c# – 使用Roslyn拆分Expression语句

2019年8月5日 233次阅读

我正在开发一个重新描述CSharp代码的应用程序.我和Roslyn一起做这个.我面临分裂表达式的问题.

样班

class Program
{
    static void Main(string[] args)
    {
        float floatVariable = 20;
        Int16 intVariable = 10;
        string str = "School";
        Console.Write(str + floatVariable.ToString() + intVariable.ToString()); // Facing problem with this statement
    }
}

我正在使用的示例代码

string code = new StreamReader(classPath).ReadToEnd();
var syntaxTree = CSharpSyntaxTree.ParseText(code);
var syntaxRoot = syntaxTree.GetRoot();

//This will get the method and local variables declared inside the method
var MyMethods = syntaxRoot.DescendantNodes().OfType<MethodDeclarationSyntax>();
foreach (MethodDeclarationSyntax mds in MyMethods)
{
    syntaxTree = CSharpSyntaxTree.ParseText(mds.ToFullString());
    IEnumerable<SyntaxNode> nodes = syntaxTree.GetRoot().DescendantNodes();
    IEnumerable<VariableDeclarationSyntax> variableDeclarations =       nodes.OfType<VariableDeclarationSyntax>();
    foreach (VariableDeclarationSyntax variable in variableDeclarations)
    {
    // I will collect the variable details like Datatype, variable names and initialized values  here
    }


    foreach (StatementSyntax statement in mds.Body.Statements)
    {
        if (statement.CSharpKind() == SyntaxKind.ExpressionStatement)
        {
            //I want to split the expressions "Console.Write(str + floatVariable.ToString() + intVariable.ToString());" as below

            //1. intVariable.ToString()
            //2. floatVariable.ToString()
            //3. str

            //Then I have to find the whole data type from the resolved result of above 3 => string here            
        }
    }
}

任何帮助将不胜感激.

编辑：
我在分割参数化表达式语句时遇到了麻烦.我试图这样做,

if (statement.CSharpKind() == SyntaxKind.ExpressionStatement)
{
    ExpressionStatementSyntax expression = statement as ExpressionStatementSyntax;
    var expressions = expression.Expression.DescendantNodes();
}

但是这会将每个标记分成一个单独的元素.我只想将Console.Write(str floatVariable.ToString()intVariable.ToString())拆分为,

> Console.Write()
> str
> intVariable.ToString()
> floatVariable.ToString()

最佳答案 很难说出你想要做什么,因为你只在一个特定情况下指定了代码应该做什么,而不是一般.

我解释它的方式是：

>对于调用表达式,返回正在调用的表达式,并返回其参数(如果有).
>对于二元运算符,下降到两个子节点.
>对于所有其他表达式,直接返回表达式.

使用此规范并使用CSharpSyntaxVisitor,代码可能如下所示：

public static IEnumerable<ExpressionSyntax> Split(ExpressionSyntax expression)
{
    return new SplitVisitor().Visit(expression);
}

class SplitVisitor : CSharpSyntaxVisitor<IEnumerable<ExpressionSyntax>>
{
    public override IEnumerable<ExpressionSyntax> VisitInvocationExpression(
        InvocationExpressionSyntax node)
    {
        yield return node.Expression;

        var argumentExpressions = node.ArgumentList.Arguments
            .SelectMany(a => Visit(a.Expression));
        foreach (var expression in argumentExpressions)
            yield return expression;
    }

    public override IEnumerable<ExpressionSyntax> VisitBinaryExpression(
        BinaryExpressionSyntax node)
    {
        foreach (var expression in Visit(node.Left))
            yield return expression;
        foreach (var expression in Visit(node.Right))
            yield return expression;
    }

    public override IEnumerable<ExpressionSyntax> DefaultVisit(SyntaxNode node)
    {
        var expression = node as ExpressionSyntax;
        if (expression != null)
            yield return expression;
    }
}
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