| // Copyright 2021 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 types2 |
| |
| import ( |
| "cmd/compile/internal/syntax" |
| "fmt" |
| "regexp" |
| "strconv" |
| "strings" |
| ) |
| |
| // langCompat reports an error if the representation of a numeric |
| // literal is not compatible with the current language version. |
| func (check *Checker) langCompat(lit *syntax.BasicLit) { |
| s := lit.Value |
| if len(s) <= 2 || check.allowVersion(check.pkg, 1, 13) { |
| return |
| } |
| // len(s) > 2 |
| if strings.Contains(s, "_") { |
| check.error(lit, "underscores in numeric literals requires go1.13 or later") |
| return |
| } |
| if s[0] != '0' { |
| return |
| } |
| radix := s[1] |
| if radix == 'b' || radix == 'B' { |
| check.error(lit, "binary literals requires go1.13 or later") |
| return |
| } |
| if radix == 'o' || radix == 'O' { |
| check.error(lit, "0o/0O-style octal literals requires go1.13 or later") |
| return |
| } |
| if lit.Kind != syntax.IntLit && (radix == 'x' || radix == 'X') { |
| check.error(lit, "hexadecimal floating-point literals requires go1.13 or later") |
| } |
| } |
| |
| // allowVersion reports whether the given package |
| // is allowed to use version major.minor. |
| func (check *Checker) allowVersion(pkg *Package, major, minor int) bool { |
| // We assume that imported packages have all been checked, |
| // so we only have to check for the local package. |
| if pkg != check.pkg { |
| return true |
| } |
| ma, mi := check.version.major, check.version.minor |
| return ma == 0 && mi == 0 || ma > major || ma == major && mi >= minor |
| } |
| |
| type version struct { |
| major, minor int |
| } |
| |
| // parseGoVersion parses a Go version string (such as "go1.12") |
| // and returns the version, or an error. If s is the empty |
| // string, the version is 0.0. |
| func parseGoVersion(s string) (v version, err error) { |
| if s == "" { |
| return |
| } |
| matches := goVersionRx.FindStringSubmatch(s) |
| if matches == nil { |
| err = fmt.Errorf(`should be something like "go1.12"`) |
| return |
| } |
| v.major, err = strconv.Atoi(matches[1]) |
| if err != nil { |
| return |
| } |
| v.minor, err = strconv.Atoi(matches[2]) |
| return |
| } |
| |
| // goVersionRx matches a Go version string, e.g. "go1.12". |
| var goVersionRx = regexp.MustCompile(`^go([1-9][0-9]*)\.(0|[1-9][0-9]*)$`) |