0002252: foamToVTK error message easy to be misunderstood - OpenFOAM Issue Tracking

ID	Project	Category	View Status	Date Submitted	Last Update

0002252	OpenFOAM	Bug	public	2016-09-22 10:52	2016-09-23 10:37

Reporter	KateEisenhower	Assigned To	henry
Priority	low	Severity	text	Reproducibility	always
Status	closed	Resolution	no change required
Platform	all	OS	all	OS Version	all

Summary	0002252: foamToVTK error message easy to be misunderstood
Description	foamToVTK -fields p yields --> FOAM FATAL IO ERROR: incorrect first token, expected <int> or '(', found on line 0 the word 'p' where it should say something like --> FOAM FATAL IO ERROR: incorrect first token, expected <int> or ''(p)'', found on line 0 the word 'p' in my opinion. or --> FOAM FATAL IO ERROR: the field name has to be wrapped in apostrophes and brackets, e. g. '(p)'
Steps To Reproduce	foamToVTK -fields p
Additional Information	In my opinion the error message is wrong. incorrect first token, expected <int> or ''', found on line 0 the word 'p' would be correct formally because obviously OpenFoam expects an apostrophe before (p).
Tags	No tags attached.

wyldckat 2016-09-22 11:38 updater ~0006891	A few more details are needed on how to reproduce the message. More specifically, which tutorial case can be used and what commands were used before using foamToVTK?

henry 2016-09-22 12:08 manager ~0006892	The error message is generated by the HashTable input parser which expects either the number of elements to be specified on an open-bracket in which case it counts the number of elements. To me the message is clear: you need to provide a list. If you would prefer error messages to contains more context information they would need to be generated at a higher-level requiring context-specific error checking code to be added at every point where user-input is parsed. This would be an enormous undertaking and probably require exception handling code to be added throughout OpenFOAM. If you are keen to see this added to OpenFOAM please submit patches for review.

henry 2016-09-22 12:27 manager ~0006893	The alternative to adding significantly to error-checking code is to provide useful and accurate help messages; in the case of 'foamToVTK -help' the following relevant information is provided: -fields <wordList> only convert the specified fields - eg '(p T U)'

KateEisenhower 2016-09-22 15:01 reporter ~0006904	@wyldckat: I don't really understand what you mean. You need to have OF installed and the command has to be given from a case directory. You can use any tutorial case you want. @henry: I agree to most of the things you say. And I don't want to nitpick. For me, the help message is wrong too. In my opinion it should say -fields <wordList> only convert the specified fields - eg ''(p T U)'' I just want to help and I really appreciate all the effort both of you are contributing in oder to make OF such a wonderful product!

wyldckat 2016-09-22 16:36 updater ~0006906	@KateEisenhower: Sorry, I didn't remember that the "-fields" option would complain straight away, regardless of the case and state of the case. It looked at first to me that the problem was file related, not due to the passed argument. As for the suggestion you made: Why the double quotes? Wont it be more confusing to those users who copy-paste what's written in the example?

henry 2016-09-22 16:52 manager ~0006907	> In my opinion it should say As Bruno says: Why the double quotes? Both foamToVTK -fields "(p)" and foamToVTK -fields '(p)' work fine and in this context single-quotes are more convenient.

KateEisenhower 2016-09-23 10:20 reporter ~0006910	@wyldckat: You made a good point here. @henry: When you look at the error message: --> FOAM FATAL IO ERROR: incorrect first token, expected <int> or '(', found on line 0 the word 'p' The synthax is not consistent from my point of view. In this message we have two cases where quotes are used: Case 1: '(' The error message is telling me that OF expects a bracket here. But that is not true because in reality OF is expecting first a quote and then a bracket. How do I know that? Because foamToVTK -fields '(p)' is working. foamToVTK -fields (p) is not working. Hence my conclusion is the error message is wrong because OF really expects a quote first, and not a bracket. Case 2: 'p' After I deleted the quotes in my mind, OF tells me that it found the word p which is right because I originally entered foamToVTK -fields p So in my opinion this part is correct. I don't know how I could make that any clearer. Hope you understand what I mean. Best regards, Kate

henry 2016-09-23 10:37 manager ~0006911	> foamToVTK -fields (p) is not working. Right, this is not an issue with OpenFOAM but with the shell you are using and the way it parses arguments to the application. To parse a list as an argument to OpenFOAM or any other applications you will need to put quotes around it if that is required by the shell you are using.

Date Modified	Username	Field	Change
2016-09-22 10:52	KateEisenhower	New Issue
2016-09-22 11:38	wyldckat	Note Added: 0006891
2016-09-22 12:08	henry	Note Added: 0006892
2016-09-22 12:27	henry	Note Added: 0006893
2016-09-22 15:01	KateEisenhower	Note Added: 0006904
2016-09-22 16:36	wyldckat	Note Added: 0006906
2016-09-22 16:52	henry	Note Added: 0006907
2016-09-22 23:06	henry	Assigned To	=> henry
2016-09-22 23:06	henry	Status	new => closed
2016-09-22 23:06	henry	Resolution	open => no change required
2016-09-23 10:20	KateEisenhower	Status	closed => feedback
2016-09-23 10:20	KateEisenhower	Resolution	no change required => reopened
2016-09-23 10:20	KateEisenhower	Note Added: 0006910
2016-09-23 10:37	henry	Status	feedback => closed
2016-09-23 10:37	henry	Resolution	reopened => no change required
2016-09-23 10:37	henry	Note Added: 0006911