open-nomad/vendor/honnef.co/go/tools/ir/util.go
Seth Hoenig 435c0d9fc8 deps: Switch to Go modules for dependency management
This PR switches the Nomad repository from using govendor to Go modules
for managing dependencies. Aspects of the Nomad workflow remain pretty
much the same. The usual Makefile targets should continue to work as
they always did. The API submodule simply defers to the parent Nomad
version on the repository, keeping the semantics of API versioning that
currently exists.
2020-06-02 14:30:36 -05:00

90 lines
2.3 KiB
Go

// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ir
// This file defines a number of miscellaneous utility functions.
import (
"fmt"
"go/ast"
"go/token"
"go/types"
"io"
"os"
"golang.org/x/tools/go/ast/astutil"
)
//// AST utilities
func unparen(e ast.Expr) ast.Expr { return astutil.Unparen(e) }
// isBlankIdent returns true iff e is an Ident with name "_".
// They have no associated types.Object, and thus no type.
//
func isBlankIdent(e ast.Expr) bool {
id, ok := e.(*ast.Ident)
return ok && id.Name == "_"
}
//// Type utilities. Some of these belong in go/types.
// isPointer returns true for types whose underlying type is a pointer.
func isPointer(typ types.Type) bool {
_, ok := typ.Underlying().(*types.Pointer)
return ok
}
func isInterface(T types.Type) bool { return types.IsInterface(T) }
// deref returns a pointer's element type; otherwise it returns typ.
func deref(typ types.Type) types.Type {
if p, ok := typ.Underlying().(*types.Pointer); ok {
return p.Elem()
}
return typ
}
// recvType returns the receiver type of method obj.
func recvType(obj *types.Func) types.Type {
return obj.Type().(*types.Signature).Recv().Type()
}
// logStack prints the formatted "start" message to stderr and
// returns a closure that prints the corresponding "end" message.
// Call using 'defer logStack(...)()' to show builder stack on panic.
// Don't forget trailing parens!
//
func logStack(format string, args ...interface{}) func() {
msg := fmt.Sprintf(format, args...)
io.WriteString(os.Stderr, msg)
io.WriteString(os.Stderr, "\n")
return func() {
io.WriteString(os.Stderr, msg)
io.WriteString(os.Stderr, " end\n")
}
}
// newVar creates a 'var' for use in a types.Tuple.
func newVar(name string, typ types.Type) *types.Var {
return types.NewParam(token.NoPos, nil, name, typ)
}
// anonVar creates an anonymous 'var' for use in a types.Tuple.
func anonVar(typ types.Type) *types.Var {
return newVar("", typ)
}
var lenResults = types.NewTuple(anonVar(tInt))
// makeLen returns the len builtin specialized to type func(T)int.
func makeLen(T types.Type) *Builtin {
lenParams := types.NewTuple(anonVar(T))
return &Builtin{
name: "len",
sig: types.NewSignature(nil, lenParams, lenResults, false),
}
}