Cannot use `and` and `or` inside a function definition after v12.1.0

[shmsula]

Describe the bug
Code stops working after migration from 12.1.0 to 12.2.0 or 12.3.0

f1(x) = x < 2 or x > 3
filter([1,2,3,4,5], f1)

To Reproduce
This can be easily reproduced on the main page using the demo widget. https://mathjs.org (math.version 12.3.0)

However, it works if the ‘or’ is removed.

On https://mathnotepad.com/ (math.version 10.3.0) it also works.

[dvd101x]

It seems related to declaring a function in the parser that includes or or and as syntax.

X = [1, 2, 3, 4, 5]
f1(x) = x < 2 or x > 3
filter(X, f1)              # TypeError: Function filter cannot apply callback arguments to function f1: Undefined symbol x
f1(1)                      # Error: Undefined symbol x

# gets fixed if the function includes `or` as a function (not as part of the syntax)
f2(x) = or(x < 2, x > 3)
filter(X, f2)              # [1, 4, 5]

# also fixed if the function is stated inline
filter(X, x < 2 or x > 3)  # [1, 4, 5]

# also works by indexing with an array of booleans
X[X < 2 or X > 3]          # [1, 4, 5]]

It might have something to do with #3090

[shmsula]

The problem is that brackets aren’t required for such simple expressions, and the workaround isn’t really obvious. I have a feeling that some kind of breaking changes were introduced, perhaps accidentally, by a commit from the 12.2.0 release. v12.1.0...v12.2.0 Even a commit with a suspiciously similar description exists.

[dvd101x]

I agree. It seems like a breaking change and probably unintended. I just tested what still works and what doesn't to help in the debugging process.

[josdejong]

Thanks for reporting. I think indeed that this is an unintended bug introduced in v12.2.0 via #3090. It looks as if the scope isn't passed to the new transform functions for the operators or, and, bitOr, and bitAnd, resulting in this "Undefined symbol X" error.

[josdejong]

I did a bit of debugging and I do understand the cause:

In FunctionNode, we create a subscope when dealing with a rawArgs function, so the function variable x will not pollute the main scope and only exists in the subscope, see FunctionNode.js#L172.

In OperatorNode, we now also have to deal with rawArgs functions now (since the introduction of lazy evaluation of and and or), see OperatorNode.js#L312. Right now, we do not create a subscope there, since we are not (always) inside a function scope, like in the expression (a=false) and (b=true). If we do create a subscope in OperatorNode, the variables a and b will be created in this subscope instead of the main scope.

I still have to think through how to solve this 🤔 . Help would be welcome.

[josdejong]

I created a branch fix/issue3143 that has unit tests for this (not yet a solution), see develop...fix/issue3143

[josdejong]

Solution is almost there (just need to work out unit tests and do some refactoring and performance tests)

[josdejong]

Fixed now in v12.3.2