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basic implementation of short circuiting with or op

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This commit is contained in:
ConnorSkees 2020-06-20 16:22:17 -04:00
parent 39d439b2c2
commit 07d6faf64b
2 changed files with 48 additions and 2 deletions
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36
src/parse/value.rs
View File

@ -887,9 +887,9 @@ impl<'a, 'b: 'a> IntermediateValueIterator<'a, 'b> {
space_separated.push(right.map_node(|n| Value::UnaryOp(op.node, Box::new(n))));
}
}
Op::And | Op::Or => {
Op::And => {
self.whitespace();
// special case when the value is literally "and" or "or"
// special case when the value is literally "and"
if self.peek().is_none() {
space_separated
.push(Value::String(op.to_string(), QuoteKind::None).span(op.span));
@ -904,6 +904,38 @@ impl<'a, 'b: 'a> IntermediateValueIterator<'a, 'b> {
return Err(("Expected expression.", op.span).into());
}
}
Op::Or => {
self.whitespace();
// special case when the value is literally "or"
if self.peek().is_none() {
space_separated
.push(Value::String(op.to_string(), QuoteKind::None).span(op.span));
} else if let Some(left) = space_separated.pop() {
self.whitespace();
if left.node.is_true(left.span)? {
// we explicitly ignore errors here as a workaround for short circuiting
while let Some(foo) = self.peek() {
if let Ok(Spanned {
node: IntermediateValue::Comma,
..
}) = foo
{
break;
}
self.next();
}
space_separated.push(left);
} else {
let right = self.single_value()?;
space_separated.push(
Value::BinaryOp(Box::new(left.node), op.node, Box::new(right.node))
.span(left.span.merge(right.span)),
);
}
} else {
return Err(("Expected expression.", op.span).into());
}
}
_ => {
if let Some(left) = space_separated.pop() {
self.whitespace();

14
tests/or.rs
View File

@ -59,3 +59,17 @@ test!(
"a {\n color: 1 - OR;\n}\n",
"a {\n color: 1-OR;\n}\n"
);
test!(
short_circuits_when_lhs_is_true,
"a {\n color: true or red % foo;\n}\n",
"a {\n color: true;\n}\n"
);
error!(
does_not_short_circuit_when_lhs_is_false,
"a {\n color: false or red % foo;\n}\n", "Error: Undefined operation \"red % foo\"."
);
test!(
short_circuiting_in_comma_separated_list,
"a {\n color: true or red % foo, red;\n}\n",
"a {\n color: true, red;\n}\n"
);