Specify data type in html tags using attributes

[PouriaSeyfi]

Due to #3444 issue
some times we need specify data type in html using attribute html.
I add new processDomElementDataType function in HTML.php and handle this.

[PouriaSeyfi]

There is no any changes. please review my PR.

[PouriaSeyfi]

I had some unwanted changes caused by phpstorm formatter. I fixed them and fixup my commits to new one .
Also I update my branch with new changes in master. there is no conflict.
Please Review and merge my changes

[oleibman]

I think there is probably some merit in this suggestion. I am trying to think through some of its ramifications. Before I start, there is one minor code change that the PR needs - you do not need to call setDataType after setCellValueExplicit.

Calling setCellValueExplicit can result in an Exception, e.g. if you supply an invalid data type. Is that what we want to happen here, or are we better off catching the Exception and ignoring the format? Regardless of that decision, we need some unit tests for this.

Your example for setting the type to formula is intriguing. However, your test case proves that formulas are already handled without the need to explicitly set the data type. What is not handled is treating a string beginning with an equal sign as a string (by setting quotePrefix to true) rather than a formula. You could accommodate this in your change by checking for this condition if data type is supplied as s.

I think that dates are an especially good use case for this change. You should add some examples for type d (ISO date, time, and date/time elements). Note that those will be converted from string to the Excel numeric representation, and that the conversion may fail.

[PouriaSeyfi]

thanks for your great explanation.
I think it is better to check datatypes in flushCell function for better performance.
And as you mentioned it is better to catch the Exception and ignore the invalid data types in HTML attributes.
Also, I considered the equal sign at the beginning of cell content in the case of string datatypes. I added some new unit tests for this scenario and iso date datatype.

[oleibman]

Thank you for your contribution.