Optional substitution

[Proektsoftbg]

Probably, it would be good to have a switch to turn the variable substitution on and off inside a worksheet, e.g.: #vs and #novs. This can be useful if you have very long expressions in your worksheet.

However, it is possible to do it even now by combining #equ and #noc switches. I got a question by email about this and want to share the answer in case anybody else need this as well. For that purpose, I made a little macro:

#def no_subst$(var$; expr$)
    #hide
    var$ = expr$
    #show
    #noc
    '<p>'var$ = expr$
    #val
    '<span class="eq"> = 'var$'</span></p>
    #equ
    #end def

You can use it by calling the macro with the variable and the expression. For example, you have c = (a + b)^2, you can write:
no_subst$(c; (a + b)^2)