Document SanitizedAnchorName algorithm, copy implementation. (#509) The goal of this change is to reduce number of non-standard library packages (repositories) that blackfriday imports (not counting imports used only for tests) from 1 to 0, and in turn, reduce the cost of importing blackfriday into other projects. Do so by documenting the algorithm of SanitizedAnchorName, and include a copy of the small function inside blackfriday itself. The same functionality continues to be available in the original location, github.com/shurcooL/sanitized_anchor_name.Create. It can be used by existing users and those that look for a small package, and don't need all of blackfriday functionality. Existing users of blackfriday can use the new SanitizedAnchorName function directly and avoid an extra package import. This change is a port of PR #352 from v1 into v2. Updates #348. Updates #350.
Dmitri Shuralyov dmitri@shuralyov.com
Sun, 20 Jan 2019 14:20:17 -0500
M
README.md
→
README.md
@@ -104,6 +104,8 @@
If you want to customize the set of options, use `blackfriday.WithExtensions`, `blackfriday.WithRenderer` and `blackfriday.WithRefOverride`. +### `blackfriday-tool` + You can also check out `blackfriday-tool` for a more complete example of how to use it. Download and install it using:@@ -122,6 +124,22 @@ blackfriday in addition to the tool itself. The tool binary will be
installed in `$GOPATH/bin`. This is a statically-linked binary that can be copied to wherever you need it without worrying about dependencies and library versions. + +### Sanitized anchor names + +Blackfriday includes an algorithm for creating sanitized anchor names +corresponding to a given input text. This algorithm is used to create +anchors for headings when `AutoHeadingIDs` extension is enabled. The +algorithm has a specification, so that other packages can create +compatible anchor names and links to those anchors. + +The specification is located at https://godoc.org/gopkg.in/russross/blackfriday.v2#hdr-Sanitized_Anchor_Names. + +[`SanitizedAnchorName`](https://godoc.org/gopkg.in/russross/blackfriday.v2#SanitizedAnchorName) exposes this functionality, and can be used to +create compatible links to the anchor names generated by blackfriday. +This algorithm is also implemented in a small standalone package at +[`github.com/shurcooL/sanitized_anchor_name`](https://godoc.org/github.com/shurcooL/sanitized_anchor_name). It can be useful for clients +that want a small package and don't need full functionality of blackfriday. Features
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block.go
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block.go
@@ -18,8 +18,7 @@ "bytes"
"html" "regexp" "strings" - - "github.com/shurcooL/sanitized_anchor_name" + "unicode" ) const (@@ -259,7 +258,7 @@ end--
} if end > i { if id == "" && p.extensions&AutoHeadingIDs != 0 { - id = sanitized_anchor_name.Create(string(data[i:end])) + id = SanitizedAnchorName(string(data[i:end])) } block := p.addBlock(Heading, data[i:end]) block.HeadingID = id@@ -1505,7 +1504,7 @@ }
id := "" if p.extensions&AutoHeadingIDs != 0 { - id = sanitized_anchor_name.Create(string(data[prev:eol])) + id = SanitizedAnchorName(string(data[prev:eol])) } block := p.addBlock(Heading, data[prev:eol])@@ -1590,3 +1589,24 @@ i++
} return i } + +// SanitizedAnchorName returns a sanitized anchor name for the given text. +// +// It implements the algorithm specified in the package comment. +func SanitizedAnchorName(text string) string { + var anchorName []rune + futureDash := false + for _, r := range text { + switch { + case unicode.IsLetter(r) || unicode.IsNumber(r): + if futureDash && len(anchorName) > 0 { + anchorName = append(anchorName, '-') + } + futureDash = false + anchorName = append(anchorName, unicode.ToLower(r)) + default: + futureDash = true + } + } + return string(anchorName) +}
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block_test.go
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block_test.go
@@ -1875,3 +1875,44 @@ }
} } } + +func TestSanitizedAnchorName(t *testing.T) { + tests := []struct { + text string + want string + }{ + { + text: "This is a header", + want: "this-is-a-header", + }, + { + text: "This is also a header", + want: "this-is-also-a-header", + }, + { + text: "main.go", + want: "main-go", + }, + { + text: "Article 123", + want: "article-123", + }, + { + text: "<- Let's try this, shall we?", + want: "let-s-try-this-shall-we", + }, + { + text: " ", + want: "", + }, + { + text: "Hello, 世界", + want: "hello-世界", + }, + } + for _, test := range tests { + if got := SanitizedAnchorName(test.text); got != test.want { + t.Errorf("SanitizedAnchorName(%q):\ngot %q\nwant %q", test.text, got, test.want) + } + } +}
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doc.go
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doc.go
@@ -15,4 +15,32 @@ // to the Markdown processor.
// // If you're interested in calling Blackfriday from command line, see // https://github.com/russross/blackfriday-tool. +// +// Sanitized Anchor Names +// +// Blackfriday includes an algorithm for creating sanitized anchor names +// corresponding to a given input text. This algorithm is used to create +// anchors for headings when AutoHeadingIDs extension is enabled. The +// algorithm is specified below, so that other packages can create +// compatible anchor names and links to those anchors. +// +// The algorithm iterates over the input text, interpreted as UTF-8, +// one Unicode code point (rune) at a time. All runes that are letters (category L) +// or numbers (category N) are considered valid characters. They are mapped to +// lower case, and included in the output. All other runes are considered +// invalid characters. Invalid characters that precede the first valid character, +// as well as invalid character that follow the last valid character +// are dropped completely. All other sequences of invalid characters +// between two valid characters are replaced with a single dash character '-'. +// +// SanitizedAnchorName exposes this functionality, and can be used to +// create compatible links to the anchor names generated by blackfriday. +// This algorithm is also implemented in a small standalone package at +// github.com/shurcooL/sanitized_anchor_name. It can be useful for clients +// that want a small package and don't need full functionality of blackfriday. package blackfriday + +// NOTE: Keep Sanitized Anchor Name algorithm in sync with package +// github.com/shurcooL/sanitized_anchor_name. +// Otherwise, users of sanitized_anchor_name will get anchor names +// that are incompatible with those generated by blackfriday.
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go.sum
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go.sum
@@ -1,4 +1,2 @@
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM= github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4= -github.com/shurcooL/sanitized_anchor_name v0.0.0-20170918181015-86672fcb3f95 h1:/vdW8Cb7EXrkqWGufVMES1OH2sU9gKVb2n9/1y5NMBY= -github.com/shurcooL/sanitized_anchor_name v0.0.0-20170918181015-86672fcb3f95/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=