texindex/jrtangle - texinfo - Git at Google

 #! /usr/bin/gawk -f
 #
 # Copyright (C) 2013, 2014, 2015, 2016, 2019 Arnold David Robbins
 #
 # This file is part of TexiWeb Jr., a literate programming system.
 #
 # TexiWeb Jr. is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 3 of the License, or
 # (at your option) any later version.
 #
 # TexiWeb Jr. is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, see <https://www.gnu.org/licenses/>.
 #
 # Up-to-date source code for TexiWeb Jr. can be obtained via
 # Git from github:
 #
 #	git clone http://github.com/arnoldrobbins/texiwebjr
 #
 BEGIN {
 	v[0] = 0
 	if ("version" in PROCINFO) {
 		match(PROCINFO["version"], /^[0-9]+\./, v);
 	}

 	if (v[0] < 4) {
 		print("gawk >= 4.0 required") > "/dev/stderr"
 		exit 63	# for "missing" script
 	}
 }
 BEGIN {
 	TRUE = 1
 	FALSE = 0
 	File_chunk_pattern = "^@\\(([^)]+)@\\)[[:space:]]*=[[:space:]]*$"
 	Code_chunk_pattern = "^@" "<(.+)" "@>[[:space:]]*=[[:space:]]*$"
 	Chunk_name_pattern = "@<[^>\n]+@>"
 }
 # Error checking:

 # Use brackets to avoid triggering the warning on ourselves!
 /(^<[@])|(>[@]([[:space:]]*=[[:space:]]*)?$)/	{
 	# Ditto, with concatenation
 	warning("<" "@ or >" "@ used instead of @" "< or @" ">\n\t%s\n",
 			$0)
 }

 END {
 	check_unfinished()
 }
 # check_unfinished --- print a fatal error when an unfinished code or
 #			file chunk is detected. Also ifweave / iftangle.

 function check_unfinished()
 {
 	if (Flags["file chunk"])
 		fatal(_"unfinished file chunk (started at %s)\n",
 			Line_numbers["file chunk"])
 	else if (Flags["code chunk"])
 		fatal(_"unfinished code chunk (started at %s)\n",
 			Line_numbers["code chunk"])

 	if ("ifweave" in Line_numbers)
 		fatal(_"unfinished @ifweave section (started at %s)\n",
 			Line_numbers["ifweave"])

 	if ("iftangle" in Line_numbers)
 		fatal(_"unfinished @iftangle section (started at %s)\n",
 			Line_numbers["iftangle"])
 }
 # strip_out_name --- get the name from name

 function strip_out_name(name,	l)
 {
 	l = length(name)
 	name = substr(name, 3, l - 4)

 	return name
 }
 # Helper functions

 # message --- write a particular kind of message out to stderr

 function message(msg, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)
 {
 	printf("%s:%d: %s: " format, FILENAME, FNR, msg,
 		a1, a2, a3, a4, a5, a6, a7, a8, a9, a10) > "/dev/stderr"

 	if (substr(format, length(format), 1) != "\n")
 		printf("\n") > "/dev/stderr"
 }

 # fatal --- print a fatal error message and exit.
 #	 No varargs, so fake it with lots of parameters.

 function fatal(format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)
 {
 	message(_"fatal", format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)
 	exit 1
 }

 # warning --- print a warning message to stderr
 #	 No varargs, so fake it with lots of parameters.

 function warning(format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)
 {
 	message(_"warning", format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)
 }

 # join.awk --- join an array into a string
 #
 # Arnold Robbins, arnold@skeeve.com, Public Domain
 # May 1993

 function join(array, start, end, sep,    result, i)
 {
 	if (sep == "")
 		sep = " "
 	else if (sep == SUBSEP) # magic value
 		sep = ""
 	result = array[start]
 	for (i = start + 1; i <= end; i++)
 		result = result sep array[i]
 	return result
 }
 # ifweave lines should be removed

 /^@ifweave[[:space:]]*$/, /^@end ifweave[[:space:]]*$/ {
 	if ("iftangle" in Line_numbers)
 		fatal(_"cannot nest @ifweave inside @iftangle\n")

 	# start of construct, save line number
 	if (/^@ifweave[[:space:]]*$/)
 		Line_numbers["ifweave"] = (FILENAME ":" FNR)

 	# end of construct, delete line number
 	if (/^@end ifweave[[:space:]]*$/)
 		delete Line_numbers["ifweave"]

 	# simply skip these lines, this is tangling
 	next
 }

 # For tangling we remove the bracketing control lines and let anything
 # in between fall through.

 /^@iftangle[[:space:]]*$/, /^@end iftangle[[:space:]]*$/ {
 	if ("ifweave" in Line_numbers)
 		fatal(_"cannot nest @iftangle inside @ifweave\n")

 	# start of construct, save line number, skip this line
 	if (/^@iftangle[[:space:]]*$/) {
 		Line_numbers["iftangle"] = (FILENAME ":" FNR)
 		next
 	}

 	# end of construct, delete line number, skip this line
 	if (/^@end iftangle[[:space:]]*$/) {
 		delete Line_numbers["iftangle"]
 		next
 	}

 	# otherwise fall through into the rest of the code
 }
 /^@ignore/, /^@end ignore/ { next }
 $0 ~ Code_chunk_pattern {
 	Chunk_type = "code chunk"
 	Pattern = Code_chunk_pattern
 	Debug_pat = "code"
 	new_chunk = gensub(Pattern, "\\1", 1)
 	if (Flags[Chunk_type]) {
 		fatal(_"%s start of %s found while still collecting %s\n",
 			Chunk_type, new_chunk, Current_chunk)
 	}
 	check_unfinished()

 	Flags[Chunk_type] = TRUE
 	Line_numbers[Chunk_type] = (FILENAME ":" FNR)
 	Current_chunk = new_chunk
 	Chunk_info[Current_chunk]["type"] = Chunk_type

 	if (Debug ~ Debug_pat)
 		printf("saw new %s %s\n", Debug_pat, Current_chunk) > "/dev/stderr"
 	next
 }
 $0 ~ File_chunk_pattern {
 	Chunk_type = "file chunk"
 	Pattern = File_chunk_pattern
 	Debug_pat = "filename"
 	new_chunk = gensub(Pattern, "\\1", 1)
 	if (Flags[Chunk_type]) {
 		fatal(_"%s start of %s found while still collecting %s\n",
 			Chunk_type, new_chunk, Current_chunk)
 	}
 	check_unfinished()

 	Flags[Chunk_type] = TRUE
 	Line_numbers[Chunk_type] = (FILENAME ":" FNR)
 	Current_chunk = new_chunk
 	Chunk_info[Current_chunk]["type"] = Chunk_type

 	if (Debug ~ Debug_pat)
 		printf("saw new %s %s\n", Debug_pat, Current_chunk) > "/dev/stderr"
 	next
 }
 /^@[[:space:]]*$/ {
 	if (Flags["file chunk"])
 		end_file_gathering()
 	else if (Flags["code chunk"])
 		end_code_gathering()
 	else
 		warning(_"unmatched terminating @-sign: ignored\n")

 	Chunk_lines = ""
 	Flags[Chunk_type] = FALSE
 	Line_numbers[Chunk_type] = ""
 	Chunk_type = ""

 	next
 }
 Flags["file chunk"] || Flags["code chunk"] {
 	if (Chunk_lines == "")
 		Chunk_lines = $0
 	else
 		Chunk_lines = Chunk_lines "\n" $0

 	next
 }
 # end_file_gathering ---finish up collecting a file

 function end_file_gathering()
 {
 	if (Current_chunk in File_contents)
 		File_contents[Current_chunk] = \
 			File_contents[Current_chunk] "\n" Chunk_lines
 	else
 		File_contents[Current_chunk] = Chunk_lines

 	if (Debug ~ /filename/)
 		printf("finished collecting file %s\n",
 						Current_chunk) > "/dev/stderr"
 }
 # end_code_gathering --- complete collecting lines of the code chunk

 function end_code_gathering()
 {
 	if (Current_chunk in Code_contents)
 		Code_contents[Current_chunk] = \
 			Code_contents[Current_chunk] "\n" Chunk_lines
 	else
 		Code_contents[Current_chunk] = Chunk_lines

 	if (Debug ~ /code/)
 		printf("finished collecting %s\n",
 					Current_chunk) > "/dev/stderr"
 }
 # Finishing off code is easy, at least from 10,000 feet.

 END {
 	if (length(Initial_setup) > 0) {
 		Initial_setup = Initial_setup "\n"
 		system(Shell_debug Initial_setup)
 	}

 	dump_files()

 	if (Debug ~ /code/)
 		dump_chunks()
 }
 # dump_files --- create files and update them as needed

 function dump_files(	i, s, update_recipe)
 {
 	for (i in File_contents) {
 		s = expand_code_chunks(File_contents[i])

 		create_update_recipe(i, update_recipe)
 		printf("%s\n", s) > update_recipe["output"]
 		close(update_recipe["output"])

 		# update the file if necessary
 		update_recipe["recipe"] = (Shell_debug update_recipe["recipe"])
 		system(update_recipe["recipe"])

 		# run any "post create" command (such as changing mode)
 		if (i in Post_create_commands)
 			system(Shell_debug Post_create_commands[i])
 	}
 }
 # expand_code_chunks --- expand embedded code chunks.

 function expand_code_chunks(contents)
 {
 	delete Currently_expanding

 	return do_expand_code_chunks(contents)
 }
 # do_expand_code_chunks --- do the actual work to expand code chunks

 function do_expand_code_chunks(contents,
 								nlines, lines, results, i, j) # locals
 {
 	nlines = split(contents, lines, "\n")

 	for (i = 1; i <= nlines; i++) {
 		if (lines[i] !~ Chunk_name_pattern) {
 			results[i] = lines[i]
 		} else
 			results[i] = expand_one_line(lines[i])
 	}

 	return join(results, 1, nlines, "\n")
 }
 # expand_one_line --- expand a line with code chunk references

 function expand_one_line(input_line,	parts, chunk_names, nparts,
 										num_names, code_lines, i, j)
 {
 	nparts = split(input_line, parts, Chunk_name_pattern, chunk_names)
 	num_names = length(chunk_names)
 	# check for recursive expansion
 	for (i = 1; i <= num_names; i++) {
 		j = strip_out_name(chunk_names[i])

 		if (! (j in Code_contents))
 			fatal(_"expand_one_line: code chunk `%s' used but not defined\n",
 				chunk_names[i])

 		if (j in Currently_expanding)
 			fatal(_"expand_one_line: code chunk `%s' expands itself recursively\n",
 				chunk_names[i])
 		else
 			Currently_expanding[j] = TRUE
 	}
 	code_lines = code_body(chunk_names[1])
 	delete Currently_expanding[strip_out_name(chunk_names[1])]

 	if (input_line !~ ("^" Chunk_name_pattern)) {
 		if (parts[1] ~ /^[[:space:]]+$/) {
 			# insert leading white space on all lines to get indentation
 			gsub(/^|\n/, ("&" parts[1]), code_lines)
 		} else {
 			code_lines = parts[1] code_lines
 		}
 	}
 	for (i = 2; i <= nparts; i++) {
 		code_lines = code_lines parts[i]
 		if (i in chunk_names) {
 			code_lines = code_lines code_body(chunk_names[i])
 			delete Currently_expanding[strip_out_name(chunk_names[i])]
 		}
 	}

 	if (code_lines ~ Chunk_name_pattern) {
 		# get any further code chunks, recursively
 		return do_expand_code_chunks(code_lines)
 	} else
 		return code_lines
 }
 # code_body --- get the code body associated with name

 function code_body(name)
 {
 	return Code_contents[strip_out_name(name)]
 }
 /^@initial_setup[[:space:]]*$/, /^@end initial_setup[[:space:]]*$/ {
 	if (/^@initial_setup[[:space:]]*$/) {
 		# start of construct, save line number, skip this line
 		if ("initial_setup" in Line_numbers)
 			fatal(_"cannot nest one @initial_setup inside another\n")
 		Line_numbers["initial_setup"] = (FILENAME ":" FNR)
 		Initial_setup = ""
 	} else if (/^@end initial_setup[[:space:]]*$/) {
 		# end of construct, delete line number, skip this line
 		delete Line_numbers["initial_setup"]
 	} else
 		Initial_setup = Initial_setup "\n" $0

 	next
 }
 BEGIN {
 	# This condition should distinguish between the native and
 	# MSYS (POSIX-ish) Gawk.  We rely on the fact that MSYS mounts
 	# /tmp and sets $TEMP to point to it, but resets the value
 	# back to the native C:/Foo/Bar value when invoking native
 	# programs.
 	if (ENVIRON["TEMP"] ~ /^[A-Z]:[\\\/]/) {
 		# MS-Windows recipe
 		Update_recipe = \
 			"fc /B \"@DIR@\\@FILE@\" \"@DIR@\\@FILE@@SUFFIX@\" >nul 2>&1 || move /Y \"@DIR@\\@FILE@\" \"@DIR@\\@FILE@@SUFFIX@\" >nul"
 	} else {
 		# POSIX recipe
 		Update_recipe = \
 			"PATH=/bin:/usr/bin\n" \
 			"export PATH\n" \
 			"destname=\"@DIR@/@FILE@\"\n" \
 			"outname=\"${destname}@SUFFIX@\"\n" \
 			"if [ ! -f \"$destname\" ]\n" \
 			"then\n" \
 			"\tmv \"$outname\" \"$destname\"\n" \
 			"elif cmp -s \"$outname\" \"$destname\" > /dev/null\n" \
 			"then\n" \
 			"\trm \"$outname\"\n" \
 			"else\n" \
 			"\tmv \"$outname\" \"$destname\"\n" \
 			"fi\n"
 	}
 }
 /^@file_update_recipe[[:space:]]*$/,
 			/^@end file_update_recipe[[:space:]]*$/ {
 	if (/^@file_update_recipe[[:space:]]*$/) {
 		# start of construct, save line number, skip this line
 		if ("file_update_recipe" in Line_numbers)
 			fatal(_"cannot nest one @file_update_recipe inside another\n")
 		Line_numbers["file_update_recipe"] = (FILENAME ":" FNR)
 		Update_recipe = ""
 	} else if (/^@end file_update_recipe[[:space:]]*$/) {
 		# end of construct, delete line number, skip this line
 		delete Line_numbers["file_update_recipe"]
 	} else
 		Update_recipe = Update_recipe "\n" $0

 	next
 }
 BEGIN {
 	# @default is an unlikely name for a real file
 	Update_value["@default"]["DIR"] = "."	# current directory
 	Update_value["@default"]["SUFFIX"] = ".tangle_tmp"	# unlikely suffix
 	# No default for filename, jrtangle knows it!
 }
 /^@file_update[[:space:]]/ {
 	if (NF != 4)
 		fatal(_"usage: @file_update name dir suffix\n")

 	if ($4 == "\"\"")
 		$4 = ""
 	Update_value[$2]["DIR"] = $3
 	Update_value[$2]["SUFFIX"] = $4

 	next
 }
 # create_update_recipe --- create update recipe per file,
 #							return dest filename

 function create_update_recipe(file, results,
 							source_file, dir, suffix, recipe) # locals
 {
 	if (file in Update_value)
 		source_file = file
 	else
 		source_file = "@default"

 	dir = Update_value[source_file]["DIR"]
 	suffix = Update_value[source_file]["SUFFIX"]

 	delete results

 	recipe = Update_recipe
 	gsub(/@DIR@/, dir, recipe)
 	gsub(/@FILE@/, file, recipe)
 	gsub(/@SUFFIX@/, suffix, recipe)

 	results["recipe"] = recipe
 	results["output"] = (dir "/" file suffix)
 }
 BEGIN {
 	if (Debug ~ /shell/ && ENVIRON["TEMP"] !~ /^[A-Z]:[\\\/]/)
 		if (length(Shell_debug) == 0)
 			Shell_debug = "set -x; "
 }
 /^@post_create[[:space:]]+/ {
 	if (NF < 3)
 		fatal(_"usage: @post_create filename command\n")
 	check_unfinished()

 	name = $2
 	$1 = $2 = ""
 	$0 = $0
 	Post_create_commands[name] = $0
 }
 # dump_chunks --- print out all the chunks

 function dump_chunks(	i, format)
 {
 	format = "@<%s"
 	format = format "@>=\n%s@\n\n"
 	for (i in Code_contents)
 		printf(format, i, Code_contents[i]) > "/dev/stderr"
 }
	#! /usr/bin/gawk -f
	#
	# Copyright (C) 2013, 2014, 2015, 2016, 2019 Arnold David Robbins
	#
	# This file is part of TexiWeb Jr., a literate programming system.
	#
	# TexiWeb Jr. is free software; you can redistribute it and/or modify
	# it under the terms of the GNU General Public License as published by
	# the Free Software Foundation; either version 3 of the License, or
	# (at your option) any later version.
	#
	# TexiWeb Jr. is distributed in the hope that it will be useful,
	# but WITHOUT ANY WARRANTY; without even the implied warranty of
	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	# GNU General Public License for more details.
	#
	# You should have received a copy of the GNU General Public License
	# along with this program; if not, see <https://www.gnu.org/licenses/>.
	#
	# Up-to-date source code for TexiWeb Jr. can be obtained via
	# Git from github:
	#
	# git clone http://github.com/arnoldrobbins/texiwebjr
	#
	BEGIN {
	v[0] = 0
	if ("version" in PROCINFO) {
	match(PROCINFO["version"], /^[0-9]+\./, v);
	}

	if (v[0] < 4) {
	print("gawk >= 4.0 required") > "/dev/stderr"
	exit 63 # for "missing" script
	}
	}
	BEGIN {
	TRUE = 1
	FALSE = 0
	File_chunk_pattern = "^@\\(([^)]+)@\\)[[:space:]]=[[:space:]]$"
	Code_chunk_pattern = "^@" "<(.+)" "@>[[:space:]]=[[:space:]]$"
	Chunk_name_pattern = "@<[^>\n]+@>"
	}
	# Error checking:

	# Use brackets to avoid triggering the warning on ourselves!
	/(^<[@])\|(>[@]([[:space:]]=[[:space:]])?$)/ {
	# Ditto, with concatenation
	warning("<" "@ or >" "@ used instead of @" "< or @" ">\n\t%s\n",
	$0)
	}

	END {
	check_unfinished()
	}
	# check_unfinished --- print a fatal error when an unfinished code or
	# file chunk is detected. Also ifweave / iftangle.

	function check_unfinished()
	{
	if (Flags["file chunk"])
	fatal(_"unfinished file chunk (started at %s)\n",
	Line_numbers["file chunk"])
	else if (Flags["code chunk"])
	fatal(_"unfinished code chunk (started at %s)\n",
	Line_numbers["code chunk"])

	if ("ifweave" in Line_numbers)
	fatal(_"unfinished @ifweave section (started at %s)\n",
	Line_numbers["ifweave"])

	if ("iftangle" in Line_numbers)
	fatal(_"unfinished @iftangle section (started at %s)\n",
	Line_numbers["iftangle"])
	}
	# strip_out_name --- get the name from name

	function strip_out_name(name, l)
	{
	l = length(name)
	name = substr(name, 3, l - 4)

	return name
	}
	# Helper functions

	# message --- write a particular kind of message out to stderr

	function message(msg, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)
	{
	printf("%s:%d: %s: " format, FILENAME, FNR, msg,
	a1, a2, a3, a4, a5, a6, a7, a8, a9, a10) > "/dev/stderr"

	if (substr(format, length(format), 1) != "\n")
	printf("\n") > "/dev/stderr"
	}

	# fatal --- print a fatal error message and exit.
	# No varargs, so fake it with lots of parameters.

	function fatal(format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)
	{
	message(_"fatal", format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)
	exit 1
	}

	# warning --- print a warning message to stderr
	# No varargs, so fake it with lots of parameters.

	function warning(format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)
	{
	message(_"warning", format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)
	}

	# join.awk --- join an array into a string
	#
	# Arnold Robbins, arnold@skeeve.com, Public Domain
	# May 1993

	function join(array, start, end, sep, result, i)
	{
	if (sep == "")
	sep = " "
	else if (sep == SUBSEP) # magic value
	sep = ""
	result = array[start]
	for (i = start + 1; i <= end; i++)
	result = result sep array[i]
	return result
	}
	# ifweave lines should be removed

	/^@ifweave[[:space:]]$/, /^@end ifweave[[:space:]]$/ {
	if ("iftangle" in Line_numbers)
	fatal(_"cannot nest @ifweave inside @iftangle\n")

	# start of construct, save line number
	if (/^@ifweave[[:space:]]*$/)
	Line_numbers["ifweave"] = (FILENAME ":" FNR)

	# end of construct, delete line number
	if (/^@end ifweave[[:space:]]*$/)
	delete Line_numbers["ifweave"]

	# simply skip these lines, this is tangling
	next
	}

	# For tangling we remove the bracketing control lines and let anything
	# in between fall through.

	/^@iftangle[[:space:]]$/, /^@end iftangle[[:space:]]$/ {
	if ("ifweave" in Line_numbers)
	fatal(_"cannot nest @iftangle inside @ifweave\n")

	# start of construct, save line number, skip this line
	if (/^@iftangle[[:space:]]*$/) {
	Line_numbers["iftangle"] = (FILENAME ":" FNR)
	next
	}

	# end of construct, delete line number, skip this line
	if (/^@end iftangle[[:space:]]*$/) {
	delete Line_numbers["iftangle"]
	next
	}

	# otherwise fall through into the rest of the code
	}
	/^@ignore/, /^@end ignore/ { next }
	$0 ~ Code_chunk_pattern {
	Chunk_type = "code chunk"
	Pattern = Code_chunk_pattern
	Debug_pat = "code"
	new_chunk = gensub(Pattern, "\\1", 1)
	if (Flags[Chunk_type]) {
	fatal(_"%s start of %s found while still collecting %s\n",
	Chunk_type, new_chunk, Current_chunk)
	}
	check_unfinished()

	Flags[Chunk_type] = TRUE
	Line_numbers[Chunk_type] = (FILENAME ":" FNR)
	Current_chunk = new_chunk
	Chunk_info[Current_chunk]["type"] = Chunk_type

	if (Debug ~ Debug_pat)
	printf("saw new %s %s\n", Debug_pat, Current_chunk) > "/dev/stderr"
	next
	}
	$0 ~ File_chunk_pattern {
	Chunk_type = "file chunk"
	Pattern = File_chunk_pattern
	Debug_pat = "filename"
	new_chunk = gensub(Pattern, "\\1", 1)
	if (Flags[Chunk_type]) {
	fatal(_"%s start of %s found while still collecting %s\n",
	Chunk_type, new_chunk, Current_chunk)
	}
	check_unfinished()

	Flags[Chunk_type] = TRUE
	Line_numbers[Chunk_type] = (FILENAME ":" FNR)
	Current_chunk = new_chunk
	Chunk_info[Current_chunk]["type"] = Chunk_type

	if (Debug ~ Debug_pat)
	printf("saw new %s %s\n", Debug_pat, Current_chunk) > "/dev/stderr"
	next
	}
	/^@[[:space:]]*$/ {
	if (Flags["file chunk"])
	end_file_gathering()
	else if (Flags["code chunk"])
	end_code_gathering()
	else
	warning(_"unmatched terminating @-sign: ignored\n")

	Chunk_lines = ""
	Flags[Chunk_type] = FALSE
	Line_numbers[Chunk_type] = ""
	Chunk_type = ""

	next
	}
	Flags["file chunk"] \|\| Flags["code chunk"] {
	if (Chunk_lines == "")
	Chunk_lines = $0
	else
	Chunk_lines = Chunk_lines "\n" $0

	next
	}
	# end_file_gathering ---finish up collecting a file

	function end_file_gathering()
	{
	if (Current_chunk in File_contents)
	File_contents[Current_chunk] = \
	File_contents[Current_chunk] "\n" Chunk_lines
	else
	File_contents[Current_chunk] = Chunk_lines

	if (Debug ~ /filename/)
	printf("finished collecting file %s\n",
	Current_chunk) > "/dev/stderr"
	}
	# end_code_gathering --- complete collecting lines of the code chunk

	function end_code_gathering()
	{
	if (Current_chunk in Code_contents)
	Code_contents[Current_chunk] = \
	Code_contents[Current_chunk] "\n" Chunk_lines
	else
	Code_contents[Current_chunk] = Chunk_lines

	if (Debug ~ /code/)
	printf("finished collecting %s\n",
	Current_chunk) > "/dev/stderr"
	}
	# Finishing off code is easy, at least from 10,000 feet.

	END {
	if (length(Initial_setup) > 0) {
	Initial_setup = Initial_setup "\n"
	system(Shell_debug Initial_setup)
	}

	dump_files()

	if (Debug ~ /code/)
	dump_chunks()
	}
	# dump_files --- create files and update them as needed

	function dump_files( i, s, update_recipe)
	{
	for (i in File_contents) {
	s = expand_code_chunks(File_contents[i])

	create_update_recipe(i, update_recipe)
	printf("%s\n", s) > update_recipe["output"]
	close(update_recipe["output"])

	# update the file if necessary
	update_recipe["recipe"] = (Shell_debug update_recipe["recipe"])
	system(update_recipe["recipe"])

	# run any "post create" command (such as changing mode)
	if (i in Post_create_commands)
	system(Shell_debug Post_create_commands[i])
	}
	}
	# expand_code_chunks --- expand embedded code chunks.

	function expand_code_chunks(contents)
	{
	delete Currently_expanding

	return do_expand_code_chunks(contents)
	}
	# do_expand_code_chunks --- do the actual work to expand code chunks

	function do_expand_code_chunks(contents,
	nlines, lines, results, i, j) # locals
	{
	nlines = split(contents, lines, "\n")

	for (i = 1; i <= nlines; i++) {
	if (lines[i] !~ Chunk_name_pattern) {
	results[i] = lines[i]
	} else
	results[i] = expand_one_line(lines[i])
	}

	return join(results, 1, nlines, "\n")
	}
	# expand_one_line --- expand a line with code chunk references

	function expand_one_line(input_line, parts, chunk_names, nparts,
	num_names, code_lines, i, j)
	{
	nparts = split(input_line, parts, Chunk_name_pattern, chunk_names)
	num_names = length(chunk_names)
	# check for recursive expansion
	for (i = 1; i <= num_names; i++) {
	j = strip_out_name(chunk_names[i])

	if (! (j in Code_contents))
	fatal(_"expand_one_line: code chunk `%s' used but not defined\n",
	chunk_names[i])

	if (j in Currently_expanding)
	fatal(_"expand_one_line: code chunk `%s' expands itself recursively\n",
	chunk_names[i])
	else
	Currently_expanding[j] = TRUE
	}
	code_lines = code_body(chunk_names[1])
	delete Currently_expanding[strip_out_name(chunk_names[1])]

	if (input_line !~ ("^" Chunk_name_pattern)) {
	if (parts[1] ~ /^[[:space:]]+$/) {
	# insert leading white space on all lines to get indentation
	gsub(/^\|\n/, ("&" parts[1]), code_lines)
	} else {
	code_lines = parts[1] code_lines
	}
	}
	for (i = 2; i <= nparts; i++) {
	code_lines = code_lines parts[i]
	if (i in chunk_names) {
	code_lines = code_lines code_body(chunk_names[i])
	delete Currently_expanding[strip_out_name(chunk_names[i])]
	}
	}

	if (code_lines ~ Chunk_name_pattern) {
	# get any further code chunks, recursively
	return do_expand_code_chunks(code_lines)
	} else
	return code_lines
	}
	# code_body --- get the code body associated with name

	function code_body(name)
	{
	return Code_contents[strip_out_name(name)]
	}
	/^@initial_setup[[:space:]]$/, /^@end initial_setup[[:space:]]$/ {
	if (/^@initial_setup[[:space:]]*$/) {
	# start of construct, save line number, skip this line
	if ("initial_setup" in Line_numbers)
	fatal(_"cannot nest one @initial_setup inside another\n")
	Line_numbers["initial_setup"] = (FILENAME ":" FNR)
	Initial_setup = ""
	} else if (/^@end initial_setup[[:space:]]*$/) {
	# end of construct, delete line number, skip this line
	delete Line_numbers["initial_setup"]
	} else
	Initial_setup = Initial_setup "\n" $0

	next
	}
	BEGIN {
	# This condition should distinguish between the native and
	# MSYS (POSIX-ish) Gawk. We rely on the fact that MSYS mounts
	# /tmp and sets $TEMP to point to it, but resets the value
	# back to the native C:/Foo/Bar value when invoking native
	# programs.
	if (ENVIRON["TEMP"] ~ /^[A-Z]:[\\\/]/) {
	# MS-Windows recipe
	Update_recipe = \
	"fc /B \"@DIR@\\@FILE@\" \"@DIR@\\@FILE@@SUFFIX@\" >nul 2>&1 \|\| move /Y \"@DIR@\\@FILE@\" \"@DIR@\\@FILE@@SUFFIX@\" >nul"
	} else {
	# POSIX recipe
	Update_recipe = \
	"PATH=/bin:/usr/bin\n" \
	"export PATH\n" \
	"destname=\"@DIR@/@FILE@\"\n" \
	"outname=\"${destname}@SUFFIX@\"\n" \
	"if [ ! -f \"$destname\" ]\n" \
	"then\n" \
	"\tmv \"$outname\" \"$destname\"\n" \
	"elif cmp -s \"$outname\" \"$destname\" > /dev/null\n" \
	"then\n" \
	"\trm \"$outname\"\n" \
	"else\n" \
	"\tmv \"$outname\" \"$destname\"\n" \
	"fi\n"
	}
	}
	/^@file_update_recipe[[:space:]]*$/,
	/^@end file_update_recipe[[:space:]]*$/ {
	if (/^@file_update_recipe[[:space:]]*$/) {
	# start of construct, save line number, skip this line
	if ("file_update_recipe" in Line_numbers)
	fatal(_"cannot nest one @file_update_recipe inside another\n")
	Line_numbers["file_update_recipe"] = (FILENAME ":" FNR)
	Update_recipe = ""
	} else if (/^@end file_update_recipe[[:space:]]*$/) {
	# end of construct, delete line number, skip this line
	delete Line_numbers["file_update_recipe"]
	} else
	Update_recipe = Update_recipe "\n" $0

	next
	}
	BEGIN {
	# @default is an unlikely name for a real file
	Update_value["@default"]["DIR"] = "." # current directory
	Update_value["@default"]["SUFFIX"] = ".tangle_tmp" # unlikely suffix
	# No default for filename, jrtangle knows it!
	}
	/^@file_update[[:space:]]/ {
	if (NF != 4)
	fatal(_"usage: @file_update name dir suffix\n")

	if ($4 == "\"\"")
	$4 = ""
	Update_value[$2]["DIR"] = $3
	Update_value[$2]["SUFFIX"] = $4

	next
	}
	# create_update_recipe --- create update recipe per file,
	# return dest filename

	function create_update_recipe(file, results,
	source_file, dir, suffix, recipe) # locals
	{
	if (file in Update_value)
	source_file = file
	else
	source_file = "@default"

	dir = Update_value[source_file]["DIR"]
	suffix = Update_value[source_file]["SUFFIX"]

	delete results

	recipe = Update_recipe
	gsub(/@DIR@/, dir, recipe)
	gsub(/@FILE@/, file, recipe)
	gsub(/@SUFFIX@/, suffix, recipe)

	results["recipe"] = recipe
	results["output"] = (dir "/" file suffix)
	}
	BEGIN {
	if (Debug ~ /shell/ && ENVIRON["TEMP"] !~ /^[A-Z]:[\\\/]/)
	if (length(Shell_debug) == 0)
	Shell_debug = "set -x; "
	}
	/^@post_create[[:space:]]+/ {
	if (NF < 3)
	fatal(_"usage: @post_create filename command\n")
	check_unfinished()

	name = $2
	$1 = $2 = ""
	$0 = $0
	Post_create_commands[name] = $0
	}
	# dump_chunks --- print out all the chunks

	function dump_chunks( i, format)
	{
	format = "@<%s"
	format = format "@>=\n%s@\n\n"
	for (i in Code_contents)
	printf(format, i, Code_contents[i]) > "/dev/stderr"
	}