MathML tweaks

[mmatera]

This PR makes some tweaks on how mathml output is render.

• adds line breaks following the WMA usage.
• Handle more carefully InterpretationBox to work with InputForm and OutputForm.
• Remove OutputForm[s_String] format rule.
• update format-tests-WMA.yaml with more tests compared against WS.
• Update format-tests.yaml accordingly.

[rocky]

Why can't this be picked up from character tables?

[mmatera]

Good question. I have to check if we are not doing already that.

[rocky]

Recently, RightDoubleBracket and LeftDoubleBracket were tagged as operators. I suspect that these can now be picked up from the character tables.

[rocky]

Is there a typographic difference here, or is this simply to make human comprehension easier when looking at the text?

[mmatera]

It is just human readability, and helps to compare with WMA output, which split the output in lines. Also, WMA uses indentation for the different levels, which we are not supporting right now. For example

In[1]:= a^b/c//MathMLForm                                                       

Out[1]//MathMLForm= <math>
                     <mfrac>
                      <msup>
                       <mi>a</mi>
                       <mi>b</mi>
                      </msup>
                      <mi>c</mi>
                     </mfrac>
                    </math>

while in Mathics3

In[1]:= a^b/c//MathMLForm
Out[1]//MathMLForm= <mfrac>
                    <msup>
                    <mi>a</mi> 
                    <mi>b</mi>
                    </msup>
                     <mi>c</mi>
                    </mfrac>

[mmatera]

Having the output split in lines, we can add the indentation later, or remove it from the WMA output for doing the comparison.

[rocky]

It is just human readability, and helps to compare with WMA output, which split the output in lines. Also, WMA uses indentation for the different levels, which we are not supporting right now. For example

In[1]:= a^b/c//MathMLForm                                                       

Out[1]//MathMLForm= <math>
                     <mfrac>
                      <msup>
                       <mi>a</mi>
                       <mi>b</mi>
                      </msup>
                      <mi>c</mi>
                     </mfrac>
                    </math>

while in Mathics3

In[1]:= a^b/c//MathMLForm
Out[1]//MathMLForm= <mfrac>
                    <msup>
                    <mi>a</mi> 
                    <mi>b</mi>
                    </msup>
                     <mi>c</mi>
                    </mfrac>

Ok. Got it. I was not opposed to it, but just wondered about the intention. (BTW, adding a comment to this effect will help others from wondering or thinking about this.)

[mmatera]

The question is where to leave the comment. Maybe in the head of the file?

[rocky]

I did realize that indentation is something that can be done on the fly. The question is if we want to do it. I had my doubts about adding the line breaks, because -differently from WMA graphics interface- we use mathml form to render output. So, adding complexity and length to the output makes harder to the browser show the output.

On the other hand, adding the line breaks makes easier the comparison between Mathics3 and WMA results. So, I proposed an intermediate format.

It's okay to discuss approaches before coding and PR's.

[mmatera]

OK, so, thoughts?

[rocky]

BoxExpression should have an integer "nesting_level" attribute, and that value times the string value of an indent is what prefaces the tags after a "\n".

INDENT_SPACES = "  " # or "\t" or whatever
(f"\n{self.nesting_level * INDENT_SPACES}).join(...)

[mmatera]

OK, but the first thing is that we want to indent the mathml code. A way to achieve that is to use an argument for the render functions tracking the indentation level of the context. If we agree that it a good idea, I can implement it.

[rocky]

If it is set in a BoxExpresssion object, MathML rendering can pick up this attribute using its self parameter.

[rocky]

This is where getting the proper indent level would be done.