Halibut output formats

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- Chapter 4: Halibut output formats
  - 4.1 Plain text
    - 4.1.1 Output file name
    - 4.1.2 Indentation and line width
    - 4.1.3 Configuring heading display
    - 4.1.4 Configuring the characters used
    - 4.1.5 Miscellaneous configuration options
    - 4.1.6 Default settings
  - 4.2 HTML
    - 4.2.1 Controlling the output file names
    - 4.2.2 Controlling the splitting into HTML files
    - 4.2.3 Including pieces of your own HTML
    - 4.2.4 Configuring heading display
    - 4.2.5 Configuring standard text
    - 4.2.6 Configuring the characters used
    - 4.2.7 Miscellaneous options
    - 4.2.8 Default settings
  - 4.3 Windows HTML Help
    - 4.3.1 Output file name
    - 4.3.2 Configuration shared with the HTML back end
    - 4.3.3 Including extra files in the CHM
    - 4.3.4 Renaming the CHM internal support files
    - 4.3.5 Default settings
    - 4.3.6 Generating input to the MS Windows HTML Help compiler
  - 4.4 Legacy Windows Help
    - 4.4.1 Output file name
    - 4.4.2 Configuring the characters used
    - 4.4.3 Miscellaneous configuration options
    - 4.4.4 Default settings
  - 4.5 Unix `man` pages
    - 4.5.1 Output file name
    - 4.5.2 Configuring headers and footers
    - 4.5.3 Configuring heading display
    - 4.5.4 Configuring the characters used
    - 4.5.5 Default settings
  - 4.6 GNU Info
    - 4.6.1 Controlling the output filenames
    - 4.6.2 Indentation and line width
    - 4.6.3 Configuring heading display
    - 4.6.4 Controlling the characters used
    - 4.6.5 Miscellaneous configuration options
    - 4.6.6 Default settings
  - 4.7 Paper formats
    - 4.7.1 PDF
    - 4.7.2 PostScript
    - 4.7.3 Configuring layout and measurements
    - 4.7.4 Configuring the characters used
    - 4.7.5 Default settings for paper formats

# Chapter 4: Halibut output formats

This chapter describes each of Halibut's current output formats. It gives some general information about the format, and also describes all the configuration directives which are specific to that format.

## 4.1 Plain text

This output format generates the document as a single plain text file. No table of contents or index is generated.

The precise formatting of the text file can be controlled by a variety of configuration directives. They are listed in the following subsections.

### 4.1.1 Output file name

`\cfg{text-filename}{`filename`}`
  Sets the output file name in which to store the text file. This directive is implicitly generated if you provide a file name parameter after the command-line option `--text` (see section 2.1).

### 4.1.2 Indentation and line width

This section describes the configuration directives which control the horizontal dimensions of the output text file: how much paragraphs are indented by and how long the lines are.

`\cfg{text-width}{`width`}`
  Sets the width of the main part of the document, in characters. This width will be used for wrapping paragraphs and for centring titles (if you have asked for titles to be centred - see section 4.1.3). This width does not include the left indentation set by `\cfg{text-indent}`; if you specify an indent of 8 and a width of 64, your maximum output line length will be 72.
`\cfg{text-indent}{`indent`}`
  Sets the left indentation for the document. If you set this to zero, your document will look like an ordinary text file as someone with a text editor might have written it; if you set it above zero, the text file will have a margin down the left in the style of some printed manuals, and you can then configure the section numbers to appear in this margin (see section 4.1.3).
`\cfg{text-indent-code}{`indent`}`
  Specifies how many extra characters of indentation (on top of the normal left indent) should be given to code paragraphs.
`\cfg{text-list-indent}{`indent`}`
  Specifies how many extra spaces should be used to indent the bullet or number in a bulletted or numbered list. The actual body of the list item will be indented by this much plus the value configured by `\cfg{text-listitem-indent}`.
`\cfg{text-listitem-indent}{`indent`}`
  Specifies how many extra spaces should be used to indent the body of a list item, over and above the number configured in `\cfg{text-list-indent}`.
`\cfg{text-indent-preamble}{`boolean`}`
  When this is set to `true`, the document preamble (i.e. any paragraphs appearing before the first chapter heading) will be indented to the level specified by `\cfg{text-indent}`. If this setting is `false`, the document preamble will not be indented at all from the left margin.

### 4.1.3 Configuring heading display

The directives in this section allow you to configure the appearance of the title, chapter and section headings in your text file.

Several of the directives listed below specify the alignment of a heading. These alignment options have three possible values:

`left`
  Align the heading to the very left of the text file (column zero).
`leftplus`
  Align the section title to the left of the main display region (in other words, indented to the level specified by `\cfg{text-indent}`). The section number is placed to the left of that (so that it goes in the margin if there is room).
`centre`
  Centre the heading.

Also, several of the directives below specify how a title should be underlined. The parameter to one of these directives should be either blank (`{}`) or a piece of text which will be repeated to produce the underline. So you might want to specify, for example, `\text-title-underline{=}` but `\text-chapter-underline{-}`.

You can also specify more than one underline setting, and Halibut will choose the first one that the output character set supports. So, for example, you could write `\text-chapter-underline{\u203e}{-}`, and Halibut would use the Unicode ‘OVERLINE’ character where possible and fall back to the ASCII minus sign otherwise.

`\cfg{text-title-align}{`alignment`}`
  Specifies the alignment of the overall document title: `left`, `leftplus` or `centre`.
`\cfg{text-title-underline}{`underline-text`}`
  Specifies how the overall document title should be underlined.
`\cfg{text-chapter-align}{`alignment`}`
  Specifies the alignment of chapter and appendix headings.
`\cfg{text-chapter-underline}{`underline-text`}`
  Specifies how chapter and appendix headings should be underlined.
`\cfg{text-chapter-numeric}{`boolean`}`
  If this is set to `true`, then chapter headings will not contain the word ‘Chapter’ (or whatever other word you have defined in its place - see section 3.3.5 and section 3.6); they will just contain the chapter number, followed by the chapter title. If you set this to `false`, chapter headings will be prefixed by ‘Chapter’ or equivalent.
`\cfg{text-chapter-shownumber}{`boolean`}`
  If this is set to `false`, then chapter headings will only contain the chapter title: they will not contain the word ‘Chapter’ (or whatever other word you have defined in its place), and neither will they contain the chapter number. If set to `false`, this overrides `\cfg{text-chapter-numeric}`.
`\cfg{text-chapter-suffix}{`text`}`
  This specifies the suffix text to be appended to the chapter number, before displaying the chapter title. For example, if you set this to ‘`:` ’, then the chapter title might look something like ‘Chapter 2: Doing Things’.
`\cfg{text-section-align}{`level`}{`alignment`}`
  Specifies the alignment of section headings at a particular level. The level parameter specifies which level of section headings you want to affect: 0 means first-level headings (`\H`), 1 means second-level headings (`\S`), 2 means the level below that (`\S2`), and so on. The alignment parameter is treated just like the other alignment directives listed above.
`\cfg{text-section-underline}{`level`}{`underline-text`}`
  Specifies how to underline section headings at a particular level.
`\cfg{text-section-numeric}{`level`}{`boolean`}`
  Specifies whether section headings at a particular level should contain the word ‘Section’ or equivalent (if `false`), or should be numeric only (if `true`).
`\cfg{text-section-shownumber}{`level`}{`boolean`}`
  If this is set to `false`, then section headings at the specified level will only contain the section title: they will not contain the word ‘Section’ (or whatever other word you have defined in its place), and neither will they contain the section number. If set to `false`, this overrides `\cfg{text-section-numeric}`.
`\cfg{text-section-suffix}{`level`}{`text`}`
  Specifies the suffix text to be appended to section numbers at a particular level, before displaying the section title.

### 4.1.4 Configuring the characters used

`\cfg{text-charset}{`character set name`}`
  This tells Halibut what character set the output should be in. Any Unicode characters representable in this set will be output verbatim; any other characters will not be output and their fallback text (if any) will be used instead.

  The character set names are the same as for `\cfg{input-charset}` (see section 3.6). However, unlike `\cfg{input-charset}`, this directive affects the entire output; it's not possible to switch encodings halfway through.

`\cfg{text-bullet}{`text`}`[`{`text...`}`]
  This specifies the text which should be used as the bullet in bulletted lists. It can be one character (`\cfg{text-bullet}{-}`), or more than one (`\cfg{text-bullet}{(*)}`).

  Like `\cfg{quotes}` (see section 3.6), you can specify multiple possible options after this command, and Halibut will choose the first one which the output character set supports. For example, you might write `\cfg{text-bullet}{\u2022}{\u00b7}{*}`, in which case Halibut would use the Unicode ‘BULLET’ character where possible, fall back to the ISO-8859-1 ‘MIDDLE DOT’ if that wasn't available, and resort to the ASCII asterisk if all else failed.

`\cfg{text-rule}{`text`}`[`{`text...`}`]
  This specifies the text which should be used for drawing horizontal rules (generated by `\rule`; see section 3.3.3). It can be one character, or more than one. The string you specify will be repeated to reach the required width, so you can specify something like ‘`-=`’ to get a rule that looks like `-=-=-=`.

  Like `\cfg{text-bullet}`, you can specify multiple fallback options in this command.

`\cfg{text-quotes}{`open-quote`}{`close-quote`}`[`{`open-quote`}{`close-quote...`}`]
  This specifies a set of quote characters for the text backend, overriding any defined by `\cfg{quotes}`. It has the same syntax (see section 3.6).

  In this backend, these quotes will also be used to mark text enclosed in the `\c` command (see section 3.2.2).

`\cfg{text-emphasis}{`start-emph`}{`end-emph`}`[`{`start-emph`}{`end-emph...`}`]
  This specifies the characters which should be used to surround emphasised text (written using the `\e` command; see section 3.2.1).
`\cfg{text-strong}{`start-strong`}{`end-strong`}`[`{`start-strong`}{`end-strong...`}`]
  This specifies the characters which should be used to surround strong text (written using the `\s` command; see section 3.2.1).

  You should separately specify the start-emphasis and end-emphasis text, each of which can be more than one character if you want. Also, like `\cfg{text-quotes}`, you can specify multiple pairs of fallback options in this command, and Halibut will always use a matching pair.

### 4.1.5 Miscellaneous configuration options

`\cfg{text-list-suffix}{`text`}`
  This text is appended to the number on a numbered list item (see section 3.3.2.2). So if you want to label your lists as ‘1)’, ‘2)’ and so on, then you would write `\cfg{text-list-suffix}{)}`.
`\cfg{text-versionid}{`boolean`}`
  If this is set to `true`, version ID paragraphs (defined using the `\versionid` command - see section 3.3.6) will be included at the bottom of the text file. If it is set to `false`, they will be omitted completely.

### 4.1.6 Default settings

The default settings for Halibut's plain text output format are:

    \cfg{text-filename}{output.txt}

    \cfg{text-width}{68}
    \cfg{text-indent}{7}
    \cfg{text-indent-code}{2}
    \cfg{text-list-indent}{1}
    \cfg{text-listitem-indent}{3}
    \cfg{text-indent-preamble}{false}

    \cfg{text-title-align}{centre}
    \cfg{text-title-underline}{\u2550}{=}

    \cfg{text-chapter-align}{left}
    \cfg{text-chapter-underline}{\u203e}{-}
    \cfg{text-chapter-numeric}{false}
    \cfg{text-chapter-shownumber}{true}
    \cfg{text-chapter-suffix}{: }

    \cfg{text-section-align}{0}{leftplus}
    \cfg{text-section-underline}{0}{}
    \cfg{text-section-numeric}{0}{true}
    \cfg{text-section-shownumber}{0}{true}
    \cfg{text-section-suffix}{0}{ }

    \cfg{text-section-align}{1}{leftplus}
    \cfg{text-section-underline}{1}{}
    \cfg{text-section-numeric}{1}{true}
    \cfg{text-section-shownumber}{1}{true}
    \cfg{text-section-suffix}{1}{ }

    ... and so on for all section levels below this ...

    \cfg{text-charset}{ASCII}
    \cfg{text-bullet}{\u2022}{-}
    \cfg{text-rule}{\u2500}{-}
    \cfg{text-quotes}{\u2018}{\u2019}{`}{'}
    \cfg{text-emphasis}{_}{_}

    \cfg{text-list-suffix}{.}
    \cfg{text-versionid}{true}

## 4.2 HTML

This output format generates an HTML version of the document. By default, this will be in multiple files, starting with `Contents.html` and splitting the document into files by chapter and/or subsection. You can configure precisely how the text is split between HTML files using the configuration commands described in this section. In particular, you can configure Halibut to output one single HTML file instead of multiple ones.

Configuration directives with an `xhtml-` prefix are synonyms for those with an `html-` prefix.

### 4.2.1 Controlling the output file names

`\cfg{html-contents-filename}{`filename`}`
  Sets the output file name in which to store the top-level contents page. Since this is the first page a user ought to see when beginning to read the document, a good choice in many cases might be `index.html` (although this is not the default, for historical reasons).
`\cfg{html-index-filename}{`filename`}`
  Sets the file name in which to store the document's index.
`\cfg{html-template-filename}{`template`}`
  Provides a template to be used when constructing the file names of each chapter or section of the document. This template should contain at least one formatting command, in the form of a per cent sign followed by a letter. (If you need a literal per cent sign, you can write `%%`.)

  The formatting commands used in this template are:

  `%N`
    Expands to the visible title of the section, with white space removed. So in a chapter declared as ‘`\C{fish} Catching Fish`’, this formatting command would expand to ‘`CatchingFish`’.
  `%n`
    Expands to the type and number of the section, without white space. So in chapter 1 this would expand to ‘`Chapter1`’; in section A.4.3 it would expand to ‘`SectionA.4.3`’, and so on. If the section has no number (an unnumbered chapter created using `\U`), this directive falls back to doing the same thing as `%N`.
  `%b`
    Expands to the number of the section, in a format suitable for an HTML fragment name. The first character of the section type is prepended to the section number. So in chapter 1 this would expand to ‘`C1`’; in section A.4.3 it would expand to ‘`SA.4.3`’, and so on. If the section has no number (an unnumbered chapter created using `\U`), this directive falls back to doing the same thing as `%N`.
  `%k`
    Expands to the internal keyword specified in the section title. So in a chapter declared as ‘`\C{fish} Catching Fish`’, this formatting command would expand to ‘`fish`’. If the section has no keyword (an unnumbered chapter created using `\U`), this directive falls back to doing the same thing as `%N`.

  These formatting directives can also be used in the `\cfg{html-template-fragment}` configuration directive (see section 4.2.7).

`\cfg{html-single-filename}{`filename`}`
  Sets the file name in which to store the entire document, if Halibut is configured (using `\cfg{html-leaf-level}{0}`) to produce a single self-contained file. Both this directive and `\cfg{html-leaf-level}{0}` are implicitly generated if you provide a file name parameter after the command-line option `--html` (see section 2.1).

### 4.2.2 Controlling the splitting into HTML files

By default, the HTML output from Halibut is split into multiple files. Each file typically contains a single chapter or section and everything below it, unless subsections of that chapter are themselves split off into further files.

Most files also contain a contents section, giving hyperlinks to the sections in the file and/or the sections below it.

The configuration directives listed below allow you to configure the splitting into files, and the details of the contents sections.

`\cfg{html-leaf-level}{`depth`}`
  This setting indicates the depth of section which should be given a ‘leaf’ file (a file with no sub-files). So if you set it to 1, for example, then every chapter will be given its own HTML file, plus a top-level contents file. If you set this to 2, then each chapter and each `\H` section will have a file, and the chapter files will mostly just contain links to their sub-files.

  If you set this option to zero, then the whole document will appear in a single file. If you do this, Halibut will call that file `Manual.html` instead of `Contents.html` by default.

  This option is automatically set to zero if you provide a file name parameter after the command-line option `--html` (see section 2.1), because you have specified a single file name and so Halibut assumes you want the whole document to be placed in that file.

  You can also specify the special name `infinity` (or `infinite` or `inf`) if you want to ensure that every section and subsection ends up in a separate file no matter how deep you go.

`\cfg{html-contents-depth}{`level`}{`depth`}`
  This directive allows you to specify how deep any contents section in a particular level of file should go.

  The level parameter indicates which level of contents section you are dealing with. 0 denotes the main contents section in the topmost file `Contents.html`; 1 denotes a contents section in a chapter file; 2 is a contents section in a file containing a `\H` heading, and so on.

  The depth parameter indicates the maximum depth of heading which will be shown in this contents section. Again, 1 denotes a chapter, 2 is a `\H` heading, 3 is a `\S` heading, and so on.

  So, for example: `\cfg{html-contents-depth}{1}{3}` instructs Halibut to put contents links in chapter files for all sections down to `\S` level, but not to go into any more detail than that.

  For backwards compatibility, the alternative syntax `\cfg{html-contents-depth-`level`}{`depth`}` is also supported.

`\cfg{html-leaf-contains-contents}{`boolean`}`
  If you set this to `true`, then each leaf file will contain its own contents section which summarises the text within it.
`\cfg{html-leaf-smallest-contents}{`number`}`
  Contents sections in leaf files are not output at all if they contain very few entries (on the assumption that it just isn't worth bothering). This directive configures the minimum number of entries required in a leaf contents section to make Halibut bother generating it at all.

### 4.2.3 Including pieces of your own HTML

The directives in this section allow you to supply pieces of verbatim HTML code, which will be included in various parts of the output files.

Note that none of Halibut's usual character set translation is applied to this code; it is assumed to already be in a suitable encoding for the target HTML files.

`\cfg{html-head-end}{`HTML text`}`
  The text you provide in this directive is placed at the end of the `<HEAD>` section of each output HTML file. So this is a good place to put, for example, a link to a CSS stylesheet.
`\cfg{html-local-head}{`HTML text`}`
  This configuration directive is local: you specify it within a document section, and it acts on that section only.

  The text you provide in this directive is placed at the end of the `<HEAD>` section of whichever output HTML file contains the section in which the directive was placed. You can specify this directive multiple times in multiple sections if you like.

  This directive is particularly useful for constructing MacOS on-line help, which is mostly normal HTML but which requires a special `<META NAME="AppleTitle">` tag in the topmost source file. You can arrange this by placing this configuration directive in the preamble or the introduction section, something like this:

      \cfg{html-local-head}{<meta name="AppleTitle"
      content="MyApp Help">}

`\cfg{html-body-tag}{`HTML text`}`
  The text you provide in this directive is used in place of the `<BODY>` tag in each output file. So if you wanted to define a background colour, for example, you could write `\cfg{html-body-tag}{<body bg="#123456">}`.
`\cfg{html-body-start}{`HTML text`}`
  The text you provide in this directive is placed at the beginning of the `<BODY>` section of each output HTML file. So if you intend your HTML files to be part of a web site with a standard house style, and the style needs a header at the top of every page, this is where you can add that header.
`\cfg{html-body-end}{`HTML text`}`
  The text you provide in this directive is placed at the end of the `<BODY>` section of each output HTML file, before any address section. So if you intend your HTML files to be part of a web site with a standard house style, and the style needs a footer at the bottom of every page, this is where you can add that footer.
`\cfg{html-address-start}{`HTML text`}`
  The text you provide in this directive is placed at the beginning of the `<ADDRESS>` section at the bottom of each output HTML file. This might be a good place to put authors' contact details, for example.
`\cfg{html-address-end}{`HTML text`}`
  The text you provide in this directive is placed at the end of the `<ADDRESS>` section at the bottom of each output HTML file, after the version IDs (if present).
`\cfg{html-navigation-attributes}{`HTML attributes`}`
  The text you provide in this directive is included inside the `<P>` tag containing the navigation links at the top of each page (‘Previous’ / ‘Contents’ / ‘Next’). So if you wanted the navigation links to have a particular CSS style, you could write `\cfg{html-navigation-attributes}{class="foo"}`, and the navigation-links paragraph would then begin with the tag `<p class="foo">`.

### 4.2.4 Configuring heading display

`\cfg{html-chapter-numeric}{`boolean`}`
  If this is set to `true`, then chapter headings will not contain the word ‘Chapter’ (or whatever other word you have defined in its place - see section 3.3.5 and section 3.6); they will just contain the chapter number, followed by the chapter title. If you set this to `false`, chapter headings will be prefixed by ‘Chapter’ or equivalent.
`\cfg{html-chapter-shownumber}{`boolean`}`
  If this is set to `false`, then chapter headings will only contain the chapter title: they will not contain the word ‘Chapter’ (or whatever other word you have defined in its place), and neither will they contain the chapter number. If set to `false`, this overrides `\cfg{html-chapter-numeric}`.
`\cfg{html-chapter-suffix}{`text`}`
  This specifies the suffix text to be appended to the chapter number, before displaying the chapter title. For example, if you set this to ‘`:` ’, then the chapter title might look something like ‘Chapter 2: Doing Things’.
`\cfg{html-section-numeric}{`level`}{`boolean`}`
  Specifies whether section headings at a particular level should contain the word ‘Section’ or equivalent (if `false`), or should be numeric only (if `true`). The level parameter specifies which level of section headings you want to affect: 0 means first-level headings (`\H`), 1 means second-level headings (`\S`), 2 means the level below that (`\S2`), and so on.
`\cfg{html-section-shownumber}{`level`}{`boolean`}`
  If this is set to `false`, then section headings at the specified level will only contain the section title: they will not contain the word ‘Section’ (or whatever other word you have defined in its place), and neither will they contain the section number. If set to `false`, this overrides `\cfg{html-section-numeric}`.
`\cfg{html-section-suffix}{`level`}{`text`}`
  Specifies the suffix text to be appended to section numbers at a particular level, before displaying the section title.

### 4.2.5 Configuring standard text

These directives let you fine-tune the names Halibut uses in places such as the navigation bar to refer to various parts of the document, and other standard pieces of text, for instance to change them to a different language.

`\cfg{html-preamble-text}{`text`}`
`\cfg{html-contents-text}{`text`}`
`\cfg{html-index-text}{`text`}`
  Text used to refer to the preamble (i.e., any paragraphs before the first chapter heading), contents, and index respectively, in the navigation bar, contents, and index.

  (`html-contents-text` and `html-index-text` override the cross-format configuration keywords `contents` and `index` (see section 3.6, if both appear. They are legacy keywords preserved for backwards compatibility; you should generally use `contents` and `index`.)

`\cfg{html-title-separator}{`text`}`
  If multiple headings are used in a file's `<TITLE>` tag, this text is used to separate them.
`\cfg{html-index-main-separator}{`text`}`
  Separator between index term and references in the index.
`\cfg{html-index-multiple-separator}{`text`}`
  Separator between multiple references for a single index term in the index.
`\cfg{html-pre-versionid}{`text`}`
`\cfg{html-post-versionid}{`text`}`
  Text surrounding each output version ID paragraph.
`\cfg{html-nav-prev-text}{`text`}`
`\cfg{html-nav-next-text}{`text`}`
`\cfg{html-nav-up-text}{`text`}`
  The text used for the ‘previous page’, ‘next page’, and ‘up’ links on the navigation bar.
`\cfg{html-nav-separator}{`text`}`
  Separator between links in the navigation bar.

### 4.2.6 Configuring the characters used

Unlike the other backends, HTML does not have a single `\cfg{html-charset}` directive, as there are several levels of character encoding to consider.

The character set names are the same as for `\cfg{input-charset}` (see section 3.6). However, unlike `\cfg{input-charset}`, these directives affect the entire output; it's not possible to switch encodings halfway through.

`\cfg{html-output-charset}{`character set name`}`
  The character encoding of the HTML file to be output. Unicode characters in this encoding's repertoire are included literally rather than as HTML entities.
`\cfg{html-restrict-charset}{`character set name`}`
  Only Unicode characters representable in this character set will be output; any others will be omitted and use their fallback text, if any. Characters not in ‘html-output-charset’ will be represented as HTML numeric entities.
`\cfg{html-quotes}{`open-quote`}{`close-quote`}`[`{`open-quote`}{`close-quote...`}`]
  Specifies the quotation marks to use, overriding any `\cfg{quotes}` directive. You can specify multiple fallback options. Works exactly like the `\cfg{text-quotes}` directive (see section 4.1.4).

### 4.2.7 Miscellaneous options

`\cfg{html-version}{`version`}`
  Identifies the precise version of HTML that is output. This affects the declaration within the HTML, and also has minor effects on the body of the HTML so that it is valid for the declared version. The available variants are:
  `html3.2`
    W3C HTML 3.2
  `html4`
    W3C HTML 4.01 Strict
  `iso-html`
    ISO/IEC 15445:2000
  `xhtml1.0transitional`
    W3C XHTML 1.0 Transitional
  `xhtml1.0strict`
    W3C XHTML 1.0 Strict
`\cfg{html-template-fragment}{`template`}`[`{`template`}{`...`}`]
  This directive lets you specify a template, with exactly the same syntax used in `\cfg{html-template-filename}` (see section 4.2.1), to be used for the anchor names (`<A NAME="...">`) used to allow URLs to refer to specific sections within a particular HTML file. So if you set this to ‘`%k`’, for example, then each individual section in your document will be addressable by means of a URL ending in a `#` followed by your internal section keyword.

  If more than one template is specified, anchors are generated in all the specified formats; Halibut's own cross-references are generated with the first template.

  Characters that are not permitted in anchor names are stripped. If there are no valid characters left, or a fragment is non-unique, Halibut starts inventing fragment names and suffixes as appropriate.

  Note that there are potentially fragment names that are not controlled by this mechanism, such as index references.

`\cfg{html-versionid}{`boolean`}`
  If this is set to `true`, version ID paragraphs (defined using the `\versionid` command - see section 3.3.6) will be included visibly in the `<ADDRESS>` section at the bottom of each HTML file. If it is set to `false`, they will only be included as HTML comments.
`\cfg{html-rellinks}{`boolean`}`
  If this is set to `true`, machine-readable relational links will be emitted in each HTML file (`<LINK REL="next">` and so on within the `<HEAD>` section) providing links to related files. The same set of links are provided as in the navigation bar (with which this should not be confused).

  Some browsers make use of this semantic information, for instance to allow easy navigation through related pages, and to prefetch the next page. (Search engines can also make use of it.) However, many browsers ignore this markup, so it would be unwise to rely on it for navigation.

  The use and rendering of this information is entirely up to the browser; none of the other Halibut options for the navigation bar will have any effect.

`\cfg{html-suppress-navlinks}{`boolean`}`
  If this is set to `true`, the usual navigation links within the body of each HTML file (near the top of the rendered page) will be suppressed.
`\cfg{html-suppress-address}{`boolean`}`
  If this is set to `true`, the `<ADDRESS>` section at the bottom of each HTML file will be omitted completely. (This will therefore also cause version IDs not to be included visibly.)
`\cfg{html-author}{`text`}`
  The text supplied here goes in a `<META name="author">` tag in the output HTML files, so that browsers which support this can automatically identify the author of the document.
`\cfg{html-description}{`text`}`
  The text supplied here goes in a `<META name="description">` tag in the output HTML files, so that browsers which support this can easily pick out a brief description of the document.

### 4.2.8 Default settings

The default settings for Halibut's HTML output format are:

    \cfg{html-contents-filename}{Contents.html}
    \cfg{html-index-filename}{IndexPage.html}
    \cfg{html-template-filename}{%n.html}
    \cfg{html-single-filename}{Manual.html}

    \cfg{html-leaf-level}{2}
    \cfg{html-leaf-contains-contents}{false}
    \cfg{html-leaf-smallest-contents}{4}
    \cfg{html-contents-depth}{0}{2}
    \cfg{html-contents-depth}{1}{3}
    ... and so on for all section levels below this ...

    \cfg{html-head-end}{}
    \cfg{html-body-tag}{<body>}
    \cfg{html-body-start}{}
    \cfg{html-body-end}{}
    \cfg{html-address-start}{}
    \cfg{html-address-end}{}
    \cfg{html-navigation-attributes}{}

    \cfg{html-chapter-numeric}{false}
    \cfg{html-chapter-shownumber}{true}
    \cfg{html-chapter-suffix}{: }

    \cfg{html-section-numeric}{0}{true}
    \cfg{html-section-shownumber}{0}{true}
    \cfg{html-section-suffix}{0}{ }

    \cfg{html-section-numeric}{1}{true}
    \cfg{html-section-shownumber}{1}{true}
    \cfg{html-section-suffix}{1}{ }

    ... and so on for all section levels below this ...

    \cfg{html-preamble-text}{Preamble}
    \cfg{html-contents-text}{Contents}
    \cfg{html-index-text}{Index}
    \cfg{html-title-separator}{ - }
    \cfg{html-index-main-separator}{: }
    \cfg{html-index-multiple-separator}{, }
    \cfg{html-pre-versionid}{[}
    \cfg{html-post-versionid}{]}
    \cfg{html-nav-prev-text}{Previous}
    \cfg{html-nav-next-text}{Next}
    \cfg{html-nav-up-text}{Up}
    \cfg{html-nav-separator}{ | }

    \cfg{html-output-charset}{ASCII}
    \cfg{html-restrict-charset}{UTF-8}
    \cfg{html-quotes}{\u2018}{\u2019}{"}{"}

    \cfg{html-version}{html4}
    \cfg{html-template-fragment}{%b}
    \cfg{html-versionid}{true}
    \cfg{html-rellinks}{true}
    \cfg{html-suppress-navlinks{false}
    \cfg{html-suppress-address}{false}
    \cfg{html-author}{}
    \cfg{html-description}{}

## 4.3 Windows HTML Help

This output format generates a `.chm` file suitable for use with the Windows HTML Help system.

Older versions of Halibut could only generate HTML Help by writing out a set of source files acceptable to the MS help compiler. Nowadays Halibut can generate CHM directly, so that's no longer necessary. However, the legacy method is still available if you need it; see section 4.3.6 for details.

### 4.3.1 Output file name

`\cfg{chm-filename}{`filename`}`
  Sets the output file name in which to store the HTML Help file. This directive is implicitly generated if you provide a file name parameter after the command-line option `--chm` (see section 2.1).

### 4.3.2 Configuration shared with the HTML back end

As the name suggests, an HTML Help file is mostly a compressed container for HTML files. So the CHM back end shares a great deal of its code with the HTML back end, and as a result, it supports the same range of format configuration options.

(One exception to this general rule is that the configuration options relating to generating HTML Help compiler input are not supported in CHM mode, because they wouldn't make any sense! The `html-mshtmlhelp-*` options described in section 4.3.6 have no analogue starting `chm-`.)

However, because HTML and CHM are used in different ways, you may need to configure the two back ends differently. So in CHM mode, Halibut supports all the same configuration directives described in section 4.2, but with their names changed so that they begin with ‘`chm-`’ in place of ‘`html-`’. This lets you maintain two sets of configuration independently; for example, you could specify `\cfg{html-chapter-numeric}{true}` and `\cfg{chm-chapter-numeric}{false}` in the same source file, and then when you ran Halibut with both the `--html` and `--chm` options, it would produce purely numeric chapter titles in the HTML output but not in the CHM file.

If you do decide to apply a piece of configuration across both these back ends, you can prefix it with ‘`htmlall-`’ instead of ‘`html-`’ or ‘`chm-`’. For example, `\cfg{htmlall-chapter-numeric}{true}` will enable purely numeric chapter titles in both the HTML and CHM output.

### 4.3.3 Including extra files in the CHM

CHM files are mostly a container for HTML, and the HTML files inside them are allowed to cross-refer to all the usual other kinds of file that HTML might refer to, such as images, stylesheets and even Javascript. If you want to make use of this capability, you need to tell Halibut what extra files it needs to incorporate into the CHM container.

`\cfg{chm-extra-file}{`filename`}`
`\cfg{chm-extra-file}{`filename`}{`name inside CHM`}`
  Tells Halibut to read an additional input file from filename and incorporate it into the CHM.

  In the first form of the directive, the file will be given the same name within the CHM's internal namespace (i.e. for the purposes of linking to it from HTML files) as Halibut used to load it from disk. If you need to include the file with a different internal name, you can use the second form of the directive, which separately specifies the name under which Halibut should look for the input file and the name it should give it inside the CHM.

  You can specify this directive multiple times, to include more than one file.

### 4.3.4 Renaming the CHM internal support files

As well as ordinary HTML, there are also two special files inside a CHM, containing the table of contents and the index. Halibut generates these automatically, and you normally don't have to worry about them. However, it is just possible (though very unlikely!) that you might find they conflict with the name of some file you wanted to include in the CHM yourself, and hence, Halibut provides configuration options to change them if you need to.

`\cfg{chm-contents-name}{`filename`}`
  Controls the name of the internal contents file in the CHM.
`\cfg{chm-index-name}{`filename`}`
  Controls the name of the internal index file in the CHM.

### 4.3.5 Default settings

The default settings for Halibut's CHM output format are mostly the same as for the standard HTML output. However, a few defaults are changed to be more in line with the way CHM wants to do things.

    \cfg{chm-filename}{output.chm}
    \cfg{chm-contents-name}{contents.hhc}
    \cfg{chm-index-name}{index.hhk}
    \cfg{chm-leaf-level}{infinite}
    \cfg{chm-suppress-navlinks{true}
    \cfg{chm-suppress-address}{true}

### 4.3.6 Generating input to the MS Windows HTML Help compiler

Before Halibut gained the ability to write out CHM files directly, it used a more cumbersome system in which you could run it in HTML mode and enable some extra options that would write out supporting files needed by the official Windows HTML Help compiler, so that you could still generate a CHM file from your Halibut source in multiple build steps.

This legacy system for HTML Help generation is still supported, partly to avoid backwards-compatibility breakage for anyone already using it, and also because it permits more flexibility in the resulting CHM files: Halibut's own CHM file generation makes some fixed decisions about window layout and styling, whereas if you use the official help compiler you can start from Halibut's default project file and make whatever manual changes you like to that sort of thing.

To enable the generation of MS HTML Help auxiliary files, use the following configuration directives:

`\cfg{html-mshtmlhelp-project}{`filename`}`
  Instructs Halibut to output an HTML Help project file with the specified name. You will almost certainly want the filename to end in the extension `.hhp` (although Halibut will not enforce this). If you use this option, you must also use the `html-mshtmlhelp-chm` option to specify the desired name of the compiled help file.
`\cfg{html-mshtmlhelp-chm}{`filename`}`
  Specifies the desired name of the compiled HTML Help file. You will almost certainly want this to have the extension `.chm` (although Halibut will not enforce this). The name you specify here will be written into the help project file. If you specify this option, you must also use the `html-mshtmlhelp-project` option to request a help project file in the first place.
`\cfg{html-mshtmlhelp-contents}{`filename`}`
  Instructs Halibut to output an HTML Help contents file with the specified name, and refer to it in the help project file. You will almost certainly want the filename to end in the extension `.hhc` (although Halibut will not enforce this). This option will be ignored if you have not also specified a help project file.

  Creating a contents file like this causes the HTML Help viewer to display a contents tree in the pane to the left of the main text window. You can choose to generate an HTML Help project without this feature, in which case the user will still be able to navigate around the document by using the ordinary internal links in the HTML files themselves just as if it were a web page. However, using a contents file is recommended.

`\cfg{html-mshtmlhelp-index}{`filename`}`
  Instructs Halibut to output an HTML Help index file with the specified name, and refer to it in the help project file. You will almost certainly want the filename to end in the extension `.hhk` (although Halibut will not enforce this). This option will be ignored if you have not also specified a help project file.

  Specifying this option suppresses the generation of an HTML-based index file (see `\cfg{html-index-filename}` in section 4.2.1).

  Creating an index file like this causes the HTML Help viewer to provide a list of index terms in a pane to the left of the main text window. You can choose to generate an HTML Help project without this feature, in which case a conventional HTML index will be generated instead (assuming you have any index terms at all defined) and the user will still be able to use that. However, using an index file is recommended.

  Halibut will not output an index file at all, or link to one from the help project file, if your document contains no index entries.

If you use the above options, Halibut will output a help project file which you should be able to feed straight to the command-line MS HTML Help compiler (`HHC.EXE`), or load into the MS HTML Help Workshop (`HHW.EXE`).

You may also wish to alter other HTML configuration options to make the resulting help file look more like a help file and less like a web page. If you use Halibut's direct CHM output, this is done for you automatically (see section 4.3.5); but if you're using the HTML output mode then I recommend the following changes.

- `\cfg{html-leaf-level}{infinite}`, because HTML Help works best with lots of small files (‘topics’) rather than a few large ones. In particular, the contents and index mechanisms can only reference files, not subsections within files.
- `\cfg{html-suppress-navlinks}{true}`, because HTML Help has its own navigation facilities and it looks a bit strange to duplicate them.
- `\cfg{html-suppress-address}{true}`, because the `<ADDRESS>` section makes less sense in a help file than it does on a web page.

## 4.4 Legacy Windows Help

This output format generates data that can be used by the legacy Windows Help program `WINHLP32.EXE`. There are two actual files generated, one ending in `.hlp` and the other ending in `.cnt`.

This legacy Windows Help format was discontinued in 2006 in favour of HTML Help, which Halibut can also generate. You probably want to use that instead for any new project. See section 4.3 for more information on this.

Currently, the Windows Help output is hardcoded to be in the ‘Win1252’ character set. (If anyone knows how character sets are encoded in Windows Help files, we'd appreciate help.)

The Windows Help output format supports the following configuration directives:

### 4.4.1 Output file name

`\cfg{winhelp-filename}{`filename`}`
  Sets the output file name in which to store the help file. This directive is implicitly generated if you provide a file name parameter after the command-line option `--winhelp` (see section 2.1).

  Your output file name should end with `.hlp`; if it doesn't, Halibut will append it. Halibut will also generate a contents file (ending in `.cnt`) alongside the file name you specify.

### 4.4.2 Configuring the characters used

`\cfg{winhelp-bullet}{`text`}`[`{`text`}`...]
  Specifies the text to use as the bullet in bulletted lists. You can specify multiple fallback options. Works exactly like the `\cfg{text-bullet}` directive (see section 4.1.4).
`\cfg{winhelp-quotes}{`open-quote`}{`close-quote`}`[`{`open-quote`}{`close-quote...`}`]
  Specifies the quotation marks to use, overriding any `\cfg{quotes}` directive. You can specify multiple fallback options. Works exactly like the `\cfg{text-quotes}` directive (see section 4.1.4).

### 4.4.3 Miscellaneous configuration options

`\cfg{winhelp-contents-titlepage}{`title`}`
  Sets the text used to describe the help page containing the blurb (see section 3.3.6) and table of contents.
`\cfg{winhelp-section-suffix}{`text`}`
  Specifies the suffix text to be appended to section numbers, before displaying the section title. (Applies to all levels.)
`\cfg{winhelp-list-suffix}{`text`}`
  This text is appended to the number on a numbered list item, in exactly the same way as `\cfg{text-list-suffix}` (see section 4.1.4).
`\cfg{winhelp-topic}{`topic-name`}`
  This directive defines a Windows Help topic name in the current section. Topic names can be used by the program invoking `WINHELP.EXE` to jump straight to a particular section. So you can use this for context-sensitive help.

  For example, if you used this directive in a particular section:

      \cfg{winhelp-topic}{savingfiles}

  then a Windows application could invoke Windows Help to jump to that particular section in the help file like this:

      WinHelp(hwnd, "mydoc.hlp", HELP_COMMAND,
              (DWORD)"JI(`',`savingfiles')");

  You can use this configuration directive many times, in many different subsections of your document, in order to define a lot of different help contexts which you can use in this way.

### 4.4.4 Default settings

The default settings for the Windows Help output format are:

    \cfg{winhelp-filename}{output.hlp}

    \cfg{winhelp-bullet}{\u2022}{-}
    \cfg{winhelp-quotes}{\u2018}{\u2019}{"}{"}

    \cfg{winhelp-contents-titlepage}{Title page}
    \cfg{winhelp-section-suffix}{: }
    \cfg{winhelp-list-suffix}{.}

and no `\cfg{winhelp-topic}` directives anywhere.

## 4.5 Unix `man` pages

This output format generates a Unix `man` page. That is to say, it generates `nroff` input designed to work with the `-mandoc` macro package.

The available configuration options for this format are as follows:

### 4.5.1 Output file name

`\cfg{man-filename}{`filename`}`
  Sets the output file name in which to store the man page. This directive is implicitly generated if you provide a file name parameter after the command-line option `--man` (see section 2.1).

### 4.5.2 Configuring headers and footers

`\cfg{man-identity}{`text`}{`text...`}`
  This directive is used to generate the initial `.TH` directive that appears at the top of a `man` page. It expects to be followed by some number of brace pairs containing text, which will be used in the headers and footers of the formatted output.

  A traditional order for the arguments appears to be:

  1. The name of the program.
  2. The (numeric) manual section.
  3. The date that the `man` page was written.
  4. The name of any containing suite of which the program is a part.
  5. The name of the author of the `man` page.

  For example, a typical `man` page might contain

      \cfg{man-identity}{make-foo}{1}{June 2003}{foo-utils}{Fred
      Bloggs}

### 4.5.3 Configuring heading display

`\cfg{man-headnumbers}{`boolean`}`
  If this is set to `true`, then section headings in the `man` page will have their section numbers displayed as usual. If set to `false`, the section numbers will be omitted. (`man` pages traditionally have section names such as ‘SYNOPSIS’, ‘OPTIONS’ and ‘BUGS’, and do not typically number them, so `false` is the setting which conforms most closely to normal `man` style.)
`\cfg{man-mindepth}{`depth`}`
  If this is set to a number greater than 0, then section headings higher than the given depth will not be displayed. If it is set to zero, all section headings will be displayed as normal.

  The point of this is so that you can use the same Halibut input file to generate a quick-reference `man` page for a program, and to include that `man` page as an appendix in your program's full manual. If you are to include the `man` page as an appendix, then the internal headings within the page will probably need to be at `\H` or `\S` level; therefore, when you format that input file on its own to create the `man` page itself, you will need to have defined a `\C` and possibly a `\H` heading beforehand, which you don't want to see displayed.

  Here's an example. You might have a file `appendix.but`, which simply says

      \A{manpages} \cw{man} pages for the Foo tool suite

      \cfg{man-mindepth}{2}

  Then you have a file `make-foo.but`, and probably others like it as well, each of which looks something like this:

      \cfg{man-identity}{make-foo}{1}{June 2003}{foo-utils}{Fred
      Bloggs}

      \H{man-foo} \cw{man} page for \c{make-foo}

      \S{man-foo-name} NAME

      \c{make-foo} - create Foo files for the Foo tool suite

      \S{man-foo-synopsis} SYNOPSIS

      ... and so on ...

  So when you're generating your main manual, you can include `appendix.but` followed by `make-foo.but` and any other `man` pages you have, and your `man` pages will be formatted neatly as part of an appendix. Then, in a separate run of Halibut, you can just do

      halibut appendix.but make-foo.but

  and this will generate a `man` page `output.1`, in which the headings ‘`man` pages for the Foo tool suite’ and ‘`man` page for `make-foo`’ will not be displayed because of the `man-mindepth` directive. So the first visible heading in the output `man` page will be ‘NAME’, exactly as a user would expect.

### 4.5.4 Configuring the characters used

`\cfg{man-charset}{`character set`}`
  Specifies what character set the output should be in, similarly to `\cfg{text-charset}` (see section 4.1.4).
`\cfg{man-bullet}{`text`}`[`{`text`}`...]
  Specifies the text to use as the bullet in bulletted lists. You can specify multiple fallback options. Works exactly like the `\cfg{text-bullet}` directive (see section 4.1.4).
`\cfg{man-rule}{`text`}`[`{`text...`}`]
  This specifies the text which should be used for drawing horizontal rules (generated by `\rule`; see section 3.3.3) when the manual page is rendered into text. It should only be one character long, but otherwise it works like the `\cfg{text-rule}` directive (see section 4.1.4).
`\cfg{man-quotes}{`open-quote`}{`close-quote`}`[`{`open-quote`}{`close-quote...`}`]
  Specifies the quotation marks to use, overriding any `\cfg{quotes}` directive. You can specify multiple fallback options. Works exactly like the `\cfg{text-quotes}` directive (see section 4.1.4).

### 4.5.5 Default settings

The default settings for the `man` page output format are:

    \cfg{man-filename}{output.1}

    \cfg{man-identity}{}

    \cfg{man-headnumbers}{false}
    \cfg{man-mindepth}{0}

    \cfg{man-charset}{ASCII}
    \cfg{man-bullet}{\u2022}{o}
    \cfg{man-rule}{\u2500}{-}
    \cfg{man-quotes}{\u2018}{\u2019}{"}{"}

## 4.6 GNU Info

This output format generates files which can be used with the GNU Info program.

There are typically multiple output files: a primary file whose name usually ends in `.info`, and one or more subsidiary files whose names have numbers on the end, so that they end in `.info-1`, `.info-2` and so on. Alternatively, this output format can be configured to output a single large file containing the whole document.

The Info output format supports the following configuration directives:

### 4.6.1 Controlling the output filenames

`\cfg{info-filename}{`filename`}`
  Sets the output file name in which to store the Info file. This directive is implicitly generated if you provide a file name parameter after the command-line option `--info` (see section 2.1).

  The suffixes `-1`, `-2`, `-3` and so on will be appended to your output file name to produce any subsidiary files required.

  Note that Info files refer to their own names internally, so these files cannot be renamed after creation and remain useful.

`\cfg{info-max-file-size}{`bytes`}`
  Sets the preferred maximum file size for each subsidiary file. As a special case, if you set this to zero, there will be no subsidiary files and the whole document will be placed in a single self-contained output file. (However, note that this file can still not be renamed usefully.)

  The preferred maximum file size is only a guideline. Halibut may be forced to exceed it if a single section of the document is larger than the maximum size (since individual Info nodes may not be split between files).

### 4.6.2 Indentation and line width

`\cfg{info-width}{`width`}`
  Sets the width of the main part of the document, in characters. Works exactly like the `\cfg{text-width}` directive (see section 4.1.2).
`\cfg{info-indent-code}{`indent`}`
  Specifies the extra indentation for code paragraphs. Works exactly like the `\cfg{text-indent-code}` directive (see section 4.1.2).
`\cfg{info-index-width}{`width`}`
  Specifies how much horizontal space to leave in the index node for the text of index terms, before displaying the sections the terms occur in.
`\cfg{info-list-indent}{`indent`}`
  Specifies the extra indentation before the bullet or number in a list item. Works exactly like the `\cfg{text-list-indent}` directive (see section 4.1.2).
`\cfg{info-listitem-indent}{`indent`}`
  Specifies the additional indentation before the body of a list item. Works exactly like the `\cfg{text-listitem-indent}` directive (see section 4.1.2).

### 4.6.3 Configuring heading display

`\cfg{info-section-suffix}{`text`}`
  Specifies the suffix text to be appended to each section number before displaying the section title. For example, if you set this to ‘`:` ’, then a typical section title might look something like ‘Section 3.1: Something Like This’.
`\cfg{info-title-underline}{`text`}`[`{`text`}`...]
  Specifies the text to be used to underline the overall document title. Works very much like the `\cfg{text-title-underline}` directive (see section 4.1.3). You can specify more than one option, and Halibut will choose the first one supported by the character set.
`\cfg{info-chapter-underline}{`text`}`[`{`text`}`...]
  Specifies how chapter and appendix headings should be underlined.
`\cfg{info-section-underline}{`level`}{`text`}`[`{`text`}`...]
  Specifies how to underline section headings at a particular level. The level parameter specifies which level of section headings you want to affect: 0 means first-level headings (`\H`), 1 means second-level headings (`\S`), 2 means the level below that (`\S2`), and so on.

### 4.6.4 Controlling the characters used

`\cfg{info-charset}{`character set`}`
  Specifies what character set the output should be in, similarly to `\cfg{text-charset}` (see section 4.1.4).
`\cfg{info-bullet}{`text`}`[`{`text`}`...]
  Specifies the text to use as the bullet in bulletted lists. You can specify multiple fallback options. Works exactly like the `\cfg{text-bullet}` directive (see section 4.1.4).
`\cfg{info-rule}{`text`}`[`{`text`}`...]
  Specifies the text used to draw horizontal rules. You can specify multiple fallback options. Works exactly like the `\cfg{text-rule}` directive (see section 4.1.4).
`\cfg{info-quotes}{`open-quote`}{`close-quote`}`[`{`open-quote`}{`close-quote...`}`]
  Specifies the quotation marks to use, overriding any `\cfg{quotes}` directive. You can specify multiple fallback options. Works exactly like the `\cfg{text-quotes}` directive (see section 4.1.4).
`\cfg{info-emphasis}{`start-emph`}{`end-emph`}`[`{`start-emph`}{`end-emph...`}`]
  Specifies how to display emphasised text. You can specify multiple fallback options. Works exactly like the `\cfg{text-emphasis}` directive (see section 4.1.4).
`\cfg{info-strong}{`start-strong`}{`end-strong`}`[`{`start-strong`}{`end-strong...`}`]
  Specifies how to display strong text. You can specify multiple fallback options. Works exactly like the `\cfg{text-emphasis}` directive (see section 4.1.4).

### 4.6.5 Miscellaneous configuration options

`\cfg{info-list-suffix}{`text`}`
  Specifies the text to append to the item numbers in a numbered list. Works exactly like the `\cfg{text-list-suffix}` directive (see section 4.1.5).
`\cfg{info-dir-entry}{`section`}{`short name`}{`long name`}`[`{`keyword`}`]
  Constructs an `INFO-DIR-ENTRY` section and places it in the header of the Info file. This mechanism is used to automatically generate the `dir` file at the root of a Unix system's Info collection.

  The parameters to this directive are:

  section
    Specifies the section of the `dir` file in which you want your document referenced. For example, ‘Development’, or ‘Games’, or ‘Miscellaneous’.
  short name
    Specifies a short name for the directory entry, which will appear at the start of the menu line.
  long name
    Specifies a long name for the directory entry, which will appear at the end of the menu line.
  keyword
    This parameter is optional. If it is present, then the directory entry will cause a jump to a particular subsection of your document, rather than starting at the top. The subsection will be the one referred to by the given keyword (see section 3.3.5 for details about assigning keywords to document sections).

  For example, in a document describing many game programs, the configuration directive

      \cfg{info-dir-entry}{Games}{Chess}{Electronic chess
      game}{chess}

  might produce text in the `dir` file looking something like this:

      Games
      * Chess: (mygames)Chapter 3.   Electronic chess game

  if the output file were called `mygames.info` and the keyword `chess` had been used to define Chapter 3 of the document.

### 4.6.6 Default settings

The default settings for the Info output format are:

    \cfg{info-filename}{output.info}
    \cfg{info-max-file-size}{65536}

    \cfg{info-width}{70}
    \cfg{info-indent-code}{2}
    \cfg{info-index-width}{40}
    \cfg{info-list-indent}{1}
    \cfg{info-listitem-indent}{3}

    \cfg{info-section-suffix}{: }
    \cfg{info-title-underline}{*}
    \cfg{info-chapter-underline}{=}
    \cfg{info-section-underline}{0}{-}
    \cfg{info-section-underline}{1}{.}
    \cfg{info-section-underline}{2}{.}
    ... and so on for all section levels below this ...

    \cfg{info-charset}{ASCII}
    \cfg{info-bullet}{\u2022}{-}
    \cfg{info-rule}{\u2500}{-}
    \cfg{info-quotes}{\u2018}{\u2019}{`}{'}
    \cfg{info-emphasis}{_}{_}
    \cfg{info-strong}{*}{*}

    \cfg{info-list-suffix}{.}

and no `\cfg{info-dir-entry}` directives.

## 4.7 Paper formats

These output formats (currently PDF and PostScript) generate printable manuals. As such, they share a number of configuration directives.

### 4.7.1 PDF

This output format generates a printable manual in PDF format. In addition, it uses some PDF interactive features to provide an outline of all the document's sections and clickable cross-references between sections.

There is one configuration option specific to PDF:

`\cfg{pdf-filename}{`filename`}`
  Sets the output file name in which to store the PDF file. This directive is implicitly generated if you provide a file name parameter after the command-line option `--pdf` (see section 2.1).

The default settings for the PDF output format are:

    \cfg{pdf-filename}{output.pdf}

### 4.7.2 PostScript

This output format generates a printable manual in PostScript format. This should look exactly identical to the PDF output (see section 4.7.2), and uses `pdfmark` to arrange that if converted to PDF it will contain the same interactive features.

There is one configuration option specific to PostScript:

`\cfg{ps-filename}{`filename`}`
  Sets the output file name in which to store the PostScript file. This directive is implicitly generated if you provide a file name parameter after the command-line option `--ps` (see section 2.1).

The default settings for the PostScript output format are:

    \cfg{ps-filename}{output.ps}

### 4.7.3 Configuring layout and measurements

All measurements are in PostScript points (72 points to the inch).

#### 4.7.3.1 Page properties

`\cfg{paper-page-width}{`points`}`
`\cfg{paper-page-height}{`points`}`
  Specify the absolute limits of the paper.
`\cfg{paper-left-margin}{`points`}`
`\cfg{paper-top-margin}{`points`}`
`\cfg{paper-right-margin}{`points`}`
`\cfg{paper-bottom-margin}{`points`}`
  Specify the margins. Most text appears within these margins, except:
  - Section numbers, which appear in the left margin.
  - The footer (containing page numbers), which appears in the bottom margin.

#### 4.7.3.2 Vertical spacing

`\cfg{paper-base-leading}{`points`}`
  Specifies the amount of space between lines of text within a paragraph. (So, if the font size is 12pt and there is 2pt of leading, there will be 14pt between successive baselines.)
`\cfg{paper-base-para-spacing}{`points`}`
  Specifies the amount of vertical space between paragraphs. (The vertical space between paragraphs does not include `paper-base-leading`.)

#### 4.7.3.3 Indentation

`\cfg{paper-list-indent}{`points`}`
  Specifies the indentation of the bullet or number in a bulletted or numbered list, similarly to `\cfg{text-list-indent}` (see section 4.1.2).
`\cfg{paper-listitem-indent}{`points`}`
  Specifies the extra indentation for the body of a list item, over and above the amount configured in `\cfg{paper-list-indent}`.
`\cfg{paper-quote-indent}{`points`}`
  Specifies the amount of indentation for a level of quoting. Used for `\quote` (see section 3.3.4) and code quotes with `\c` (see section 3.2.2).

#### 4.7.3.4 Headings

`\cfg{paper-chapter-top-space}{`points`}`
  Specifies the space between the top margin and the top of the chapter heading. (Each chapter begins on a new page.)
`\cfg{paper-chapter-underline-thickness}{`points`}`
  Specifies the vertical thickness of the black rule under chapter headings.
`\cfg{paper-chapter-underline-depth}{`points`}`
  Specifies the distance between the base of the chapter heading and the base of the underlying rule.
`\cfg{paper-sect-num-left-space}{`points`}`
  Specifies the distance between the left margin and the right of section numbers (which are in the left margin).

#### 4.7.3.5 Contents and index

`\cfg{paper-contents-indent-step}{`points`}`
  Specifies by how much to indent each entry in the table of contents per level of subdivision in the document. (In other words, chapter titles appear at the left of the table of contents, headings within the chapter are indented by the amount configured here, subheadings by twice that, and so on.)
`\cfg{paper-contents-margin}{`points`}`
  Specifies the amount of space on the right of the table of contents which should be reserved for page numbers only. Headings in the table of contents which extend into this space will be wrapped.
`\cfg{paper-leader-separation}{`points`}`
  Specifies the horizontal spacing between dots in leaders (the dotted lines that appear between section headings and page numbers in the table of contents).
`\cfg{paper-footer-distance}{`points`}`
  Specifies the distance between the bottom margin and the base of the footer (which contains page numbers).
`\cfg{paper-index-columns}{`columns`}`
  Specifies the number of columns the index should be divided into.
`\cfg{paper-index-gutter}{`points`}`
  Specifies the amount of horizontal space between index columns.
`\cfg{paper-index-minsep}{`points`}`
  Specifies the minimum allowable horizontal space between an index entry and its page number. If the gap is smaller, the page number is moved to the next line.

#### 4.7.3.6 Fonts

The directives in this section control which fonts Halibut uses for various kinds of text. Directives for setting the font normally take three font names, the first of which is used for normal text, the second for emphasised text, and the third for code. Any fonts which aren't specified are left unchanged.

Halibut intrinsically knows about some fonts, and these fonts are also built into all PDF and most PostScript implementations. These fonts can be used without further formality. Halibut can also use other fonts, and can embed them it its PDF and PostScript output. These other fonts are supplied to Halibut by simply adding them to the list of input files on its command line.

To use a Type 1 font Halibut needs both the font file itself, in either hexadecimal (PFA) or IBM PC (PFB) format, and an Adobe Font Metrics (AFM) file. The AFM file must be specified first on the command line. If Halibut gets an AFM file without a corresponding Type 1 font file, the PostScript and PDF output files will still use that font, but they won't contain it.

Using a TrueType font is rather simpler, and simply requires you to pass the font file to Halibut. Halibut does place a few restrictions on TrueType fonts, notably that they must include a Unicode mapping table and a PostScript name.

Fonts are specified using their PostScript names. Running Halibut with the `--list-fonts` option causes it to display the PostScript names of all the fonts it intrinsically knows about, along with any fonts the were supplied as input files.

Font sizes are specified in PostScript points (72 to the inch).

`\cfg{paper-title-fonts}{`normal-font`}`[`{`emph-font`}`[`{`code-font`}`]]
  Specifies the fonts to use for text in the document title.
`\cfg{paper-title-font-size}{`points`}`
  Specifies the font size of the document title.
`\cfg{paper-chapter-fonts}{`normal-font`}`[`{`emph-font`}`[`{`code-font`}`]]
  Specifies the fonts to use for text in chapter titles.
`\cfg{paper-chapter-font-size}{`points`}`
  Specifies the font size of chapter titles.
`\cfg{paper-section-fonts}{`level`}{`normal-font`}`[`{`emph-font`}`[`{`code-font`}`]]
  Specifies the fonts to use for text in section headings at the level specified.
`\cfg{paper-section-font-size}{`level`}{`points`}`
  Specifies the font size of section headings at the level specified.
`\cfg{paper-base-fonts}{`normal-font`}`[`{`emph-font`}`[`{`code-font`}`]]
  Specifies the fonts to use for text in the body text.
`\cfg{paper-base-font-size}{`points`}`
  Specifies the font size of body text.
`\cfg{paper-code-fonts}{`bold-font`}`[`{`italic-font`}`[`{`normal-font`}`]]
  Specifies the fonts to use for text in code paragraphs. The bold-font is used for bold text, the italic-font for emphasised text, and the normal-font for normal code.
`\cfg{paper-code-font-size}{`points`}`
  Specifies the font size of text in code paragraphs.
`\cfg{paper-pagenum-font-size}{`points`}`
  Specifies the font size to use for page numbers.

#### 4.7.3.7 Miscellaneous

`\cfg{paper-rule-thickness}{`points`}`
  Specifies the vertical thickness of the rule produced by the `\rule` command (see section 3.3.3). (Note that no extra space is reserved for thicker rules.)

### 4.7.4 Configuring the characters used

`\cfg{paper-bullet}{`text`}`[`{`text`}`...]
  Specifies the text to use as the bullet in bulletted lists. You can specify multiple fallback options. Works exactly like the `\cfg{text-bullet}` directive (see section 4.1.4).
`\cfg{paper-quotes}{`open-quote`}{`close-quote`}`[`{`open-quote`}{`close-quote...`}`]
  Specifies the quotation marks to use, overriding any `\cfg{quotes}` directive. You can specify multiple fallback options. Works exactly like the `\cfg{text-quotes}` directive (see section 4.1.4).

### 4.7.5 Default settings for paper formats

The default page size corresponds to 210 × 297 mm, i.e., A4 paper.

    \cfg{paper-page-width}{595}
    \cfg{paper-page-height}{842}

    \cfg{paper-left-margin}{72}
    \cfg{paper-top-margin}{72}
    \cfg{paper-right-margin}{72}
    \cfg{paper-bottom-margin}{108}

    \cfg{paper-base-leading}{1}
    \cfg{paper-base-para-spacing}{10}

    \cfg{paper-list-indent}{6}
    \cfg{paper-listitem-indent}{18}
    \cfg{paper-quote-indent}{18}

    \cfg{paper-chapter-top-space}{72}
    \cfg{paper-chapter-underline-thickness}{3}
    \cfg{paper-chapter-underline-depth}{14}
    \cfg{paper-sect-num-left-space}{12}

    \cfg{paper-contents-indent-step}{24}
    \cfg{paper-contents-margin}{84}
    \cfg{paper-leader-separation}{12}
    \cfg{paper-footer-distance}{32}
    \cfg{paper-index-columns}{2}
    \cfg{paper-index-gutter}{36}
    \cfg{paper-index-minsep}{18}

    \cfg{paper-base-fonts}{Times-Roman}{Times-Italic}{Courier}
    \cfg{paper-base-font-size}{12}
    \cfg{paper-code-fonts}{Courier-Bold}{Courier-Oblique}{Courier}
    \cfg{paper-code-font-size}{12}
    \cfg{paper-title-fonts}{Helvetica-Bold}
        {Helvetica-BoldOblique}{Courier-Bold}
    \cfg{paper-title-font-size}{24}
    \cfg{paper-chapter-fonts}{Helvetica-Bold}
        {Helvetica-BoldOblique}{Courier-Bold}
    \cfg{paper-chapter-font-size}{20}
    \cfg{paper-section-fonts}{0}{Helvetica-Bold}
        {Helvetica-BoldOblique}{Courier-Bold}
    \cfg{paper-section-font-size}{0}{16}
    \cfg{paper-section-fonts}{1}{Helvetica-Bold}
        {Helvetica-BoldOblique}{Courier-Bold}
    \cfg{paper-section-font-size}{1}{14}
    \cfg{paper-section-fonts}{2}{Helvetica-Bold}
        {Helvetica-BoldOblique}{Courier-Bold}
    \cfg{paper-section-font-size}{2}{13}
    ... and so on for all section levels below this ...

    \cfg{paper-pagenum-font-size}{12}

    \cfg{paper-rule-thickness}{1}

    \cfg{paper-bullet}{\u2022}{-}
    \cfg{paper-quotes}{\u2018}{\u2019}{'}{'}