feat(tazjin/rlox): Add support for print statement

Change-Id: Ic3e7e722325c8784b848c0bcd573c2e51e123c40
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2583
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI
This commit is contained in:
Vincent Ambo 2021-03-02 22:15:08 +02:00 committed by tazjin
parent 432e7a7ddd
commit 2cd77ea26d
3 changed files with 61 additions and 5 deletions

View file

@ -156,11 +156,10 @@ fn rule_for<T: Iterator<Item = Token>>(token: &TokenKind) -> ParseRule<T> {
impl<T: Iterator<Item = Token>> Compiler<T> {
fn compile(&mut self) -> LoxResult<()> {
self.advance();
self.expression()?;
self.consume(
&TokenKind::Eof,
ErrorKind::ExpectedToken("Expected end of expression"),
);
while !self.match_token(&TokenKind::Eof) {
self.declaration()?;
}
self.end_compiler()
}
@ -174,6 +173,28 @@ impl<T: Iterator<Item = Token>> Compiler<T> {
self.parse_precedence(Precedence::Assignment)
}
fn declaration(&mut self) -> LoxResult<()> {
self.statement()
}
fn statement(&mut self) -> LoxResult<()> {
if self.match_token(&TokenKind::Print) {
return self.print_statement();
}
Ok(())
}
fn print_statement(&mut self) -> LoxResult<()> {
self.expression()?;
self.consume(
&TokenKind::Semicolon,
ErrorKind::ExpectedToken("Expected ';' after value"),
);
self.emit_op(OpCode::OpPrint);
Ok(())
}
fn number(&mut self) -> LoxResult<()> {
if let TokenKind::Number(num) = self.previous().kind {
self.emit_constant(Value::Number(num));
@ -352,6 +373,19 @@ impl<T: Iterator<Item = Token>> Compiler<T> {
self.panic = true;
self.errors.push(Error { kind, line })
}
fn match_token(&mut self, token: &TokenKind) -> bool {
if !self.check(token) {
return false;
}
self.advance();
true
}
fn check(&self, token: &TokenKind) -> bool {
return self.current().kind == *token;
}
}
pub fn compile(code: &str) -> Result<(Interner, Chunk), Vec<Error>> {

View file

@ -25,4 +25,7 @@ pub enum OpCode {
OpSubtract,
OpMultiply,
OpDivide,
// Built in operations
OpPrint,
}

View file

@ -72,6 +72,10 @@ impl VM {
match op {
OpCode::OpReturn => {
if self.stack.is_empty() {
return Ok(Value::Nil);
}
let val = self.pop();
return Ok(self.return_value(val));
}
@ -135,6 +139,11 @@ impl VM {
})
}
}
OpCode::OpPrint => {
let val = self.pop();
println!("{}", self.print_value(val));
}
}
#[cfg(feature = "disassemble")]
@ -159,6 +168,16 @@ impl VM {
LoxString::Interned(id) => self.strings.lookup(*id),
}
}
fn print_value(&self, val: Value) -> String {
match val {
Value::String(LoxString::Heap(s)) => s,
Value::String(LoxString::Interned(id)) => {
self.strings.lookup(id).into()
}
_ => format!("{:?}", val),
}
}
}
pub fn interpret(strings: Interner, chunk: chunk::Chunk) -> LoxResult<Value> {