在 .NET 中解析 VB6 代码 [英] parsing VB6 code in .NET

问题描述

我有一个用 C# 编写的 WPF 项目，为了获取有关外部依赖项的一些信息，我需要解析一个 VB6 脚本.脚本的位置发生了变化，其内容也发生了一些变化，但我感兴趣的主要代码将是以下格式:

I have a WPF project written in C#, and in order to get some information about an external dependency, I need to parse a VB6 script. The script's location changes and its content changes some, but the main code I'm interested in will be of the format:

Select Case Fields("blah").Value
    Case "Some value"
        Fields("other blah").List = Lists("a list name")
    ...
End Select

我需要从中提取当字段 'blah' 设置为 'some value' 时，字段 'other blah' 的列表更改为列表 'a list name'.我尝试在谷歌上搜索一个编写为 .NET 库的 VB6 解析器，但还没有找到任何东西.冒着得到这个答案的风险，我应该只使用正则表达式在VB6脚本中找到这样的代码，然后提取我需要的数据吗?该代码在子例程中找到，因此我无法传入blah"、some value"并取回other blah"、列表名称".我无法控制这个 VB6 脚本的内容.

I need to extract from this that when field 'blah' is set to 'some value', the list for field 'other blah' changes to list 'a list name'. I tried Googling around for a VB6 parser written as a .NET library but haven't found anything yet. At the risk of getting an answer like this one, should I just use regular expressions to find the code like this in the VB6 script, and extract the data I need? The code is found in a subroutine such that I can't pass in 'blah', 'some value' and get back 'other blah', 'a list name'. I have no control over the contents of this VB6 script.

推荐答案

你可以分几步解析它.请注意，正则表达式会遗漏字符串和注释，因此请谨慎使用.

You can parse it in a few steps. Please note the regex misses strings and comments, so use with care.

首先，我们将为 Fields("Target").List = Lists("Value") 行使用帮助类:

First, we'll use a helper class for the Fields("Target").List = Lists("Value") lines:

class ListData
{
    public string Target { get; set; }
    public string Value { get; set; }
}

输出模式:

string patternSelectCase = @"
Selects+Cases+Fields(""(?<CaseField>[ws]+)"").Value
(?<Cases>.*?)
Ends+Select
";

string patternCase = @"
Cases+""(?<Case>[ws]+)""s+
(?:Fields(""(?<Target>[ws]+)"").Lists*=s*Lists(""(?<Value>[ws]+)"")s+)*
";

接下来，我们可以尝试分两遍解析文本(顺便说一下，代码有点难看，但相当基本):

Next, we can try to parse the text in two passes (the code is a little ugly, by the way, but fairly basic):

MatchCollection matches = Regex.Matches(vb, patternSelectCase,
        RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace | 
        RegexOptions.Singleline);

Console.WriteLine(matches.Count);

var data = new Dictionary<String, Dictionary<String, List<ListData>>>();
foreach (Match match in matches)
{
    var caseData = new Dictionary<String, List<ListData>>();
    string caseField = match.Groups["CaseField"].Value;
    string cases = match.Groups["Cases"].Value;

    MatchCollection casesMatches = Regex.Matches(cases, patternCase,
             RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace | 
             RegexOptions.Singleline);
    foreach (Match caseMatch in casesMatches)
    {
        string caseTitle = caseMatch.Groups["Case"].Value;
        var targetCaptures = caseMatch.Groups["Target"].Captures.Cast<Capture>();
        var valueCaptures = caseMatch.Groups["Value"].Captures.Cast<Capture>();
        caseData.Add(caseTitle, targetCaptures.Zip(valueCaptures, (t, v) =>
            new ListData
            {
                Target = t.Value,
                Value = v.Value
            }).ToList());
    }

    data.Add(caseField, caseData);
}

现在您有了一个包含所有数据的字典.例如:

Now you have a dictionary with all data. For example:

string s = data["foo"]["Some value2"].First().Value;

这是一个工作示例:https://gist.github.com/880148

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