Confusing boolean logic

[uncenter]

To reproduce:

The Less preview doesn't want me to use the correct share link so here's the Less for it:

@foo: 1;
@bar: a;
@foo-is-one: boolean(@foo = 1);
@bar-is-a: boolean(@bar = a);
@is-qar: boolean(@foo-is-one = @bar-is-a);
/* @is-baz: boolean((@foo = 1) = (@bar = a)); */

:root {
  --qar: @is-qar;
/*   --baz: @is-baz; */
}

Current behavior:

Commenting in the @is-baz variable on line 6 (and line 10 to use it in an expression) causes the error variable @is-baz is undefined. As you can see, the expression @is-baz contains is the same is the (working) @is-qar expression, but inlines the @foo-is-one and @bar-is-a checks.

Expected behavior:

There shouldn't be any undefined variable, because the variable is defined — I should be allowed to inline boolean expressions / logical comparisons like so.

Environment information:

• less version: latest
• nodejs version: n/a
• operating system: n/a

[dosubot]

This is a parser design limitation rather than a bug. When you write boolean((@foo = 1) = (@bar = a)), the parser creates Condition objects for each comparison (@foo = 1 and @bar = a), but these Condition objects cannot be used as operands in another comparison.

Your working example succeeds because boolean() returns actual boolean keyword values (true/false) when evaluated. When you store those in @foo-is-one and @bar-is-a, they become regular values that can be compared.

The parser only allows multiple conditions to be combined through logical and/or operators, not through nested comparisons. So you'd need to stick with the intermediate variable approach you've already found.

To reply, just mention @dosu.

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