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diff --git a/contrib/groff/doc/groff-6 b/contrib/groff/doc/groff-6 deleted file mode 100644 index f7f01e1..0000000 --- a/contrib/groff/doc/groff-6 +++ /dev/null @@ -1,1462 +0,0 @@ -This is groff, produced by makeinfo version 4.3d from ./groff.texinfo. - -This manual documents GNU `troff' version 1.19. - - Copyright (C) 1994-2000, 2001, 2002, 2003 Free Software Foundation, -Inc. - - Permission is granted to copy, distribute and/or modify this - document under the terms of the GNU Free Documentation License, - Version 1.1 or any later version published by the Free Software - Foundation; with no Invariant Sections, with the Front-Cover texts - being `A GNU Manual," and with the Back-Cover Texts as in (a) - below. A copy of the license is included in the section entitled - `GNU Free Documentation License." - - (a) The FSF's Back-Cover Text is: `You have freedom to copy and - modify this GNU Manual, like GNU software. Copies published by - the Free Software Foundation raise funds for GNU development." - -INFO-DIR-SECTION Typesetting -START-INFO-DIR-ENTRY -* Groff: (groff). The GNU troff document formatting system. -END-INFO-DIR-ENTRY - - -File: groff, Node: Changing Type Sizes, Next: Fractional Type Sizes, Prev: Sizes, Up: Sizes - -Changing Type Sizes -------------------- - - - Request: .ps [size] - - Request: .ps +size - - Request: .ps -size - - Escape: \ssize - - Register: \n[.s] - Use the `ps' request or the `\s' escape to change (increase, - decrease) the type size (in points). Specify SIZE as either an - absolute point size, or as a relative change from the current size. - The size 0, or no argument, goes back to the previous size. - - Default scaling indicator of `size' is `z'. If `size' is zero or - negative, it is set to 1u. - - The read-only number register `.s' returns the point size in - points as a decimal fraction. This is a string. To get the point - size in scaled points, use the `.ps' register instead. - - `.s' is associated with the current environment (*note - Environments::). - - - snap, snap, - .ps +2 - grin, grin, - .ps +2 - wink, wink, \s+2nudge, nudge,\s+8 say no more! - .ps 10 - - The `\s' escape may be called in a variety of ways. Much like - other escapes there must be a way to determine where the argument - ends and the text begins. Any of the following forms are valid: - - `\sN' - Set the point size to N points. N must be either 0 or in the - range 4 to 39. - - `\s+N' - `\s-N' - Increase or decrease the point size by N points. N must be - exactly one digit. - - `\s(NN' - Set the point size to NN points. NN must be exactly two - digits. - - `\s+(NN' - `\s-(NN' - `\s(+NN' - `\s(-NN' - Increase or decrease the point size by NN points. NN must be - exactly two digits. - - Note that `\s' doesn't produce an input token in `gtroff'. As a - consequence, it can be used in requests like `mc' (which expects a - single character as an argument) to change the font on the fly: - - - .mc \s[20]x\s[0] - - *Note Fractional Type Sizes::, for yet another syntactical form of - using the `\s' escape. - - - Request: .sizes s1 s2 ... sn [0] - Some devices may only have certain permissible sizes, in which case - `gtroff' rounds to the nearest permissible size. The `DESC' file - specifies which sizes are permissible for the device. - - Use the `sizes' request to change the permissible sizes for the - current output device. Arguments are in scaled points; the - `sizescale' line in the `DESC' file for the output device provides - the scaling factor. For example, if the scaling factor is 1000, - then the value 12000 is 12 points. - - Each argument can be a single point size (such as `12000'), or a - range of sizes (such as `4000-72000'). You can optionally end the - list with a zero. - - - Request: .vs [space] - - Request: .vs +space - - Request: .vs -space - - Register: \n[.v] - Change (increase, decrease) the vertical spacing by SPACE. The - default scaling indicator is `p'. - - If `vs' is called without an argument, the vertical spacing is - reset to the previous value before the last call to `vs'. - - `gtroff' creates a warning of type `range' if SPACE is negative; - the vertical spacing is then set to the vertical resolution (as - given in the `.V' register). - - The read-only number register `.v' contains the current vertical - spacing; it is associated with the current environment (*note - Environments::). - - The effective vertical line spacing consists of four components. - - * The vertical line spacing as set with the `vs' request. - - * The "post-vertical line spacing" as set with the `pvs' request. - This is vertical space which will be added after a line has been - output. - - * The "extra pre-vertical line space" as set with the `\x' request, - using a negative value. This is vertical space which will be - added once before the current line has been output. - - * The "extra post-vertical line space" as set with the `\x' request, - using a positive value. This is vertical space which will be - added once after the current line has been output. - - It is usually better to use `vs' or `pvs' instead of `ls' to produce -double-spaced documents: `vs' and `pvs' have a finer granularity for -the inserted vertical space compared to `ls'; furthermore, certain -preprocessors assume single-spacing. - - *Note Manipulating Spacing::, for more details on the `\x' escape -and the `ls' request. - - - Request: .pvs [space] - - Request: .pvs +space - - Request: .pvs -space - - Register: \n[.pvs] - Change (increase, decrease) the post-vertical spacing by SPACE. - The default scaling indicator is `p'. - - If `pvs' is called without an argument, the post-vertical spacing - is reset to the previous value before the last call to `pvs'. - - `gtroff' creates a warning of type `range' if SPACE is zero or - negative; the vertical spacing is then set to zero. - - The read-only number register `.pvs' contains the current - post-vertical spacing; it is associated with the current - environment (*note Environments::). - - -File: groff, Node: Fractional Type Sizes, Prev: Changing Type Sizes, Up: Sizes - -Fractional Type Sizes ---------------------- - - A "scaled point" is equal to 1/SIZESCALE points, where SIZESCALE is -specified in the `DESC' file (1 by default). There is a new scale -indicator `z' which has the effect of multiplying by SIZESCALE. -Requests and escape sequences in `gtroff' interpret arguments that -represent a point size as being in units of scaled points, but they -evaluate each such argument using a default scale indicator of `z'. -Arguments treated in this way are the argument to the `ps' request, the -third argument to the `cs' request, the second and fourth arguments to -the `tkf' request, the argument to the `\H' escape sequence, and those -variants of the `\s' escape sequence that take a numeric expression as -their argument (see below). - - For example, suppose SIZESCALE is 1000; then a scaled point is -equivalent to a millipoint; the request `.ps 10.25' is equivalent to -`.ps 10.25z' and thus sets the point size to 10250 scaled points, which -is equal to 10.25 points. - - `gtroff' disallows the use of the `z' scale indicator in instances -where it would make no sense, such as a numeric expression whose -default scale indicator was neither `u' nor `z'. Similarly it would -make no sense to use a scaling indicator other than `z' or `u' in a -numeric expression whose default scale indicator was `z', and so -`gtroff' disallows this as well. - - There is also new scale indicator `s' which multiplies by the number -of units in a scaled point. So, for example, `\n[.ps]s' is equal to -`1m'. Be sure not to confuse the `s' and `z' scale indicators. - - - Register: \n[.ps] - A read-only number register returning the point size in scaled - points. - - `.ps' is associated with the current environment (*note - Environments::). - - - Register: \n[.psr] - - Register: \n[.sr] - The last-requested point size in scaled points is contained in the - `.psr' read-only number register. The last requested point size - in points as a decimal fraction can be found in `.sr'. This is a - string-valued read-only number register. - - Note that the requested point sizes are device-independent, whereas - the values returned by the `.ps' and `.s' registers are not. For - example, if a point size of 11pt is requested, and a `sizes' - request (or a `sizescale' line in a `DESC' file) specifies 10.95pt - instead, this value is actually used. - - Both registers are associated with the current environment (*note - Environments::). - - The `\s' escape has the following syntax for working with fractional -type sizes: - -`\s[N]' -`\s'N'' - Set the point size to N scaled points; N is a numeric expression - with a default scale indicator of `z'. - -`\s[+N]' -`\s[-N]' -`\s+[N]' -`\s-[N]' -`\s'+N'' -`\s'-N'' -`\s+'N'' -`\s-'N'' - Increase or or decrease the point size by N scaled points; N is a - numeric expression with a default scale indicator of `z'. - - *Note Font Files::. - - -File: groff, Node: Strings, Next: Conditionals and Loops, Prev: Sizes, Up: gtroff Reference - -Strings -======= - - `gtroff' has string variables, which are entirely for user -convenience (i.e. there are no built-in strings exept `.T', but even -this is a read-write string variable). - - - Request: .ds name [string] - - Request: .ds1 name [string] - - Escape: \*n - - Escape: \*(nm - - Escape: \*[name arg1 arg2 ...] - Define and access a string variable NAME (one-character name N, - two-character name NM). If NAME already exists, `ds' overwrites - the previous definition. Only the syntax form using brackets can - take arguments which are handled identically to macro arguments; - the single exception is that a closing bracket as an argument must - be enclosed in double quotes. *Note Request and Macro - Arguments::, and *Note Parameters::. - - Example: - - - .ds foo a \\$1 test - . - This is \*[foo nice]. - => This is a nice test. - - The `\*' escape "interpolates" (expands in-place) a - previously-defined string variable. To be more precise, the stored - string is pushed onto the input stack which is then parsed by - `gtroff'. Similar to number registers, it is possible to nest - strings, i.e. string variables can be called within string - variables. - - If the string named by the `\*' escape does not exist, it is - defined as empty, and a warning of type `mac' is emitted (see - *Note Debugging::, for more details). - - *Caution:* Unlike other requests, the second argument to the `ds' - request takes up the entire line including trailing spaces. This - means that comments on a line with such a request can introduce - unwanted space into a string. - - - .ds UX \s-1UNIX\s0\u\s-3tm\s0\d \" UNIX trademark - - Instead the comment should be put on another line or have the - comment escape adjacent with the end of the string. - - - .ds UX \s-1UNIX\s0\u\s-3tm\s0\d\" UNIX trademark - - To produce leading space the string can be started with a double - quote. No trailing quote is needed; in fact, any trailing quote is - included in your string. - - - .ds sign " Yours in a white wine sauce, - - Strings are not limited to a single line of text. A string can - span several lines by escaping the newlines with a backslash. The - resulting string is stored _without_ the newlines. - - - .ds foo lots and lots \ - of text are on these \ - next several lines - - It is not possible to have real newlines in a string. To put a - single double quote character into a string, use two consecutive - double quote characters. - - The `ds1' request turns off compatibility mode while interpreting - a string. To be more precise, a "compatibility save" input token - is inserted at the beginning of the string, and a "compatibility - restore" input token at the end. - - - .nr xxx 12345 - .ds aa The value of xxx is \\n[xxx]. - .ds1 bb The value of xxx ix \\n[xxx]. - . - .cp 1 - . - \*(aa - => warning: number register `[' not defined - => The value of xxx is 0xxx]. - \*(bb - => The value of xxx ix 12345. - - Strings, macros, and diversions (and boxes) share the same name - space. Internally, even the same mechanism is used to store them. - This has some interesting consequences. For example, it is - possible to call a macro with string syntax and vice versa. - - - .de xxx - a funny test. - .. - This is \*[xxx] - => This is a funny test. - - .ds yyy a funny test - This is - .yyy - => This is a funny test. - - Diversions and boxes can be also called with string syntax. - - Another consequence is that you can copy one-line diversions or - boxes to a string. - - - .di xxx - a \fItest\fR - .br - .di - .ds yyy This is \*[xxx]\c - \*[yyy]. - => This is a test. - - As the previous example shows, it is possible to store formatted - output in strings. The `\c' escape prevents the insertion of an - additional blank line in the output. - - Copying diversions longer than a single output line produces - unexpected results. - - - .di xxx - a funny - .br - test - .br - .di - .ds yyy This is \*[xxx]\c - \*[yyy]. - => test This is a funny. - - Usually, it is not predictable whether a diversion contains one or - more output lines, so this mechanism should be avoided. With UNIX - `troff', this was the only solution to strip off a final newline - from a diversion. Another disadvantage is that the spaces in the - copied string are already formatted, making them unstretchable. - This can cause ugly results. - - A clean solution to this problem is available in GNU `troff', - using the requests `chop' to remove the final newline of a - diversion, and `unformat' to make the horizontal spaces - stretchable again. - - - .box xxx - a funny - .br - test - .br - .box - .chop xxx - .unformat xxx - This is \*[xxx]. - => This is a funny test. - - *Note Gtroff Internals::, for more information. - - - Request: .as name [string] - - Request: .as1 name [string] - The `as' request is similar to `ds' but appends STRING to the - string stored as NAME instead of redefining it. If NAME doesn't - exist yet, it is created. - - - .as sign " with shallots, onions and garlic, - - The `as1' request is similar to `as', but compatibility mode is - switched off while the appended string is interpreted. To be more - precise, a "compatibility save" input token is inserted at the - beginning of the appended string, and a "compatibility restore" - input token at the end. - - Rudimentary string manipulation routines are given with the next two -requests. - - - Request: .substring str n1 [n2] - Replace the string named STR with the substring defined by the - indices N1 and N2. The first character in the string has index 0. - If N2 is omitted, it is taken to be equal to the string's length. - If the index value N1 or N2 is negative, it is counted from the - end of the string, going backwards: The last character has - index -1, the character before the last character has index -2, - etc. - - - .ds xxx abcdefgh - .substring xxx 1 -4 - \*[xxx] - => bcde - - - - Request: .length reg str - Compute the number of characters of STR and return it in the - number register REG. If REG doesn't exist, it is created. `str' - is read in copy mode. - - - .ds xxx abcd\h'3i'efgh - .length yyy \*[xxx] - \n[yyy] - => 14 - - - - Request: .rn xx yy - Rename the request, macro, diversion, or string XX to YY. - - - Request: .rm xx - Remove the request, macro, diversion, or string XX. `gtroff' - treats subsequent invocations as if the object had never been - defined. - - - Request: .als new old - Create an alias named NEW for the request, string, macro, or - diversion object named OLD. The new name and the old name are - exactly equivalent (it is similar to a hard rather than a soft - link). If OLD is undefined, `gtroff' generates a warning of type - `mac' and ignores the request. - - - Request: .chop xx - Remove (chop) the last character from the macro, string, or - diversion named XX. This is useful for removing the newline from - the end of diversions that are to be interpolated as strings. - This command can be used repeatedly; see *Note Gtroff Internals::, - for details on nodes inserted additionally by `gtroff'. - - *Note Identifiers::, and *Note Comments::. - - -File: groff, Node: Conditionals and Loops, Next: Writing Macros, Prev: Strings, Up: gtroff Reference - -Conditionals and Loops -====================== - -* Menu: - -* Operators in Conditionals:: -* if-else:: -* while:: - - -File: groff, Node: Operators in Conditionals, Next: if-else, Prev: Conditionals and Loops, Up: Conditionals and Loops - -Operators in Conditionals -------------------------- - - In `if' and `while' requests, there are several more operators -available: - -`e' -`o' - True if the current page is even or odd numbered (respectively). - -`n' - True if the document is being processed in nroff mode (i.e., the - `.nroff' command has been issued). - -`t' - True if the document is being processed in troff mode (i.e., the - `.troff' command has been issued). - -`v' - Always false. This condition is for compatibility with other - `troff' versions only. - -`'XXX'YYY'' - True if the string XXX is equal to the string YYY. Other - characters can be used in place of the single quotes; the same set - of delimiters as for the `\D' escape is used (*note Escapes::). - `gtroff' formats the strings before being compared: - - - .ie "|"\fR|\fP" \ - true - .el \ - false - => true - - The resulting motions, glyph sizes, and fonts have to match,(1) - (*note Operators in Conditionals-Footnote-1::) and not the - individual motion, size, and font requests. In the previous - example, `|' and `\fR|\fP' both result in a roman `|' glyph with - the same point size and at the same location on the page, so the - strings are equal. If `.ft I' had been added before the `.ie', - the result would be "false" because (the first) `|' produces an - italic `|' rather than a roman one. - -`r XXX' - True if there is a number register named XXX. - -`d XXX' - True if there is a string, macro, diversion, or request named XXX. - -`m XXX' - True if there is a color named XXX. - -`c G' - True if there is a glyph G available(2) (*note Operators in - Conditionals-Footnote-2::); G is either an ASCII character or a - special character (`\(GG' or `\[GGG]'); the condition is also true - if G has been defined by the `char' request. - - Note that these operators can't be combined with other operators like -`:' or `&'; only a leading `!' (without whitespace between the -exclamation mark and the operator) can be used to negate the result. - - - .nr xxx 1 - .ie !r xxx \ - true - .el \ - false - => false - - A whitespace after `!' always evaluates to zero (this bizarre -behaviour is due to compatibility with UNIX `troff'). - - - .nr xxx 1 - .ie ! r xxx \ - true - .el \ - false - => r xxx true - - It is possible to omit the whitespace before the argument to the -`r', `d', and `c' operators. - - *Note Expressions::. - - -File: groff, Node: Operators in Conditionals-Footnotes, Up: Operators in Conditionals - - (1) The created output nodes must be identical. *Note Gtroff -Internals::. - - (2) The name of this conditional operator is a misnomer since it -tests names of output glyphs. - - -File: groff, Node: if-else, Next: while, Prev: Operators in Conditionals, Up: Conditionals and Loops - -if-else -------- - - `gtroff' has if-then-else constructs like other languages, although -the formatting can be painful. - - - Request: .if expr anything - Evaluate the expression EXPR, and executes ANYTHING (the remainder - of the line) if EXPR evaluates to non-zero (true). ANYTHING is - interpreted as though it was on a line by itself (except that - leading spaces are swallowed). *Note Expressions::, for more info. - - - .nr xxx 1 - .nr yyy 2 - .if ((\n[xxx] == 1) & (\n[yyy] == 2)) true - => true - - - - Request: .nop anything - Executes ANYTHING. This is similar to `.if 1'. - - - Request: .ie expr anything - - Request: .el anything - Use the `ie' and `el' requests to write an if-then-else. The - first request is the `if' part and the latter is the `else' part. - - - .ie n .ls 2 \" double-spacing in nroff - .el .ls 1 \" single-spacing in troff - - - - Escape: \{ - - Escape: \} - In many cases, an if (or if-else) construct needs to execute more - than one request. This can be done using the `\{' and `\}' - escapes. The following example shows the possible ways to use - these escapes (note the position of the opening and closing - braces). - - - .ie t \{\ - . ds lq `` - . ds rq '' - .\} - .el \ - .\{\ - . ds lq " - . ds rq "\} - - - *Note Expressions::. - - -File: groff, Node: while, Prev: if-else, Up: Conditionals and Loops - -while ------ - - `gtroff' provides a looping construct using the `while' request, -which is used much like the `if' (and related) requests. - - - Request: .while expr anything - Evaluate the expression EXPR, and repeatedly execute ANYTHING (the - remainder of the line) until EXPR evaluates to 0. - - - .nr a 0 1 - .while (\na < 9) \{\ - \n+a, - .\} - \n+a - => 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 - - Some remarks. - - * The body of a `while' request is treated like the body of a - `de' request: `gtroff' temporarily stores it in a macro which - is deleted after the loop has been exited. It can - considerably slow down a macro if the body of the `while' - request (within the macro) is large. Each time the macro is - executed, the `while' body is parsed and stored again as a - temporary macro. - - - .de xxx - . nr num 10 - . while (\\n[num] > 0) \{\ - . \" many lines of code - . nr num -1 - . \} - .. - - The traditional and ofter better solution (UNIX `troff' - doesn't have the `while' request) is to use a recursive macro - instead which is parsed only once during its definition. - - - .de yyy - . if (\\n[num] > 0) \{\ - . \" many lines of code - . nr num -1 - . yyy - . \} - .. - . - .de xxx - . nr num 10 - . yyy - .. - - Note that the number of available recursion levels is set - to 1000 (this is a compile-time constant value of `gtroff'). - - * The closing brace of a `while' body must end a line. - - - .if 1 \{\ - . nr a 0 1 - . while (\n[a] < 10) \{\ - . nop \n+[a] - .\}\} - => unbalanced \{ \} - - - - Request: .break - Break out of a `while' loop. Be sure not to confuse this with the - `br' request (causing a line break). - - - Request: .continue - Finish the current iteration of a `while' loop, immediately - restarting the next iteration. - - *Note Expressions::. - - -File: groff, Node: Writing Macros, Next: Page Motions, Prev: Conditionals and Loops, Up: gtroff Reference - -Writing Macros -============== - - A "macro" is a collection of text and embedded commands which can be -invoked multiple times. Use macros to define common operations. - - - Request: .de name [end] - - Request: .de1 name [end] - - Request: .dei name [end] - Define a new macro named NAME. `gtroff' copies subsequent lines - (starting with the next one) into an internal buffer until it - encounters the line `..' (two dots). The optional second argument - to `de' changes this to a macro to `.END'. - - There can be whitespace after the first dot in the line containing - the ending token (either `.' or macro `END'). - - Here a small example macro called `P' which causes a break and - inserts some vertical space. It could be used to separate - paragraphs. - - - .de P - . br - . sp .8v - .. - - The following example defines a macro within another. Remember - that expansion must be protected twice; once for reading the macro - and once for executing. - - - \# a dummy macro to avoid a warning - .de end - .. - . - .de foo - . de bar end - . nop \f[B]Hallo \\\\$1!\f[] - . end - .. - . - .foo - .bar Joe - => Hallo Joe! - - Since `\f' has no expansion, it isn't necessary to protect its - backslash. Had we defined another macro within `bar' which takes - a parameter, eight backslashes would be necessary before `$1'. - - The `de1' request turns off compatibility mode while executing the - macro. On entry, the current compatibility mode is saved and - restored at exit. - - - .nr xxx 12345 - . - .de aa - The value of xxx is \\n[xxx]. - .. - .de1 bb - The value of xxx ix \\n[xxx]. - .. - . - .cp 1 - . - .aa - => warning: number register ' not defined - => The value of xxx is 0xxx]. - .bb - => The value of xxx ix 12345. - - The `dei' request defines a macro indirectly. That is, it expands - strings whose names are NAME or END before performing the append. - - This: - - - .ds xx aa - .ds yy bb - .dei xx yy - - is equivalent to: - - - .de aa bb - - Using `trace.tmac', you can trace calls to `de' and `de1'. - - Note that macro identifiers are shared with identifiers for - strings and diversions. - - - Request: .am name [end] - - Request: .am1 name [end] - - Request: .ami name [end] - Works similarly to `de' except it appends onto the macro named - NAME. So, to make the previously defined `P' macro actually do - indented instead of block paragraphs, add the necessary code to the - existing macro like this: - - - .am P - .ti +5n - .. - - The `am1' request turns off compatibility mode while executing the - appended macro piece. To be more precise, a "compatibility save" - input token is inserted at the beginning of the appended code, and - a "compatibility restore" input token at the end. - - The `ami' request appends indirectly, meaning that `gtroff' - expands strings whose names are NAME or END before performing the - append. - - Using `trace.tmac', you can trace calls to `am' and `am1'. - - *Note Strings::, for the `als' request to rename a macro. - - The `de', `am', `di', `da', `ds', and `as' requests (together with -its variants) only create a new object if the name of the macro, -diversion or string diversion is currently undefined or if it is -defined to be a request; normally they modify the value of an existing -object. - - - Request: .return - Exit a macro, immediately returning to the caller. - -* Menu: - -* Copy-in Mode:: -* Parameters:: - - -File: groff, Node: Copy-in Mode, Next: Parameters, Prev: Writing Macros, Up: Writing Macros - -Copy-in Mode ------------- - - When `gtroff' reads in the text for a macro, string, or diversion, -it copies the text (including request lines, but excluding escapes) into -an internal buffer. Escapes are converted into an internal form, -except for `\n', `\$', `\*', `\\' and `\<RET>' which are evaluated and -inserted into the text where the escape was located. This is known as -"copy-in" mode or "copy" mode. - - What this means is that you can specify when these escapes are to be -evaluated (either at copy-in time or at the time of use) by insulating -the escapes with an extra backslash. Compare this to the `\def' and -`\edef' commands in TeX. - - The following example prints the numbers 20 and 10: - - - .nr x 20 - .de y - .nr x 10 - \&\nx - \&\\nx - .. - .y - - -File: groff, Node: Parameters, Prev: Copy-in Mode, Up: Writing Macros - -Parameters ----------- - - The arguments to a macro or string can be examined using a variety of -escapes. - - - Register: \n[.$] - The number of arguments passed to a macro or string. This is a - read-only number register. - - Any individual argument can be retrieved with one of the following -escapes: - - - Escape: \$n - - Escape: \$(nn - - Escape: \$[nnn] - Retrieve the Nth, NNth or NNNth argument. As usual, the first - form only accepts a single number (larger than zero), the second a - two-digit number (larger or equal to 10), and the third any - positive integer value (larger than zero). Macros and strings can - have an unlimited number of arguments. Note that due to copy-in - mode, use two backslashes on these in actual use to prevent - interpolation until the macro is actually invoked. - - - Request: .shift [n] - Shift the arguments 1 position, or as many positions as specified - by its argument. After executing this request, argument I becomes - argument I-N; arguments 1 to N are no longer available. Shifting - by negative amounts is currently undefined. - - - Escape: \$* - - Escape: \$@ - In some cases it is convenient to use all of the arguments at once - (for example, to pass the arguments along to another macro). The - `\$*' escape concatenates all the arguments separated by spaces. A - similar escape is `\$@', which concatenates all the arguments with - each surrounded by double quotes, and separated by spaces. If not - in compatibility mode, the input level of double quotes is - preserved (see *Note Request and Macro Arguments::). - - - Escape: \$0 - The name used to invoke the current macro. The `als' request can - make a macro have more than one name. - - - .de generic-macro - . ... - . if \\n[error] \{\ - . tm \\$0: Houston, we have a problem. - . return - . \} - .. - . - .als foo generic-macro - .als bar generic-macro - - - *Note Request and Macro Arguments::. - - -File: groff, Node: Page Motions, Next: Drawing Requests, Prev: Writing Macros, Up: gtroff Reference - -Page Motions -============ - - *Note Manipulating Spacing::, for a discussion of the main request -for vertical motion, `sp'. - - - Request: .mk [reg] - - Request: .rt [dist] - The request `mk' can be used to mark a location on a page, for - movement to later. This request takes a register name as an - argument in which to store the current page location. With no - argument it stores the location in an internal register. The - results of this can be used later by the `rt' or the `sp' request - (or the `\v' escape). - - The `rt' request returns _upwards_ to the location marked with the - last `mk' request. If used with an argument, return to a position - which distance from the top of the page is DIST (no previous call - to `mk' is necessary in this case). Default scaling indicator is - `v'. - - Here a primitive solution for a two-column macro. - - - .nr column-length 1.5i - .nr column-gap 4m - .nr bottom-margin 1m - . - - - .de 2c - . br - . mk - . ll \\n[column-length]u - . wh -\\n[bottom-margin]u 2c-trap - . nr right-side 0 - .. - . - - - .de 2c-trap - . ie \\n[right-side] \{\ - . nr right-side 0 - . po -(\\n[column-length]u + \\n[column-gap]u) - . \" remove trap - . wh -\\n[bottom-margin]u - . \} - . el \{\ - . \" switch to right side - . nr right-side 1 - . po +(\\n[column-length]u + \\n[column-gap]u) - . rt - . \} - .. - . - - - .pl 1.5i - .ll 4i - This is a small test which shows how the - rt request works in combination with mk. - - .2c - Starting here, text is typeset in two columns. - Note that this implementation isn't robust - and thus not suited for a real two-column - macro. - - Result: - - - This is a small test which shows how the - rt request works in combination with mk. - - Starting here, isn't robust - text is typeset and thus not - in two columns. suited for a - Note that this real two-column - implementation macro. - - - The following escapes give fine control of movements about the page. - - - Escape: \v'e' - Move vertically, usually from the current location on the page (if - no absolute position operator `|' is used). The argument E - specifies the distance to move; positive is downwards and negative - upwards. The default scaling indicator for this escape is `v'. - Beware, however, that `gtroff' continues text processing at the - point where the motion ends, so you should always balance motions - to avoid interference with text processing. - - `\v' doesn't trigger a trap. This can be quite useful; for - example, consider a page bottom trap macro which prints a marker - in the margin to indicate continuation of a footnote or something - similar. - - There are some special-case escapes for vertical motion. - - - Escape: \r - Move upwards 1v. - - - Escape: \u - Move upwards .5v. - - - Escape: \d - Move down .5v. - - - Escape: \h'e' - Move horizontally, usually from the current location (if no - absolute position operator `|' is used). The expression E - indicates how far to move: positive is rightwards and negative - leftwards. The default scaling indicator for this escape is `m'. - - This horizontal space is not discarded at the end of a line. To - insert discardable space of a certain length use the `ss' request. - - There are a number of special-case escapes for horizontal motion. - - - Escape: \<SP> - An unbreakable and unpaddable (i.e. not expanded during filling) - space. (Note: This is a backslash followed by a space.) - - - Escape: \~ - An unbreakable space that stretches like a normal inter-word space - when a line is adjusted. - - - Escape: \| - A 1/6th em space. Ignored for TTY output devices (rounded to - zero). - - - Escape: \^ - A 1/12th em space. Ignored for TTY output devices (rounded to - zero). - - - Escape: \0 - A space the size of a digit. - - The following string sets the TeX logo: - - - .ds TeX T\h'-.1667m'\v'.224m'E\v'-.224m'\h'-.125m'X - - - Escape: \w'text' - - Register: \n[st] - - Register: \n[sb] - - Register: \n[rst] - - Register: \n[rsb] - - Register: \n[ct] - - Register: \n[ssc] - - Register: \n[skw] - Return the width of the specified TEXT in basic units. This - allows horizontal movement based on the width of some arbitrary - text (e.g. given as an argument to a macro). - - - The length of the string `abc' is \w'abc'u. - => The length of the string `abc' is 72u. - - Font changes may occur in TEXT which don't affect current settings. - - After use, `\w' sets several registers: - - `st' - `sb' - The highest and lowest point of the baseline, respectively, - in TEXT. - - `rst' - `rsb' - Like the `st' and `sb' registers, but takes account of the - heights and depths of glyphs. With other words, this gives - the highest and lowest point of TEXT. Values below the - baseline are negative. - - `ct' - Defines the kinds of glyphs occurring in TEXT: - - 0 - only short glyphs, no descenders or tall glyphs. - - 1 - at least one descender. - - 2 - at least one tall glyph. - - 3 - at least one each of a descender and a tall glyph. - - `ssc' - The amount of horizontal space (possibly negative) that - should be added to the last glyph before a subscript. - - `skw' - How far to right of the center of the last glyph in the `\w' - argument, the center of an accent from a roman font should be - placed over that glyph. - - - Escape: \kp - - Escape: \k(ps - - Escape: \k[position] - Store the current horizontal position in the _input_ line in - number register with name POSITION (one-character name P, - two-character name PS). Use this, for example, to return to the - beginning of a string for highlighting or other decoration. - - - Register: \n[hp] - The current horizontal position at the input line. - - - Register: \n[.k] - A read-only number register containing the current horizontal - output position. - - - Escape: \o'abc' - Overstrike glyphs A, B, C, ...; the glyphs are centered, and the - resulting spacing is the largest width of the affected glyphs. - - - Escape: \zg - Print glyph G with zero width, i.e., without spacing. Use this to - overstrike glyphs left-aligned. - - - Escape: \Z'anything' - Print ANYTHING, then restore the horizontal and vertical position. - The argument may not contain tabs or leaders. - - The following is an example of a strike-through macro: - - - .de ST - .nr ww \w'\\$1' - \Z@\v'-.25m'\l'\\n[ww]u'@\\$1 - .. - . - This is - .ST "a test" - an actual emergency! - - - -File: groff, Node: Drawing Requests, Next: Traps, Prev: Page Motions, Up: gtroff Reference - -Drawing Requests -================ - - `gtroff' provides a number of ways to draw lines and other figures -on the page. Used in combination with the page motion commands (see -*Note Page Motions::, for more info), a wide variety of figures can be -drawn. However, for complex drawings these operations can be quite -cumbersome, and it may be wise to use graphic preprocessors like `gpic' -or `ggrn'. *Note gpic::, and *Note ggrn::, for more information. - - All drawing is done via escapes. - - - Escape: \l'l' - - Escape: \l'lg' - Draw a line horizontally. L is the length of the line to be - drawn. If it is positive, start the line at the current location - and draw to the right; its end point is the new current location. - Negative values are handled differently: The line starts at the - current location and draws to the left, but the current location - doesn't move. - - L can also be specified absolutely (i.e. with a leading `|') which - draws back to the beginning of the input line. Default scaling - indicator is `m'. - - The optional second parameter G is a glyph to draw the line with. - If this second argument is not specified, `gtroff' uses the - underscore glyph, `\[ru]'. - - To separate the two arguments (to prevent `gtroff' from - interpreting a drawing glyph as a scaling indicator if the glyph is - represented by a single character) use `\&'. - - Here a small useful example: - - - .de box - \[br]\\$*\[br]\l'|0\[rn]'\l'|0\[ul]' - .. - - Note that this works by outputting a box rule (a vertical line), - then the text given as an argument and then another box rule. - Finally, the line drawing escapes both draw from the current - location to the beginning of the _input_ line - this works because - the line length is negative, not moving the current point. - - - Escape: \L'l' - - Escape: \L'lg' - Draw vertical lines. Its parameters are similar to the `\l' - escape, except that the default scaling indicator is `v'. The - movement is downwards for positive values, and upwards for - negative values. The default glyph is the box rule glyph, - `\[br]'. As with the vertical motion escapes, text processing - blindly continues where the line ends. - - - This is a \L'3v'test. - - Here the result, produced with `grotty'. - - - This is a - | - | - |test. - - - - Escape: \D'command arg ...' - The `\D' escape provides a variety of drawing functions. Note - that on character devices, only vertical and horizontal lines are - supported within `grotty'; other devices may only support a subset - of the available drawing functions. - - The default scaling indicator for all subcommands of `\D' is `m' - for horizontal distances and `v' for vertical ones. Exceptions - are `\D'f ...'' and `\D't ...'' which use `u' as the default, and - `\D'FX ...'' which arguments are treated similar to the `defcolor' - request. - - `\D'l DX DY'' - Draw a line from the current location to the relative point - specified by (DX,DY). - - The following example is a macro for creating a box around a - text string; for simplicity, the box margin is taken as a - fixed value, 0.2m. - - - .de BOX - . nr @wd \w'\\$1' - \h'.2m'\ - \h'-.2m'\v'(.2m - \\n[rsb]u)'\ - \D'l 0 -(\\n[rst]u - \\n[rsb]u + .4m)'\ - \D'l (\\n[@wd]u + .4m) 0'\ - \D'l 0 (\\n[rst]u - \\n[rsb]u + .4m)'\ - \D'l -(\\n[@wd]u + .4m) 0'\ - \h'.2m'\v'-(.2m - \\n[rsb]u)'\ - \\$1\ - \h'.2m' - .. - - First, the width of the string is stored in register `@wd'. - Then, four lines are drawn to form a box, properly offset by - the box margin. The registers `rst' and `rsb' are set by the - `\w' escape, containing the largest height and depth of the - whole string. - - `\D'c D'' - Draw a circle with a diameter of D with the leftmost point at - the current position. After drawing, the current location is - positioned at the rightmost point of the circle. - - `\D'C D'' - Draw a solid circle with the same parameters and behaviour as - an outlined circle. No outline is drawn. - - `\D'e X Y'' - Draw an ellipse with a horizontal diameter of X and a vertical - diameter of Y with the leftmost point at the current position. - After drawing, the current location is positioned at the - rightmost point of the ellipse. - - `\D'E X Y'' - Draw a solid ellipse with the same parameters and behaviour - as an outlined ellipse. No outline is drawn. - - `\D'a DX1 DY1 DX2 DY2'' - Draw an arc clockwise from the current location through the - two specified relative locations (DX1,DY1) and (DX2,DY2). - The coordinates of the first point are relative to the - current position, and the coordinates of the second point are - relative to the first point. After drawing, the current - position is moved to the final point of the arc. - - `\D'~ DX1 DY1 DX2 DY2 ...'' - Draw a spline from the current location to the relative point - (DX1,DY1) and then to (DX2,DY2), and so on. The current - position is moved to the terminal point of the drawn curve. - - `\D'f N'' - Set the shade of gray to be used for filling solid objects - to N; N must be an integer between 0 and 1000, where 0 - corresponds solid white and 1000 to solid black, and values - in between correspond to intermediate shades of gray. This - applies only to solid circles, solid ellipses, and solid - polygons. By default, a level of 1000 is used. - - Despite of being silly, the current point is moved - horizontally to the right by N. - - Don't use this command! It has the serious drawback that it - will be always rounded to the next integer multiple of the - horizontal resolution (the value of the `hor' keyword in the - `DESC' file). Use `\M' (*note Colors::) or `\D'Fg ...'' - instead. - - `\D'p DX1 DY1 DX2 DY2 ...'' - Draw a polygon from the current location to the relative - position (DX1,DY1) and then to (DX2,DY2) and so on. When the - specified data points are exhausted, a line is drawn back to - the starting point. The current position is changed by - adding the sum of all arguments with odd index to the actual - horizontal position and the even ones to the vertical - position. - - `\D'P DX1 DY1 DX2 DY2 ...'' - Draw a solid polygon with the same parameters and behaviour - as an outlined polygon. No outline is drawn. - - Here a better variant of the box macro to fill the box with - some color. Note that the box must be drawn before the text - since colors in `gtroff' are not transparent; the filled - polygon would hide the text completely. - - - .de BOX - . nr @wd \w'\\$1' - \h'.2m'\ - \h'-.2m'\v'(.2m - \\n[rsb]u)'\ - \M[lightcyan]\ - \D'P 0 -(\\n[rst]u - \\n[rsb]u + .4m) \ - (\\n[@wd]u + .4m) 0 \ - 0 (\\n[rst]u - \\n[rsb]u + .4m) \ - -(\\n[@wd]u + .4m) 0'\ - \h'.2m'\v'-(.2m - \\n[rsb]u)'\ - \M[]\ - \\$1\ - \h'.2m' - .. - - `\D't N'' - Set the current line thickness to N machine units. A value of - zero selects the smallest available line thickness. A - negative value makes the line thickness proportional to the - current point size (this is the default behaviour of AT&T - `troff'). - - Despite of being silly, the current point is moved - horizontally to the right by N. - - `\D'FSCHEME COLOR_COMPONENTS'' - Change current fill color. SCHEME is a single letter - denoting the color scheme: `r' (rgb), `c' (cmy), `k' (cmyk), - `g' (gray), or `d' (default color). The color components use - exactly the same syntax as in the `defcolor' request (*note - Colors::); the command `\D'Fd'' doesn't take an argument. - - _No_ position changing! - - Examples: - - - \D'Fg .3' \" same gray as \D'f 700' \D'Fr #0000ff' \" - blue - - *Note Graphics Commands::. - - - Escape: \b'string' - "Pile" a sequence of glyphs vertically, and center it vertically - on the current line. Use it to build large brackets and braces. - - Here an example how to create a large opening brace: - - - \b'\[lt]\[bv]\[lk]\[bv]\[lb]' - - The first glyph is on the top, the last glyph in STRING is at the - bottom. Note that `gtroff' separates the glyphs vertically by 1m, - and the whole object is centered 0.5m above the current baseline; - the largest glyph width is used as the width for the whole object. - This rather unflexible positioning algorithm doesn't work with - `-Tdvi' since the bracket pieces vary in height for this device. - Instead, use the `eqn' preprocessor. - - *Note Manipulating Spacing::, how to adjust the vertical spacing - with the `\x' escape. - - -File: groff, Node: Traps, Next: Diversions, Prev: Drawing Requests, Up: gtroff Reference - -Traps -===== - - "Traps" are locations, which, when reached, call a specified macro. -These traps can occur at a given location on the page, at a given -location in the current diversion, at a blank line, after a certain -number of input lines, or at the end of input. - - Setting a trap is also called "planting". It is also said that a -trap is "sprung" if the associated macro is executed. - -* Menu: - -* Page Location Traps:: -* Diversion Traps:: -* Input Line Traps:: -* Blank Line Traps:: -* End-of-input Traps:: - |
