proper counting of switch/case/default control structures

[paulbuis]

gocyclo simply counts ast.CaseClause nodes to compute the cyclomatic complexity of a switch/case with optional default. The the default case should be counted even if it is absent (in which case we can ignore it if it is present and count the ast.SwitchStmt node instead) or maybe it should be ignored when it is present. I suppose ignoring it would be equivalent to not counting the else in an if/else.

The way the code is now is simple and elegant and I doubt the occasional off-by-one is a big deal.

There may be a similar issue with select statement and ast.CommClause nodes, but I haven't looked at that as closely.

[paulbuis]

Perhaps something like this modification would deal with this issue?

func (v *complexityVisitor) Visit(n ast.Node) ast.Visitor {
    switch n := n.(type) {
    case *ast.FuncDecl, *ast.FuncLit, *ast.IfStmt, *ast.ForStmt, *ast.RangeStmt:
        v.Complexity++
    case *ast.CaseClause: 
        if n.List != nil { // ignore default case
            v.Complexity++
        }
    case *ast.CommClause:
        if n.Stmt != nil { // ignore default case
            v.Complexity++
        }
    case *ast.BinaryExpr:
        if n.Op == token.LAND || n.Op == token.LOR {
            v.Complexity++
        }
    }
    return v
}