Expression tree inspection for redundant signs, parentheses and operators

[ThunderFrame]

VBA allows for multiple negative signs. In most cases, they can be simplified.

  Dim bankBalance As Double

  bankBalance = -----1 ' -1
  bankBalance = ----1  '  1
  bankBalance = ---1#  ' -1#
  bankBalance = ----1& '  1&

[ThunderFrame]

lol - #2222 for an issue about repeated characters 😄

[retailcoder]

I think this inspection needs to be a bit broader - it's going to have to analyze expression trees, and doing that only to issue an inspection result the odd time a double negative sign is encountered seems a bit of a waste. Let's make it about redundant signs, parentheses and operators - and make it trip when it encounters convoluted expressions such as:

If Not (foo <> 42) Then

..which would simplify/fix to:

If foo = 42 Then

[retailcoder]

Inspection for redundant parentheses will be a problem until #2206 is fixed.

[ThunderFrame]

Could we perhaps make a distinction between expressions that can be optimized, and expressions that are just wrapped in parentheses for no good reason?

Optimization seems potentially hard:
If Not (foo <> 42) Then
If foo = 42 Then

These seem easier:
If (foo = 42) Then
If foo = 42 Then

Do: i = i + 1: Loop While (a(i) < v)
Do: i = i + 1: Loop While a(i) < v

[PeterMTaylor]

Would RegEx compliment or complicate this?

[ThunderFrame]

Regex would probably be inadequate. You need to find balanced parentheses around an expression, where removing the parentheses would result in an identical expression.

This expression starts and ends with ( and ), but the removal of the parentheses would result in an invalid expression:

x = (1 - 2) / (3 + 4) becomes a syntax error: x = 1 - 2) / (3 + 4

This expression is still valid, after the removal of the surrounding parentheses (even if there is further optimization possible:

x = (1 + (2 + 3)) becomes x = 1 + (2 + 3)

[ThunderFrame]

we should be able to identify the most basic forms:

x = (True)
If (True) Then
While (True)