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Opened 9 months ago

Closed 6 months ago

Last modified 6 months ago

#3869 closed Bug (Fixed)

Subtraction operator before power operation is parsed incorrectly

Reported by: AspirinJunkie Owned by: Jon
Milestone: 3.3.16.1 Component: AutoIt
Version: 3.3.16.0 Severity: None
Keywords: power minus Cc:

Description

For the operation of the basic form a - b^e, the result depends on the data type of the base b and the parity of the exponent e.

The following test script:

Global $sString = ""

$x = 2

$y = 4
$sString = StringFormat("% 15s = %d\n", "11 - 2 ^ 4", 11 - 2 ^ 4) & _
    StringFormat("% 15s = %d\n", "11 - 2.0 ^ 4", 11 - 2.0 ^ 4) & _
        StringFormat("% 15s = %d\n", "11 - 2e0 ^ 4", 11 - 2e0 ^ 4) & _
        StringFormat("% 15s = %d\n", "11 - '2' ^ 4", 11 - '2' ^ 4) & _
        StringFormat("% 15s = %d\n", "11 - $x ^ 4", 11 - $x ^ 4) & _
        StringFormat("% 15s = %d\n", "11 - (2 ^ 4)", 11 - (2 ^ 4)) & _
        StringFormat("% 15s = %d\n", "11 - - 2 ^ 4", 11 - - 2 ^ 4) & _
        StringFormat("% 15s = %d\n\n", "11 - 2 ^ $y", 11 - 2 ^ $y) 

$y = 3
$sString &= StringFormat("% 15s = %d\n", "11 - 2 ^ 3", 11 - 2 ^ 3) & _
    StringFormat("% 15s = %d\n", "11 - 2.0 ^ 3", 11 - 2.0 ^ 3) & _
        StringFormat("% 15s = %d\n", "11 - 2e0 ^ 3", 11 - 2e0 ^ 3) & _
        StringFormat("% 15s = %d\n", "11 - '2' ^ 3", 11 - '2' ^ 3) & _
        StringFormat("% 15s = %d\n", "11 - $x ^ 3", 11 - $x ^ 3) & _
        StringFormat("% 15s = %d\n", "11 - (2 ^ 3)", (11 - 2 ^ 3)) & _
        StringFormat("% 15s = %d\n", "11 - - 2 ^ 3", 11 - 2 ^ 3) & _
        StringFormat("% 15s = %d\n\n", "11 - 2 ^ $y", 11 - 2 ^ $y) 

ConsoleWrite($sString)

produces under 3.3.16.0:

     11 - 2 ^ 4 = 27
   11 - 2.0 ^ 4 = 27
   11 - 2e0 ^ 4 = 27
   11 - '2' ^ 4 = -5
    11 - $x ^ 4 = -5
   11 - (2 ^ 4) = -5
   11 - - 2 ^ 4 = -5
    11 - 2 ^ $y = 27

     11 - 2 ^ 3 = 3
   11 - 2.0 ^ 3 = 3
   11 - 2e0 ^ 3 = 3
   11 - '2' ^ 3 = 3
    11 - $x ^ 3 = 3
   11 - (2 ^ 3) = 3
   11 - - 2 ^ 3 = 3
    11 - 2 ^ $y = 3

and under 3.3.14.5:

  11 - 2 ^ 4 = 27
11 - 2.0 ^ 4 = -5
11 - 2e0 ^ 4 = -5
11 - '2' ^ 4 = -5
 11 - $x ^ 4 = -5
11 - (2 ^ 4) = -5
11 - - 2 ^ 4 = -5
 11 - 2 ^ $y = 27

  11 - 2 ^ 3 = 3
11 - 2.0 ^ 3 = 3
11 - 2e0 ^ 3 = 3
11 - '2' ^ 3 = 3
 11 - $x ^ 3 = 3
11 - (2 ^ 3) = 3
11 - - 2 ^ 3 = 3
 11 - 2 ^ $y = 3

Two possible explanations for this behaviour:

  1. binary minus is misinterpreted as unary minus:
    • The minus has two functions - once as a binary minus operator and once as a unary sign operator.
    • The tricky thing about this is that the binary operator has a lower priority than the power operator.
    • The sign operator, on the other hand, has a higher priority (in contrast to mathematics) than the power operator.
    • This leads to the implicit execution (-2)^4
    • The basic problem here, however, is that even if the minus here is only interpreted as a sign operator, we still lack a binary operator that links the right side with the 11. The parser seems to assume a plus operator for this.
    • Furthermore, there is no indication in the AutoIt documentation so far that the sign operator has a higher valence than the power operator.
  1. the minus is executed twice:
    • the --Operator seem to be executed twice - once as a unary operator (sign) and once as a binary operator (the minus operation).
    • This leads to the implicit calculation 11 - (-(2^4))

Attachments (0)

Change History (5)

comment:1 Changed 8 months ago by Jpm

Hi,
the main problem was coming from a regression introduce by #3772
But it was still a pb with 3.3.14.5 which must return -5 all the time
The unary operator is not really handled in AutoIt
The fix has been sent to Jon

comment:2 Changed 8 months ago by Jpm

  • Owner set to Jpm
  • Status changed from new to assigned

comment:3 Changed 6 months ago by Jpm

  • Milestone set to 3.3.15.6
  • Resolution set to Fixed
  • Status changed from assigned to closed

Fixed by revision [12735] in version: 3.3.15.6

comment:4 Changed 6 months ago by Jpm

  • Milestone changed from 3.3.15.6 to 3.3.16.1

Fixed by revision [12736] in version: 3.3.16.1

comment:5 Changed 6 months ago by Jon

  • Owner changed from Jpm to Jon

Fixed by revision [12757] in version: 3.3.16.1

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