schala/src/schala_lang/parsing.rs
2017-09-19 22:11:02 -07:00

114 lines
2.9 KiB
Rust

use language::{TokenError, ParseError};
use std::rc::Rc;
#[allow(dead_code)]
#[derive(Debug)]
pub enum TokenType {
Newline,
Semicolon,
LParen,
RParen,
LSquareBracket,
RSquareBracket,
LCurlyBrace,
RCurlyBrace,
Comma,
Period,
Colon,
Digit(u8),
StrLiteral(Rc<String>),
Identifier(Rc<String>),
Keyword(Kw),
Operator(Rc<String>),
}
#[derive(Debug)]
pub enum Kw {
If,
Else,
Func,
Loop,
}
#[derive(Debug)]
pub struct Token {
token_type: TokenType,
line_number: u32,
char_number: u32,
}
pub fn tokenize(_input: &str) -> Result<Vec<Token>, TokenError> {
Ok(vec!())
}
/*
Schala EBNF grammar
type alias <name> = <other type>
type <name> = struct { <field> : <type>,* }
type <name> = Variant1 | Variant2(type, type) | Variant3 struct { }
'' = literal, all other symbols are nonterminals
program := (statement delimiter ?)*
delimiter := 'Newline' | ';'
statement := declaration | expression
declaration := module | function | type_decl
type_decl := 'type' type_format
type_format := 'alias' '=' type | type_constructor
type_constructor := capital_ident '=' type_rhs
type_rhs := struct_decl | type_variant ('|' type_variant)*
struct_decl := 'struct' '{' (ident ':' type)* '}'
type_variant := capital_ident | tuple_type | capital_ident struct_decl
tuple_type := // something like Variant(a,b)
type := // something like Type[A[b]]
ascription := expression (':' type)+
function := 'fn' prototype '{' (statement)* '}'
prototype := identifier '(' identlist ')'
identlist := identifier (',' identifier)* | ε
declaration := FN prototype LCurlyBrace (statement)* RCurlyBrace
prototype := identifier LParen identlist RParen
identlist := Ident (Comma Ident)* | ε
exprlist := Expression (Comma Expression)* | ε
itemlist := Ident COLON Expression (Comma Ident COLON Expression)* | ε
expression := postop_expression (op postop_expression)*
postop_expression := primary_expression postop
primary_expression := number_expr | String | identifier_expr | paren_expr | conditional_expr | while_expr | lambda_expr | list_expr | struct_expr
number_expr := (PLUS | MINUS ) number_expr | Number
identifier_expr := call_expression | Variable
list_expr := LSquareBracket exprlist RSquareBracket
struct_expr := LCurlyBrace itemlist RCurlyBrace
call_expression := Identifier LParen exprlist RParen
while_expr := WHILE primary_expression LCurlyBrace (expression delimiter)* RCurlyBrace
paren_expr := LParen expression RParen
conditional_expr := IF expression LCurlyBrace (expression delimiter)* RCurlyBrace (LCurlyBrace (expresion delimiter)* RCurlyBrace)?
lambda_expr := FN LParen identlist RParen LCurlyBrace (expression delimiter)* RCurlyBrace
lambda_call := | LParen exprlist RParen
postop := ε | LParen exprlist RParen | LBracket expression RBracket
op := '+', '-', etc.
*/
#[allow(dead_code)]
#[derive(Debug)]
pub struct AST { }
#[allow(dead_code)]
pub fn parse(_input: Vec<Token>) -> Result<AST, ParseError> {
Ok(AST { })
}