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Backus-Naur-vorm: How to parse a list?


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Hi everyone ;)

Are there any people here that know how to use a parser generator that uses 'bnf' (not 'ebnf'!)

i'm using the gold parser:

http://goldparser.org/index.htm

not possible in autoit:

https://www.autoitscript.com/forum/topic/167663-activex-gold-parser-in-autoit-is-this-possible/

What i'm looking for is the best way to parse a list:

<List> ::= <Item> ',' <List> | <Item>
<Item> ::= Number | String

for example, the tree returned from:

'test', 1, 2

is:

Knipsel.thumb.GIF.23c30c1664da3eaabf9996

since its not possible in AutoIT code I did it in vb script.

this is what i did:

' in the parse loop:

Case Rule_List_Comma
    set result = new list
    call result.input(.tokens(0).data,.tokens(2).data)

' the list class:

class list
    private arg0
    private arg1
    public sub input(a,b)
        set arg0 = a
        set arg1 = b
    end sub
    private sub push(item,byref stack)
        redim preserve stack(ubound(stack) + 1)
        stack(ubound(stack)) = item
    end sub
    public function value
        value = array(arg0.value)
        value2 = arg1.value
        if isarray(value2) then
            for each thing in value2
                push thing,value
            next
        else
            push value2,value
        end if
    end function
end class

 

is there a better way to do this?

 

regards,

TheAutomator

Edited by TheAutomator
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  • 3 weeks later...
  • Moderators

TheAutomator,

can anyone help me translate [...] to vb?

You might have more luck on a specialist VB forum.

M23 

Public_Domain.png.2d871819fcb9957cf44f4514551a2935.png Any of my own code posted anywhere on the forum is available for use by others without any restriction of any kind

Open spoiler to see my UDFs:

Spoiler

ArrayMultiColSort ---- Sort arrays on multiple columns
ChooseFileFolder ---- Single and multiple selections from specified path treeview listing
Date_Time_Convert -- Easily convert date/time formats, including the language used
ExtMsgBox --------- A highly customisable replacement for MsgBox
GUIExtender -------- Extend and retract multiple sections within a GUI
GUIFrame ---------- Subdivide GUIs into many adjustable frames
GUIListViewEx ------- Insert, delete, move, drag, sort, edit and colour ListView items
GUITreeViewEx ------ Check/clear parent and child checkboxes in a TreeView
Marquee ----------- Scrolling tickertape GUIs
NoFocusLines ------- Remove the dotted focus lines from buttons, sliders, radios and checkboxes
Notify ------------- Small notifications on the edge of the display
Scrollbars ----------Automatically sized scrollbars with a single command
StringSize ---------- Automatically size controls to fit text
Toast -------------- Small GUIs which pop out of the notification area

 

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I don't know (nor care) for VB, but you can parse much with AutoIt:

Local $pattern =    "(?x)" & _      ; spaces in expression aren't significant
                    "(?(DEFINE) (?<Arg> \s* \w+ \s* ))" & _     ; define what an argument should match
                    "(?(DEFINE) (?<ArgList> (?&Arg) , (?&ArgList) | (?&Arg) ))" & _     ; recursively define a list of arguments
                    "^ \s* \w+ \s* \( (?: \s* | (?&ArgList) ) \) \s* $"     ; check that the statement matches a fonction call
Local $res
Local $a = [ _
    "fct(arg) ", _                          ; valid
    " fct ( arg1,  arg2,arg3 )", _      ; valid
    "fct() ", _                         ; valid
    " fct ( arg1, , arg2,arg3 )", _     ; empty arg = invalid
    " fct ( arg1, arg2,arg3 , )", _     ; extra comma = invalid
    " fct  arg1, arg2,arg3 , )", _      ; no opening parenthesis = invalid
    " fct ( arg1, arg2,arg3 , ***)", _  ; invalid argument = invalid
    "( arg1, arg2,arg3 )", _            ; no function name = invalid
    " fct ( arg1  arg2,arg3 )" _        ; missing comma = invalid
]
For $s In $a
    $res = StringRegExp($s, $pattern)
    ConsoleWrite($s & " " & ($res ? "matched" : "doesn't match") & @LF)
Next

I ain't going to dig deeper into this BTW.

This wonderful site allows debugging and testing regular expressions (many flavors available). An absolute must have in your bookmarks.
Another excellent RegExp tutorial. Don't forget downloading your copy of up-to-date pcretest.exe and pcregrep.exe here
RegExp tutorial: enough to get started
PCRE v8.33 regexp documentation latest available release and currently implemented in AutoIt beta.

SQLitespeed is another feature-rich premier SQLite manager (includes import/export). Well worth a try.
SQLite Expert (freeware Personal Edition or payware Pro version) is a very useful SQLite database manager.
An excellent eBook covering almost every aspect of SQLite3: a must-read for anyone doing serious work.
SQL tutorial (covers "generic" SQL, but most of it applies to SQLite as well)
A work-in-progress SQLite3 tutorial. Don't miss other LxyzTHW pages!
SQLite official website with full documentation (may be newer than the SQLite library that comes standard with AutoIt)

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