☑ cool new feature

☑ could help many users!

☑ removes something that feels like a „bug“

☐ nice to have

☐ nobody needs it

**What inspired this wish list request? **

Substitute is a very powerful function for expression handling:

Using JSL to Develop Efficient, Robust Applications (EU 2018 415)

A big disadvantage of Substitute: it evaluates it's arguments : (

Therefore, Expressions with Substitute() get quite lengthy and hard to read. Besides that, a new JSL scripter has to learn the correct syntax - nobody expects that all those Expr() are necessary.

Example:

`Substitute( Expr( a + Sqrt( a ) ), Expr( a ), Expr( b ) )`

**What is the improvement you would like to see? **

A new function subst () which doesn't evaluate it's arguments. Then one can write :

`Substitute( a + Sqrt( a ), a, b )`

**Why is this idea important? **

Subst() and Eval(Subst()) will be used millions of times - and each time a JSL scripter will be happy that you implemented it!

other wishes from