Annotation of src/usr.bin/m4/m4.1, Revision 1.63
1.63 ! schwarze 1: .\" @(#) $OpenBSD: m4.1,v 1.62 2014/04/14 07:00:47 jmc 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
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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
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1.63 ! schwarze 33: .Dd $Mdocdate: April 14 2014 $
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
1.57 espie 40: .Nm
1.56 sthen 41: .Op Fl gPs
1.41 jmc 42: .Oo
43: .Sm off
44: .Fl D Ar name Op No = Ar value
45: .Sm on
46: .Oc
1.23 espie 47: .Op Fl d Ar flags
1.41 jmc 48: .Op Fl I Ar dirname
1.28 espie 49: .Op Fl o Ar filename
1.41 jmc 50: .Op Fl t Ar macro
1.1 deraadt 51: .Op Fl U Ns Ar name
1.47 grunk 52: .Op Ar
1.1 deraadt 53: .Sh DESCRIPTION
54: The
1.57 espie 55: .Nm
1.1 deraadt 56: utility is a macro processor that can be used as a front end to any
57: language (e.g., C, ratfor, fortran, lex, and yacc).
1.47 grunk 58: If no input files are given,
1.57 espie 59: .Nm
1.48 jmc 60: reads from the standard input,
61: otherwise files specified on the command line are
1.47 grunk 62: processed in the given order.
63: Input files can be regular files, files in the m4 include paths, or a
64: single dash
65: .Pq Sq - ,
66: denoting standard input.
1.57 espie 67: .Nm
1.47 grunk 68: writes
69: the processed text to the standard output, unless told otherwise.
1.1 deraadt 70: .Pp
1.8 espie 71: Macro calls have the form name(argument1[, argument2, ..., argumentN]).
1.1 deraadt 72: .Pp
73: There cannot be any space following the macro name and the open
1.10 aaron 74: parenthesis
1.58 jmc 75: .Pq Sq \&( .
1.10 aaron 76: If the macro name is not followed by an open
1.5 aaron 77: parenthesis it is processed with no arguments.
1.1 deraadt 78: .Pp
79: Macro names consist of a leading alphabetic or underscore
1.9 espie 80: possibly followed by alphanumeric or underscore characters, e.g.,
1.10 aaron 81: valid macro names match the pattern
82: .Dq [a-zA-Z_][a-zA-Z0-9_]* .
1.1 deraadt 83: .Pp
1.10 aaron 84: In arguments to macros, leading unquoted space, tab, and newline
1.33 jmc 85: .Pq Sq \en
1.10 aaron 86: characters are ignored.
1.33 jmc 87: To quote strings, use left and right single quotes
1.62 jmc 88: .Pq e.g., Sq \ \&this is a string with a leading space .
1.10 aaron 89: You can change the quote characters with the
1.5 aaron 90: .Ic changequote
91: built-in macro.
1.9 espie 92: .Pp
1.12 espie 93: Most built-ins don't make any sense without arguments, and hence are not
1.9 espie 94: recognized as special when not followed by an open parenthesis.
1.1 deraadt 95: .Pp
96: The options are as follows:
1.20 aaron 97: .Bl -tag -width Ds
1.63 ! schwarze 98: .It Fl D Ns Ar name Ns Op = Ns Ar value
1.1 deraadt 99: Define the symbol
100: .Ar name
1.10 aaron 101: to have some value (or
102: .Dv NULL ) .
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 .
1.12 espie 130: .It Fl g
1.13 aaron 131: Activate GNU-m4 compatibility mode.
1.40 espie 132: In this mode, translit handles simple character
1.19 espie 133: ranges (e.g., a-z), regular expressions mimic emacs behavior,
1.38 espie 134: multiple m4wrap calls are handled as a stack,
1.53 espie 135: the number of diversions is unlimited,
136: empty names for macro definitions are allowed,
137: and eval understands
138: .Sq 0rbase:value
139: numbers.
1.41 jmc 140: .It Fl I Ar "dirname"
141: Add directory
142: .Ar dirname
143: to the include path.
144: .It Fl o Ar filename
145: Send trace output to
146: .Ar filename .
1.56 sthen 147: .It Fl P
148: Prefix all built-in macros with
149: .Sq m4_ .
150: For example, instead of writing
151: .Ic define ,
152: use
153: .Ic m4_define .
1.25 espie 154: .It Fl s
155: Output line synchronization directives, suitable for
156: .Xr cpp 1 .
1.41 jmc 157: .It Fl t Ar macro
158: Turn tracing on for
159: .Ar macro .
160: .It Fl "U" Ns Ar "name"
161: Undefine the symbol
162: .Ar name .
1.17 aaron 163: .El
1.1 deraadt 164: .Sh SYNTAX
1.57 espie 165: .Nm
1.10 aaron 166: provides the following built-in macros.
167: They may be redefined, losing their original meaning.
168: Return values are null unless otherwise stated.
1.36 espie 169: .Bl -tag -width changequote
170: .It Fn builtin name
1.37 jmc 171: Calls a built-in by its
172: .Fa name ,
1.36 espie 173: overriding possible redefinitions.
174: .It Fn changecom startcomment endcomment
1.39 espie 175: Changes the start comment and end comment sequences.
176: Comment sequences may be up to five characters long.
1.42 jmc 177: The default values are the hash sign
1.10 aaron 178: and the newline character.
1.39 espie 179: .Bd -literal -offset indent
180: # This is a comment
181: .Ed
182: .Pp
183: With no arguments, comments are turned off.
184: With one single argument, the end comment sequence is set
185: to the newline character.
1.36 espie 186: .It Fn changequote beginquote endquote
1.39 espie 187: Defines the open quote and close quote sequences.
188: Quote sequences may be up to five characters long.
189: The default values are the backquote character and the quote
190: character.
191: .Bd -literal -offset indent
192: `Here is a quoted string'
193: .Ed
194: .Pp
195: With no arguments, the default quotes are restored.
196: With one single argument, the close quote sequence is set
197: to the newline character.
1.36 espie 198: .It Fn decr arg
1.37 jmc 199: Decrements the argument
200: .Fa arg
1.36 espie 201: by 1.
1.37 jmc 202: The argument
1.36 espie 203: .Fa arg
204: must be a valid numeric string.
205: .It Fn define name value
1.37 jmc 206: Define a new macro named by the first argument
207: .Fa name
1.36 espie 208: to have the
209: value of the second argument
210: .Fa value .
1.10 aaron 211: Each occurrence of
1.33 jmc 212: .Sq $n
1.10 aaron 213: (where
214: .Ar n
215: is 0 through 9) is replaced by the
216: .Ar n Ns 'th
217: argument.
1.33 jmc 218: .Sq $0
1.10 aaron 219: is the name of the calling macro.
220: Undefined arguments are replaced by a null string.
1.33 jmc 221: .Sq $#
1.10 aaron 222: is replaced by the number of arguments;
1.33 jmc 223: .Sq $*
1.10 aaron 224: is replaced by all arguments comma separated;
1.33 jmc 225: .Sq $@
1.10 aaron 226: is the same as
1.33 jmc 227: .Sq $*
1.10 aaron 228: but all arguments are quoted against further expansion.
1.36 espie 229: .It Fn defn name ...
1.10 aaron 230: Returns the quoted definition for each argument.
231: This can be used to rename
1.1 deraadt 232: macro definitions (even for built-in macros).
1.36 espie 233: .It Fn divert num
1.1 deraadt 234: There are 10 output queues (numbered 0-9).
235: At the end of processing
1.57 espie 236: .Nm
1.1 deraadt 237: concatenates all the queues in numerical order to produce the
1.10 aaron 238: final output.
239: Initially the output queue is 0.
240: The divert
1.1 deraadt 241: macro allows you to select a new output queue (an invalid argument
242: passed to divert causes output to be discarded).
1.5 aaron 243: .It Ic divnum
1.1 deraadt 244: Returns the current output queue number.
1.5 aaron 245: .It Ic dnl
1.1 deraadt 246: Discard input characters up to and including the next newline.
1.36 espie 247: .It Fn dumpdef name ...
1.1 deraadt 248: Prints the names and definitions for the named items, or for everything
249: if no arguments are passed.
1.36 espie 250: .It Fn errprint msg
1.1 deraadt 251: Prints the first argument on the standard error output stream.
1.36 espie 252: .It Fn esyscmd cmd
1.26 pvalchev 253: Passes its first argument to a shell and returns the shell's standard output.
1.18 espie 254: Note that the shell shares its standard input and standard error with
1.57 espie 255: .Nm .
1.61 jmc 256: .It Fn eval expr[,radix[,minimum]]
1.1 deraadt 257: Computes the first argument as an arithmetic expression using 32-bit
1.10 aaron 258: arithmetic.
259: Operators are the standard C ternary, arithmetic, logical,
260: shift, relational, bitwise, and parentheses operators.
261: You can specify
262: octal, decimal, and hexadecimal numbers as in C.
1.61 jmc 263: The optional second argument
264: .Fa radix
265: specifies the radix for the result and the optional third argument
266: .Fa minimum
1.10 aaron 267: specifies the minimum number of digits in the result.
1.36 espie 268: .It Fn expr expr
1.5 aaron 269: This is an alias for
270: .Ic eval .
1.44 espie 271: .It Fn format formatstring arg1 ...
1.45 jmc 272: Returns
273: .Fa formatstring
1.44 espie 274: with escape sequences substituted with
275: .Fa arg1
276: and following arguments, in a way similar to
277: .Xr printf 3 .
1.53 espie 278: This built-in is only available in GNU-m4 compatibility mode, and the only
279: parameters implemented are there for autoconf compatibility:
1.54 jmc 280: left-padding flag, an optional field width, a maximum field width,
1.53 espie 281: *-specified field widths, and the %s and %c data type.
1.36 espie 282: .It Fn ifdef name yes no
1.1 deraadt 283: If the macro named by the first argument is defined then return the second
1.10 aaron 284: argument, otherwise the third.
285: If there is no third argument, the value is
286: .Dv NULL .
287: The word
288: .Qq unix
289: is predefined.
1.36 espie 290: .It Fn ifelse a b yes ...
1.37 jmc 291: If the first argument
1.36 espie 292: .Fa a
1.37 jmc 293: matches the second argument
1.36 espie 294: .Fa b
295: then
296: .Fn ifelse
1.5 aaron 297: returns
1.36 espie 298: the third argument
299: .Fa yes .
1.10 aaron 300: If the match fails the three arguments are
1.1 deraadt 301: discarded and the next three arguments are used until there is
1.10 aaron 302: zero or one arguments left, either this last argument or
303: .Dv NULL
304: is returned if no other matches were found.
1.36 espie 305: .It Fn include name
1.1 deraadt 306: Returns the contents of the file specified in the first argument.
1.7 espie 307: If the file is not found as is, look through the include path:
308: first the directories specified with
309: .Fl I
310: on the command line, then the environment variable
1.10 aaron 311: .Ev M4PATH ,
1.7 espie 312: as a colon-separated list of directories.
1.1 deraadt 313: Include aborts with an error message if the file cannot be included.
1.36 espie 314: .It Fn incr arg
1.10 aaron 315: Increments the argument by 1.
316: The argument must be a valid numeric string.
1.36 espie 317: .It Fn index string substring
1.1 deraadt 318: Returns the index of the second argument in the first argument (e.g.,
1.10 aaron 319: .Ic index(the quick brown fox jumped, fox)
320: returns 16).
321: If the second
322: argument is not found index returns \-1.
1.36 espie 323: .It Fn indir macro arg1 ...
1.26 pvalchev 324: Indirectly calls the macro whose name is passed as the first argument,
1.11 espie 325: with the remaining arguments passed as first, ... arguments.
1.36 espie 326: .It Fn len arg
1.10 aaron 327: Returns the number of characters in the first argument.
328: Extra arguments
1.1 deraadt 329: are ignored.
1.36 espie 330: .It Fn m4exit code
1.1 deraadt 331: Immediately exits with the return value specified by the first argument,
332: 0 if none.
1.36 espie 333: .It Fn m4wrap todo
1.10 aaron 334: Allows you to define what happens at the final
335: .Dv EOF ,
336: usually for cleanup purposes (e.g.,
337: .Ic m4wrap("cleanup(tempfile)")
338: causes the macro cleanup to be
1.16 aaron 339: invoked after all other processing is done).
1.38 espie 340: .Pp
341: Multiple calls to
342: .Fn m4wrap
343: get inserted in sequence at the final
344: .Dv EOF .
1.36 espie 345: .It Fn maketemp template
1.57 espie 346: Like
347: .Ic mkstemp .
348: .It Fn mkstemp template
1.35 miod 349: Invokes
350: .Xr mkstemp 3
351: on the first argument, and returns the modified string.
1.10 aaron 352: This can be used to create unique
1.1 deraadt 353: temporary file names.
1.36 espie 354: .It Fn paste file
1.1 deraadt 355: Includes the contents of the file specified by the first argument without
1.10 aaron 356: any macro processing.
357: Aborts with an error message if the file cannot be
1.1 deraadt 358: included.
1.36 espie 359: .It Fn patsubst string regexp replacement
1.11 espie 360: Substitutes a regular expression in a string with a replacement string.
361: Usual substitution patterns apply: an ampersand
1.33 jmc 362: .Pq Sq \&&
1.11 espie 363: is replaced by the string matching the regular expression.
364: The string
1.33 jmc 365: .Sq \e# ,
1.11 espie 366: where
1.33 jmc 367: .Sq #
1.11 espie 368: is a digit, is replaced by the corresponding back-reference.
1.36 espie 369: .It Fn popdef arg ...
1.5 aaron 370: Restores the
371: .Ic pushdef Ns ed
372: definition for each argument.
1.36 espie 373: .It Fn pushdef macro def
1.5 aaron 374: Takes the same arguments as
375: .Ic define ,
376: but it saves the definition on a
377: stack for later retrieval by
1.36 espie 378: .Fn popdef .
379: .It Fn regexp string regexp replacement
1.13 aaron 380: Finds a regular expression in a string.
381: If no further arguments are given,
1.14 aaron 382: it returns the first match position or \-1 if no match.
383: If a third argument
1.11 espie 384: is provided, it returns the replacement string, with sub-patterns replaced.
1.36 espie 385: .It Fn shift arg1 ...
1.1 deraadt 386: Returns all but the first argument, the remaining arguments are
1.10 aaron 387: quoted and pushed back with commas in between.
388: The quoting
1.1 deraadt 389: nullifies the effect of the extra scan that will subsequently be
390: performed.
1.36 espie 391: .It Fn sinclude file
1.5 aaron 392: Similar to
393: .Ic include ,
394: except it ignores any errors.
1.36 espie 395: .It Fn spaste file
1.5 aaron 396: Similar to
1.36 espie 397: .Fn paste ,
1.5 aaron 398: except it ignores any errors.
1.36 espie 399: .It Fn substr string offset length
1.1 deraadt 400: Returns a substring of the first argument starting at the offset specified
401: by the second argument and the length specified by the third argument.
402: If no third argument is present it returns the rest of the string.
1.36 espie 403: .It Fn syscmd cmd
1.10 aaron 404: Passes the first argument to the shell.
405: Nothing is returned.
1.5 aaron 406: .It Ic sysval
407: Returns the return value from the last
408: .Ic syscmd .
1.36 espie 409: .It Fn traceon arg ...
1.22 espie 410: Enables tracing of macro expansions for the given arguments, or for all
411: macros if no argument is given.
1.36 espie 412: .It Fn traceoff arg ...
1.22 espie 413: Disables tracing of macro expansions for the given arguments, or for all
414: macros if no argument is given.
1.36 espie 415: .It Fn translit string mapfrom mapto
1.1 deraadt 416: Transliterate the characters in the first argument from the set
1.10 aaron 417: given by the second argument to the set given by the third.
1.21 aaron 418: You cannot use
1.1 deraadt 419: .Xr tr 1
420: style abbreviations.
1.36 espie 421: .It Fn undefine name1 ...
1.24 espie 422: Removes the definition for the macros specified by its arguments.
1.36 espie 423: .It Fn undivert arg ...
1.1 deraadt 424: Flushes the named output queues (or all queues if no arguments).
1.5 aaron 425: .It Ic unix
1.1 deraadt 426: A pre-defined macro for testing the OS platform.
1.11 espie 427: .It Ic __line__
428: Returns the current file's line number.
429: .It Ic __file__
430: Returns the current file's name.
1.1 deraadt 431: .El
1.59 jmc 432: .Sh EXIT STATUS
433: .Ex -std m4
434: .Pp
435: But note that the
436: .Ic m4exit
437: macro can modify the exit status.
1.32 jmc 438: .Sh STANDARDS
1.49 jmc 439: The
1.23 espie 440: .Nm
1.62 jmc 441: utility is compliant with the
1.55 jmc 442: .St -p1003.1-2008
1.49 jmc 443: specification.
444: .Pp
445: The flags
1.62 jmc 446: .Op Fl dgIPot
1.49 jmc 447: and the macros
448: .Ic builtin ,
449: .Ic esyscmd ,
450: .Ic expr ,
451: .Ic format ,
452: .Ic indir ,
453: .Ic paste ,
454: .Ic patsubst ,
455: .Ic regexp ,
456: .Ic spaste ,
457: .Ic unix ,
458: .Ic __line__ ,
459: and
460: .Ic __file__
461: are extensions to that specification.
1.23 espie 462: .Pp
1.57 espie 463: .Ic maketemp
464: is not supposed to be a synonym for
465: .Ic mkstemp ,
466: but instead to be an insecure temporary file name creation function.
1.62 jmc 467: It is marked by
468: .St -p1003.1-2008
469: as being obsolescent and should not be used if portability is a concern.
1.57 espie 470: .Pp
1.62 jmc 471: The output format of
472: .Ic traceon
473: and
1.32 jmc 474: .Ic dumpdef
475: are not specified in any standard,
1.23 espie 476: are likely to change and should not be relied upon.
1.32 jmc 477: The current format of tracing is closely modelled on
478: .Nm gnu-m4 ,
1.23 espie 479: to allow
1.32 jmc 480: .Nm autoconf
1.23 espie 481: to work.
1.34 espie 482: .Pp
483: The built-ins
484: .Ic pushdef
485: and
486: .Ic popdef
487: handle macro definitions as a stack.
488: However,
489: .Ic define
490: interacts with the stack in an undefined way.
491: In this implementation,
492: .Ic define
493: replaces the top-most definition only.
494: Other implementations may erase all definitions on the stack instead.
1.23 espie 495: .Pp
1.32 jmc 496: All built-ins do expand without arguments in many other
1.57 espie 497: .Nm .
1.23 espie 498: .Pp
499: Many other
500: .Nm
501: have dire size limitations with respect to buffer sizes.
1.21 aaron 502: .Sh AUTHORS
1.43 jaredy 503: .An -nosplit
1.60 schwarze 504: .An Ozan Yigit Aq Mt oz@sis.yorku.ca
1.32 jmc 505: and
1.60 schwarze 506: .An Richard A. O'Keefe Aq Mt ok@goanna.cs.rmit.OZ.AU .
1.32 jmc 507: .Pp
508: GNU-m4 compatibility extensions by
1.60 schwarze 509: .An Marc Espie Aq Mt espie@cvs.openbsd.org .
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