A.1 Settings m4 Macros

The main documentation of the Settings m4 Macros contains additional explanation of this code listing.

dnl
dnl Author: Michael L. Hall
dnl         P.O. Box 1663, MS-D409, LANL
dnl         Los Alamos, NM 87545
dnl         ph: 505-665-4312
dnl         email: hall@lanl.gov
dnl 
dnl Created on: 02/26/98
dnl Date:       03/21/00, 17:15:20
dnl Version:    6.8


dnl Change the quotation characters to avoid F90 conflicts.

m4_changequote([,])


dnl Change the comment characters to eliminate m4 macro 
dnl expansion in F90 comments.

m4_changecom([!])


dnl Redefine the "dnl" command to be unprefixed. Note that the "dnl"
dnl command is nonfunctional before this definition is made, but that
dnl unwanted output from the processing of this file is avoided by
dnl diverting the entire output (up until now) to nowhere. (Notice the 
dnl m4_divert(-1) command in the initialization.)

m4_define([dnl],m4_defn([m4_dnl]))
m4_divert


dnl Define unprefixed versions of m4 builtin macros that are 
dnl commonly used. All other m4 builtin macros must be prefixed 
dnl by "m4_".

m4_define([define],m4_defn([m4_define]))
m4_define([ifdef],m4_defn([m4_ifdef]))
m4_define([ifelse],m4_defn([m4_ifelse]))
m4_define([include],m4_defn([m4_include]))
m4_define([popdef],m4_defn([m4_popdef]))
m4_define([pushdef],m4_defn([m4_pushdef]))
m4_define([undefine],m4_defn([m4_undefine]))


dnl The m4_chop macro (based on perl's chop command) returns the 
dnl input string minus its final character. m4_chop is useful for 
dnl removing "\n" from m4_esyscmd strings. 

define([m4_chop], [m4_substr($1, 0, m4_decr(m4_len($1)))])


dnl Define cpp-style predefined macros for date and time information.
dnl These names correspond to those described in "The C Programming 
dnl Language", B. W. Kernighan and D. M. Ritchie (1988), page 233.
dnl The __file__ and __line__ predefined macros are already defined
dnl in Gnu m4, but are redefined here to remove the "m4_" prefix.

define([__date__], [m4_chop(m4_esyscmd(date +%D))])
define([__time__], [m4_chop(m4_esyscmd(date +%T))])
define([__file__], m4_defn([m4___file__]))
define([__line__], m4_defn([m4___line__]))


dnl The m4_die macro (based on perl's die command) prints an error 
dnl message and then terminates.

define([m4_die],[m4_errprint([m4:]__FILE__:__LINE__: [$1]) m4_m4exit(1)]) 


dnl The expand macro is used to force macro expansion in a word
dnl containing underscores, since underscores are not a word-delimiter
dnl in standard m4.

define([expand], [m4_translit(m4_translit([$1], [_], [*]), [*], [_])])


dnl The forloop macro, which iterates a section of text numerically,
dnl letting the loop variable take on successive numerical values when
dnl expressing the section of text. This version is better than the
dnl version in the Gnu m4 manual because it checks for the case of
dnl starting loop value greater than final loop value, and produces
dnl no output when this occurs.
dnl
dnl The arguments for the forloop macro are:
dnl
dnl   $1 - The name of the iteration variable.
dnl   $2 - The starting value.
dnl   $3 - The final value.
dnl   $4 - The text to be expanded for each iteration.

define([forloop],
[ifelse(
  m4_eval($2 > $3),  1,
    [],
  m4_eval($2 <= $3), 1, 
    [pushdef([$1], [$2])$4[]popdef([$1])])[]dnl
ifelse(
  m4_eval($2 < $3), 1,
    [forloop([$1], m4_incr($2), [$3], [$4])])])


dnl The firstword and tailwords macros operate on a space-delimited list  
dnl of words. The firstword macro returns the first word in the list, and 
dnl the tailwords macro returns a space-delimited list of words derived 
dnl by eliminating the first word.

define([firstword],
[ifelse(
  m4_index([$1], [ ]), [-1],
    [$1],
    [m4_substr([$1],0,m4_index([$1], [ ]))])[]dnl
])

define([tailwords],
[ifelse(
  m4_index([$1], [ ]), [-1],
    [],
    [m4_substr([$1],m4_incr(m4_index([$1], [ ])))])[]dnl
])


dnl The fortext macro is similar to the forloop macro, except that the 
dnl loop variable takes on successive textual values instead of numerical 
dnl values. The arguments for the fortext macro are:
dnl
dnl   $1 - The name of the iteration variable.
dnl   $2 - A string of values for the iteration variable, separated by 
dnl        spaces.
dnl   $3 - The text to be expanded for each iteration.

define([fortext],
[ifelse(
  firstword($2), [],
    [],
    [pushdef([$1],[firstword($2)])$3[]fortext(
      [$1], tailwords($2), [$3])])popdef([$1])[]dnl
])