Use of custom functions resulted in "Access violation...Read of address 00000000"

[edwinyzh]

The code can be found in this github gist.

It's form with its .pas file, just create a new vcl project and add this testing form to the project.

Compile, run and hit 'btnTest', you'll get the "Access violation...Read of address 00000000" error.

Not sure why...

Thanks.

[edwinyzh]

Stack trace captured by madExcept:

exception class : ETemplateEvaluationError exception message : (Line 1, Column 10) Access violation at address 0063A7BD in module 'Prog1'. Read of address 00000000.

main thread ($2c78): 0063a96e +13a Prog1 Sempare.Template.Common 177 +1 RaiseError 0063aa39 +02d Prog1 Sempare.Template.Common 182 +1 RaiseError 00713be6 +106 Prog1 Sempare.Template.Evaluate 781 +5 TEvaluationTemplateVisitor.Visit 77e5012e +00a ntdll.dll KiUserExceptionDispatcher 0076dc4d +031 Prog1 Sempare.Template.Parser 1528 +1 TBinopExpr.Accept 0063a7e6 +086 Prog1 Sempare.Template.Common 138 +1 AcceptVisitor 007106b0 +058 Prog1 Sempare.Template.Evaluate 186 +3 TEvaluationTemplateVisitor.Visit 0076d649 +031 Prog1 Sempare.Template.Parser 1417 +1 TExprList.Accept 00712cd6 +042 Prog1 Sempare.Template.Evaluate 570 +1 TEvaluationTemplateVisitor.ExprListArgs 00713b34 +054 Prog1 Sempare.Template.Evaluate 778 +2 TEvaluationTemplateVisitor.Visit 0076d981 +031 Prog1 Sempare.Template.Parser 1479 +1 TFunctionCallExpr.Accept 0063a7e6 +086 Prog1 Sempare.Template.Common 138 +1 AcceptVisitor 00713f34 +044 Prog1 Sempare.Template.Evaluate 815 +1 TEvaluationTemplateVisitor.Visit 0076eacd +031 Prog1 Sempare.Template.Parser 1830 +1 TEncodeExpr.Accept 0063a7e6 +086 Prog1 Sempare.Template.Common 138 +1 AcceptVisitor 007135b1 +065 Prog1 Sempare.Template.Evaluate 708 +3 TEvaluationTemplateVisitor.Visit 0076de0d +031 Prog1 Sempare.Template.Parser 1565 +1 TPrintStmt.Accept 0076e2ba +05e Prog1 Sempare.Template.Parser 1653 +2 TTemplate.Accept 0063a712 +086 Prog1 Sempare.Template.Common 133 +1 AcceptVisitor 00770c1f +0a7 Prog1 MainFormU 153 +4 Template.Eval 00770b18 +064 Prog1 MainFormU 270 +3 Template.Eval 00770a82 +046 Prog1 MainFormU 279 +1 Template.Eval 007707f5 +06d Prog1 MainFormU 98 +5 TfrmMain.btnTestClick

[edwinyzh]

Oh, the error happened seems to be because full-width comma (a unicode character) took place of the ASCII comma...

[darnocian]

Where was the comma?

[edwinyzh]

Forget about comma, the error happened because full-width quotes (unicode characters) appeared in the function calls in the template code.

[darnocian]

Shall I close this?

[darnocian]

I'll double check the gist to see if I can reproduce

[darnocian]

It seemed to work fine for me.

I just had to change: cTmplStr = '{{ FuncB('/file1.txt') }}'; to cTmplStr = '{{ FuncB("/file1.txt") }}';

but I think that may have been a copy paste conversion issue rather than your code.

[edwinyzh]

Those are not full-width symbols, check this gist.

[darnocian]

Thanks. I think this may be worth reviewing to support with more flexibility... I think there may be an option that doesn't impose too much of an overhead to support this.

[edwinyzh]

Just to clarify, the post is not to request support for these full-width Chinese single/double quotes...

Maybe just emitting more meaningful error message like "Invalid character found at (line number, column number)" is enough.

[sempare]

The following improvement will be released shortly:

• support for single/double quotes according to the gist (just to be friendly)
• improved error message