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Consistent Datatype for values [message #1779336]

Fri, 05 January 2018 14:47

Dennis Melzer

Messages: 48
Registered: December 2014

Member

Hello,

I would like to check for an "in" operator, that always consistent data types are included in the values:

e.g.

only Strings

in(attr,("A","B")

only numbers

in(attr,1,2.0)

The xtext grammar:

In:
	'in' '(' attribute=FIELD_VALUE ',' '(' values+=Literal (',' values+=Literal)* ')' ')';

Can I do that directly in the grammar?

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Re: Consistent Datatype for values [message #1779337 is a reply to message #1779336]

Fri, 05 January 2018 15:03

Ed Willink

Messages: 7655
Registered: July 2009

Senior Member

Hi

You can but your users won't thank you. Every typo will be a syntax error. If instead you have a semantic validation, you can provide a much more informative warning and maybe even a quick fix. Subsequent maintainers won't thank you either since your grammar will have excessive complexity.

Regards

Ed Willink

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Re: Consistent Datatype for values [message #1779347 is a reply to message #1779337]

Fri, 05 January 2018 16:34

Dennis Melzer

Messages: 48
Registered: December 2014

Member

Hi,

thanks for the quick answer.

But i have no UI, so the User cannot use a quickfix ;).

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Re: Consistent Datatype for values [message #1779360 is a reply to message #1779347]

Fri, 05 January 2018 17:27

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

well even then a simple validation with an error message like: "please use the same type" would be better than "parse error"
never do such things in the grammar

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Consistent Datatype for values [message #1779363 is a reply to message #1779360]

Fri, 05 January 2018 17:44

Dennis Melzer

Messages: 48
Registered: December 2014

Member

Christian Dietrich wrote on Fri, 05 January 2018 17:27

well even then a simple validation with an error message like: "please use the same type" would be better than "parse error"
never do such things in the grammar

Okay thanks. Then i will do that in AbstractValidator, or?

[Updated on: Fri, 05 January 2018 17:47]

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Re: Consistent Datatype for values [message #1779364 is a reply to message #1779363]

Fri, 05 January 2018 17:45

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

you have already a MyDslValidator pregenerated. yes

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Consistent Datatype for values [message #1779365 is a reply to message #1779364]

Fri, 05 January 2018 17:48

Dennis Melzer

Messages: 48
Registered: December 2014

Member

Christian Dietrich wrote on Fri, 05 January 2018 17:45

you have already a MyDslValidator pregenerated. yes

Okay thanks :)

Antoher related question. A attribute (like in Java) should always start with a character. My solution is:

terminal FIELD_VALUE:
	('A'..'Z' | 'a'..'z') ('A'..'Z' | 'a'..'z' | '0'..'9' | '.' | '_' | '-')*;

Is this ok? Or should i create a validation as well?

[Updated on: Fri, 05 January 2018 17:51]

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Re: Consistent Datatype for values [message #1779366 is a reply to message #1779365]

Fri, 05 January 2018 17:50

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

that's ok, depends on other places you use similar IDs.

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Consistent Datatype for values [message #1779368 is a reply to message #1779366]

Fri, 05 January 2018 17:52

Dennis Melzer

Messages: 48
Registered: December 2014

Member

Christian Dietrich wrote on Fri, 05 January 2018 17:50

that's ok, depends on other places you use similar IDs.

Okay, then i will try to create a validation

EDIT: okay now i have the same issue like in my other thread all values are strings ;). So i cannot check the data type. First i have to fix this, before i can create a validation

[Updated on: Fri, 05 January 2018 18:08]

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