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forgejo/modules/markup/markdown/math/math.go
zeripath 88c2e24360
Add KaTeX rendering to Markdown. (#20571)
This PR adds mathematical rendering with KaTeX.

The first step is to add a Goldmark extension that detects the latex
(and tex) mathematics delimiters.

The second step to make this extension only run if math support is
enabled.

The second step is to then add KaTeX CSS and JS to the head which will
load after the dom is rendered.

Fix #3445

Signed-off-by: Andrew Thornton <art27@cantab.net>

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
2022-09-14 00:33:37 +08:00

108 lines
2.4 KiB
Go

// Copyright 2022 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package math
import (
"github.com/yuin/goldmark"
"github.com/yuin/goldmark/parser"
"github.com/yuin/goldmark/renderer"
"github.com/yuin/goldmark/util"
)
// Extension is a math extension
type Extension struct {
enabled bool
parseDollarInline bool
parseDollarBlock bool
}
// Option is the interface Options should implement
type Option interface {
SetOption(e *Extension)
}
type extensionFunc func(e *Extension)
func (fn extensionFunc) SetOption(e *Extension) {
fn(e)
}
// Enabled enables or disables this extension
func Enabled(enable ...bool) Option {
value := true
if len(enable) > 0 {
value = enable[0]
}
return extensionFunc(func(e *Extension) {
e.enabled = value
})
}
// WithInlineDollarParser enables or disables the parsing of $...$
func WithInlineDollarParser(enable ...bool) Option {
value := true
if len(enable) > 0 {
value = enable[0]
}
return extensionFunc(func(e *Extension) {
e.parseDollarInline = value
})
}
// WithBlockDollarParser enables or disables the parsing of $$...$$
func WithBlockDollarParser(enable ...bool) Option {
value := true
if len(enable) > 0 {
value = enable[0]
}
return extensionFunc(func(e *Extension) {
e.parseDollarBlock = value
})
}
// Math represents a math extension with default rendered delimiters
var Math = &Extension{
enabled: true,
parseDollarBlock: true,
parseDollarInline: true,
}
// NewExtension creates a new math extension with the provided options
func NewExtension(opts ...Option) *Extension {
r := &Extension{
enabled: true,
parseDollarBlock: true,
parseDollarInline: true,
}
for _, o := range opts {
o.SetOption(r)
}
return r
}
// Extend extends goldmark with our parsers and renderers
func (e *Extension) Extend(m goldmark.Markdown) {
if !e.enabled {
return
}
m.Parser().AddOptions(parser.WithBlockParsers(
util.Prioritized(NewBlockParser(e.parseDollarBlock), 701),
))
inlines := []util.PrioritizedValue{
util.Prioritized(NewInlineBracketParser(), 501),
}
if e.parseDollarInline {
inlines = append(inlines, util.Prioritized(NewInlineDollarParser(), 501))
}
m.Parser().AddOptions(parser.WithInlineParsers(inlines...))
m.Renderer().AddOptions(renderer.WithNodeRenderers(
util.Prioritized(NewBlockRenderer(), 501),
util.Prioritized(NewInlineRenderer(), 502),
))
}