Annotation of src/usr.bin/m4/m4.1, Revision 1.39
1.39 ! espie 1: .\" @(#) $OpenBSD: m4.1,v 1.38 2005/03/02 10:12:15 espie Exp $
1.32 jmc 2: .\"
1.29 jmc 3: .\" Copyright (c) 1989, 1993
4: .\" The Regents of the University of California. All rights reserved.
1.1 deraadt 5: .\"
1.29 jmc 6: .\" This code is derived from software contributed to Berkeley by
7: .\" Ozan Yigit at York University.
1.1 deraadt 8: .\"
1.29 jmc 9: .\" Redistribution and use in source and binary forms, with or without
10: .\" modification, are permitted provided that the following conditions
11: .\" are met:
12: .\" 1. Redistributions of source code must retain the above copyright
13: .\" notice, this list of conditions and the following disclaimer.
14: .\" 2. Redistributions in binary form must reproduce the above copyright
15: .\" notice, this list of conditions and the following disclaimer in the
16: .\" documentation and/or other materials provided with the distribution.
1.31 millert 17: .\" 3. Neither the name of the University nor the names of its contributors
1.29 jmc 18: .\" may be used to endorse or promote products derived from this software
19: .\" without specific prior written permission.
20: .\"
21: .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22: .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23: .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24: .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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26: .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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29: .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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31: .\" SUCH DAMAGE.
1.32 jmc 32: .\"
1.1 deraadt 33: .Dd January 26, 1993
1.5 aaron 34: .Dt M4 1
1.1 deraadt 35: .Os
36: .Sh NAME
37: .Nm m4
38: .Nd macro language processor
39: .Sh SYNOPSIS
40: .Nm m4
1.23 espie 41: .Op Fl d Ar flags
42: .Op Fl t Ar name
1.28 espie 43: .Op Fl o Ar filename
1.12 espie 44: .Op Fl g
1.25 espie 45: .Op Fl s
1.1 deraadt 46: .Oo
47: .Fl D Ns Ar name Ns Op Ar =value
48: .Oc
49: .Op Fl U Ns Ar name
1.7 espie 50: .Op Fl I Ar dirname
1.1 deraadt 51: .Sh DESCRIPTION
52: The
53: .Nm m4
54: utility is a macro processor that can be used as a front end to any
55: language (e.g., C, ratfor, fortran, lex, and yacc).
56: .Nm m4
57: reads from the standard input and writes
58: the processed text to the standard output.
59: .Pp
1.8 espie 60: Macro calls have the form name(argument1[, argument2, ..., argumentN]).
1.1 deraadt 61: .Pp
62: There cannot be any space following the macro name and the open
1.10 aaron 63: parenthesis
1.33 jmc 64: .Pq Sq ( .
1.10 aaron 65: If the macro name is not followed by an open
1.5 aaron 66: parenthesis it is processed with no arguments.
1.1 deraadt 67: .Pp
68: Macro names consist of a leading alphabetic or underscore
1.9 espie 69: possibly followed by alphanumeric or underscore characters, e.g.,
1.10 aaron 70: valid macro names match the pattern
71: .Dq [a-zA-Z_][a-zA-Z0-9_]* .
1.1 deraadt 72: .Pp
1.10 aaron 73: In arguments to macros, leading unquoted space, tab, and newline
1.33 jmc 74: .Pq Sq \en
1.10 aaron 75: characters are ignored.
1.33 jmc 76: To quote strings, use left and right single quotes
77: .Po e.g.,\ \&
78: .Sq "\ this is a string with a leading space"
79: .Pc .
1.10 aaron 80: You can change the quote characters with the
1.5 aaron 81: .Ic changequote
82: built-in macro.
1.9 espie 83: .Pp
1.12 espie 84: Most built-ins don't make any sense without arguments, and hence are not
1.9 espie 85: recognized as special when not followed by an open parenthesis.
1.1 deraadt 86: .Pp
87: The options are as follows:
1.20 aaron 88: .Bl -tag -width Ds
1.1 deraadt 89: .It Fl D Ns Ar name Ns Oo
90: .Ar =value
91: .Oc
92: Define the symbol
93: .Ar name
1.10 aaron 94: to have some value (or
95: .Dv NULL ) .
1.1 deraadt 96: .It Fl "U" Ns Ar "name"
97: Undefine the symbol
98: .Ar name .
1.7 espie 99: .It Fl I Ar "dirname"
1.15 aaron 100: Add directory
1.7 espie 101: .Ar dirname
102: to the include path.
1.23 espie 103: .It Fl d Ar "flags"
104: Set trace flags.
1.32 jmc 105: .Ar flags
1.23 espie 106: may hold the following:
107: .Bl -tag -width Ds
108: .It Ar a
109: print macro arguments.
110: .It Ar c
111: print macro expansion over several lines.
112: .It Ar e
113: print result of macro expansion.
114: .It Ar f
115: print filename location.
116: .It Ar l
117: print line number.
118: .It Ar q
119: quote arguments and expansion with the current quotes.
120: .It Ar t
121: start with all macros traced.
122: .It Ar x
123: number macro expansions.
124: .It Ar V
125: turn on all options.
126: .El
127: .Pp
1.32 jmc 128: By default, trace is set to
1.23 espie 129: .Qq eq .
1.28 espie 130: .It Fl o Ar filename
131: Send trace output to
132: .Ar filename .
1.23 espie 133: .It Fl t Ar macro
1.32 jmc 134: Turn tracing on for
1.23 espie 135: .Ar macro .
1.12 espie 136: .It Fl g
1.13 aaron 137: Activate GNU-m4 compatibility mode.
1.15 aaron 138: In this mode, changequote with
1.12 espie 139: two empty parameters deactivates quotes, translit handles simple character
1.19 espie 140: ranges (e.g., a-z), regular expressions mimic emacs behavior,
1.38 espie 141: multiple m4wrap calls are handled as a stack,
1.19 espie 142: and the number of diversions is unlimited.
1.25 espie 143: .It Fl s
144: Output line synchronization directives, suitable for
145: .Xr cpp 1 .
1.17 aaron 146: .El
1.1 deraadt 147: .Sh SYNTAX
148: .Nm m4
1.10 aaron 149: provides the following built-in macros.
150: They may be redefined, losing their original meaning.
151: Return values are null unless otherwise stated.
1.36 espie 152: .Bl -tag -width changequote
153: .It Fn builtin name
1.37 jmc 154: Calls a built-in by its
155: .Fa name ,
1.36 espie 156: overriding possible redefinitions.
157: .It Fn changecom startcomment endcomment
1.39 ! espie 158: Changes the start comment and end comment sequences.
! 159: Comment sequences may be up to five characters long.
! 160: The default values are the pound sign
1.10 aaron 161: and the newline character.
1.39 ! espie 162: .Bd -literal -offset indent
! 163: # This is a comment
! 164: .Ed
! 165: .Pp
! 166: With no arguments, comments are turned off.
! 167: With one single argument, the end comment sequence is set
! 168: to the newline character.
1.36 espie 169: .It Fn changequote beginquote endquote
1.39 ! espie 170: Defines the open quote and close quote sequences.
! 171: Quote sequences may be up to five characters long.
! 172: The default values are the backquote character and the quote
! 173: character.
! 174: .Bd -literal -offset indent
! 175: `Here is a quoted string'
! 176: .Ed
! 177: .Pp
! 178: With no arguments, the default quotes are restored.
! 179: With one single argument, the close quote sequence is set
! 180: to the newline character.
1.36 espie 181: .It Fn decr arg
1.37 jmc 182: Decrements the argument
183: .Fa arg
1.36 espie 184: by 1.
1.37 jmc 185: The argument
1.36 espie 186: .Fa arg
187: must be a valid numeric string.
188: .It Fn define name value
1.37 jmc 189: Define a new macro named by the first argument
190: .Fa name
1.36 espie 191: to have the
192: value of the second argument
193: .Fa value .
1.10 aaron 194: Each occurrence of
1.33 jmc 195: .Sq $n
1.10 aaron 196: (where
197: .Ar n
198: is 0 through 9) is replaced by the
199: .Ar n Ns 'th
200: argument.
1.33 jmc 201: .Sq $0
1.10 aaron 202: is the name of the calling macro.
203: Undefined arguments are replaced by a null string.
1.33 jmc 204: .Sq $#
1.10 aaron 205: is replaced by the number of arguments;
1.33 jmc 206: .Sq $*
1.10 aaron 207: is replaced by all arguments comma separated;
1.33 jmc 208: .Sq $@
1.10 aaron 209: is the same as
1.33 jmc 210: .Sq $*
1.10 aaron 211: but all arguments are quoted against further expansion.
1.36 espie 212: .It Fn defn name ...
1.10 aaron 213: Returns the quoted definition for each argument.
214: This can be used to rename
1.1 deraadt 215: macro definitions (even for built-in macros).
1.36 espie 216: .It Fn divert num
1.1 deraadt 217: There are 10 output queues (numbered 0-9).
218: At the end of processing
219: .Nm m4
220: concatenates all the queues in numerical order to produce the
1.10 aaron 221: final output.
222: Initially the output queue is 0.
223: The divert
1.1 deraadt 224: macro allows you to select a new output queue (an invalid argument
225: passed to divert causes output to be discarded).
1.5 aaron 226: .It Ic divnum
1.1 deraadt 227: Returns the current output queue number.
1.5 aaron 228: .It Ic dnl
1.1 deraadt 229: Discard input characters up to and including the next newline.
1.36 espie 230: .It Fn dumpdef name ...
1.1 deraadt 231: Prints the names and definitions for the named items, or for everything
232: if no arguments are passed.
1.36 espie 233: .It Fn errprint msg
1.1 deraadt 234: Prints the first argument on the standard error output stream.
1.36 espie 235: .It Fn esyscmd cmd
1.26 pvalchev 236: Passes its first argument to a shell and returns the shell's standard output.
1.18 espie 237: Note that the shell shares its standard input and standard error with
1.33 jmc 238: .Nm m4 .
1.36 espie 239: .It Fn eval expr
1.1 deraadt 240: Computes the first argument as an arithmetic expression using 32-bit
1.10 aaron 241: arithmetic.
242: Operators are the standard C ternary, arithmetic, logical,
243: shift, relational, bitwise, and parentheses operators.
244: You can specify
245: octal, decimal, and hexadecimal numbers as in C.
246: The second argument (if any)
247: specifies the radix for the result and the third argument (if any)
248: specifies the minimum number of digits in the result.
1.36 espie 249: .It Fn expr expr
1.5 aaron 250: This is an alias for
251: .Ic eval .
1.36 espie 252: .It Fn ifdef name yes no
1.1 deraadt 253: If the macro named by the first argument is defined then return the second
1.10 aaron 254: argument, otherwise the third.
255: If there is no third argument, the value is
256: .Dv NULL .
257: The word
258: .Qq unix
259: is predefined.
1.36 espie 260: .It Fn ifelse a b yes ...
1.37 jmc 261: If the first argument
1.36 espie 262: .Fa a
1.37 jmc 263: matches the second argument
1.36 espie 264: .Fa b
265: then
266: .Fn ifelse
1.5 aaron 267: returns
1.36 espie 268: the third argument
269: .Fa yes .
1.10 aaron 270: If the match fails the three arguments are
1.1 deraadt 271: discarded and the next three arguments are used until there is
1.10 aaron 272: zero or one arguments left, either this last argument or
273: .Dv NULL
274: is returned if no other matches were found.
1.36 espie 275: .It Fn include name
1.1 deraadt 276: Returns the contents of the file specified in the first argument.
1.7 espie 277: If the file is not found as is, look through the include path:
278: first the directories specified with
279: .Fl I
280: on the command line, then the environment variable
1.10 aaron 281: .Ev M4PATH ,
1.7 espie 282: as a colon-separated list of directories.
1.1 deraadt 283: Include aborts with an error message if the file cannot be included.
1.36 espie 284: .It Fn incr arg
1.10 aaron 285: Increments the argument by 1.
286: The argument must be a valid numeric string.
1.36 espie 287: .It Fn index string substring
1.1 deraadt 288: Returns the index of the second argument in the first argument (e.g.,
1.10 aaron 289: .Ic index(the quick brown fox jumped, fox)
290: returns 16).
291: If the second
292: argument is not found index returns \-1.
1.36 espie 293: .It Fn indir macro arg1 ...
1.26 pvalchev 294: Indirectly calls the macro whose name is passed as the first argument,
1.11 espie 295: with the remaining arguments passed as first, ... arguments.
1.36 espie 296: .It Fn len arg
1.10 aaron 297: Returns the number of characters in the first argument.
298: Extra arguments
1.1 deraadt 299: are ignored.
1.36 espie 300: .It Fn m4exit code
1.1 deraadt 301: Immediately exits with the return value specified by the first argument,
302: 0 if none.
1.36 espie 303: .It Fn m4wrap todo
1.10 aaron 304: Allows you to define what happens at the final
305: .Dv EOF ,
306: usually for cleanup purposes (e.g.,
307: .Ic m4wrap("cleanup(tempfile)")
308: causes the macro cleanup to be
1.16 aaron 309: invoked after all other processing is done).
1.38 espie 310: .Pp
311: Multiple calls to
312: .Fn m4wrap
313: get inserted in sequence at the final
314: .Dv EOF .
1.36 espie 315: .It Fn maketemp template
1.35 miod 316: Invokes
317: .Xr mkstemp 3
318: on the first argument, and returns the modified string.
1.10 aaron 319: This can be used to create unique
1.1 deraadt 320: temporary file names.
1.36 espie 321: .It Fn paste file
1.1 deraadt 322: Includes the contents of the file specified by the first argument without
1.10 aaron 323: any macro processing.
324: Aborts with an error message if the file cannot be
1.1 deraadt 325: included.
1.36 espie 326: .It Fn patsubst string regexp replacement
1.11 espie 327: Substitutes a regular expression in a string with a replacement string.
328: Usual substitution patterns apply: an ampersand
1.33 jmc 329: .Pq Sq \&&
1.11 espie 330: is replaced by the string matching the regular expression.
331: The string
1.33 jmc 332: .Sq \e# ,
1.11 espie 333: where
1.33 jmc 334: .Sq #
1.11 espie 335: is a digit, is replaced by the corresponding back-reference.
1.36 espie 336: .It Fn popdef arg ...
1.5 aaron 337: Restores the
338: .Ic pushdef Ns ed
339: definition for each argument.
1.36 espie 340: .It Fn pushdef macro def
1.5 aaron 341: Takes the same arguments as
342: .Ic define ,
343: but it saves the definition on a
344: stack for later retrieval by
1.36 espie 345: .Fn popdef .
346: .It Fn regexp string regexp replacement
1.13 aaron 347: Finds a regular expression in a string.
348: If no further arguments are given,
1.14 aaron 349: it returns the first match position or \-1 if no match.
350: If a third argument
1.11 espie 351: is provided, it returns the replacement string, with sub-patterns replaced.
1.36 espie 352: .It Fn shift arg1 ...
1.1 deraadt 353: Returns all but the first argument, the remaining arguments are
1.10 aaron 354: quoted and pushed back with commas in between.
355: The quoting
1.1 deraadt 356: nullifies the effect of the extra scan that will subsequently be
357: performed.
1.36 espie 358: .It Fn sinclude file
1.5 aaron 359: Similar to
360: .Ic include ,
361: except it ignores any errors.
1.36 espie 362: .It Fn spaste file
1.5 aaron 363: Similar to
1.36 espie 364: .Fn paste ,
1.5 aaron 365: except it ignores any errors.
1.36 espie 366: .It Fn substr string offset length
1.1 deraadt 367: Returns a substring of the first argument starting at the offset specified
368: by the second argument and the length specified by the third argument.
369: If no third argument is present it returns the rest of the string.
1.36 espie 370: .It Fn syscmd cmd
1.10 aaron 371: Passes the first argument to the shell.
372: Nothing is returned.
1.5 aaron 373: .It Ic sysval
374: Returns the return value from the last
375: .Ic syscmd .
1.36 espie 376: .It Fn traceon arg ...
1.22 espie 377: Enables tracing of macro expansions for the given arguments, or for all
378: macros if no argument is given.
1.36 espie 379: .It Fn traceoff arg ...
1.22 espie 380: Disables tracing of macro expansions for the given arguments, or for all
381: macros if no argument is given.
1.36 espie 382: .It Fn translit string mapfrom mapto
1.1 deraadt 383: Transliterate the characters in the first argument from the set
1.10 aaron 384: given by the second argument to the set given by the third.
1.21 aaron 385: You cannot use
1.1 deraadt 386: .Xr tr 1
387: style abbreviations.
1.36 espie 388: .It Fn undefine name1 ...
1.24 espie 389: Removes the definition for the macros specified by its arguments.
1.36 espie 390: .It Fn undivert arg ...
1.1 deraadt 391: Flushes the named output queues (or all queues if no arguments).
1.5 aaron 392: .It Ic unix
1.1 deraadt 393: A pre-defined macro for testing the OS platform.
1.11 espie 394: .It Ic __line__
395: Returns the current file's line number.
396: .It Ic __file__
397: Returns the current file's name.
1.1 deraadt 398: .El
1.32 jmc 399: .Sh STANDARDS
1.23 espie 400: .Nm
1.39 ! espie 401: follows the Single Unix 3 specification, along with a few extensions taken
1.32 jmc 402: from
1.23 espie 403: .Nm gnu-m4 .
404: .Pp
405: Flags
406: .Fl I ,
407: .Fl d ,
408: .Fl t
409: are non-standard.
410: .Pp
1.32 jmc 411: The output format of tracing and of
412: .Ic dumpdef
413: are not specified in any standard,
1.23 espie 414: are likely to change and should not be relied upon.
1.32 jmc 415: The current format of tracing is closely modelled on
416: .Nm gnu-m4 ,
1.23 espie 417: to allow
1.32 jmc 418: .Nm autoconf
1.23 espie 419: to work.
1.34 espie 420: .Pp
421: The built-ins
422: .Ic pushdef
423: and
424: .Ic popdef
425: handle macro definitions as a stack.
426: However,
427: .Ic define
428: interacts with the stack in an undefined way.
429: In this implementation,
430: .Ic define
431: replaces the top-most definition only.
432: Other implementations may erase all definitions on the stack instead.
1.23 espie 433: .Pp
434: For portability, one should not use the macros
435: .Ic builtin ,
436: .Ic esycmd ,
437: .Ic expr ,
438: .Ic indir ,
439: .Ic paste ,
440: .Ic patsubst ,
441: .Ic regexp ,
442: .Ic spaste ,
443: .Ic unix ,
444: .Ic __line__ ,
445: .Ic __file__ .
446: .Pp
1.32 jmc 447: All built-ins do expand without arguments in many other
1.23 espie 448: .Nm m4 .
449: .Pp
450: Many other
451: .Nm
452: have dire size limitations with respect to buffer sizes.
1.21 aaron 453: .Sh AUTHORS
1.32 jmc 454: .An Ozan Yigit Aq oz@sis.yorku.ca
455: and
456: .An Richard A. O'Keefe Aq ok@goanna.cs.rmit.OZ.AU .
457: .Pp
458: GNU-m4 compatibility extensions by
459: .An Marc Espie Aq espie@cvs.openbsd.org .
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