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Diffstat (limited to 'doc/gawk.texi')
| -rw-r--r-- | doc/gawk.texi | 81 |
1 files changed, 80 insertions, 1 deletions
diff --git a/doc/gawk.texi b/doc/gawk.texi index d7b65a66..930f9345 100644 --- a/doc/gawk.texi +++ b/doc/gawk.texi @@ -11357,6 +11357,7 @@ currently used only by the @uref{http://xmlgawk.sourceforge.net, XMLgawk project The @code{ENDFILE} rule is called when @command{gawk} has finished processing the last record in an input file. For the last input file, it will be called before any @code{END} rules. +The @code{ENDFILE} rule is executed even for empty input files. Normally, when an error occurs when reading input in the normal input processing loop, the error is fatal. However, if an @code{ENDFILE} @@ -18544,7 +18545,7 @@ $ @kbd{gawk 'BEGIN @{} @print{} 4 4 @print{} 3 3 $ @kbd{gawk 'BEGIN @{} -> @kbd{ PROCINFO["sorted_in"] = "@@str_ind_asc"} +> @kbd{ PROCINFO["sorted_in"] = "@@ind_str_asc"} > @kbd{ a[4] = 4} > @kbd{ a[3] = 3} > @kbd{ for (i in a)} @@ -25070,6 +25071,84 @@ O+X*(o*(o+O)+O),+x+O+X*o,x*(x-o),(o+X+x)*o*o-(x-O-O),O+(X-x)*(X+O),x-O@}' We leave it to you to determine what the program does. +@ignore +To: "Arnold Robbins" <arnold@skeeve.com> +Date: Sat, 20 Aug 2011 13:50:46 -0400 +Subject: The GNU Awk User's Guide, Section 13.3.11 +From: "Chris Johansen" <johansen@main.nc.us> +Message-ID: <op.v0iw6wlv7finx3@asusodin.thrudvang.lan> + +Arnold, you don't know me, but we have a tenuous connection. My wife is +Barbara A. Field, FAIA, GIT '65 (B. Arch.). + +I have had a couple of paper copies of "Effective Awk Programming" for +years, and now I'm going through a Kindle version of "The GNU Awk User's +Guide" again. When I got to section 13.3.11, I reformatted and lightly +commented Davide Brin's signature script to understand its workings. + +It occurs to me that this might have pedagogical value as an example +(although imperfect) of the value of whitespace and comments, and a +starting point for that discussion. It certainly helped _me_ understand +what's going on. You are welcome to it, as-is or modified (subject to +Davide's constraints, of course, which I think I have met). + +If I were to include it in a future edition, I would put it at some +distance from section 13.3.11, say, as a note or an appendix, so as not to +be a "spoiler" to the puzzle. + +Best regards, +-- +Chris Johansen {johansen at main dot nc dot us} + . . . collapsing the probability wave function, sending ripples of +certainty through the space-time continuum. + + +#! /usr/bin/gawk -f + +# From "13.3.11 And Now For Something Completely Different" +# http://www.gnu.org/software/gawk/manual/html_node/Signature-Program.html#Signature-Program + +# Copyright © 2008 Davide Brini + +# Copying and distribution of the code published in this page, with +# or without modification, are permitted in any medium without +# royalty provided the copyright notice and this notice are preserved. + +BEGIN { + O = "~" ~ "~"; # 1 + o = "==" == "=="; # 1 + o += +o; # 2 + x = O "" O; # 11 + + + while ( X++ <= x + o + o ) c = c "%c"; + + # O is 1 + # o is 2 + # x is 11 + # X is 17 + # c is "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c" + + printf c, + ( x - O )*( x - O), # 100 d + x*( x - o ) - o, # 97 a + x*( x - O ) + x - O - o, # 118 v + +x*( x - O ) - x + o, # 101 e + X*( o*o + O ) + x - O, # 95 _ + X*( X - x ) - o*o, # 98 b + ( x + X )*o*o + o, # 114 r + x*( X - x ) - O - O, # 64 @ + x - O + ( O + o + X + x )*( o + O ), # 103 g + X*X - X*( x - O ) - x + O, # 109 m + O + X*( o*( o + O ) + O ), # 120 x + +x + O + X*o, # 46 . + x*( x - o), # 99 c + ( o + X + x )*o*o - ( x - O - O ), # 111 0 + O + ( X - x )*( X + O ), # 109 m + x - O # 10 \n +} +@end ignore + @c The original text for this chapter was contributed by Efraim Yawitz. @c FIXME: Add more indexing. |