language/go/package.go
func getPlatformStringsAddFunction(c *config.Config, info fileInfo, cgoTags tagLine) func(sb *platformStringsBuilder, ss ...string) {
	isOSSpecific, isArchSpecific := isOSArchSpecific(info, cgoTags)

	switch {
	case !isOSSpecific && !isArchSpecific:
		if checkConstraints(c, "", "", info.goos, info.goarch, info.tags, cgoTags) {
			return func(sb *platformStringsBuilder, ss ...string) {
				for _, s := range ss {
					sb.addGenericString(s)
				}
			}
		}

	case isOSSpecific && !isArchSpecific:
		var osMatch []string
		for _, os := range rule.KnownOSs {
			if checkConstraints(c, os, "", info.goos, info.goarch, info.tags, cgoTags) {
				osMatch = append(osMatch, os)
			}
		}
		if len(osMatch) > 0 {
			return func(sb *platformStringsBuilder, ss ...string) {
				for _, s := range ss {
					sb.addOSString(s, osMatch)
				}
			}
		}

	case !isOSSpecific && isArchSpecific:
		var archMatch []string
		for _, arch := range rule.KnownArchs {
			if checkConstraints(c, "", arch, info.goos, info.goarch, info.tags, cgoTags) {
				archMatch = append(archMatch, arch)
			}
		}
		if len(archMatch) > 0 {
			return func(sb *platformStringsBuilder, ss ...string) {
				for _, s := range ss {
					sb.addArchString(s, archMatch)
				}
			}
		}

	default:
		var platformMatch []rule.Platform
		for _, platform := range rule.KnownPlatforms {
			if checkConstraints(c, platform.OS, platform.Arch, info.goos, info.goarch, info.tags, cgoTags) {
				platformMatch = append(platformMatch, platform)
			}
		}
		if len(platformMatch) > 0 {
			return func(sb *platformStringsBuilder, ss ...string) {
				for _, s := range ss {
					sb.addPlatformString(s, platformMatch)
				}
			}
		}
	}

	return func(_ *platformStringsBuilder, _ ...string) {}
}
func getPlatformStringsAddFunction(c *config.Config, info fileInfo, cgoTags tagLine) func(sb *platformStringsBuilder, ss ...string) {
	isOSSpecific, isArchSpecific := isOSArchSpecific(info, cgoTags)

	switch {
	case !isOSSpecific && !isArchSpecific:
		if checkConstraints(c, "", "", info.goos, info.goarch, info.tags, cgoTags) {
			return func(sb *platformStringsBuilder, ss ...string) {
				for _, s := range ss {
					sb.addGenericString(s)
				}
			}
		}

	case isOSSpecific && !isArchSpecific:
		var osMatch []string
		for _, os := range rule.KnownOSs {
			if checkConstraints(c, os, "", info.goos, info.goarch, info.tags, cgoTags) {
				osMatch = append(osMatch, os)
			}
		}
		if len(osMatch) > 0 {
			return func(sb *platformStringsBuilder, ss ...string) {
				for _, s := range ss {
					sb.addOSString(s, osMatch)
				}
			}
		}

	case !isOSSpecific && isArchSpecific:
		var archMatch []string
		for _, arch := range rule.KnownArchs {
			if checkConstraints(c, "", arch, info.goos, info.goarch, info.tags, cgoTags) {
				archMatch = append(archMatch, arch)
			}
		}
		if len(archMatch) > 0 {
			return func(sb *platformStringsBuilder, ss ...string) {
				for _, s := range ss {
					sb.addArchString(s, archMatch)
				}
			}
		}

	default:
		var platformMatch []rule.Platform
		for _, platform := range rule.KnownPlatforms {
			if checkConstraints(c, platform.OS, platform.Arch, info.goos, info.goarch, info.tags, cgoTags) {
				platformMatch = append(platformMatch, platform)
			}
		}
		if len(platformMatch) > 0 {
			return func(sb *platformStringsBuilder, ss ...string) {
				for _, s := range ss {
					sb.addPlatformString(s, platformMatch)
				}
			}
		}
	}

	return func(_ *platformStringsBuilder, _ ...string) {}
}
// getPlatformStringsAddFunction returns a function used to add strings to
// a *platformStringsBuilder under the same set of constraints. This is a
// performance optimization to avoid evaluating constraints repeatedly.