Hans, that is *not* supposed to work in those cases because a \par or an empty line determine an end-of-paragraph, so the formula starts a new paragraph and the lenght of the previous line is *irrelevant* --you don't have a mid-paragraph display.
I know that you like those freeform spacey sources, but they are not really 100% compatible with the empty line => paragraph concept of TeX :)
Thursday, September 18, 2003 Hans Hagen wrote:
well, the problem is that in both cases:
text $$math$$ text
text \par $$math$$ \par text
one wants to optimize spacing, so the limitation of not having access to the last line length is a pitty (i understand that it can be tricky in cases like:
text \par somevboxmanipulation $$math$$
since then one may wonder what the last line length applies to
The point is that it's not true that in both cases one wants to optimize spacing because the two cases have a totally different meaning: in the first case you have a displayed equation within a paragraph, so it makes sense to "optimize spacing" to put the text and the formula as close together as possible (within aesthetical limits). In the second case you have a formula which is on a paragraph of its own, and is therefore "absolute" from the surrounding text. In this case you *don't* want to put the formula and text as close together as possible because they are (supposedly) logically *independent* concepts and having them more spaced in the printout helps noticing this difference. In the end it always end up on the totally different views on displayed material that you and TeX have. We discussed this for the "autoindent" stuff, remember? You always consider displays a "separate entity" from the surrounding text, whereas TeX allows it to be separate or not (depending on \pars around it). TeX approach is both more flexible and more "correct". Let's say for example that we're discussing Einstein's equation. The following three examples have different logical meaning and should therefore be formatted appropriately differently: === EXAMPLE 1: Display part of the paragraph === Einstein's equation $$E=mc^2$$ ties energy and mass of a body to etc === EXAMPLE 2: Display part of the previous paragraph but not of the following one === A relation between mass and energy of a body is expressed by Einstein's equation $$E=mc^2.$$ We shall see further on that etc === EXAMPLE 3: Display part of the following paragraph but not of the previous one === some text etc. $$E=mc^2$$ is Einstein equation and it ties energy and mass of a body etc. ================================================ In Ex1, you want the displayed equation to have as little spacing as possible both above and below, and the following text should NOT start with an indent. In Ex2, you want the displayed equation to be as close as possible to the previous text, and to have some spacing below, to ensure that it's clearly distinguishable from the next paragraph, which is a new entity. Also, the following text should start with an indent. In Ex3, you want there to be more space above than below because the previous text is independent from the equation. On the contrary, it should be close together with the following text which is in the same paragraph as the equation. The following text should NOT be indented. Now, while we solved the indenting issue with the introduction of the indentnext=auto key=value, which automatically takes care of the various cases, you now have to convince yourself that the same must hold true for spacing around displayed material: text $$math$$ text and text\par $$math$$\par text are NOT the same thing and should be treated differently! -- Giuseppe "Oblomov" Bilotta