Merge differences and correct the manual page.

1 files changed, 309 insertions, 144 deletions

diff --git a/usr.bin/m4/m4.1 b/usr.bin/m4/m4.1
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--- a/usr.bin/m4/m4.1
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@@ -1,216 +1,381 @@
+.\"	@(#) $OpenBSD: m4.1,v 1.24 2002/04/18 18:57:23 espie Exp $
+.\" $FreeBSD$
 .\"
-.\"	@(#) $FreeBSD$
-.\"
-.Dd April 17, 2002
+.Dd January 26, 1993
 .Dt M4 1
 .Os
 .Sh NAME
 .Nm m4
 .Nd macro language processor
 .Sh SYNOPSIS
-.Nm
+.Nm m4
+.Op Fl d Ar flags
+.Op Fl t Ar name
+.Op Fl g
 .Oo
-.Fl D Ar name Ns Op Ar =value
+.Fl D Ns Ar name Ns Op Ar =value
 .Oc
-.Op Fl U Ar name
-.Op Ar filename
-\|.\|.\|.
+.Op Fl U Ns Ar name
+.Op Fl I Ar dirname
 .Sh DESCRIPTION
 The
-.Nm
+.Nm m4
 utility is a macro processor that can be used as a front end to any
 language (e.g., C, ratfor, fortran, lex, and yacc).
-Each of the argument files is processed in order.
-If there are no files, or if a filename is \`-\', the standard input is read.
-The processed text is sent to the standard output.
+.Nm m4
+reads from the standard input and writes
+the processed text to the standard output.
 .Pp
-Macro calls have the form name(argument1[, argument2, ...,] argumentN).
+Macro calls have the form name(argument1[, argument2, ..., argumentN]).
 .Pp
 There cannot be any space following the macro name and the open
-parentheses '('.  If the macro name is not followed by an open
-parentheses it is processed with no arguments.
+parenthesis
+.Pq Ql ( .
+If the macro name is not followed by an open
+parenthesis it is processed with no arguments.
 .Pp
 Macro names consist of a leading alphabetic or underscore
-possibly followed by alphanumeric or underscore characters, therefore
-valid macro names match this pattern [a-zA-Z_][a-zA-Z0-9_]*.
+possibly followed by alphanumeric or underscore characters, e.g.,
+valid macro names match the pattern
+.Dq [a-zA-Z_][a-zA-Z0-9_]* .
 .Pp
-In arguments to macros, leading unquoted space, tab and newline
-characters are ignored.  To quote strings use left and right single
-quotes (e.g., ` this is a string with a leading space').  You can change
-the quote characters with the changequote built-in macro.
+In arguments to macros, leading unquoted space, tab, and newline
+.Pq Ql \en
+characters are ignored.
+To quote strings, use left and right single
+quotes (e.g.,
+.Sq \ this is a string with a leading space ) .
+You can change the quote characters with the
+.Ic changequote
+built-in macro.
+.Pp
+Most built-ins don't make any sense without arguments, and hence are not
+recognized as special when not followed by an open parenthesis.
 .Pp
 The options are as follows:
-.Bl -tag -width "-Dname[=value]xxx"
-.It Fl s
-Emit
-.Em #line
-directives for
-.Xr cpp 1 .
-.It Fl D Ar name Ns Oo
+.Bl -tag -width Ds
+.It Fl D Ns Ar name Ns Oo
 .Ar =value
 .Oc
 Define the symbol
 .Ar name
-to have some value (or NULL).
-.It Fl "U" Ar "name"
+to have some value (or
+.Dv NULL ) .
+.It Fl "U" Ns Ar "name"
 Undefine the symbol
 .Ar name .
+.It Fl I Ar "dirname"
+Add directory
+.Ar dirname
+to the include path.
+.It Fl d Ar "flags"
+Set trace flags.
+.Ar flags 
+may hold the following:
+.Bl -tag -width Ds
+.It Ar a
+print macro arguments.
+.It Ar c
+print macro expansion over several lines.
+.It Ar e
+print result of macro expansion.
+.It Ar f
+print filename location.
+.It Ar l
+print line number.
+.It Ar q
+quote arguments and expansion with the current quotes.
+.It Ar t
+start with all macros traced.
+.It Ar x
+number macro expansions.
+.It Ar V
+turn on all options.
+.El
+.Pp
+By default, trace is set to 
+.Qq eq .
+.It Fl t Ar macro
+Turn tracing on for 
+.Ar macro .
+.It Fl g
+Activate GNU-m4 compatibility mode.
+In this mode, changequote with
+two empty parameters deactivates quotes, translit handles simple character
+ranges (e.g., a-z), regular expressions mimic emacs behavior,
+and the number of diversions is unlimited.
 .El
 .Sh SYNTAX
-.Nm
-provides the following built-in macros.  They may be
-redefined, losing their original meaning.
-Return values are NULL unless otherwise stated.
+.Nm m4
+provides the following built-in macros.
+They may be redefined, losing their original meaning.
+Return values are null unless otherwise stated.
 .Bl -tag -width changequotexxx
-.It changecom
-Change the start and end comment sequences.  The default is
-the pound sign `#' and the newline character.  With no arguments
-comments are turned off.  The maximum length for a comment marker is
-five characters.
-.It changequote
+.It Ic builtin
+Calls a built-in by its name, overriding possible redefinitions.
+.It Ic changecom
+Change the start and end comment sequences.
+The default is the pound sign
+.Pq Ql #
+and the newline character.
+With no arguments comments are turned off.
+The maximum length for a comment marker is five characters.
+.It Ic changequote
 Defines the quote symbols to be the first and second arguments.
-Note, only the first character of each argument is used.  If no arguments are
+The symbols may be up to five characters long.
+If no arguments are
 given it restores the default open and close single quotes.
-.It decr
-Decrements the argument by 1.  The argument must be a valid numeric string.
-.It define
+.It Ic decr
+Decrements the argument by 1.
+The argument must be a valid numeric string.
+.It Ic define
 Define a new macro named by the first argument to have the
-value of the second argument.  Each occurrence of $n (where n
-is 0 through 9) is replaced by the n'th argument.  $0 is the name
-of the calling macro.  Undefined arguments are replaced by a
-NULL string.  $# is replaced by the number of arguments; $*
-is replaced by all arguments comma separated; $@ is the same
-as $* but all arguments are quoted against further expansion.
-.It defn
-Returns the quoted definition for each argument.  This can be used to rename
+value of the second argument.
+Each occurrence of
+.Ql $n
+(where
+.Ar n
+is 0 through 9) is replaced by the
+.Ar n Ns 'th
+argument.
+.Ql $0
+is the name of the calling macro.
+Undefined arguments are replaced by a null string.
+.Ql $#
+is replaced by the number of arguments;
+.Ql $*
+is replaced by all arguments comma separated;
+.Ql $@
+is the same as
+.Ql $*
+but all arguments are quoted against further expansion.
+.It Ic defn
+Returns the quoted definition for each argument.
+This can be used to rename
 macro definitions (even for built-in macros).
-.It divert
+.It Ic divert
 There are 10 output queues (numbered 0-9).
 At the end of processing
-.Nm
+.Nm m4
 concatenates all the queues in numerical order to produce the
-final output.  Initially the output queue is 0.  The divert
+final output.
+Initially the output queue is 0.
+The divert
 macro allows you to select a new output queue (an invalid argument
 passed to divert causes output to be discarded).
-.It divnum
+.It Ic divnum
 Returns the current output queue number.
-.It dnl
+.It Ic dnl
 Discard input characters up to and including the next newline.
-.It dumpdef
+.It Ic dumpdef
 Prints the names and definitions for the named items, or for everything
 if no arguments are passed.
-.It errprint
+.It Ic errprint
 Prints the first argument on the standard error output stream.
-.It eval
+.It Ic esyscmd
+Pass its first argument to a shell and returns the shell's standard output.
+Note that the shell shares its standard input and standard error with
+.Nm
+.It Ic eval
 Computes the first argument as an arithmetic expression using 32-bit
-arithmetic.  Operators are the standard C ternary, arithmetic, logical,
-shift, relational, bitwise, and parentheses operators.  You can specify
-octal, decimal, and hexadecimal numbers as in C.  The second argument (if
-any) specifies the radix for the result and the third argument (if
-any) specifies the minimum number of digits in the result.
-.It expr
-This is an alias for eval.
-.It ifdef
+arithmetic.
+Operators are the standard C ternary, arithmetic, logical,
+shift, relational, bitwise, and parentheses operators.
+You can specify
+octal, decimal, and hexadecimal numbers as in C.
+The second argument (if any)
+specifies the radix for the result and the third argument (if any)
+specifies the minimum number of digits in the result.
+.It Ic expr
+This is an alias for
+.Ic eval .
+.It Ic ifdef
 If the macro named by the first argument is defined then return the second
-argument, otherwise the third.  If there is no third argument,
-the value is NULL.  The word `unix' is predefined.
-.It ifelse
-If the first argument matches the second argument then ifelse returns
-the third argument.  If the match fails the three arguments are
+argument, otherwise the third.
+If there is no third argument, the value is
+.Dv NULL .
+The word
+.Qq unix
+is predefined.
+.It Ic ifelse
+If the first argument matches the second argument then
+.Ic ifelse
+returns
+the third argument.
+If the match fails the three arguments are
 discarded and the next three arguments are used until there is
-zero or one arguments left, either this last argument or NULL is
-returned if no other matches were found.
-.It include
+zero or one arguments left, either this last argument or
+.Dv NULL
+is returned if no other matches were found.
+.It Ic include
 Returns the contents of the file specified in the first argument.
+If the file is not found as is, look through the include path:
+first the directories specified with
+.Fl I
+on the command line, then the environment variable
+.Ev M4PATH ,
+as a colon-separated list of directories.
 Include aborts with an error message if the file cannot be included.
-.It incr
-Increments the argument by 1.  The argument must be a valid numeric string.
-.It index
+.It Ic incr
+Increments the argument by 1.
+The argument must be a valid numeric string.
+.It Ic index
 Returns the index of the second argument in the first argument (e.g.,
-index(the quick brown fox jumped, fox) returns 16).  If the second
-argument is not found index returns -1.
-.It len
-Returns the number of characters in the first argument.  Extra arguments
+.Ic index(the quick brown fox jumped, fox)
+returns 16).
+If the second
+argument is not found index returns \-1.
+.It Ic indir
+Indirectly calls the macro whose name is passed as the first arguments,
+with the remaining arguments passed as first, ... arguments.
+.It Ic len
+Returns the number of characters in the first argument.
+Extra arguments
 are ignored.
-.It m4exit
+.It Ic m4exit
 Immediately exits with the return value specified by the first argument,
 0 if none.
-.It m4wrap
-Allows you to define what happens at the final EOF, usually for cleanup
-purposes (e.g., m4wrap("cleanup(tempfile)") causes the macro cleanup to be
-invoked after all other processing is done.)
-.It maketemp
-Translates the string XXXXX in the first argument with the current process
-ID leaving other characters alone.  This can be used to create unique
+.It Ic m4wrap
+Allows you to define what happens at the final
+.Dv EOF ,
+usually for cleanup purposes (e.g.,
+.Ic m4wrap("cleanup(tempfile)")
+causes the macro cleanup to be
+invoked after all other processing is done).
+.It Ic maketemp
+Translates the string
+.Dq XXXXX
+in the first argument with the current process
+ID leaving other characters alone.
+This can be used to create unique
 temporary file names.
-.It paste
+.It Ic paste
 Includes the contents of the file specified by the first argument without
-any macro processing.  Aborts with an error message if the file cannot be
+any macro processing.
+Aborts with an error message if the file cannot be
 included.
-.It popdef
-Restores the pushdef'ed definition for each argument.
-.It pushdef
-Takes the same arguments as define, but it saves the definition on a
-stack for later retrieval by popdef.
-.It shift
+.It Ic patsubst
+Substitutes a regular expression in a string with a replacement string.
+Usual substitution patterns apply: an ampersand
+.Pq Ql &
+is replaced by the string matching the regular expression.
+The string
+.Ql \e# ,
+where
+.Ql #
+is a digit, is replaced by the corresponding back-reference.
+.It Ic popdef
+Restores the
+.Ic pushdef Ns ed
+definition for each argument.
+.It Ic pushdef
+Takes the same arguments as
+.Ic define ,
+but it saves the definition on a
+stack for later retrieval by
+.Ic popdef .
+.It Ic regexp
+Finds a regular expression in a string.
+If no further arguments are given,
+it returns the first match position or \-1 if no match.
+If a third argument
+is provided, it returns the replacement string, with sub-patterns replaced.
+.It Ic shift
 Returns all but the first argument, the remaining arguments are
-quoted and pushed back with commas in between.  The quoting
+quoted and pushed back with commas in between.
+The quoting
 nullifies the effect of the extra scan that will subsequently be
 performed.
-.It sinclude
-Similar to include, except it ignores any errors.
-.It spaste
-Similar to paste, except it ignores any errors.
-.It substr
+.It Ic sinclude
+Similar to
+.Ic include ,
+except it ignores any errors.
+.It Ic spaste
+Similar to
+.Ic paste ,
+except it ignores any errors.
+.It Ic substr
 Returns a substring of the first argument starting at the offset specified
 by the second argument and the length specified by the third argument.
 If no third argument is present it returns the rest of the string.
-.It syscmd
-Passes the first argument to the shell.  Nothing is returned.
-.It sysval
-Returns the return value from the last syscmd.
-.It translit
+.It Ic syscmd
+Passes the first argument to the shell.
+Nothing is returned.
+.It Ic sysval
+Returns the return value from the last
+.Ic syscmd .
+.It Ic traceon
+Enables tracing of macro expansions for the given arguments, or for all
+macros if no argument is given.
+.It Ic traceoff
+Disables tracing of macro expansions for the given arguments, or for all
+macros if no argument is given.
+.It Ic translit
 Transliterate the characters in the first argument from the set
-given by the second argument to the set given by the third.  You cannot
-use
+given by the second argument to the set given by the third.
+You cannot use
 .Xr tr 1
 style abbreviations.
-.It undefine
-Removes the definition for the macro specified by the first argument.
-.It undivert
+.It Ic undefine
+Removes the definition for the macros specified by its arguments.
+.It Ic undivert
 Flushes the named output queues (or all queues if no arguments).
-.It unix
+.It Ic unix
 A pre-defined macro for testing the OS platform.
+.It Ic __line__
+Returns the current file's line number.
+.It Ic __file__
+Returns the current file's name.
 .El
-.Sh DIAGNOSTICS
-.Ex -std
-.Pp
-The exit status can be specified by the input file using the
-.Em m4exit
-macro.
-.Sh "SEE ALSO"
-.Xr cpp 1
-.Sh STANDARDS
-The
+.Sh COMPATIBILITY
 .Nm
-utility is compatible with the
-.St -p1003.1-2001
-specification with the exception of the
-.Em traceon
-and
-.Em traceoff
-built-in macros, which are not implemented.
+follows the Single Unix 2 specification, along with a few extensions taken
+from 
+.Nm gnu-m4 .
 .Pp
 The
-.Em expr ,
-.Em paste ,
-.Em spaste
-and
-.Em unix
-built-in macros are extensions to the standard.
+.Fl s
+option
+.Po
+.Xr cpp 1 's
+#line directives
+.Pc
+is currently not supported.
+Flags
+.Fl I ,
+.Fl d ,
+.Fl t
+are non-standard.
+.Pp
+The output format of tracing and of 
+.Ic dumpdef 
+are not specified in any standard, 
+are likely to change and should not be relied upon.
+The current format of tracing is closely modelled on 
+.Nm gnu-m4 , 
+to allow
+.Nm autoconf 
+to work.
+.Pp
+For portability, one should not use the macros
+.Ic builtin ,
+.Ic esycmd ,
+.Ic expr ,
+.Ic indir ,
+.Ic paste ,
+.Ic patsubst ,
+.Ic regexp ,
+.Ic spaste ,
+.Ic unix ,
+.Ic __line__ ,
+.Ic __file__ .
+.Pp
+All builtins do expand without arguments in many other 
+.Nm m4 .
+.Pp
+Many other
+.Nm
+have dire size limitations with respect to buffer sizes.
 .Sh AUTHORS
-.An Ozan Yigit Aq oz@sis.yorku.ca
-and
-.An Richard A. O'Keefe Aq ok@goanna.cs.rmit.OZ.AU
-.Sh BUGS
-The tracing macros are not implemented.
+Ozan Yigit <oz@sis.yorku.ca> and Richard A. O'Keefe (ok@goanna.cs.rmit.OZ.AU).
+GNU-m4 compatibility extensions by Marc Espie <espie@cvs.openbsd.org>.