Function topLevelFenceOpener

cli/cli_rendering.go:164–180

topLevelFenceOpener reports whether a line opens a fenced code block at column 0, returning the fence token ("```" or "~~~") and the declared language (the info string's first word, lowercased).

(line string)

// column 0, returning the fence token ("```" or "~~~") and the declared
// language (the info string's first word, lowercased).
func topLevelFenceOpener(line string) (fence, lang string, ok bool) {
	switch {
	case strings.HasPrefix(line, "```"):
		fence = "```"
	case strings.HasPrefix(line, "~~~"):
		fence = "~~~"
	default:
		return "", "", false
	}
	info := strings.TrimSpace(strings.TrimPrefix(line, fence))
	// A line that is only the fence with trailing back-ticks is not an opener
	// with a language; info may be empty (plain code block).
	if idx := strings.IndexAny(info, " \t"); idx >= 0 {
		info = info[:idx]
	}
	return fence, strings.ToLower(info), true
}

// isFenceCloser reports whether a line closes a fence opened with the given
// token. A closer is the fence token at column 0 with only optional trailing