mirror of
https://github.com/alecthomas/chroma.git
synced 2025-03-21 21:17:50 +02:00
d6e61d3cbe
Apparently only "phrasing content" are permitted inside `pre` and `code`, and `div` is not one of them, so replace it with `span`, `div` wasn't necessary anyway. Also it makes sense to put code inside `code` tag(except for line numbers). Removed `overflow:auto` and `width: auto` as they didn't seem to be necessary and actually prevented horizontal scroll bar to appear when content didn't fit in the viewport.
501 lines
14 KiB
Go
501 lines
14 KiB
Go
package html
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import (
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"fmt"
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"html"
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"io"
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"sort"
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"strings"
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"github.com/alecthomas/chroma"
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)
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// Option sets an option of the HTML formatter.
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type Option func(f *Formatter)
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// Standalone configures the HTML formatter for generating a standalone HTML document.
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func Standalone(b bool) Option { return func(f *Formatter) { f.standalone = b } }
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// ClassPrefix sets the CSS class prefix.
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func ClassPrefix(prefix string) Option { return func(f *Formatter) { f.prefix = prefix } }
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// WithClasses emits HTML using CSS classes, rather than inline styles.
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func WithClasses(b bool) Option { return func(f *Formatter) { f.Classes = b } }
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// WithAllClasses disables an optimisation that omits redundant CSS classes.
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func WithAllClasses(b bool) Option { return func(f *Formatter) { f.allClasses = b } }
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// TabWidth sets the number of characters for a tab. Defaults to 8.
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func TabWidth(width int) Option { return func(f *Formatter) { f.tabWidth = width } }
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// PreventSurroundingPre prevents the surrounding pre tags around the generated code.
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func PreventSurroundingPre(b bool) Option {
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return func(f *Formatter) {
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if b {
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f.preWrapper = nopPreWrapper
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} else {
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f.preWrapper = defaultPreWrapper
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}
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}
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}
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// WithPreWrapper allows control of the surrounding pre tags.
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func WithPreWrapper(wrapper PreWrapper) Option {
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return func(f *Formatter) {
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f.preWrapper = wrapper
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}
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}
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// WrapLongLines wraps long lines.
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func WrapLongLines(b bool) Option {
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return func(f *Formatter) {
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f.wrapLongLines = b
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}
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}
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// WithLineNumbers formats output with line numbers.
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func WithLineNumbers(b bool) Option {
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return func(f *Formatter) {
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f.lineNumbers = b
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}
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}
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// LineNumbersInTable will, when combined with WithLineNumbers, separate the line numbers
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// and code in table td's, which make them copy-and-paste friendly.
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func LineNumbersInTable(b bool) Option {
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return func(f *Formatter) {
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f.lineNumbersInTable = b
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}
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}
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// LinkableLineNumbers decorates the line numbers HTML elements with an "id"
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// attribute so they can be linked.
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func LinkableLineNumbers(b bool, prefix string) Option {
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return func(f *Formatter) {
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f.linkableLineNumbers = b
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f.lineNumbersIDPrefix = prefix
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}
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}
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// HighlightLines higlights the given line ranges with the Highlight style.
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//
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// A range is the beginning and ending of a range as 1-based line numbers, inclusive.
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func HighlightLines(ranges [][2]int) Option {
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return func(f *Formatter) {
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f.highlightRanges = ranges
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sort.Sort(f.highlightRanges)
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}
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}
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// BaseLineNumber sets the initial number to start line numbering at. Defaults to 1.
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func BaseLineNumber(n int) Option {
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return func(f *Formatter) {
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f.baseLineNumber = n
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}
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}
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// New HTML formatter.
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func New(options ...Option) *Formatter {
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f := &Formatter{
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baseLineNumber: 1,
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preWrapper: defaultPreWrapper,
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}
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for _, option := range options {
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option(f)
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}
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return f
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}
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// PreWrapper defines the operations supported in WithPreWrapper.
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type PreWrapper interface {
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// Start is called to write a start <pre> element.
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// The code flag tells whether this block surrounds
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// highlighted code. This will be false when surrounding
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// line numbers.
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Start(code bool, styleAttr string) string
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// End is called to write the end </pre> element.
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End(code bool) string
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}
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type preWrapper struct {
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start func(code bool, styleAttr string) string
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end func(code bool) string
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}
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func (p preWrapper) Start(code bool, styleAttr string) string {
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return p.start(code, styleAttr)
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}
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func (p preWrapper) End(code bool) string {
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return p.end(code)
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}
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var (
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nopPreWrapper = preWrapper{
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start: func(code bool, styleAttr string) string { return "" },
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end: func(code bool) string { return "" },
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}
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defaultPreWrapper = preWrapper{
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start: func(code bool, styleAttr string) string {
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if code {
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return fmt.Sprintf(`<pre tabindex="0"%s><code>`, styleAttr)
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}
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return fmt.Sprintf(`<pre tabindex="0"%s>`, styleAttr)
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},
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end: func(code bool) string {
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if code {
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return `</code></pre>`
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}
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return `</pre>`
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},
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}
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)
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// Formatter that generates HTML.
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type Formatter struct {
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standalone bool
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prefix string
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Classes bool // Exported field to detect when classes are being used
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allClasses bool
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preWrapper PreWrapper
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tabWidth int
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wrapLongLines bool
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lineNumbers bool
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lineNumbersInTable bool
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linkableLineNumbers bool
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lineNumbersIDPrefix string
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highlightRanges highlightRanges
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baseLineNumber int
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}
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type highlightRanges [][2]int
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func (h highlightRanges) Len() int { return len(h) }
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func (h highlightRanges) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
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func (h highlightRanges) Less(i, j int) bool { return h[i][0] < h[j][0] }
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func (f *Formatter) Format(w io.Writer, style *chroma.Style, iterator chroma.Iterator) (err error) {
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return f.writeHTML(w, style, iterator.Tokens())
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}
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// We deliberately don't use html/template here because it is two orders of magnitude slower (benchmarked).
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//
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// OTOH we need to be super careful about correct escaping...
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func (f *Formatter) writeHTML(w io.Writer, style *chroma.Style, tokens []chroma.Token) (err error) { // nolint: gocyclo
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css := f.styleToCSS(style)
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if !f.Classes {
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for t, style := range css {
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css[t] = compressStyle(style)
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}
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}
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if f.standalone {
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fmt.Fprint(w, "<html>\n")
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if f.Classes {
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fmt.Fprint(w, "<style type=\"text/css\">\n")
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err = f.WriteCSS(w, style)
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if err != nil {
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return err
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}
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fmt.Fprintf(w, "body { %s; }\n", css[chroma.Background])
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fmt.Fprint(w, "</style>")
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}
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fmt.Fprintf(w, "<body%s>\n", f.styleAttr(css, chroma.Background))
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}
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wrapInTable := f.lineNumbers && f.lineNumbersInTable
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lines := chroma.SplitTokensIntoLines(tokens)
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lineDigits := len(fmt.Sprintf("%d", f.baseLineNumber+len(lines)-1))
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highlightIndex := 0
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if wrapInTable {
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// List line numbers in its own <td>
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fmt.Fprintf(w, "<div%s>\n", f.styleAttr(css, chroma.PreWrapper))
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fmt.Fprintf(w, "<table%s><tr>", f.styleAttr(css, chroma.LineTable))
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fmt.Fprintf(w, "<td%s>\n", f.styleAttr(css, chroma.LineTableTD))
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fmt.Fprintf(w, f.preWrapper.Start(false, f.styleAttr(css, chroma.PreWrapper)))
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for index := range lines {
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line := f.baseLineNumber + index
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highlight, next := f.shouldHighlight(highlightIndex, line)
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if next {
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highlightIndex++
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}
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if highlight {
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fmt.Fprintf(w, "<span%s>", f.styleAttr(css, chroma.LineHighlight))
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}
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fmt.Fprintf(w, "<span%s%s>%s\n</span>", f.styleAttr(css, chroma.LineNumbersTable), f.lineIDAttribute(line), f.lineTitleWithLinkIfNeeded(lineDigits, line))
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if highlight {
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fmt.Fprintf(w, "</span>")
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}
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}
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fmt.Fprint(w, f.preWrapper.End(false))
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fmt.Fprint(w, "</td>\n")
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fmt.Fprintf(w, "<td%s>\n", f.styleAttr(css, chroma.LineTableTD, "width:100%"))
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}
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fmt.Fprintf(w, f.preWrapper.Start(true, f.styleAttr(css, chroma.PreWrapper)))
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highlightIndex = 0
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for index, tokens := range lines {
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// 1-based line number.
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line := f.baseLineNumber + index
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highlight, next := f.shouldHighlight(highlightIndex, line)
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if next {
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highlightIndex++
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}
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// Start of Line
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fmt.Fprint(w, `<span`)
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if highlight {
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// Line + LineHighlight
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if f.Classes {
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fmt.Fprintf(w, ` class="%s %s"`, f.class(chroma.Line), f.class(chroma.LineHighlight))
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} else {
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fmt.Fprintf(w, ` style="%s %s"`, css[chroma.Line], css[chroma.LineHighlight])
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}
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fmt.Fprint(w, `>`)
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} else {
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fmt.Fprintf(w, "%s>", f.styleAttr(css, chroma.Line))
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}
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// Line number
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if f.lineNumbers && !wrapInTable {
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fmt.Fprintf(w, "<span%s%s>%s</span>", f.styleAttr(css, chroma.LineNumbers), f.lineIDAttribute(line), f.lineTitleWithLinkIfNeeded(lineDigits, line))
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}
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fmt.Fprintf(w, `<span%s>`, f.styleAttr(css, chroma.CodeLine))
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for _, token := range tokens {
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html := html.EscapeString(token.String())
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attr := f.styleAttr(css, token.Type)
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if attr != "" {
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html = fmt.Sprintf("<span%s>%s</span>", attr, html)
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}
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fmt.Fprint(w, html)
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}
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fmt.Fprint(w, `</span>`) // End of CodeLine
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fmt.Fprint(w, `</span>`) // End of Line
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}
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fmt.Fprintf(w, f.preWrapper.End(true))
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if wrapInTable {
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fmt.Fprint(w, "</td></tr></table>\n")
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fmt.Fprint(w, "</div>\n")
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}
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if f.standalone {
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fmt.Fprint(w, "\n</body>\n")
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fmt.Fprint(w, "</html>\n")
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}
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return nil
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}
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func (f *Formatter) lineIDAttribute(line int) string {
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if !f.linkableLineNumbers {
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return ""
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}
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return fmt.Sprintf(" id=\"%s\"", f.lineID(line))
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}
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func (f *Formatter) lineTitleWithLinkIfNeeded(lineDigits, line int) string {
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title := fmt.Sprintf("%*d", lineDigits, line)
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if !f.linkableLineNumbers {
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return title
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}
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return fmt.Sprintf("<a style=\"outline: none; text-decoration:none; color:inherit\" href=\"#%s\">%s</a>", f.lineID(line), title)
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}
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func (f *Formatter) lineID(line int) string {
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return fmt.Sprintf("%s%d", f.lineNumbersIDPrefix, line)
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}
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func (f *Formatter) shouldHighlight(highlightIndex, line int) (bool, bool) {
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next := false
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for highlightIndex < len(f.highlightRanges) && line > f.highlightRanges[highlightIndex][1] {
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highlightIndex++
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next = true
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}
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if highlightIndex < len(f.highlightRanges) {
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hrange := f.highlightRanges[highlightIndex]
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if line >= hrange[0] && line <= hrange[1] {
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return true, next
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}
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}
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return false, next
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}
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func (f *Formatter) class(t chroma.TokenType) string {
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for t != 0 {
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if cls, ok := chroma.StandardTypes[t]; ok {
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if cls != "" {
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return f.prefix + cls
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}
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return ""
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}
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t = t.Parent()
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}
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if cls := chroma.StandardTypes[t]; cls != "" {
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return f.prefix + cls
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}
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return ""
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}
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func (f *Formatter) styleAttr(styles map[chroma.TokenType]string, tt chroma.TokenType, extraCSS ...string) string {
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if f.Classes {
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cls := f.class(tt)
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if cls == "" {
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return ""
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}
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return fmt.Sprintf(` class="%s"`, cls)
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}
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if _, ok := styles[tt]; !ok {
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tt = tt.SubCategory()
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if _, ok := styles[tt]; !ok {
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tt = tt.Category()
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if _, ok := styles[tt]; !ok {
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return ""
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}
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}
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}
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css := []string{styles[tt]}
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css = append(css, extraCSS...)
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return fmt.Sprintf(` style="%s"`, strings.Join(css, ";"))
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}
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func (f *Formatter) tabWidthStyle() string {
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if f.tabWidth != 0 && f.tabWidth != 8 {
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return fmt.Sprintf("; -moz-tab-size: %[1]d; -o-tab-size: %[1]d; tab-size: %[1]d", f.tabWidth)
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}
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return ""
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}
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// WriteCSS writes CSS style definitions (without any surrounding HTML).
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func (f *Formatter) WriteCSS(w io.Writer, style *chroma.Style) error {
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css := f.styleToCSS(style)
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// Special-case background as it is mapped to the outer ".chroma" class.
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if _, err := fmt.Fprintf(w, "/* %s */ .%sbg { %s }\n", chroma.Background, f.prefix, css[chroma.Background]); err != nil {
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return err
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}
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// Special-case PreWrapper as it is the ".chroma" class.
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if _, err := fmt.Fprintf(w, "/* %s */ .%schroma { %s }\n", chroma.PreWrapper, f.prefix, css[chroma.PreWrapper]); err != nil {
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return err
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}
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// Special-case code column of table to expand width.
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if f.lineNumbers && f.lineNumbersInTable {
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if _, err := fmt.Fprintf(w, "/* %s */ .%schroma .%s:last-child { width: 100%%; }",
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chroma.LineTableTD, f.prefix, f.class(chroma.LineTableTD)); err != nil {
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return err
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}
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}
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// Special-case line number highlighting when targeted.
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if f.lineNumbers || f.lineNumbersInTable {
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targetedLineCSS := StyleEntryToCSS(style.Get(chroma.LineHighlight))
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for _, tt := range []chroma.TokenType{chroma.LineNumbers, chroma.LineNumbersTable} {
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fmt.Fprintf(w, "/* %s targeted by URL anchor */ .%schroma .%s:target { %s }\n", tt, f.prefix, f.class(tt), targetedLineCSS)
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}
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}
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tts := []int{}
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for tt := range css {
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tts = append(tts, int(tt))
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}
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sort.Ints(tts)
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for _, ti := range tts {
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tt := chroma.TokenType(ti)
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switch tt {
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case chroma.Background, chroma.PreWrapper:
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continue
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}
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class := f.class(tt)
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if class == "" {
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continue
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}
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styles := css[tt]
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if _, err := fmt.Fprintf(w, "/* %s */ .%schroma .%s { %s }\n", tt, f.prefix, class, styles); err != nil {
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return err
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}
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}
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return nil
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}
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func (f *Formatter) styleToCSS(style *chroma.Style) map[chroma.TokenType]string {
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classes := map[chroma.TokenType]string{}
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bg := style.Get(chroma.Background)
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// Convert the style.
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for t := range chroma.StandardTypes {
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entry := style.Get(t)
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if t != chroma.Background {
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entry = entry.Sub(bg)
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}
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if !f.allClasses && entry.IsZero() {
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continue
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}
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classes[t] = StyleEntryToCSS(entry)
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}
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classes[chroma.Background] += f.tabWidthStyle()
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classes[chroma.PreWrapper] += classes[chroma.Background] + `;`
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// Make PreWrapper a grid to show highlight style with full width.
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if len(f.highlightRanges) > 0 {
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classes[chroma.PreWrapper] += `display: grid;`
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}
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// Make PreWrapper wrap long lines.
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if f.wrapLongLines {
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classes[chroma.PreWrapper] += `white-space: pre-wrap; word-break: break-word;`
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}
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lineNumbersStyle := `white-space: pre; user-select: none; margin-right: 0.4em; padding: 0 0.4em 0 0.4em;`
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// All rules begin with default rules followed by user provided rules
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classes[chroma.Line] = `display: flex;` + classes[chroma.Line]
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classes[chroma.LineNumbers] = lineNumbersStyle + classes[chroma.LineNumbers]
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classes[chroma.LineNumbersTable] = lineNumbersStyle + classes[chroma.LineNumbersTable]
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classes[chroma.LineTable] = "border-spacing: 0; padding: 0; margin: 0; border: 0;" + classes[chroma.LineTable]
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classes[chroma.LineTableTD] = "vertical-align: top; padding: 0; margin: 0; border: 0;" + classes[chroma.LineTableTD]
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return classes
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}
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// StyleEntryToCSS converts a chroma.StyleEntry to CSS attributes.
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func StyleEntryToCSS(e chroma.StyleEntry) string {
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styles := []string{}
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if e.Colour.IsSet() {
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styles = append(styles, "color: "+e.Colour.String())
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}
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if e.Background.IsSet() {
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styles = append(styles, "background-color: "+e.Background.String())
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}
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if e.Bold == chroma.Yes {
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styles = append(styles, "font-weight: bold")
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}
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if e.Italic == chroma.Yes {
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styles = append(styles, "font-style: italic")
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}
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if e.Underline == chroma.Yes {
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styles = append(styles, "text-decoration: underline")
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}
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return strings.Join(styles, "; ")
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}
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// Compress CSS attributes - remove spaces, transform 6-digit colours to 3.
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func compressStyle(s string) string {
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parts := strings.Split(s, ";")
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out := []string{}
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for _, p := range parts {
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p = strings.Join(strings.Fields(p), " ")
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p = strings.Replace(p, ": ", ":", 1)
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if strings.Contains(p, "#") {
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c := p[len(p)-6:]
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|
if c[0] == c[1] && c[2] == c[3] && c[4] == c[5] {
|
|
p = p[:len(p)-6] + c[0:1] + c[2:3] + c[4:5]
|
|
}
|
|
}
|
|
out = append(out, p)
|
|
}
|
|
return strings.Join(out, ";")
|
|
}
|