Beispiel #1
0
func (ctxt *Context) visitExpr(f *ast.File, e ast.Expr, local bool, visitf func(*Info) bool) bool {
	var info Info
	info.Expr = e
	switch e := e.(type) {
	case *ast.Ident:
		if e.Name == "_" {
			return true
		}
		info.Pos = e.Pos()
		info.Ident = e
	case *ast.SelectorExpr:
		info.Pos = e.Sel.Pos()
		info.Ident = e.Sel
	}
	obj, t := types.ExprType(e, ctxt.importer)
	if obj == nil {
		ctxt.logf(e.Pos(), "no object for %s", pretty(e))
		return true
	}
	info.ExprType = t
	info.ReferObj = obj
	if parser.Universe.Lookup(obj.Name) != obj {
		info.ReferPos = types.DeclPos(obj)
		if info.ReferPos == token.NoPos {
			name := pretty(e)
			if name != "init" {
				ctxt.logf(e.Pos(), "no declaration for %s", pretty(e))
			}
			return true
		}
	} else {
		info.Universe = true
	}
	info.Local = local
	oldName := info.Ident.Name
	more := visitf(&info)
	if info.Ident.Name != oldName {
		ctxt.ChangedFiles[ctxt.filename(f)] = f
	}
	return more
}
Beispiel #2
0
func checkExprs(t *testing.T, pkg *ast.File, importer Importer) {
	var visit astVisitor
	stopped := false
	visit = func(n ast.Node) bool {
		if stopped {
			return false
		}
		mustResolve := false
		var e ast.Expr
		switch n := n.(type) {
		case *ast.ImportSpec:
			// If the file imports a package to ".", abort
			// because we don't support that (yet).
			if n.Name != nil && n.Name.Name == "." {
				stopped = true
				return false
			}
			return true

		case *ast.FuncDecl:
			// add object for init functions
			if n.Recv == nil && n.Name.Name == "init" {
				n.Name.Obj = ast.NewObj(ast.Fun, "init")
			}
			return true

		case *ast.Ident:
			if n.Name == "_" {
				return false
			}
			e = n
			mustResolve = true

		case *ast.KeyValueExpr:
			// don't try to resolve the key part of a key-value
			// because it might be a map key which doesn't
			// need resolving, and we can't tell without being
			// complicated with types.
			ast.Walk(visit, n.Value)
			return false

		case *ast.SelectorExpr:
			ast.Walk(visit, n.X)
			e = n
			mustResolve = true

		case *ast.File:
			for _, d := range n.Decls {
				ast.Walk(visit, d)
			}
			return false

		case ast.Expr:
			e = n

		default:
			return true
		}
		defer func() {
			if err := recover(); err != nil {
				t.Fatalf("panic (%v) on %T", err, e)
				//t.Fatalf("panic (%v) on %v at %v\n", err, e, FileSet.Position(e.Pos()))
			}
		}()
		obj, _ := ExprType(e, importer)
		if obj == nil && mustResolve {
			t.Errorf("no object for %v(%p, %T) at %v\n", e, e, e, FileSet.Position(e.Pos()))
		}
		return false
	}
	ast.Walk(visit, pkg)
}
Beispiel #3
0
// Sets multiLine to true if the expression spans multiple lines.
func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
	p.print(expr.Pos())

	switch x := expr.(type) {
	case *ast.BadExpr:
		p.print("BadExpr")

	case *ast.Ident:
		p.print(x)

	case *ast.BinaryExpr:
		if depth < 1 {
			p.internalError("depth < 1:", depth)
			depth = 1
		}
		p.binaryExpr(x, prec1, cutoff(x, depth), depth, multiLine)

	case *ast.KeyValueExpr:
		p.expr(x.Key, multiLine)
		p.print(x.Colon, token.COLON, blank)
		p.expr(x.Value, multiLine)

	case *ast.StarExpr:
		const prec = token.UnaryPrec
		if prec < prec1 {
			// parenthesis needed
			p.print(token.LPAREN)
			p.print(token.MUL)
			p.expr(x.X, multiLine)
			p.print(token.RPAREN)
		} else {
			// no parenthesis needed
			p.print(token.MUL)
			p.expr(x.X, multiLine)
		}

	case *ast.UnaryExpr:
		const prec = token.UnaryPrec
		if prec < prec1 {
			// parenthesis needed
			p.print(token.LPAREN)
			p.expr(x, multiLine)
			p.print(token.RPAREN)
		} else {
			// no parenthesis needed
			p.print(x.Op)
			if x.Op == token.RANGE {
				// TODO(gri) Remove this code if it cannot be reached.
				p.print(blank)
			}
			p.expr1(x.X, prec, depth, multiLine)
		}

	case *ast.BasicLit:
		p.print(x)

	case *ast.FuncLit:
		p.expr(x.Type, multiLine)
		p.funcBody(x.Body, p.distance(x.Type.Pos(), p.pos), true, multiLine)

	case *ast.ParenExpr:
		if _, hasParens := x.X.(*ast.ParenExpr); hasParens {
			// don't print parentheses around an already parenthesized expression
			// TODO(gri) consider making this more general and incorporate precedence levels
			p.expr0(x.X, reduceDepth(depth), multiLine) // parentheses undo one level of depth
		} else {
			p.print(token.LPAREN)
			p.expr0(x.X, reduceDepth(depth), multiLine) // parentheses undo one level of depth
			p.print(x.Rparen, token.RPAREN)
		}

	case *ast.SelectorExpr:
		parts := selectorExprList(expr)
		p.exprList(token.NoPos, parts, depth, periodSep, multiLine, token.NoPos)

	case *ast.TypeAssertExpr:
		p.expr1(x.X, token.HighestPrec, depth, multiLine)
		p.print(token.PERIOD, token.LPAREN)
		if x.Type != nil {
			p.expr(x.Type, multiLine)
		} else {
			p.print(token.TYPE)
		}
		p.print(token.RPAREN)

	case *ast.IndexExpr:
		// TODO(gri): should treat[] like parentheses and undo one level of depth
		p.expr1(x.X, token.HighestPrec, 1, multiLine)
		p.print(x.Lbrack, token.LBRACK)
		p.expr0(x.Index, depth+1, multiLine)
		p.print(x.Rbrack, token.RBRACK)

	case *ast.SliceExpr:
		// TODO(gri): should treat[] like parentheses and undo one level of depth
		p.expr1(x.X, token.HighestPrec, 1, multiLine)
		p.print(x.Lbrack, token.LBRACK)
		if x.Low != nil {
			p.expr0(x.Low, depth+1, multiLine)
		}
		// blanks around ":" if both sides exist and either side is a binary expression
		if depth <= 1 && x.Low != nil && x.High != nil && (isBinary(x.Low) || isBinary(x.High)) {
			p.print(blank, token.COLON, blank)
		} else {
			p.print(token.COLON)
		}
		if x.High != nil {
			p.expr0(x.High, depth+1, multiLine)
		}
		p.print(x.Rbrack, token.RBRACK)

	case *ast.CallExpr:
		if len(x.Args) > 1 {
			depth++
		}
		p.expr1(x.Fun, token.HighestPrec, depth, multiLine)
		p.print(x.Lparen, token.LPAREN)
		p.exprList(x.Lparen, x.Args, depth, commaSep|commaTerm, multiLine, x.Rparen)
		if x.Ellipsis.IsValid() {
			p.print(x.Ellipsis, token.ELLIPSIS)
		}
		p.print(x.Rparen, token.RPAREN)

	case *ast.CompositeLit:
		// composite literal elements that are composite literals themselves may have the type omitted
		if x.Type != nil {
			p.expr1(x.Type, token.HighestPrec, depth, multiLine)
		}
		p.print(x.Lbrace, token.LBRACE)
		p.exprList(x.Lbrace, x.Elts, 1, commaSep|commaTerm, multiLine, x.Rbrace)
		// do not insert extra line breaks because of comments before
		// the closing '}' as it might break the code if there is no
		// trailing ','
		p.print(noExtraLinebreak, x.Rbrace, token.RBRACE, noExtraLinebreak)

	case *ast.Ellipsis:
		p.print(token.ELLIPSIS)
		if x.Elt != nil {
			p.expr(x.Elt, multiLine)
		}

	case *ast.ArrayType:
		p.print(token.LBRACK)
		if x.Len != nil {
			p.expr(x.Len, multiLine)
		}
		p.print(token.RBRACK)
		p.expr(x.Elt, multiLine)

	case *ast.StructType:
		p.print(token.STRUCT)
		p.fieldList(x.Fields, true, x.Incomplete)

	case *ast.FuncType:
		p.print(token.FUNC)
		p.signature(x.Params, x.Results, multiLine)

	case *ast.InterfaceType:
		p.print(token.INTERFACE)
		p.fieldList(x.Methods, false, x.Incomplete)

	case *ast.MapType:
		p.print(token.MAP, token.LBRACK)
		p.expr(x.Key, multiLine)
		p.print(token.RBRACK)
		p.expr(x.Value, multiLine)

	case *ast.ChanType:
		switch x.Dir {
		case ast.SEND | ast.RECV:
			p.print(token.CHAN)
		case ast.RECV:
			p.print(token.ARROW, token.CHAN)
		case ast.SEND:
			p.print(token.CHAN, token.ARROW)
		}
		p.print(blank)
		p.expr(x.Value, multiLine)

	default:
		panic("unreachable")
	}

	return
}