459 lines
15 KiB
Go
459 lines
15 KiB
Go
// Package renderer provides functions to convert various data into a cview primitive.
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// Example objects include a Gemini response, and an error.
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//
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// Rendered lines always end with \r\n, in an effort to be Window compatible.
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package renderer
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import (
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"bytes"
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"fmt"
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urlPkg "net/url"
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"regexp"
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"strconv"
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"strings"
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"code.rocketnine.space/tslocum/cview"
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"github.com/alecthomas/chroma/formatters"
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"github.com/alecthomas/chroma/lexers"
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"github.com/alecthomas/chroma/styles"
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"github.com/makeworld-the-better-one/amfora/config"
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"github.com/spf13/viper"
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)
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// Terminal color information, set during display initialization by display/display.go
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var TermColor string
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// Regex for identifying ANSI color codes
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var ansiRegex = regexp.MustCompile(`\x1b\[[0-9;]*m`)
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// Regex for identifying possible language string, based on RFC 6838 and lexers used by Chroma
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var langRegex = regexp.MustCompile(`^([a-zA-Z0-9]+/)?[a-zA-Z0-9]+([a-zA-Z0-9!_\#\$\&\-\^\.\+]+)*`)
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// Regex for removing trailing newline (without disturbing ANSI codes) from code formatted with Chroma
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var trailingNewline = regexp.MustCompile(`(\r?\n)(?:\x1b\[[0-9;]*m)*$`)
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// RenderANSI renders plain text pages containing ANSI codes.
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// Practically, it is used for the text/x-ansi.
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func RenderANSI(s string) string {
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s = cview.Escape(s)
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if viper.GetBool("a-general.color") && viper.GetBool("a-general.ansi") {
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s = cview.TranslateANSI(s)
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} else {
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s = ansiRegex.ReplaceAllString(s, "")
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}
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return s
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}
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// RenderPlainText should be used to format plain text pages.
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func RenderPlainText(s string) string {
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// It used to add a left margin, now this is done elsewhere.
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// The function is kept for convenience and in case rendering
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// is needed in the future.
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return cview.Escape(s)
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}
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// wrapLine wraps a line to the provided width, and adds the provided prefix and suffix to each wrapped line.
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// It recovers from wrapping panics and should never cause a panic.
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// It returns a slice of lines, without newlines at the end.
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//
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// Set includeFirst to true if the prefix and suffix should be applied to the first wrapped line as well
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func wrapLine(line string, width int, prefix, suffix string, includeFirst bool) []string {
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if width < 1 {
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width = 1
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}
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// Anonymous function to allow recovery from potential WordWrap panic
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var ret []string
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func() {
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defer func() {
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if r := recover(); r != nil {
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// Use unwrapped line instead
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if includeFirst {
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ret = []string{prefix + line + suffix}
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} else {
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ret = []string{line}
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}
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}
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}()
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wrapped := cview.WordWrap(line, width)
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for i := range wrapped {
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if !includeFirst && i == 0 {
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continue
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}
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wrapped[i] = prefix + wrapped[i] + suffix
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}
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ret = wrapped
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}()
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return ret
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}
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// convertRegularGemini converts non-preformatted blocks of text/gemini
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// into a cview-compatible format.
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// Since this only works on non-preformatted blocks, RenderGemini
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// should always be used instead.
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//
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// It also returns a slice of link URLs.
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// numLinks is the number of links that exist so far.
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// width is the number of columns to wrap to.
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//
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//
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// proxied is whether the request is through the gemini:// scheme.
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// If it's not a gemini:// page, set this to true.
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func convertRegularGemini(s string, numLinks, width int, proxied bool) (string, []string) {
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links := make([]string, 0)
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lines := strings.Split(s, "\n")
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wrappedLines := make([]string, 0) // Final result
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for i := range lines {
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lines[i] = strings.TrimRight(lines[i], " \r\t\n")
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if strings.HasPrefix(lines[i], "#") {
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// Headings
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var tag string
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if viper.GetBool("a-general.color") {
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if strings.HasPrefix(lines[i], "###") {
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tag = fmt.Sprintf("[%s::b]", config.GetColorString("hdg_3"))
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} else if strings.HasPrefix(lines[i], "##") {
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tag = fmt.Sprintf("[%s::b]", config.GetColorString("hdg_2"))
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} else if strings.HasPrefix(lines[i], "#") {
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tag = fmt.Sprintf("[%s::b]", config.GetColorString("hdg_1"))
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}
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wrappedLines = append(wrappedLines, wrapLine(lines[i], width, tag, "[-::-]", true)...)
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} else {
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// Just bold, no colors
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wrappedLines = append(wrappedLines, wrapLine(lines[i], width, "[::b]", "[-::-]", true)...)
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}
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// Links
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} else if strings.HasPrefix(lines[i], "=>") && len([]rune(lines[i])) >= 3 {
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// Trim whitespace and separate link from link text
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lines[i] = strings.Trim(lines[i][2:], " \t") // Remove `=>` part too
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delim := strings.IndexAny(lines[i], " \t") // Whitespace between link and link text
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var url string
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var linkText string
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if delim == -1 {
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// No link text
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url = lines[i]
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linkText = url
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} else {
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// There is link text
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url = lines[i][:delim]
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linkText = strings.Trim(lines[i][delim:], " \t")
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if viper.GetBool("a-general.show_link") {
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linkText += " (" + url + ")"
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}
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}
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if strings.TrimSpace(lines[i]) == "" || strings.TrimSpace(url) == "" {
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// Link was just whitespace, reset it and move on
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lines[i] = "=>"
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wrappedLines = append(wrappedLines, lines[i])
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continue
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}
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links = append(links, url)
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num := numLinks + len(links) // Visible link number, one-indexed
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var indent int
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if num > 99 {
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// Indent link text by 3 or more spaces
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indent = len(strconv.Itoa(num)) + 4 // +4 indent for spaces and brackets
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} else {
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// One digit and two digit links have the same spacing - see #60
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indent = 5 // +4 indent for spaces and brackets, and 1 for link number
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}
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// Spacing after link number: 1 or 2 spaces?
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var spacing string
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if num > 9 {
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// One space to keep it in line with other links - see #60
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spacing = " "
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} else {
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// One digit numbers use two spaces
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spacing = " "
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}
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// Underline non-gemini links if enabled
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var linkTag string
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if viper.GetBool("a-general.underline") {
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linkTag = `[` + config.GetColorString("foreign_link") + `::u]`
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} else {
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linkTag = `[` + config.GetColorString("foreign_link") + `]`
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}
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// Wrap and add link text
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// Wrap the link text, but add some spaces to indent the wrapped lines past the link number
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// Set the style tags
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// Add them to the first line
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var wrappedLink []string
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pU, err := urlPkg.Parse(url)
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if !proxied && err == nil &&
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(pU.Scheme == "" || pU.Scheme == "gemini" || pU.Scheme == "about") {
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// A gemini link
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if viper.GetBool("a-general.color") {
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// Add the link text in blue (in a region), and a gray link number to the left of it
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// Those are the default colors, anyway
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wrappedLink = wrapLine(linkText, width-indent,
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strings.Repeat(" ", indent)+
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`["`+strconv.Itoa(num-1)+`"][`+config.GetColorString("amfora_link")+`]`,
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`[-][""]`,
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false, // Don't indent the first line, it's the one with link number
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)
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// Add special stuff to first line, like the link number
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wrappedLink[0] = fmt.Sprintf(`[%s::b][`, config.GetColorString("link_number")) +
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strconv.Itoa(num) + "[]" + "[-::-]" + spacing +
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`["` + strconv.Itoa(num-1) + `"][` + config.GetColorString("amfora_link") + `]` +
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wrappedLink[0] + `[-][""]`
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} else {
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// No color
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wrappedLink = wrapLine(linkText, width-indent,
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strings.Repeat(" ", indent)+ // +4 for spaces and brackets
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`["`+strconv.Itoa(num-1)+`"]`,
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`[""]`,
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false, // Don't indent the first line, it's the one with link number
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)
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wrappedLink[0] = `[::b][` + strconv.Itoa(num) + "[][::-] " +
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`["` + strconv.Itoa(num-1) + `"]` +
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wrappedLink[0] + `[""]`
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}
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} else {
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// Not a gemini link
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if viper.GetBool("a-general.color") {
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// Color
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wrappedLink = wrapLine(linkText, width-indent,
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strings.Repeat(" ", indent)+
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`["`+strconv.Itoa(num-1)+`"]`+linkTag,
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`[-::-][""]`,
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false, // Don't indent the first line, it's the one with link number
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)
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wrappedLink[0] = fmt.Sprintf(`[%s::b][`, config.GetColorString("link_number")) +
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strconv.Itoa(num) + "[][-::-]" + spacing +
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`["` + strconv.Itoa(num-1) + `"]` + linkTag +
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wrappedLink[0] + `[-::-][""]`
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} else {
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// No color
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wrappedLink = wrapLine(linkText, width-indent,
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strings.Repeat(" ", indent)+
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`["`+strconv.Itoa(num-1)+`"]`,
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`[::-][""]`,
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false, // Don't indent the first line, it's the one with link number
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)
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wrappedLink[0] = `[::b][` + strconv.Itoa(num) + "[][::-]" + spacing +
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`["` + strconv.Itoa(num-1) + `"]` +
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wrappedLink[0] + `[::-][""]`
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}
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}
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wrappedLines = append(wrappedLines, wrappedLink...)
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// Lists
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} else if strings.HasPrefix(lines[i], "* ") {
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if viper.GetBool("a-general.bullets") {
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// Wrap list item, and indent wrapped lines past the bullet
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wrappedItem := wrapLine(lines[i][1:],
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width-4, // Subtract the 4 indent spaces
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fmt.Sprintf(" [%s]", config.GetColorString("list_text")),
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"[-]", false)
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// Add bullet
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wrappedItem[0] = fmt.Sprintf(" [%s]\u2022", config.GetColorString("list_text")) +
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wrappedItem[0] + "[-]"
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wrappedLines = append(wrappedLines, wrappedItem...)
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} else {
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wrappedItem := wrapLine(lines[i][1:],
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width-4, // Subtract the 4 indent spaces
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fmt.Sprintf(" [%s]", config.GetColorString("list_text")),
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"[-]", false)
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// Add "*"
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wrappedItem[0] = fmt.Sprintf(" [%s]*", config.GetColorString("list_text")) +
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wrappedItem[0] + "[-]"
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wrappedLines = append(wrappedLines, wrappedItem...)
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}
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// Optionally list lines could be colored here too, if color is enabled
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} else if strings.HasPrefix(lines[i], ">") {
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// It's a quote line, add extra quote symbols and italics to the start of each wrapped line
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if len(lines[i]) == 1 {
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// Just an empty quote line
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wrappedLines = append(wrappedLines, fmt.Sprintf("[%s::i]>[-::-]", config.GetColorString("quote_text")))
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} else {
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// Remove beginning quote and maybe space
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lines[i] = strings.TrimPrefix(lines[i], ">")
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lines[i] = strings.TrimPrefix(lines[i], " ")
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wrappedLines = append(wrappedLines,
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wrapLine(lines[i],
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width-2, // Subtract 2 for width of prefix string
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fmt.Sprintf("[%s::i]> ", config.GetColorString("quote_text")),
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"[-::-]", true)...,
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)
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}
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} else if strings.TrimSpace(lines[i]) == "" {
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// Just add empty line without processing
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wrappedLines = append(wrappedLines, "")
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} else {
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// Regular line, just wrap it
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wrappedLines = append(wrappedLines, wrapLine(lines[i], width,
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fmt.Sprintf("[%s]", config.GetColorString("regular_text")),
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"[-]", true)...)
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}
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}
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return strings.Join(wrappedLines, "\r\n"), links
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}
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// RenderGemini converts text/gemini into a cview displayable format.
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// It also returns a slice of link URLs.
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//
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// width is the number of columns to wrap to.
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// leftMargin is the number of blank spaces to prepend to each line.
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//
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// proxied is whether the request is through the gemini:// scheme.
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// If it's not a gemini:// page, set this to true.
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func RenderGemini(s string, width int, proxied bool) (string, []string) {
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s = cview.Escape(s)
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lines := strings.Split(s, "\n")
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links := make([]string, 0)
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// Process and wrap non preformatted lines
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rendered := "" // Final result
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pre := false
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buf := "" // Block of regular or preformatted lines
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// Language, formatter, and style for syntax highlighting
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lang := ""
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formatterName := TermColor
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styleName := viper.GetString("a-general.highlight_style")
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// processPre is for rendering preformatted blocks
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processPre := func() {
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syntaxHighlighted := false
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// Perform syntax highlighting if language is set
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if lang != "" {
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style := styles.Get(styleName)
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if style == nil {
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style = styles.Fallback
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}
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formatter := formatters.Get(formatterName)
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if formatter == nil {
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formatter = formatters.Fallback
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}
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lexer := lexers.Get(lang)
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if lexer == nil {
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lexer = lexers.Fallback
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}
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// Tokenize and format the text after stripping ANSI codes, replacing buffer if there are no errors
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iterator, err := lexer.Tokenise(nil, ansiRegex.ReplaceAllString(buf, ""))
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if err == nil {
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formattedBuffer := new(bytes.Buffer)
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if formatter.Format(formattedBuffer, style, iterator) == nil {
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// Strip extra newline added by Chroma and replace buffer
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buf = string(trailingNewline.ReplaceAll(formattedBuffer.Bytes(), []byte{}))
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}
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syntaxHighlighted = true
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}
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}
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// Support ANSI color codes in preformatted blocks - see #59
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// This will also execute if code highlighting was successful for this block
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if viper.GetBool("a-general.color") && (viper.GetBool("a-general.ansi") || syntaxHighlighted) {
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buf = cview.TranslateANSI(buf)
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// The TranslateANSI function will reset the colors when it encounters
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// an ANSI reset code, injecting a full reset tag: [-:-:-]
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// This uses the default foreground and background colors of the
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// application, but in this case we want it to use the preformatted text
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// color as the foreground, as we're still in a preformat block.
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buf = strings.ReplaceAll(
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buf, "[-:-:-]",
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fmt.Sprintf("[%s:-:-]", config.GetColorString("preformatted_text")),
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)
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} else {
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buf = ansiRegex.ReplaceAllString(buf, "")
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}
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// The final newline is removed (and re-added) to prevent background glitches
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// where the terminal background color slips through. This only happens on
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// preformatted blocks with ANSI characters.
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//
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// Lines are modified below to always end with \r\n
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buf = strings.TrimSuffix(buf, "\r\n")
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if viper.GetBool("a-general.color") {
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rendered += fmt.Sprintf("[%s]", config.GetColorString("preformatted_text")) +
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buf + fmt.Sprintf("[%s:%s:-]\r\n", config.GetColorString("regular_text"), config.GetColorString("bg"))
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} else {
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rendered += buf + "\r\n"
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}
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}
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// processRegular processes non-preformatted sections
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processRegular := func() {
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// ANSI not allowed in regular text - see #59
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buf = ansiRegex.ReplaceAllString(buf, "")
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ren, lks := convertRegularGemini(buf, len(links), width, proxied)
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links = append(links, lks...)
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rendered += ren
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}
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for i := range lines {
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if strings.HasPrefix(lines[i], "```") {
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if pre {
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// In a preformatted block, so add the text as is
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// Don't add the current line with backticks
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processPre()
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// Clear the language
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lang = ""
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} else {
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// Not preformatted, regular text
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processRegular()
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if viper.GetBool("a-general.highlight_code") {
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// Check for alt text indicating a language that Chroma can highlight
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alt := strings.TrimSpace(strings.TrimPrefix(lines[i], "```"))
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if matches := langRegex.FindStringSubmatch(alt); matches != nil {
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if lexers.Get(matches[0]) != nil {
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lang = matches[0]
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}
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}
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}
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}
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buf = "" // Clear buffer for next block
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pre = !pre
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continue
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}
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// Lines always end with \r\n for Windows compatibility
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buf += strings.TrimSuffix(lines[i], "\r") + "\r\n"
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}
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// Gone through all the lines, but there still is likely a block in the buffer
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if pre {
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// File ended without closing the preformatted block
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processPre()
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} else {
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// Not preformatted, regular text
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processRegular()
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}
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return rendered, links
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}
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