -07:00
expect!(self, Keyword(Kw::Is));
let pattern = self.pattern()?;
2018-06-20 02:07:11 -07:00
expect!(self, Keyword(Kw::Then));
let then_case = self.expr_or_block()?;
let else_case = self.else_case()?;
Ok(IfExpressionBody::SimplePatternMatch { pattern, then_case, else_case })
}
2018-06-20 02:07:11 -07:00
#[recursive_descent_method]
fn else_case(&mut self) -> ParseResult<Option<Block>> {
Ok(if let Keyword(Kw::Else) = self.token_handler.peek_kind() {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
2018-08-19 15:58:31 -07:00
Some(self.expr_or_block()?)
2017-09-18 23:22:28 -07:00
} else {
None
})
}
2017-09-18 23:22:28 -07:00
#[recursive_descent_method]
fn cond_block(&mut self) -> ParseResult<IfExpressionBody> {
expect!(self, LCurlyBrace);
let mut cond_arms = vec![];
loop {
match self.token_handler.peek_kind() {
RCurlyBrace | EOF => break,
2019-01-05 18:29:24 -08:00
Semicolon | Newline => { self.token_handler.next(); continue},
_ => {
cond_arms.push(self.cond_arm()?);
match self.token_handler.peek_kind() {
Comma | Semicolon | Newline => { self.token_handler.next(); continue; },
_ => break,
}
}
}
}
expect!(self, RCurlyBrace);
Ok(IfExpressionBody::CondList(cond_arms))
}
2018-07-13 20:18:57 -07:00
#[recursive_descent_method]
2019-10-10 10:34:54 -07:00
fn cond_arm(&mut self) -> ParseResult<ConditionArm> {
let (condition, guard) = if let Keyword(Kw::Else) = self.token_handler.peek_kind() {
self.token_handler.next();
2019-10-10 10:34:54 -07:00
(Condition::Else, None)
} else {
let condition = self.condition()?;
let guard = self.guard()?;
expect!(self, Keyword(Kw::Then));
(condition, guard)
};
let body = self.expr_or_block()?;
Ok(ConditionArm { condition, guard, body })
}
2018-07-13 21:50:38 -07:00
#[recursive_descent_method]
fn condition(&mut self) -> ParseResult<Condition> {
Ok(match self.token_handler.peek_kind() {
Keyword(Kw::Is) => {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
Condition::Pattern(self.pattern()?)
},
2019-10-10 17:50:20 -07:00
ref tok if BinOp::from_sigil_token(tok).is_some() => {
2019-10-10 10:34:54 -07:00
let op = BinOp::from_sigil_token(&self.token_handler.next().kind).unwrap();
let expr = self.expression()?;
Condition::TruncatedOp(op, expr)
2018-08-22 16:41:31 -07:00
},
2018-10-20 00:55:37 -07:00
_ => {
Condition::Expression(self.expression()?)
},
})
}
#[recursive_descent_method]
fn guard(&mut self) -> ParseResult<Option<Expression>> {
Ok(match self.token_handler.peek_kind() {
Keyword(Kw::If) => {
self.token_handler.next();
Some(self.expression()?)
},
_ => None
})
}
2018-07-13 20:18:57 -07:00
#[recursive_descent_method]
fn pattern(&mut self) -> ParseResult<Pattern> {
if let LParen = self.token_handler.peek_kind() {
2018-07-01 01:26:19 -07:00
let tuple_pattern_variants = delimited!(self, LParen, pattern, Comma, RParen);
Ok(Pattern::TuplePattern(tuple_pattern_variants))
} else {
self.simple_pattern()
}
}
2018-07-01 01:26:19 -07:00
2019-09-03 21:14:12 -07:00
#[recursive_descent_method]
fn simple_pattern(&mut self) -> ParseResult<Pattern> {
2019-09-06 02:23:04 -07:00
Ok(match self.token_handler.peek_kind() {
2019-09-03 21:14:12 -07:00
Identifier(_) => {
2019-09-21 02:30:28 -07:00
let components = self.qualified_identifier()?;
let qualified_identifier = QualifiedName { id: self.id_store.fresh(), components };
2019-09-03 21:14:12 -07:00
match self.token_handler.peek_kind() {
LCurlyBrace => {
let members = delimited!(self, LCurlyBrace, record_pattern_entry, Comma, RCurlyBrace);
2019-09-21 02:30:28 -07:00
Pattern::Record(qualified_identifier, members)
2019-09-03 21:14:12 -07:00
},
LParen => {
let members = delimited!(self, LParen, pattern, Comma, RParen);
2019-09-21 02:30:28 -07:00
Pattern::TupleStruct(qualified_identifier, members)
2019-09-03 21:14:12 -07:00
},
_ => {
2019-09-21 02:30:28 -07:00
Pattern::VarOrName(qualified_identifier)
2019-09-03 21:14:12 -07:00
},
}
},
2019-09-06 02:23:04 -07:00
_ => self.pattern_literal()?
})
2019-09-03 21:14:12 -07:00
}
#[recursive_descent_method]
fn pattern_literal(&mut self) -> ParseResult<Pattern> {
2019-09-06 02:23:04 -07:00
let tok = self.token_handler.peek();
2019-09-06 02:30:18 -07:00
Ok(match tok.get_kind() {
Keyword(Kw::True) => {
self.token_handler.next();
Pattern::Literal(PatternLiteral::BoolPattern(true))
},
Keyword(Kw::False) => {
self.token_handler.next();
Pattern::Literal(PatternLiteral::BoolPattern(false))
},
StrLiteral(s) => {
self.token_handler.next();
Pattern::Literal(PatternLiteral::StringPattern(s))
},
DigitGroup(_) | HexLiteral(_) | BinNumberSigil | Period => self.signed_number_literal()?,
Operator(ref op) if **op == "-" => self.signed_number_literal()?,
Underscore => {
self.token_handler.next();
Pattern::Ignored
},
other => return ParseError::new_with_token(format!("{:?} is not a valid Pattern", other), tok)
2019-09-06 02:23:04 -07:00
})
}
#[recursive_descent_method]
fn signed_number_literal(&mut self) -> ParseResult<Pattern> {
let neg = match self.token_handler.peek_kind() {
2018-08-21 19:57:45 -07:00
Operator(ref op) if **op == "-" => {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
2018-08-21 19:57:45 -07:00
true
},
_ => false
};
let Expression { kind, .. } = self.number_literal()?;
Ok(Pattern::Literal(PatternLiteral::NumPattern { neg, num: kind }))
}
2018-08-21 19:57:45 -07:00
#[recursive_descent_method]
fn record_pattern_entry(&mut self) -> ParseResult<(Rc<String>, Pattern)> {
2018-07-13 21:21:27 -07:00
let name = self.identifier()?;
Ok(match self.token_handler.peek_kind() {
2018-07-13 21:21:27 -07:00
Colon => {
expect!(self, Colon);
let pat = self.pattern()?;
(name, pat)
},
_ => (name.clone(), Pattern::Literal(PatternLiteral::StringPattern(name.clone())))
})
}
2018-07-13 03:19:02 -07:00
#[recursive_descent_method]
fn block(&mut self) -> ParseResult<Block> {
2019-01-04 22:58:25 -08:00
let block = delimited!(self, LCurlyBrace, statement, Newline | Semicolon, RCurlyBrace, nonstrict);
Ok(block)
}
2017-09-18 23:22:28 -07:00
#[recursive_descent_method]
fn expr_or_block(&mut self) -> ParseResult<Block> {
match self.token_handler.peek_kind() {
2018-08-19 15:58:31 -07:00
LCurlyBrace => self.block(),
_ => {
let expr = self.expression()?;
2019-10-01 02:19:12 -07:00
let s = Statement { id: self.id_store.fresh(), kind: StatementKind::Expression(expr) };
Ok(vec![s])
2018-08-19 15:58:31 -07:00
}
}
}
2018-08-19 15:58:31 -07:00
#[recursive_descent_method]
fn while_expr(&mut self) -> ParseResult<Expression> {
use self::ExpressionKind::*;
expect!(self, Keyword(Kw::While));
let condition = {
self.restrictions.no_struct_literal = true;
let x = self.while_cond();
self.restrictions.no_struct_literal = false;
2019-10-01 02:19:12 -07:00
x?.map(|expr| bx!(expr))
};
let body = self.block()?;
2019-09-18 14:15:05 -07:00
Ok(Expression::new(self.id_store.fresh(), WhileExpression {condition, body}))
}
#[recursive_descent_method]
fn while_cond(&mut self) -> ParseResult<Option<Expression>> {
Ok(match self.token_handler.peek_kind() {
LCurlyBrace => None,
_ => Some(self.expression()?),
})
}
#[recursive_descent_method]
fn for_expr(&mut self) -> ParseResult<Expression> {
expect!(self, Keyword(Kw::For));
let enumerators = if let LCurlyBrace = self.token_handler.peek_kind() {
2018-05-13 02:50:43 -07:00
delimited!(self, LCurlyBrace, enumerator, Comma | Newline, RCurlyBrace)
2018-05-13 01:40:14 -07:00
} else {
let single_enum = {
self.restrictions.no_struct_literal = true;
let s = self.enumerator();
self.restrictions.no_struct_literal = false;
s?
};
vec![single_enum]
};
let body = Box::new(self.for_expr_body()?);
2019-09-18 14:15:05 -07:00
Ok(Expression::new(self.id_store.fresh(), ExpressionKind::ForExpression { enumerators, body }))
}
2018-05-13 01:40:14 -07:00
#[recursive_descent_method]
fn enumerator(&mut self) -> ParseResult<Enumerator> {
2018-05-13 01:40:14 -07:00
let id = self.identifier()?;
expect!(self, Operator(ref c) if **c == "<-");
2019-10-01 02:19:12 -07:00
let generator = self.expression()?;
2018-05-13 01:40:14 -07:00
Ok(Enumerator { id, generator })
}
2018-05-13 01:40:14 -07:00
#[recursive_descent_method]
fn for_expr_body(&mut self) -> ParseResult<ForBody> {
2018-05-13 01:40:14 -07:00
use self::ForBody::*;
let tok = self.token_handler.peek();
2019-01-05 17:40:05 -08:00
Ok(match tok.get_kind() {
2018-05-13 01:40:14 -07:00
LCurlyBrace => {
2018-05-13 02:50:43 -07:00
let statements = delimited!(self, LCurlyBrace, statement, Newline | Semicolon, RCurlyBrace, nonstrict);
StatementBlock(statements)
2018-05-13 01:40:14 -07:00
},
Keyword(Kw::Return) => {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
2019-10-01 02:19:12 -07:00
MonadicReturn(self.expression()?)
2018-05-13 01:40:14 -07:00
},
2019-01-05 17:40:05 -08:00
_ => return ParseError::new_with_token("for expressions must end in a block or 'return'", tok),
2018-05-13 01:40:14 -07:00
})
}
2017-10-08 22:02:58 -07:00
#[recursive_descent_method]
fn identifier(&mut self) -> ParseResult<Rc<String>> {
2019-01-05 18:29:24 -08:00
let tok = self.token_handler.next();
2019-01-05 17:50:54 -08:00
match tok.get_kind() {
2017-09-11 15:42:49 -07:00
Identifier(s) => Ok(s),
p => ParseError::new_with_token(format!("Expected an identifier, got {:?}", p), tok),
2017-09-11 15:42:49 -07:00
}
}
2017-09-11 02:07:17 -07:00
#[recursive_descent_method]
fn literal(&mut self) -> ParseResult<Expression> {
use self::ExpressionKind::*;
let tok = self.token_handler.peek();
2019-01-05 17:28:35 -08:00
match tok.get_kind() {
2018-01-08 06:12:45 -08:00
DigitGroup(_) | HexLiteral(_) | BinNumberSigil | Period => self.number_literal(),
2017-09-27 22:27:50 -07:00
Keyword(Kw::True) => {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
2019-09-18 14:15:05 -07:00
let id = self.id_store.fresh();
Ok(Expression::new(id, BoolLiteral(true)))
2017-09-27 22:27:50 -07:00
},
Keyword(Kw::False) => {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
2019-09-18 14:15:05 -07:00
let id = self.id_store.fresh();
Ok(Expression::new(id, BoolLiteral(false)))
2017-09-27 22:27:50 -07:00
},
2017-09-16 15:57:48 -07:00
StrLiteral(s) => {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
2019-09-18 14:15:05 -07:00
let id = self.id_store.fresh();
Ok(Expression::new(id, StringLiteral(s.clone())))
2017-09-16 15:57:48 -07:00
}
e => ParseError::new_with_token(format!("Expected a literal expression, got {:?}", e), tok),
2017-09-11 02:07:17 -07:00
}
}
#[recursive_descent_method]
fn number_literal(&mut self) -> ParseResult<Expression> {
match self.token_handler.peek_kind() {
2018-01-08 06:12:45 -08:00
HexLiteral(_) | BinNumberSigil => self.int_literal(),
2017-09-11 02:07:17 -07:00
_ => self.float_literal(),
}
}
2017-09-11 02:07:17 -07:00
#[recursive_descent_method]
fn int_literal(&mut self) -> ParseResult<Expression> {
use self::ExpressionKind::*;
2019-01-05 18:29:24 -08:00
let tok = self.token_handler.next();
2019-01-05 17:50:54 -08:00
match tok.get_kind() {
2018-11-17 01:10:23 -08:00
BinNumberSigil => {
let digits = self.digits()?;
let n = parse_binary(digits, tok)?;
2019-09-18 14:15:05 -07:00
Ok(Expression::new(self.id_store.fresh(), NatLiteral(n)))
2018-11-17 01:10:23 -08:00
},
HexLiteral(text) => {
let digits: String = text.chars().filter(|c| c.is_digit(16)).collect();
let n = parse_hex(digits, tok)?;
2019-09-18 14:15:05 -07:00
Ok(Expression::new(self.id_store.fresh(), NatLiteral(n)))
2018-11-17 01:10:23 -08:00
},
2019-01-05 17:50:54 -08:00
_ => return ParseError::new_with_token("Expected '0x' or '0b'", tok),
2017-09-11 02:07:17 -07:00
}
}
2017-09-11 02:07:17 -07:00
#[recursive_descent_method]
fn float_literal(&mut self) -> ParseResult<Expression> {
use self::ExpressionKind::*;
let tok = self.token_handler.peek();
2017-09-11 02:38:27 -07:00
let mut digits = self.digits()?;
if let Period = self.token_handler.peek_kind() {
2019-01-05 18:29:24 -08:00
self.token_handler.next();
2017-09-11 02:38:27 -07:00
digits.push_str(".");
digits.push_str(&self.digits()?);
match digits.parse::<f64>() {
2019-09-18 14:15:05 -07:00
Ok(f) => Ok(Expression::new(self.id_store.fresh(), FloatLiteral(f))),
Err(e) => ParseError::new_with_token(format!("Float failed to parse with error: {}", e), tok),
2017-09-11 02:38:27 -07:00
}
} else {
match digits.parse::<u64>() {
2019-09-18 14:15:05 -07:00
Ok(d) => Ok(Expression::new(self.id_store.fresh(), NatLiteral(d))),
Err(e) => ParseError::new_with_token(format!("Integer failed to parse with error: {}", e), tok),
2017-09-11 02:38:27 -07:00
}
2017-09-11 02:07:17 -07:00
}
}
2017-09-11 02:07:17 -07:00
#[recursive_descent_method]
fn digits(&mut self) -> ParseResult<String> {
2017-09-11 02:07:17 -07:00
let mut ds = String::new();
loop {
match self.token_handler.peek_kind() {
2019-01-05 18:29:24 -08:00
Underscore => { self.token_handler.next(); continue; },
DigitGroup(ref s) => { self.token_handler.next(); ds.push_str(s)},
2017-09-11 02:07:48 -07:00
_ => break,
2017-09-11 02:07:17 -07:00
}
}
Ok(ds)
}
2019-09-21 02:30:28 -07:00
#[recursive_descent_method]
fn import_declaration(&mut self) -> ParseResult<ImportSpecifier> {
expect!(self, Keyword(Import));
let mut path_components = vec![];
path_components.push(self.identifier()?);
loop {
match (self.token_handler.peek_kind(), self.token_handler.peek_kind_n(1)) {
(Colon, Colon) => {
self.token_handler.next(); self.token_handler.next();
if let Identifier(_) = self.token_handler.peek_kind() {
path_components.push(self.identifier()?);
} else {
break;
}
},
_ => break,
}
}
let imported_names = match self.token_handler.peek_kind() {
LCurlyBrace => {
let names = delimited!(self, LCurlyBrace, identifier, Comma, RCurlyBrace);
ImportedNames::List(names)
},
Operator(ref s) if **s == "*" => {
self.token_handler.next();
ImportedNames::All
},
_ => ImportedNames::LastOfPath
};
Ok(ImportSpecifier {
id: self.id_store.fresh(),
path_components,
imported_names
})
}
#[recursive_descent_method]
fn import_suffix(&mut self) -> ParseResult<ImportedNames> {
Ok(match self.token_handler.peek_kind() {
Operator(ref s) if **s == "*" => {
self.token_handler.next();
ImportedNames::All
},
LCurlyBrace => {
let names = delimited!(self, LCurlyBrace, identifier, Comma, RCurlyBrace);
ImportedNames::List(names)
},
_ => return ParseError::new_with_token("Expected '{{' or '*'", self.token_handler.peek()),
})
}
2019-10-22 03:15:14 -07:00
#[recursive_descent_method]
fn module_declaration(&mut self) -> ParseResult<ModuleSpecifier> {
expect!(self, Keyword(Kw::Module));
let name = self.identifier()?;
let contents = delimited!(self, LCurlyBrace, statement, Newline | Semicolon, RCurlyBrace, nonstrict);
Ok(ModuleSpecifier { name, contents })
}
2017-09-11 02:07:17 -07:00
}
2017-09-09 00:31:15 -07:00
fn parse_binary(digits: String, tok: Token) -> ParseResult<u64> {
2017-09-11 23:27:15 -07:00
let mut result: u64 = 0;
let mut multiplier = 1;
for d in digits.chars().rev() {
match d {
'1' => result += multiplier,
'0' => (),
_ => return ParseError::new_with_token("Encountered a character not '1' or '0 while parsing a binary literal", tok),
2017-09-11 23:27:15 -07:00
}
multiplier = match multiplier.checked_mul(2) {
Some(m) => m,
None => return ParseError::new_with_token("This binary expression will overflow", tok)
}
2017-09-11 23:27:15 -07:00
}
Ok(result)
}
fn parse_hex(digits: String, tok: Token) -> ParseResult<u64> {
2018-01-08 05:57:36 -08:00
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_with_token("Encountered a non-hex digit in a hex literal", tok),
2018-01-08 05:57:36 -08:00
}
multiplier = match multiplier.checked_mul(16) {
Some(m) => m,
None => return ParseError::new_with_token("This hex expression will overflow", tok)
}
2018-01-08 05:57:36 -08:00
}
Ok(result)
}
2019-09-21 02:30:28 -07:00