# Fixed Point Maths does not work (Inform 7)

Hello there!

The Fixed Point Maths extension seems not to work anymore, at least not for me. Is it because of the new Inform 7 version? (I used Inform 7 v. 6G60 and Fixed Points Math v. 4)

Look for yourself:

``````Include Fixed Point Maths by Michael Callaghan.
Hello is a room.``````

Output:

[code]This is the report produced by Inform 7 (build 6G60) on its most recent run through:

In Chapter 9 - Some mathematical functions, Section 6 - Sines in the extension Fixed Point Maths by Michael Callaghan:

Problem. In ‘let X be X plus 1’ , it looks as if you want to use ‘let’ to change the value of the temporary variable ‘X’. Ordinarily that would be fine, but it’s not allowed when the variable is used as the counter in a ‘repeat’ loop, or has some other do-not-disturb purpose - this could cause chaotic effects. The rule is: you can only change an existing value with ‘let’ if it was created by ‘let’ in the first place.

In Section 8 - Tangents in the extension Fixed Point Maths by Michael Callaghan:

Problem. In the sentence ‘decide on result in degrees’ , I was expecting to read a real number, but instead found some text that I couldn’t understand - ‘result’.

I was trying to match one of these phrases:

1. (result - real number) in degrees

2. (result - number) in degrees

This was what I found out:

result = something unrecognised

In Section 9 - Natural logarithms in the extension Fixed Point Maths by Michael Callaghan:

Problem. In ‘let X be X plus 1’ , it looks as if you want to use ‘let’ to change the value of the temporary variable ‘X’. Ordinarily that would be fine, but it’s not allowed when the variable is used as the counter in a ‘repeat’ loop, or has some other do-not-disturb purpose - this could cause chaotic effects. The rule is: you can only change an existing value with ‘let’ if it was created by ‘let’ in the first place.
[/code]

Pretty annoying, because without the extension you can’t use the Glimmr extensions either.
Any way to fix this? (I’m still hoping that it’s just a matter of changing a couple of lines.)

Thanks,
T. R. Z.

Huh! Thanks for pointing this out… I’ve had no trouble building Glimmr projects, and neither have a couple of other folks I’ve corresponded with, but it seems that there’s a simple reason for that–I’m using a version of Fixed Point Maths that differs from the one on the website. Whether I hacked it myself and forgot about it (very likely) or whether there is some other reason for the discrepancy, I’m not sure…

You might want to let the folks that run the extensions library at inform7.com know that version 4 isn’t compatible with 6G60.

Anyway, I’ve attached the repaired version of Fixed Point Maths that I’m using. If you want to see the very minor differences between the two versions, you can compare them using diffchecker.com.

Just FYI: Once there is wide support for the new native Glulx floating point features, I am planning to transition Glimmr to use those features rather than FPM.

–Erik

UPDATE: I’ve emailed Michael Callaghan to let him know about the incompatibility, and also incorporated the modified version of FPM into release 3.2 of the complete Glimmr package.
Fixed Point Maths.txt (39.2 KB)

Thanks a lot!

I checked the difference. It was minimal indeed, but I would’nt have managed to fix it myself, as I’m really new to Inform 7 (my third day).

It’s great to see that there are so many IF-enthusiasts around these days!

Huh. Welcome to the community, and good work. Three days in, and already you’ve made your mark.