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Check nature of XExpression [message #992407]

Fri, 21 December 2012 15:06

Tommaso De Sica

Messages: 131
Registered: March 2012
Location: Italy

Senior Member

Goodevening guys.

I have to check if a generic XExpression is a boolean condition.
I'll try to check type of expression, but it is insufficient: in fact something like this have boolean type but isn't a boolean condition

if (true) true

Very thank you!

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Re: Check nature of XExpression [message #992418 is a reply to message #992407]

Fri, 21 December 2012 15:36

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi if this is your own IF you have to implement the type provider
yourself

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Re: Check nature of XExpression [message #993875 is a reply to message #992407]

Tue, 25 December 2012 19:45

Lorenzo Bettini

Messages: 1812
Registered: July 2009
Location: Firenze, Italy

Senior Member

On 12/21/2012 04:06 PM, Tommaso De Sica wrote:
> Goodevening guys.
>
> I have to check if a generic XExpression is a boolean condition.
> I'll try to check type of expression, but it is insufficient: in fact
> something like this have boolean type but isn't a boolean condition
>
> if (true) true
>
> Very thank you!

Hi Tommaso

if it has boolean type it is a boolean condition actually :)

if you need to accept only XExpressions with boolean type but with a
specific "shape" you'll have to perform the additional check yourself;
in Xsemantics I do something similar (see
http://sourceforge.net/p/xsemantics/code/ci/759c09eb49b1d8ec11bc386805e88762431174b9/tree/plugins/it.xsemantics.dsl/src/it/xsemantics/dsl/typing/XsemanticsTypeSystem.xtend
in particular the method isBooleanPremise)

hope this helps
cheers
Lorenzo

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Re: Check nature of XExpression [message #994459 is a reply to message #992407]

Thu, 27 December 2012 11:17

Tommaso De Sica

Messages: 131
Registered: March 2012
Location: Italy

Senior Member

I've implemented check myself, thank you.

A curiosity: why a char expression in XExpression has always String type?

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Re: Check nature of XExpression [message #994466 is a reply to message #994459]

Thu, 27 December 2012 11:33

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Xbase has not char literals but string literals only. Have a look at
the xbasetypeprovider for further details on the type system

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Re: Check nature of XExpression [message #994506 is a reply to message #994466]

Thu, 27 December 2012 14:12

Tommaso De Sica

Messages: 131
Registered: March 2012
Location: Italy

Senior Member

Christian Dietrich wrote on Thu, 27 December 2012 12:33

Xbase has not char literals but string literals only. Have a look at
the xbasetypeprovider for further details on the type system

Yes, I know it.
But my curiosity was about the reason of it.

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Re: Check nature of XExpression [message #996481 is a reply to message #994506]

Wed, 02 January 2013 07:23

Sebastian Zarnekow

Messages: 3118
Registered: July 2009

Senior Member

Am 27.12.12 15:12, schrieb Tommaso De Sica:
> Christian Dietrich wrote on Thu, 27 December 2012 12:33
>> Xbase has not char literals but string literals only. Have a look at
>> the xbasetypeprovider for further details on the type system
>
>
> Yes, I know it.
> But my curiosity was about the reason of it.

This is a current limitation that we want to get rid of, e.g. by means
of target typing. Both expression will be valid in future versions of Xbase:

val char c = 'c'
val String s = 's'

Regards,
Sebastian
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