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

[TheAutomator]

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:

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 August 5, 2015 by TheAutomator

[TheAutomator]

I found this:

https://code.google.com/p/bsn-goldparser/wiki/CodePatterns

can anyone help me translate what the code for "<ArgumentList>" does to vb?

Help would be very appreciated!

Edited August 7, 2015 by TheAutomator

[TheAutomator]

Nobody? 

[Melba23]

TheAutomator,

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

You might have more luck on a specialist VB forum.

M23 

[jchd]

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.

[TheAutomator]

Melba23,

Yes, I guess so, I tried here because I saw "vbscript" as one at the languages in the description of the "Language Specific Discussion" board.

Also the forums here are very active and most of the time you get a reply quickly here .

jchd,

Nice example .