AutoHotkey Community

[Joy2DWorld]

[Lexikos]

There are too many operations in the expression. If you split it up into multiple lines, it works fine.

[Joy2DWorld]

thanks for the input, but

1. What syntax rule has been violated ? ie. where do you see a limitation in the number of operations allowed in an expression ???

2. notice that if you change the variable a to, for example "*" (instead of the current number sequence). the number of operations stays exactly the same.. and no error is generated...

[engunneer]

this is certainly confusing. If I make a 50 chars, I can build a string up to 7000ish chars long. If a is 100 chars, I can only build to 13400ish chars

VarSetCapacity doesn't help.
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[PhiLho]

Looks like you have encountered a hard limit in script.
It is not the length of the line (I can use a longer variable name) but somehow the number of variable uses.
Beyond 125 references, we get this out of memory error, even in older versions of AHK. If the string is longer, the number of allowed variables decreases.
I fear it will fall in the "obscure bugs not worth documenting", as one rarely create such super-long script lines.
Unless Chris finds out the problem and fix it.
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[Titan]

I think the maximum number of items allowed in expressions is 100 (#define MAX_EXPR_MEM_ITEMS 100?) which is why it generates an error - stack has not enough memory.
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[Joy2DWorld]

[Titan]

Documenting everything is unnecessary, remember it's only Chris who writes it all. 100+ expression items is an exceptional case, and bad design. You can split the expression to one assignment and another concat.
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[Joy2DWorld]

[Titan]

You're starting to sound like Laszlo... everything is actually documented, you can find all technical notes in the source code. The docs is written as a reference for both newbie non-programmers and experts so Chris decided that a simplistic formal tone would be best understood by everybody. In all fairness you have to exercise reasonable judgement of your own, writing megs of documentation takes a lot of time and energy which should really be spent on developing AutoHotkey itself.
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[Joy2DWorld]

[Lexikos]

@Titan: Is there a comment documenting the maximum number of concatenations or variable references per expression, or is it not that explicit?


The source of this limitation seems to be (near the top of Line::ExpandExpression()):

[Joy2DWorld]

something like this,

if you want to manage callbacks, or messages, etc.. which come as new 'threads', variable management becomes a critical part of the coding logic.

Where you have multiple connections, (say, 4 spreadsheets and 2 word docs, with 2 web connections = 8 connections), expressions (obviously, can be recoded around any limitation issues), can look like:

RESPONDER := (FACTOR7 ? (BASE3_fACTOR > lower_limit2 ? local2 : local 3) : (base4_factor7 < limit7 ) ? LOCAL l4v3 : LOCAL8) || (FACTOR7B ? (BASE3D_fACTOR > limit8 ? local3 : local7) : (base4_factor7C < var32) ? LOCAL3d : LOCAL8f) ... etc. (this is already what... 20 references )...

moreover, sometimes how we want to Join is controlled by the content itself, vrb := a . ( x > vd ? b : c ) . ( v < etrd ? zy : yw ) . ... etc.
and result := (a > b ? a : b ) . ( a > c ? a2 : c2).... is sure a legit and nice way to build a result string. etc.).. and when re-combining multiple connections into a single var, sure is easier to just do it all in one place... but if we have 15 vars returned on 8 connections... that violates the 100 reference rule... (and ERRORS OUT!! AHK) (but only when the vars are large enough to... so intermittent error)... depending upon the var content!! ugggg!!
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[Chris]

I didn't even know it was possible to hit the MAX_EXPR_MEM_ITEMS limit; but apparently having a lot of concat operators is a way to do it. In the next release, the limit will be doubled, which will allow the example in the topmost post to work (that example actually needs less than a 10% increase).

This change shouldn't affect performance because all it does is use a little more stack memory during execution, which is strictly temporary memory -- it won't raise the program's memory utilization (except in extreme cases where a script does deep recursion).

Thanks for reporting it.