Maximum Characters used in a variable Name?

DavidM · 2010-11-28 22:49

HI,

What is the MAXIMUM number of characters that can be used in a variable Name?

I am having a strange problem, I am using two variables which look similar but SHOULD Be considered as Different Variables, Unless there is a character limit

These are my two variables.

SequenceTimePtr
SequenceTimerPtr

I had a look through the manual and its not mentioned!

I believe you can use very long variable names, but the compiler will only use UP TO a certain amount for TAGGING Purposes,

Can someone please show me were the specification for this is?

Thanks
Dave M

kuroneko · 2010-11-28 23:04

Those variables look fine (they are different). It's something else. Regarding limit, just enter a very long variable name into the proptool, it complains for 30+. HTH.

DavidM · 2010-11-28 23:05

HI,

I just did a test,

I changed the first character of one of my variables to a "Z" instead of an "S",

and now the code runs as it should,

So I conclude that Variable names are not used FULLY during COMPILING,

( But I could be wrong)

regards

Dave

kuroneko · 2010-11-28 23:13

I only did a simple test (assignment, then check which value stays) but now that you mention it I remember that there is an issue which was discussed in the past. I'll try to find the thread.

Simple test:

VAR
  long  SequenceTimePtr
  long  SequenceTimerPtr

PUB null

  SequenceTimePtr  := $FF
  SequenceTimerPtr := $80
  dira[16..23]~~
  repeat
    outa[16..23] := SequenceTimePtr
    waitcnt(clkfreq + cnt)
    outa[16..23] := SequenceTimerPtr
    waitcnt(clkfreq + cnt)

DAT

kuroneko · 2010-11-28 23:32

http://forums.parallax.com/showthread.php?t=105528

After re-reading it it may not be related to your issue at all but it sounded familiar (duplication/removal). Do you have more details or a minimal test case? Also, is the generated byte code (*.binary) the same for both (S/Z)? That may be a starting point.

DavidM · 2010-11-28 23:50

I havent got time to fully test this, I have my code working, I have to finish of the rest of my code as i have a deadline to meet!

My guess it 8 Characters!

Anybody else dare to differ!

Thanks
Dave M

MacTuxLin · 2010-11-29 00:42

That's weird. Taking Kye's SD2.0 code as example, a lot of his variables are > 8 char. E.g.

word rootDirectorySectors, rootDirectorySectorNumber

Heater. · 2010-11-29 00:52

I just compiled that simple test with BST and took a look at the listing output. Seems that BST has no problem with those two variable names and compiles different code for read and write of each one. I have no way to actually run this code here at the momemt but it looks good.

So at least BST is happy.

|===========================================================================|
Objects : -
Untitled1

Object Address : 0010 : Object Name : Untitled1

Binary Image Information :
PBASE : 0010
VBASE : 0044
DBASE : 0054
PCURR : 0018
DCURR : 0058
|===========================================================================|
|===========================================================================|
Object Untitled1
Object Base is 0010
|===========================================================================|
Object Constants
|===========================================================================|
|===========================================================================|
|===========================================================================|
VBASE Global Variables
|===========================================================================|
VBASE : 0000 LONG Size 0004 Variable SequenceTimePtr
VBASE : 0004 LONG Size 0004 Variable SequenceTimerPtr
|===========================================================================|
Object DAT Blocks
|===========================================================================|
|===========================================================================|
|===========================================================================|
Spin Block null with 0 Parameters and 0 Extra Stack Longs. Method 1
PUB null

Local Parameter DBASE:0000 - Result
|===========================================================================|
7                        SequenceTimePtr  := $FF
Addr : 0018:          37 27  : Constant Mask Y=39 Decrement 000000FF 255
Addr : 001A:             41  : Variable Operation Global Offset - 0 Write
8                        SequenceTimerPtr := $80
Addr : 001B:          37 06  : Constant Mask Y=6 00000080 128
Addr : 001D:             45  : Variable Operation Global Offset - 1 Write
9                        dira[16..23]~~
Addr : 001E:          37 03  : Constant Mask Y=3 00000010 16
Addr : 0020:          38 17  : Constant 1 Bytes - 17 - $00000017 23
Addr : 0022:       3E D6 1C  : Register [Bit..Bit] op DIRA VAR~~ Post-set
Addr : 0025: Label0002
11                          outa[16..23] := SequenceTimePtr
Addr : 0025:             40  : Variable Operation Global Offset - 0 Read
Addr : 0026:          37 03  : Constant Mask Y=3 00000010 16
Addr : 0028:          38 17  : Constant 1 Bytes - 17 - $00000017 23
Addr : 002A:          3E B4  : Register [Bit..Bit] op OUTA Write
12                          waitcnt(clkfreq + cnt)
Addr : 002C:             35  : Constant 1 $00000000
Addr : 002D:             C0  : Memory Op Long POP Address READ 
Addr : 002E:          3F 91  : Register op CNT Read
Addr : 0030:             EC  : Math Op +     
Addr : 0031:             23  : WaitCnt(count)
13                          outa[16..23] := SequenceTimerPtr
Addr : 0032:             44  : Variable Operation Global Offset - 1 Read
Addr : 0033:          37 03  : Constant Mask Y=3 00000010 16
Addr : 0035:          38 17  : Constant 1 Bytes - 17 - $00000017 23
Addr : 0037:          3E B4  : Register [Bit..Bit] op OUTA Write
14                          waitcnt(clkfreq + cnt)
Addr : 0039:             35  : Constant 1 $00000000
Addr : 003A:             C0  : Memory Op Long POP Address READ 
Addr : 003B:          3F 91  : Register op CNT Read
Addr : 003D:             EC  : Math Op +     
Addr : 003E:             23  : WaitCnt(count)
Addr : 003F: Label0003
Addr : 003F: JMP Label0002
Addr : 003F:          04 64  : Jmp 0025 -28  
Addr : 0041: Label0004
Addr : 0041:             32  : Return

mpark · 2010-11-29 01:23

Propeller Manual v1.01 p. 159 (symbol rules):

3) Must be 32 characters or less.

DavidM · 2010-11-29 01:40

Well then,

Thanks for the language reference, hard to find, still doesn't explain the problem!

Possible SPIN COMPILER BUG??

Dave M

wjsteele · 2010-11-29 01:43

I think we need to see your code. I'm betting that you have a reference somewhere in the code that is stepping on the other one. Possibly an extra or missing @.

Bill

kuroneko · 2010-11-29 01:50

mpark wrote: »

Propeller Manual v1.01 p. 159 (symbol rules): 32 characters or less

Odd, why is the proptool then complaining about 30+?

Edit: rev 1.1 actually mentions 30

DavidM · 2010-11-29 02:05

Hi wjsteele,

As much as i would love to, I cannot post my code, as it is company confidential ( especially where this problem occurred)

But heres what I know/did

This OBJECT that I "HAD" the problem in, has been reliable and workings for MONTHS! no changes.

I needed to change just ONE VARIABLE NAME from "MasterTimer" to "SequenceTimer" as I was modifying my master timer code ( another object) to be more useful, and I like to have descriptive variable names.

So I did a FIND & REPLACE ( in all of this object) , knowing that I had a few variations of this variable name within this object.

i.e
SequenceTimerPtr ( A LONG declared in the VAR BLOCK , which hold the Address of the variable for later use)

vSequenceTimerPtr ( A reference to an address used to point to the values used in the calling object ( declared in my INIT Method of this object) , this is my standard naming convention)

So I did the find and replace, and checked each variable name change carefully and then compiled and ran my code, only to discover that my timer was not running, in fact the system froze!

When I replace the "S" in sequence with a Z, in all the same places, I got the code to function just as it did before.

I am not using any "@" address references.

thanks
Dave M

ElectricAye · 2010-11-29 06:25

DavidM wrote: »

...

I am having a strange problem, I am using two variables which look similar but SHOULD Be considered as Different Variables, Unless there is a character limit...

I've used nothing but very long variable names, very often pushing 30 characters, for the past 2+ years and I've never seen this problem before. But now you have me worried about it. Please keep us posted on this possible bug.

thanks,

Duane Degn · 2010-11-29 06:37

Dave M,

Thanks for the heads up. I also like to use discriptive variable names. I can't find mention of which version of the Propeller Tool you're using. Maybe it's a bug that has been fixed in a more recent version. (Or one introduced in a later version.) Which version did you use?

Thanks,

Duane

Phil Pilgrim (PhiPi) · 2010-11-29 07:56

I'm confident that this is not a compiler issue. If the compiler were treating distinct, but similar, variable names as the same symbol, it would throw an error when the second "version" of the variable was encountered in the VAR or DAT section. IOW, you can't define the same variable in two different places.

-Phil

Maximum Characters used in a variable Name?

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