Post Reply 
Somewhere between a bug or feature:
12-12-2016, 11:31 AM (This post was last modified: 12-12-2016 03:54 PM by Jan_D.)
Post: #10
RE: Somewhere between a bug or feature:
Like in many other cases I think it increases clarity when we turn off Textbook Display for History, so uncheck Textbook Display in second page of Home Settings.

When we do this the substitution operation is always displayed in History with parentheses, in the form (argument | a=b), so we clearly see what we are doing.

Like Han pointed out ‘argument’ is generally not evaluated prior to substitution, apart from the exceptional case where ‘argument’ is a simple identifier which represents a variable containing an expression.

With simple identifier I mean that when ‘argument’ =k(1), k(1) is not evaluated prior to substitution.
k(1) can be the first element of a list.

This is often not what we expect, and therefore it can be a good idea to first store argument into a variable, say f, and then calculate (f |a=b).

Another possibility is to use subst(expression, a=b), which causes no problems.
Find all posts by this user
Quote this message in a reply
Post Reply 


Messages In This Thread
Somewhere between a bug or feature: - DrD - 11-13-2014, 05:52 PM
RE: Somewhere between a bug or feature: - Jan_D - 12-12-2016 11:31 AM



User(s) browsing this thread: 1 Guest(s)