QB64 Phoenix Edition
Illegal string-number conversion - Printable Version

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Illegal string-number conversion - Herve - 07-02-2025

Hello,

I am new to this forum and also to using QB64PE.
Here is a piece of code that causes the following error. 
Could you tell me what is wrong?

Illegal string-number conversion
Caused by (or after):GLOP . ELEMENT . S = "Home",4
LINE 15:glop.element.s = "Home"

Code: (Select All)
type SomeType
    i as Integer
    s as string
    d as double
end type

type OtherType
    element as SomeType
end type

dim shared glop.element as OtherType

glop.element.I = 1
glop.element.d = 5.726E45
glop.element.s = "Home"
thank's

RE: Illegal string-number conversion - Jack - 07-02-2025

use Dim Shared glop As OtherType

RE: Illegal string-number conversion - Herve - 07-02-2025

Thank's a lot !

RE: Illegal string-number conversion - TempodiBasic - 07-05-2025

@Herve 
welcome

it is an interesting glitch of parser

[Image: Rules-for-naming-variables-in-Qbasic.png]


[Image: Rules-of-DOT-in-naming-an-UDT-variables-by-TYPES.png]




[Image: Rules-ofnamingvariables-by-DIM.png]




Code: (Select All)
Option _Explicit

Type SomeType

    i As Integer

    s As String

    d As Double

End Type



Type OtherType

    element As SomeType

End Type



Dim S.t.Q As String

Dim Shared S.t.S As Single

Dim Shared glop.w As OtherType 'glop.element has been changed into glop.w to avoid misunderstandment



S.t.Q = "Mio"

' it is legal to use DOT "." in the name of variable, so how can the Parser distinguish between an UDT and a simple variable?

S.t.S = 1.0



glop.w.element.i = 0

glop.w.element.d = 5.726E45

glop.w.element.s = "Home"

End
In Lubuntu and QB64pe 4.1.

RE: Illegal string-number conversion - eoredson - 07-06-2025

btw: before you even get into it, this cannot be done:

Code: (Select All)
Type Struct
   Array(1 to 10) As Integer
End Type
Dim StructVar As Struct
because QB64 does not support UDT arrays (yet)..

Wish I knew who is currently working on them now!?

However you can make an array of a UDT such as:

Code: (Select All)
Type Struct
   Var1 As Integer
End Type
Dim StrucArray(1 To 10) As Struct
For L = 1 To 10
   StrucArray(L).Var1 = L
Next


RE: Illegal string-number conversion - Herve - 07-06-2025

@TempodiBasic
We can also see this on the page https://qb64phoenix.com/qb64wiki/index.php/Variable  :

"Variables in QB64 can be any name except the names of QB64 or QBasic keywords and may not contain spaces or non-alphabetical/non-numerical characters (except "." and "_"). Numerical characters cannot be used as the first character of a variable or array name! QB64 reserves the use of a leading underscore to QB64 procedural or variable type names only!"

I notice that with OPTION _EXPLICIT we no longer get “Illegal string-number conversion” but instead:
“Variable ‘glop__ASCII_CHR_046__w__ASCII_CHR_046__element__ASCII_CHR_046__i’ (SINGLE) not defined”

I will now prefer using an underscore instead of a dot when naming variables; by using the dot exclusively for variables in a UDT, I’ll avoid triggering the parser bug. 

And from now on, I’ll be using OPTION _EXPLICIT.

RE: Illegal string-number conversion - TempodiBasic - 07-06-2025

Hi @Herve
yeah there must be something to define and rule, 
the first image about rules for naming a variable it has been taken from a online tutorial about Qbasic.
I dunno if in Qbasic and in QB4.5  the DOT is allowed out of UDT's name reference in the code.

and I totally agree that Option _Explicit is a handy wonderful tool!

RE: Illegal string-number conversion - a740g - 07-07-2025

IMO, it would be a nice to have an option under Options > Compiler Settings to enable Option _Explicit behavior by default. The QB64-PE compiler already supports this via the -e switch, so the functionality exists.

Many modern BASIC IDEs provide a similar setting, allowing users to enforce explicit variable declarations as a project-wide preference.