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Change syntax for type alias

This commit is contained in:
greg 2017-10-04 22:02:31 -07:00
parent 50ceb92d6b
commit 184a2ae03a
1 changed files with 21 additions and 13 deletions
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34
src/schala_lang/parsing.rs
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@ -276,10 +276,11 @@ program := (statement delimiter)* EOF
delimiter := NEWLINE | ';'
statement := expression | declaration
declaration := type_alias | type_declaration | func_declaration | binding_declaration | impl_declaration
declaration := type_declaration | func_declaration | binding_declaration | impl_declaration
type_alias := 'alias' IDENTIFIER '=' IDENTIFIER
type_declaration := 'type' IDENTIFIER '=' type_body
type_declaration := 'type' type_declaration_body
type_declaration_body := 'alias' type_alias | IDENTIFIER '=' type_body
type_alias := IDENTIFIER '=' IDENTIFIER
type_body := variant_specifier ('|' variant_specifier)*
variant_specifier := '{' member_list '}'
member_list := (IDENTIFIER type_anno)*
@ -565,7 +566,6 @@ impl Parser {
parse_method!(statement(&mut self) -> ParseResult<Statement> {
//TODO handle error recovery here
match self.peek() {
Keyword(Alias) => self.type_alias().map(|alias| { Statement::Declaration(alias) }),
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)),
@ -575,6 +575,22 @@ impl Parser {
}
});
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()?;
@ -583,14 +599,6 @@ impl Parser {
Ok(Declaration::TypeAlias(alias, original))
});
parse_method!(type_declaration(&mut self) -> ParseResult<Declaration> {
expect!(self, Keyword(Type), "'type'");
let name = self.identifier()?;
expect!(self, Operator(ref c) if **c == "=", "'='");
let body = self.type_body()?;
Ok(Declaration::TypeDecl(name, body))
});
parse_method!(type_body(&mut self) -> ParseResult<TypeBody> {
let variant = Variant::Singleton(self.identifier()?);
Ok(TypeBody(vec!(variant)))
@ -1046,7 +1054,7 @@ mod parse_tests {
#[test]
fn parsing_types() {
parse_test!("type Yolo = Yolo", AST(vec![Declaration(TypeDecl(rc!(Yolo), TypeBody(vec![Variant::Singleton(rc!(Yolo))])))]));
parse_test!("alias Sex = Drugs", AST(vec![Declaration(TypeAlias(rc!(Sex), rc!(Drugs)))]));
parse_test!("type alias Sex = Drugs", AST(vec![Declaration(TypeAlias(rc!(Sex), rc!(Drugs)))]));
}
#[test]