github.com/jhump/golang-x-tools@v0.0.0-20220218190644-4958d6d39439/present/doc.go (about) 1 // Copyright 2011 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 /* 6 Package present implements parsing and rendering of present files, 7 which can be slide presentations as in golang.org/x/tools/cmd/present 8 or articles as in golang.org/x/blog (the Go blog). 9 10 File Format 11 12 Present files begin with a header giving the title of the document 13 and other metadata, which looks like: 14 15 # Title of document 16 Subtitle of document 17 15:04 2 Jan 2006 18 Tags: foo, bar, baz 19 Summary: This is a great document you want to read. 20 OldURL: former-path-for-this-doc 21 22 The "# " prefix before the title indicates that this is 23 a Markdown-enabled present file: it uses 24 Markdown for text markup in the body of the file. 25 If the "# " prefix is missing, the file uses 26 legacy present markup, described below. 27 28 The date line may be written without a time: 29 2 Jan 2006 30 In this case, the time will be interpreted as 10am UTC on that date. 31 32 The tags line is a comma-separated list of tags that may be used to categorize 33 the document. 34 35 The summary line gives a short summary used in blog feeds. 36 37 The old URL line, which may be repeated, gives an older (perhaps relative) URL 38 for this document. 39 A server might use these to generate appropriate redirects. 40 41 Only the title is required; 42 the subtitle, date, tags, summary, and old URL lines are optional. 43 In Markdown-enabled present, the summary defaults to being empty. 44 In legacy present, the summary defaults to the first paragraph of text. 45 46 After the header come zero or more author blocks, like this: 47 48 Author Name 49 Job title, Company 50 joe@example.com 51 https://url/ 52 @twitter_name 53 54 The first line of the author block is conventionally the author name. 55 Otherwise, the author section may contain a mixture of text, twitter names, and links. 56 For slide presentations, only the plain text lines will be displayed on the 57 first slide. 58 59 If multiple author blocks are listed, each new block must be preceded 60 by its own blank line. 61 62 After the author blocks come the presentation slides or article sections, 63 which can in turn have subsections. 64 In Markdown-enabled present files, each slide or section begins with a "##" header line, 65 subsections begin with a "###" header line, and so on. 66 In legacy present files, each slide or section begins with a "*" header line, 67 subsections begin with a "**" header line, and so on. 68 69 In addition to the marked-up text in a section (or subsection), 70 a present file can contain present command invocations, each of which begins 71 with a dot, as in: 72 73 .code x.go /^func main/,/^}/ 74 .play y.go 75 .image image.jpg 76 .background image.jpg 77 .iframe https://foo 78 .link https://foo label 79 .html file.html 80 .caption _Gopher_ by [[https://instagram.com/reneefrench][Renee French]] 81 82 Other than the commands, the text in a section is interpreted 83 either as Markdown or as legacy present markup. 84 85 Markdown Syntax 86 87 Markdown typically means the generic name for a family of similar markup languages. 88 The specific variant used in present is CommonMark. 89 See https://commonmark.org/help/tutorial/ for a quick tutorial. 90 91 In Markdown-enabled present, 92 section headings can end in {#name} to set the HTML anchor ID for the heading to "name". 93 94 Lines beginning with "//" (outside of code blocks, of course) 95 are treated as present comments and have no effect. 96 97 Lines beginning with ": " are treated as speaker notes, described below. 98 99 Example: 100 101 # Title of Talk 102 103 My Name 104 9 Mar 2020 105 me@example.com 106 107 ## Title of Slide or Section (must begin with ##) 108 109 Some Text 110 111 ### Subsection {#anchor} 112 113 - bullets 114 - more bullets 115 - a bullet continued 116 on the next line 117 118 #### Sub-subsection 119 120 Some More text 121 122 Preformatted text (code block) 123 is indented (by one tab, or four spaces) 124 125 Further Text, including command invocations. 126 127 ## Section 2: Example formatting {#fmt} 128 129 Formatting: 130 131 _italic_ 132 // A comment that is completely ignored. 133 : Speaker notes. 134 **bold** 135 `program` 136 Markup—_especially italic text_—can easily be overused. 137 _Why use scoped\_ptr_? Use plain **\*ptr** instead. 138 139 Visit [the Go home page](https://golang.org/). 140 141 Legacy Present Syntax 142 143 Compared to Markdown, 144 in legacy present 145 slides/sections use "*" instead of "##", 146 whole-line comments begin with "#" instead of "//", 147 bullet lists can only contain single (possibly wrapped) text lines, 148 and the font styling and link syntaxes are subtly different. 149 150 Example: 151 152 Title of Talk 153 154 My Name 155 1 Jan 2013 156 me@example.com 157 158 * Title of Slide or Section (must begin with *) 159 160 Some Text 161 162 ** Subsection 163 164 - bullets 165 - more bullets 166 - a bullet continued 167 on the next line (indented at least one space) 168 169 *** Sub-subsection 170 171 Some More text 172 173 Preformatted text (code block) 174 is indented (however you like) 175 176 Further Text, including command invocations. 177 178 * Section 2: Example formatting 179 180 Formatting: 181 182 _italic_ 183 *bold* 184 `program` 185 Markup—_especially_italic_text_—can easily be overused. 186 _Why_use_scoped__ptr_? Use plain ***ptr* instead. 187 188 Visit [[https://golang.org][the Go home page]]. 189 190 Within the input for plain text or lists, text bracketed by font 191 markers will be presented in italic, bold, or program font. 192 Marker characters are _ (italic), * (bold) and ` (program font). 193 An opening marker must be preceded by a space or punctuation 194 character or else be at start of a line; similarly, a closing 195 marker must be followed by a space or punctuation character or 196 else be at the end of a line. Unmatched markers appear as plain text. 197 There must be no spaces between markers. Within marked text, 198 a single marker character becomes a space and a doubled single 199 marker quotes the marker character. 200 201 Links can be included in any text with the form [[url][label]], or 202 [[url]] to use the URL itself as the label. 203 204 Command Invocations 205 206 A number of special commands are available through invocations 207 in the input text. Each such invocation contains a period as the 208 first character on the line, followed immediately by the name of 209 the function, followed by any arguments. A typical invocation might 210 be 211 212 .play demo.go /^func show/,/^}/ 213 214 (except that the ".play" must be at the beginning of the line and 215 not be indented as in this comment.) 216 217 Here follows a description of the functions: 218 219 code: 220 221 Injects program source into the output by extracting code from files 222 and injecting them as HTML-escaped <pre> blocks. The argument is 223 a file name followed by an optional address that specifies what 224 section of the file to display. The address syntax is similar in 225 its simplest form to that of ed, but comes from sam and is more 226 general. See 227 https://plan9.io/sys/doc/sam/sam.html Table II 228 for full details. The displayed block is always rounded out to a 229 full line at both ends. 230 231 If no pattern is present, the entire file is displayed. 232 233 Any line in the program that ends with the four characters 234 OMIT 235 is deleted from the source before inclusion, making it easy 236 to write things like 237 .code test.go /START OMIT/,/END OMIT/ 238 to find snippets like this 239 tedious_code = boring_function() 240 // START OMIT 241 interesting_code = fascinating_function() 242 // END OMIT 243 and see only this: 244 interesting_code = fascinating_function() 245 246 Also, inside the displayed text a line that ends 247 // HL 248 will be highlighted in the display. A highlighting mark may have a 249 suffix word, such as 250 // HLxxx 251 Such highlights are enabled only if the code invocation ends with 252 "HL" followed by the word: 253 .code test.go /^type Foo/,/^}/ HLxxx 254 255 The .code function may take one or more flags immediately preceding 256 the filename. This command shows test.go in an editable text area: 257 .code -edit test.go 258 This command shows test.go with line numbers: 259 .code -numbers test.go 260 261 play: 262 263 The function "play" is the same as "code" but puts a button 264 on the displayed source so the program can be run from the browser. 265 Although only the selected text is shown, all the source is included 266 in the HTML output so it can be presented to the compiler. 267 268 link: 269 270 Create a hyperlink. The syntax is 1 or 2 space-separated arguments. 271 The first argument is always the HTTP URL. If there is a second 272 argument, it is the text label to display for this link. 273 274 .link https://golang.org golang.org 275 276 image: 277 278 The template uses the function "image" to inject picture files. 279 280 The syntax is simple: 1 or 3 space-separated arguments. 281 The first argument is always the file name. 282 If there are more arguments, they are the height and width; 283 both must be present, or substituted with an underscore. 284 Replacing a dimension argument with the underscore parameter 285 preserves the aspect ratio of the image when scaling. 286 287 .image images/betsy.jpg 100 200 288 .image images/janet.jpg _ 300 289 290 video: 291 292 The template uses the function "video" to inject video files. 293 294 The syntax is simple: 2 or 4 space-separated arguments. 295 The first argument is always the file name. 296 The second argument is always the file content-type. 297 If there are more arguments, they are the height and width; 298 both must be present, or substituted with an underscore. 299 Replacing a dimension argument with the underscore parameter 300 preserves the aspect ratio of the video when scaling. 301 302 .video videos/evangeline.mp4 video/mp4 400 600 303 304 .video videos/mabel.ogg video/ogg 500 _ 305 306 background: 307 308 The template uses the function "background" to set the background image for 309 a slide. The only argument is the file name of the image. 310 311 .background images/susan.jpg 312 313 caption: 314 315 The template uses the function "caption" to inject figure captions. 316 317 The text after ".caption" is embedded in a figcaption element after 318 processing styling and links as in standard text lines. 319 320 .caption _Gopher_ by [[https://instagram.com/reneefrench][Renee French]] 321 322 iframe: 323 324 The function "iframe" injects iframes (pages inside pages). 325 Its syntax is the same as that of image. 326 327 html: 328 329 The function html includes the contents of the specified file as 330 unescaped HTML. This is useful for including custom HTML elements 331 that cannot be created using only the slide format. 332 It is your responsibility to make sure the included HTML is valid and safe. 333 334 .html file.html 335 336 Presenter Notes 337 338 Lines that begin with ": " are treated as presenter notes, 339 in both Markdown and legacy present syntax. 340 By default, presenter notes are collected but ignored. 341 342 When running the present command with -notes, 343 typing 'N' in your browser displaying your slides 344 will create a second window displaying the notes. 345 The second window is completely synced with the main 346 window, except that presenter notes are only visible in the second window. 347 348 Notes may appear anywhere within the slide text. For example: 349 350 * Title of slide 351 352 Some text. 353 354 : Presenter notes (first paragraph) 355 356 Some more text. 357 358 : Presenter notes (subsequent paragraph(s)) 359 360 */ 361 package present // import "github.com/jhump/golang-x-tools/present"