“Substitute Into”: I am not sure if I understand correctly. What I frequently do is for example: subs((2),(1)). Here I do not need to attribute a name to (1) in order to substitute something into it.
But maybe you refer to the following behavior of Maple that I overlooked: When hiding an equation label by Format>Equation Labels>Selection each instance of an equation label in a Maple input is replaced by the output the equation label is referring to. This could cause two unwanted effects: Firstly, all Maple inputs referring to equation labels to be hidden would blow up by output insertion. Secondly, this replacement process might be not reversible (although it is in the attached example on “hidden labels” in text passages; see Note 1).
With that in mind only two supposedly low hanging fruits are left from my original list:
- In a text passage or Maple input: Double click on a label reference to open the insert label dialogue (crtl-L) in order to change the reference (instead of deleting the reference and inserting a new reference). A nice time saver because I frequently have to correct or modify input.
- For larger documents: A search function for equation labels in a document.
Would this be feasible without changing the equation label iimplementaion too much?
In case a rethink of equation labels is something you consider it might be an opportunity to rename them to “expression labels” since they refer to much more than equations.