Show HN: I made a web-based notepad with a built in unit calculator

Re:Show HN: I made a web-based notepad with a built in unit ... by brospars on Wednesday August 17, 2022 @06:05AM (#32494296)

There is something wrong with the order of operations. When I type 2+2*2-6 i get -6 which should be 0.

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Re:Show HN: I made a web-based notepad with a built in unit ... by sneak on Wednesday August 17, 2022 @06:08AM (#32494313)

I would think this might be the first unit test one would write for a calculator program.

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Re:Show HN: I made a web-based notepad with a built in unit ... by simonz05 on Wednesday August 17, 2022 @07:27AM (#32494791)

Yep, this should be evaluated as `(- (+ 2 (* 2 2)) 6)`

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Re:Show HN: I made a web-based notepad with a built in unit ... by unsafecast on Wednesday August 17, 2022 @06:07AM (#32494308)

It looks like APL order? Right-to-left.

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Re:Show HN: I made a web-based notepad with a built in unit ... by JackFr on Wednesday August 17, 2022 @10:35PM (#32504576)

No. It’s not right to left. It’s just weird:

  3 ^ 1 * 2   6
  3 ^ 1 / 2   1.73205
  3 ^ 1 + 2   5
  3 ^ 1 - 2   1

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Re:Show HN: I made a web-based notepad with a built in unit ... by unsafecast on Thursday August 18, 2022 @09:40AM (#32509427)

Huh.

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Re:Show HN: I made a web-based notepad with a built in unit ... by bdwjn on Wednesday August 17, 2022 @06:11AM (#32494333)

Oh there's more:

9 - 3 ^ 2 = 0

9 -3 ^ 2 = 18 ???

pi = 3.1415926536

2 pi = 5.1415926536 ???

sin(3.1415926536 radians) = -0

sin(pi radians) = Incompatible units ???

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Re:Show HN: I made a web-based notepad with a built in unit ... by wizofaus on Wednesday August 17, 2022 @06:12AM (#32494342)

Seems to assume + if an arithmetic operator is missing?

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Re:Show HN: I made a web-based notepad with a built in unit ... by tonyonodi on Wednesday August 17, 2022 @06:30AM (#32494443)

This is correct, the idea is that you can type things like "6 foot 3 inches" and have it evaluate as an addition. But the example shown above is definitely a problem, I'll try to think of a work around.

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Re:Show HN: I made a web-based notepad with a built in unit ... by wizofaus on Wednesday August 17, 2022 @07:26AM (#32494778)

I'd think that rule only makes sense after a symbol representing a unit (including potentially 6'3"). Certainly <number> <named constant> should logically assume multiplication.

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