PureBasic

'''PureBasic''' is a high-level programming language by Fantaisie Software based on BASIC rules. PureBasic has been created for beginners and experts alike.

PureBasic is a portable programming language with current up-to-date implementations on Windows, Linux, and MacOS. The same code can be compiled and run natively on each OS. An older version for the Amiga platform is also available, but no longer maintained.

See Also

Merged content

  • uses an integer cell size and memory size is allowed to grow as needed.
Procedure displayEndingMsg()
  Print(#CRLF$ + #CRLF$ + "Press ENTER to exit")
  Input()
  CloseConsole()
  End
EndProcedure

Procedure displayErrorThenEnd(msg.s)
  PrintN(msg)
  displayEndingMsg()
EndProcedure

Macro bracketSearch(drx = 1) ;drx = -1 to search backwards
  bktCnt = drx ;start count with the current bracket
  ;count nested loops till matching one is found
  Repeat
    i + drx ;move the code pointer
    If Mid(code$, i, 1) = "]"
      bktCnt - 1
    ElseIf Mid(code$, i, 1) = "["
      bktCnt + 1
    EndIf
  Until bktCnt = 0
EndMacro

If Not OpenConsole()
  MessageRequester("Error", "Unable to open console.")
  End
EndIf

Define memsize = 1000          ;this may grow as needed
Define instChars$ = "+-<>.,[]" ;valid characters
Define ptr = 0                 ;memory pointer

Print("Filename (blank to use std in)...? ")
filename$ = Input()
If filename$ = ""
  Repeat
    line$ = Input()
    source$ = source$ + line$
  Until line$ = ""
Else
  OpenFile(1, filename$)
  Repeat
    line$ = ReadString(1)
    source$ = source$ + line$
  Until Eof(1)
  CloseFile(1)
EndIf

;remove non-code and validate number of brackets
bktCnt = 0
For i = 1 To Len(source$)
  char$ = Mid(source$, i, 1)
  ;validate instruction character
  If FindString(instChars$, char$, 1)
    code$ + char$
    ;count brackets
    Select char$
      Case "["
        bktCnt + 1
      Case "]"
        bktCnt - 1
    EndSelect
  EndIf
Next

If bktCnt  ;mismatched brackets
  displayErrorThenEnd("Uneven brackets")
EndIf

Dim memory(memsize) ;use integer cell size
Define inLine$ = "" ;input buffer
For i = 1 To Len(code$) ;loop through the code
  Select Mid(code$, i, 1) ;examine the current instruction
    Case "+"
      memory(ptr) + 1
    Case "-"
      memory(ptr) - 1
    Case "."
      Print(Chr(memory(ptr)))
    Case ","
      If inLine$ = "": inLine$ = Input(): EndIf ;buffer input
      memory(ptr) = Asc(Left(inLine$, 1))       ;store first char off the buffer
      inLine$ = Mid(inLine$, 2)                 ;delete first char from the buffer
    Case ">"
      ptr + 1
      If ptr > memsize
        memsize + 1000
        Redim memory(memsize)
      EndIf
    Case "<"
      ptr - 1
      If ptr < 0
        displayErrorThenEnd("Memory pointer out of range")
      EndIf
    Case "["
      If memory(ptr) = 0
        bracketSearch()
      EndIf
    Case "]"
      If memory(ptr) <> 0
        bracketSearch(-1)
      EndIf
  EndSelect
Next
displayEndingMsg()

Tasks