[Info-vax] Any Way to Pass Arrays of Strings from C to Basic?

[Arne Vajhøj]

On 11/8/2019 10:18 AM, Dave Froble wrote:
> On 11/8/2019 8:16 AM, Simon Clubley wrote:
>> If there are not, then I don't see why you can't just use one of
>> the various C language SAX parsers and register your BASIC function
>> as the callback handler if you didn't want to bother with one of
>> the DOM style parsers.
> 
> If a simple routine similar to:
> 
> 100     !************************************************************
>          !                      Parse a String
>          !************************************************************
>          !
>          SUB PARSE( STG$ , DELIM$ , FRONT$ , BACK$ )
>          !
>          !       STG$            - String to parse
>          !       DELIM$          - Delimiter string
>          !       FRONT$          - Segment of string preceeding delimiter
>          !       BACK$           - Segment of string following delimiter
>          !
>          !************************************************************
>          !
>          OPTION SIZE=( INTEGER WORD , REAL DOUBLE )
> 
>          Z% = INSTR( 1% , STG$ , DELIM$ )                !  Search for 
> delimiter
>          Z% = LEN(STG$)+1% UNLESS Z%                     !  Not found, 
> whole stri
> ng
>          FRONT$ = LEFT( STG$ , Z%-1% )                   !  Preceeding 
> segment
>          BACK$ = RIGHT( STG$ , Z%+LEN(DELIM$) )          !  Following 
> segment
>                                                          !
>          SUBEND
> 
> is available, then just about anything can be extracted with two calls 
> to the routine.  For example:
> 
> <customer_number>987654321</customer_number>
> 
> can easily get the data by parsing first the front tag, then the rear tag.
> 
> I just don't see why I should f*** around with anyone else's bloatware, 
> which does so much more than what I need.

I think it depends on whether you are parsing XML or
parsing DFSML (Dave Froble Simple Markup Language).

:-)

It is actually not trivial to parse XML. Nested tags, CDATA
sections and namespaces can make it tricky to get right.

Example (VB.NET):

Imports System
Imports System.Xml

Namespace E
	Public Class Program
		Public Shared Sub Main(args As String())
			Dim xmlstr As String = "<a xmlns:df='http://df2'><b 
xmlns='http://df1'><x><![CDATA[ABC<x></x>]]></x></b><c 
xmlns='http://df2'><x><![CDATA[DEF<x></x>]]></x></c><c 
xmlns='http://df3'><x><![CDATA[GHI<x></x>]]></x></c><df:c><df:x><![CDATA[JKL<x></x>]]></df:x></df:c></a>"
			Dim doc As New XmlDocument()
			doc.LoadXml(xmlstr)
			Dim nsm As New XmlNamespaceManager(doc.NameTable)
			nsm.AddNamespace("df1", "http://df1")
			nsm.AddNamespace("df2", "http://df2")
			nsm.AddNamespace("df3", "http://df3")
			For Each n As XmlNode In doc.SelectNodes("/a/df2:c/df2:x/text()", nsm)
				Console.WriteLine(n.Value)
			Next
			Console.ReadKey()
		End Sub
	End Class
End Namespace

correctly outputs:

DEF<x></x>
JKL<x></x>

It finds all text inside a namespace http://df2 tag x element
inside inside a namespace http://df2 tag c element inside a
no namespace a element.

I would not want to code that using string functions.

Arne