What are libraries

[bplus]

Form https://qb64phoenix.com/forum/showthread.php?tid=59

PhilOfPerth asks, "Being something of a novice myself (what are "libraries"?),..."

Good question.

Libraries are code that can be used in several different apps or programs without having to rewrite same set of Constants, Types, Subs or Functions, no need to Copy/Paste into your programs.

You just put an Include statement,

         syntax: '$Include: 'MyLibrary.extension' 
            Note the comment at the start and the single quotes around the filename, these are for the compiler.

in the proper place(s) of you program to reuse code from a special "BI" file. It use to be one .BI file in older versions of QB when you had to Declare all your Subs and Functions. 

Now in QB64 there are 2 places to insert code from another file in an Include statement:
An Include statement for Constants and Types goes at the beginning of your program and typically uses the old .BI extension but not mandatory. 

The Include statement for all the Subs and Functions should go at the very bottom of your code, like you are just adding more Subs and Function in. This code file contains just Subs and Functions and the file extension is typically .BM again just a convention so people know what kind of file it is compared to a .BAS file.

Here is an example of a library I made for Arrays of Floats Type:

Here is just a normal looking Bas program dealing with Arrays of Floats

Code: (Select All)

'OPTION _EXPLICIT
' Build a set of Floats Array tools for handling Tomaaz challenge
' Build Floats Array Tools.bm from these
Randomize Timer
Dim i As Long, test$, TomaazTest$
TomaazTest$ = "120 135 345 345 1890 12 120 12 135 712 78 120"
'FOR i = 1 TO 500
'    test$ = test$ + LTRIM$(STR$(INT(RND * 100))) + " "
'NEXT
'test$ = RTRIM$(test$)
test$ = TomaazTest$
Print "Test string: "; test$

ReDim temp(0) As _Float
Split2Floats test$, " ", temp()
uniqueFloats temp()
qSortFloats LBound(temp), UBound(temp), temp()
reverseFloats temp()
Print "Output: "; JoinFloats$(temp(), 0, 10, " ")

'''''$include: 'Floats Array Tools.bm'

'a() must be initialized as redim a(lb to ub)
Sub uniqueFloats (a() As _Float) 'make all the items in the a array unique like a proper set
    Dim i As Long, ti As Long, j As Long, u As Integer, lba As Long
    lba = LBound(a)
    ReDim t(lba To lba) As _Float 'rebuild container
    t(lba) = a(lba): ti = lba
    For i = lba + 1 To UBound(a) 'for each element in array
        u = -1
        For j = lba To ti 'check if not already in new build
            If a(i) = t(j) Then u = 0: Exit For 'oh it is unique is false
        Next
        If u Then 'OK add it to rebuild
            ti = ti + 1
            ReDim _Preserve t(lba To ti) As _Float
            t(ti) = a(i)
        End If
    Next
    ReDim a(lba To ti) As _Float 'goodbye old array
    For i = lba To ti 'now copy the unique elements into array
        a(i) = t(i)
    Next
End Sub

Sub qSortFloats (start As Long, finish As Long, a() As _Float)
    Dim Hi As Long, Lo As Long, Middle As _Float
    Hi = finish: Lo = start
    Middle = a((Lo + Hi) / 2) 'find middle of array
    Do
        Do While a(Lo) < Middle: Lo = Lo + 1: Loop
        Do While a(Hi) > Middle: Hi = Hi - 1: Loop
        If Lo <= Hi Then
            Swap a(Lo), a(Hi)
            Lo = Lo + 1: Hi = Hi - 1
        End If
    Loop Until Lo > Hi
    If Hi > start Then qSortFloats start, Hi, a()
    If Lo < finish Then qSortFloats Lo, finish, a()
End Sub

Sub reverseFloats (a() As _Float)
    Dim i As Long, ti As Long
    ReDim t(LBound(a) To UBound(a)) As _Float
    ti = LBound(a)
    For i = UBound(a) To LBound(a) Step -1 'load t from top to bottom of a
        t(ti) = a(i)
        ti = ti + 1
    Next
    For i = LBound(a) To UBound(a) 'reload a from t
        a(i) = t(i)
    Next
End Sub

'notes: REDIM the a(0) as _float to be loaded before calling Split '<<<<<<<<<<<<<<<<<<<<<<< IMPORTANT!!!!
Sub Split2Floats (mystr As String, delim As String, a() As _Float)
    ' I am hoping _floats will cover any number type
    ' bplus modifications of Galleon fix of Bulrush Split reply #13
    ' http://www.qb64.net/forum/index.php?topic=1612.0
    ' this sub further developed and tested here: \test\Strings\Split test.bas
    Dim copy As String, p As Long, curpos As Long, arrpos As Long, lc As Long, dpos As Long
    copy = mystr 'make copy since we are messing with mystr
    'special case if delim is space, probably want to remove all excess space
    If delim = " " Then
        copy = RTrim$(LTrim$(copy))
        p = InStr(copy, "  ")
        While p > 0
            copy = Mid$(copy, 1, p - 1) + Mid$(copy, p + 1)
            p = InStr(copy, "  ")
        Wend
    End If
    curpos = 1
    arrpos = 0
    lc = Len(copy)
    dpos = InStr(curpos, copy, delim)
    Do Until dpos = 0
        a(arrpos) = Val(Mid$(copy, curpos, dpos - curpos))
        arrpos = arrpos + 1
        ReDim _Preserve a(arrpos + 1) As _Float
        curpos = dpos + Len(delim)
        dpos = InStr(curpos, copy, delim)
    Loop
    a(arrpos) = Val(Mid$(copy, curpos))
    ReDim _Preserve a(arrpos) As _Float
End Sub

Function JoinFloats$ (a() As _Float, aStart As Long, aStop As Long, delimiter As String)
    Dim i As Long, iStart, iStop, b As String
    If aStart < LBound(a) Then iStart = LBound(a) Else iStart = aStart
    If aStop > UBound(a) Then iStop = UBound(a) Else iStop = aStop
    For i = iStart To iStop
        If i = iStop Then
            b = b + LTrim$(Str$(a(i)))
        Else
            b = b + LTrim$(Str$(a(i))) + delimiter
        End If
    Next
    JoinFloats$ = b
End Function

---

Dang I must have run out of room couldn't continue in last post, so

What are libraries Part 2:

Now just copy all the Subs and Functions from this code, paste it into a New File in IDE, I named this file, 
"Floats Array Tools.bm"

Now you can select all those subs and functions in bas code file and delete it! Then just put one ' single quote before the Include:
Like this now:

Code: (Select All)

'OPTION _EXPLICIT
' Build a set of Floats Array tools for handling Tomaaz challenge
' Build Floats Array Tools.bm from these
Randomize Timer
Dim i As Long, test$, TomaazTest$
TomaazTest$ = "120 135 345 345 1890 12 120 12 135 712 78 120"
'FOR i = 1 TO 500
'    test$ = test$ + LTRIM$(STR$(INT(RND * 100))) + " "
'NEXT
'test$ = RTRIM$(test$)
test$ = TomaazTest$
Print "Test string: "; test$

ReDim temp(0) As _Float
Split2Floats test$, " ", temp()
uniqueFloats temp()
qSortFloats LBound(temp), UBound(temp), temp()
reverseFloats temp()
Print "Output: "; JoinFloats$(temp(), 0, 10, " ")

'$include: 'Floats Array Tools.bm'

Keep the .bm file in same folder as the bas code or worry about paths to the .bm when you include it.

Now here is the beauty of libraries, you can use that same .bm file for another program that also works with Arrays of Floats (I am keeping in same folder as .BM file)

Here I am testing a new fancy Function that will work with the Arrays of Floats that employs already developed tools in my Include file Floats Array Tools.bm

Code: (Select All)

'Test Floats Array Tools Library.bas for QB64
Print UniqueSortSlice$("120 135 345 345 1890 12 120 12 135 712 78 120", "descend", 0, 3)
Print UniqueSortSlice$("120 135 345 345 1890 12 120 12 135 712 78 120", "ascend", -10, 5) 'test join tolerance
Print UniqueSortSlice$("120 135 345 345 1890 12 120 12 135 712 78 120", "descend", 3, 16)
Print UniqueSortSlice$("1 1.1 1.11 1.1 1.11 1. 1.0 1.111 .999999999999999999999999999999999999999", "ascend", 0, 2) 'oh that's nice!!!

Function UniqueSortSlice$ (NumberStr$, ascendDescend$, SliceStart As Long, SliceEnd As Long)
    ReDim temp(0) As _Float
    Split2Floats NumberStr$, " ", temp()
    uniqueFloats temp()
    qSortFloats LBound(temp), UBound(temp), temp()
    If ascendDescend$ <> "ascend" Then reverseFloats temp()
    UniqueSortSlice$ = JoinFloats$(temp(), SliceStart, SliceEnd, " Tomaaz ")
End Function

'$include: 'Floats Array Tools.bm'

Keep in same folder and everything should work.