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refactor(tazjin/rlox): Refactor Compiler::consume into a macro

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Making this function a macro instead makes it possible to match
arbitrary token kinds, even the ones that carry data, without changing
the syntax too much.

Change-Id: I5cda9e36d6833bd9c259f7d4d8340db6e783b4e8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2593
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI
This commit is contained in:
Vincent Ambo 2021-03-05 21:43:28 +02:00 committed by tazjin
parent 822e5ae57f
commit b7b94335cc
1 changed files with 21 additions and 18 deletions
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39
users/tazjin/rlox/src/bytecode/compiler.rs
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@ -153,6 +153,15 @@ fn rule_for<T: Iterator<Item = Token>>(token: &TokenKind) -> ParseRule<T> {
}
}
macro_rules! consume {
( $self:ident, $expected:pat, $err:expr ) => {
match $self.current().kind {
$expected => $self.advance(),
_ => $self.error_at($self.current().line, $err),
}
};
}
impl<T: Iterator<Item = Token>> Compiler<T> {
fn compile(&mut self) -> LoxResult<()> {
self.advance();
@ -193,9 +202,10 @@ impl<T: Iterator<Item = Token>> Compiler<T> {
fn print_statement(&mut self) -> LoxResult<()> {
self.expression()?;
self.consume(
&TokenKind::Semicolon,
ErrorKind::ExpectedToken("Expected ';' after value"),
consume!(
self,
TokenKind::Semicolon,
ErrorKind::ExpectedToken("Expected ';' after value")
);
self.emit_op(OpCode::OpPrint);
Ok(())
@ -203,9 +213,10 @@ impl<T: Iterator<Item = Token>> Compiler<T> {
fn expression_statement(&mut self) -> LoxResult<()> {
self.expression()?;
self.consume(
&TokenKind::Semicolon,
ErrorKind::ExpectedToken("Expected ';' after expression"),
consume!(
self,
TokenKind::Semicolon,
ErrorKind::ExpectedToken("Expected ';' after expression")
);
self.emit_op(OpCode::OpPop);
Ok(())
@ -222,9 +233,10 @@ impl<T: Iterator<Item = Token>> Compiler<T> {
fn grouping(&mut self) -> LoxResult<()> {
self.expression()?;
self.consume(
&TokenKind::RightParen,
ErrorKind::ExpectedToken("Expected ')' after expression"),
consume!(
self,
TokenKind::RightParen,
ErrorKind::ExpectedToken("Expected ')' after expression")
);
Ok(())
}
@ -334,15 +346,6 @@ impl<T: Iterator<Item = Token>> Compiler<T> {
Ok(())
}
fn consume(&mut self, expected: &TokenKind, err: ErrorKind) {
if self.current().kind == *expected {
self.advance();
return;
}
self.error_at(self.current().line, err);
}
fn current_chunk(&mut self) -> &mut Chunk {
&mut self.chunk
}