draft-ietf-netmod-artwork-folding-08.txt		draft-ietf-netmod-artwork-folding-09.txt
	NETMOD Working Group K. Watsen		NETMOD Working Group K. Watsen
	Internet-Draft Watsen Networks		Internet-Draft Watsen Networks
	Intended status: Best Current Practice A. Farrel		Intended status: Best Current Practice A. Farrel
	Expires: February 3, 2020 Old Dog Consulting		Expires: March 1, 2020 Old Dog Consulting
	Q. Wu		Q. Wu
	Huawei Technologies		Huawei Technologies
	August 2, 2019		August 29, 2019
	Handling Long Lines in Inclusions in Internet-Drafts and RFCs		Handling Long Lines in Inclusions in Internet-Drafts and RFCs
	draft-ietf-netmod-artwork-folding-08		draft-ietf-netmod-artwork-folding-09
	Abstract		Abstract
	This document defines two strategies for handling long lines in		This document defines two strategies for handling long lines in
	width-bounded text content. One strategy is based on the historic		width-bounded text content. One strategy is based on the historic
	use of a single backslash ('\') character to indicate where line-		use of a single backslash ('\') character to indicate where line-
	folding has occurred, with the continuation occurring with the first		folding has occurred, with the continuation occurring with the first
	non-space (' ') character on the next line. The second strategy		non-space (' ') character on the next line. The second strategy
	extends the first strategy by adding a second backslash character to		extends the first strategy by adding a second backslash character to
	identify where the continuation begins and thereby able to handle		identify where the continuation begins and thereby able to handle
	skipping to change at page 1, line 42 ¶		skipping to change at page 1, line 42 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on February 3, 2020.		This Internet-Draft will expire on March 1, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2019 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 31 ¶		skipping to change at page 2, line 31 ¶
	4.1. Automated Folding of Long Lines in Text Content . . . . . 4		4.1. Automated Folding of Long Lines in Text Content . . . . . 4
	4.2. Automated Reconstitution of the Original Text Content . . 5		4.2. Automated Reconstitution of the Original Text Content . . 5
	5. Limitations . . . . . . . . . . . . . . . . . . . . . . . . . 5		5. Limitations . . . . . . . . . . . . . . . . . . . . . . . . . 5
	5.1. Not Recommended for Graphical Artwork . . . . . . . . . . 5		5.1. Not Recommended for Graphical Artwork . . . . . . . . . . 5
	5.2. Doesn't Work as Well as Format-Specific Options . . . . . 5		5.2. Doesn't Work as Well as Format-Specific Options . . . . . 5
	6. Two Folding Strategies . . . . . . . . . . . . . . . . . . . 6		6. Two Folding Strategies . . . . . . . . . . . . . . . . . . . 6
	6.1. Comparison . . . . . . . . . . . . . . . . . . . . . . . 6		6.1. Comparison . . . . . . . . . . . . . . . . . . . . . . . 6
	6.2. Recommendation . . . . . . . . . . . . . . . . . . . . . 6		6.2. Recommendation . . . . . . . . . . . . . . . . . . . . . 6
	7. The Single Backslash Strategy ('\') . . . . . . . . . . . . . 6		7. The Single Backslash Strategy ('\') . . . . . . . . . . . . . 6
	7.1. Folded Structure . . . . . . . . . . . . . . . . . . . . 6		7.1. Folded Structure . . . . . . . . . . . . . . . . . . . . 6
	7.1.1. Header . . . . . . . . . . . . . . . . . . . . . . . 7		7.1.1. Header . . . . . . . . . . . . . . . . . . . . . . . 6
	7.1.2. Body . . . . . . . . . . . . . . . . . . . . . . . . 7		7.1.2. Body . . . . . . . . . . . . . . . . . . . . . . . . 7
	7.2. Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 7		7.2. Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 7
	7.2.1. Folding . . . . . . . . . . . . . . . . . . . . . . . 7		7.2.1. Folding . . . . . . . . . . . . . . . . . . . . . . . 7
	7.2.2. Unfolding . . . . . . . . . . . . . . . . . . . . . . 9		7.2.2. Unfolding . . . . . . . . . . . . . . . . . . . . . . 9
	8. The Double Backslash Strategy ('\\') . . . . . . . . . . . . 9		8. The Double Backslash Strategy ('\\') . . . . . . . . . . . . 9
	8.1. Folded Structure . . . . . . . . . . . . . . . . . . . . 9		8.1. Folded Structure . . . . . . . . . . . . . . . . . . . . 9
	8.1.1. Header . . . . . . . . . . . . . . . . . . . . . . . 9		8.1.1. Header . . . . . . . . . . . . . . . . . . . . . . . 9
	8.1.2. Body . . . . . . . . . . . . . . . . . . . . . . . . 10		8.1.2. Body . . . . . . . . . . . . . . . . . . . . . . . . 10
	8.2. Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 10		8.2. Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 10
	8.2.1. Folding . . . . . . . . . . . . . . . . . . . . . . . 10		8.2.1. Folding . . . . . . . . . . . . . . . . . . . . . . . 10
	skipping to change at page 3, line 13 ¶		skipping to change at page 3, line 13 ¶
	9.3.2. Using '\\' . . . . . . . . . . . . . . . . . . . . . 15		9.3.2. Using '\\' . . . . . . . . . . . . . . . . . . . . . 15
	9.4. Example Showing "Forced" Folding . . . . . . . . . . . . 16		9.4. Example Showing "Forced" Folding . . . . . . . . . . . . 16
	9.4.1. Using '\' . . . . . . . . . . . . . . . . . . . . . . 17		9.4.1. Using '\' . . . . . . . . . . . . . . . . . . . . . . 17
	9.4.2. Using '\\' . . . . . . . . . . . . . . . . . . . . . 17		9.4.2. Using '\\' . . . . . . . . . . . . . . . . . . . . . 17
	10. Security Considerations . . . . . . . . . . . . . . . . . . . 17		10. Security Considerations . . . . . . . . . . . . . . . . . . . 17
	11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18		11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
	12. References . . . . . . . . . . . . . . . . . . . . . . . . . 18		12. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
	12.1. Normative References . . . . . . . . . . . . . . . . . . 18		12.1. Normative References . . . . . . . . . . . . . . . . . . 18
	12.2. Informative References . . . . . . . . . . . . . . . . . 18		12.2. Informative References . . . . . . . . . . . . . . . . . 18
	Appendix A. POSIX Shell Script: rfcfold . . . . . . . . . . . . 19		Appendix A. POSIX Shell Script: rfcfold . . . . . . . . . . . . 20
	Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 28		Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 29
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29
	1. Introduction		1. Introduction
	[RFC7994] sets out the requirements for plain-text RFCs and states		[RFC7994] sets out the requirements for plain-text RFCs and states
	that each line of an RFC (and hence of an Internet-Draft) must be		that each line of an RFC (and hence of an Internet-Draft) must be
	limited to 72 characters followed by the character sequence that		limited to 72 characters followed by the character sequence that
	denotes an end-of-line (EOL).		denotes an end-of-line (EOL).
	Internet-Drafts and RFCs often include example text or code		Internet-Drafts and RFCs often include example text or code
	fragments. Many times the example text or code exceeds the 72		fragments. Many times the example text or code exceeds the 72
	skipping to change at page 4, line 48 ¶		skipping to change at page 4, line 48 ¶
	Generally, in order for tooling to be able to process input files,		Generally, in order for tooling to be able to process input files,
	the files must be in their original/natural state, which may entail		the files must be in their original/natural state, which may entail
	them having some long lines. Thus, these source files need to be		them having some long lines. Thus, these source files need to be
	modified before inclusion in the document in order to satisfy the		modified before inclusion in the document in order to satisfy the
	line length limits. This modification SHOULD be automated to reduce		line length limits. This modification SHOULD be automated to reduce
	effort and errors resulting from manual processing.		effort and errors resulting from manual processing.
	Similarly, dynamically generated output (e.g., tree diagrams) must		Similarly, dynamically generated output (e.g., tree diagrams) must
	also be modified, if necessary, in order for the resulting document		also be modified, if necessary, in order for the resulting document
	to satisfy the line length limits. When needed, this effort again		to satisfy the line length limits. This work should also be
	SHOULD be automated to reduce effort and errors resulting from manual		automated to reduce effort and errors resulting from manual
	processing.		processing.
	4.2. Automated Reconstitution of the Original Text Content		4.2. Automated Reconstitution of the Original Text Content
	Automated reconstitution of the exact original text content is needed		Automated reconstitution of the exact original text content is needed
	to support validation of text-based content extracted from documents.		to support validation of text-based content extracted from documents.
	For instance, already YANG [RFC7950] modules are extracted from		For instance, already YANG [RFC7950] modules are extracted from
	Internet-Drafts and validated as part of the draft-submission		Internet-Drafts and validated as part of the draft-submission
	process. Additionally, the desire to validate instance examples		process. Additionally, the desire to validate instance examples
	skipping to change at page 5, line 40 ¶		skipping to change at page 5, line 40 ¶
	It is NOT RECOMMENDED to use the solution presented in this document		It is NOT RECOMMENDED to use the solution presented in this document
	on graphical artwork.		on graphical artwork.
	5.2. Doesn't Work as Well as Format-Specific Options		5.2. Doesn't Work as Well as Format-Specific Options
	The solution presented in this document works generically for all		The solution presented in this document works generically for all
	text-based content, as it only views content as plain text. However,		text-based content, as it only views content as plain text. However,
	various formats sometimes have built-in mechanisms that are better		various formats sometimes have built-in mechanisms that are better
	suited to prevent long lines.		suited to prevent long lines.
	For instance, both the `pyang` and `yanglint` utilities have the		For instance, both the `pyang` [pyang] and `yanglint` [yanglint]
	command line option "--tree-line-length" that can be used to indicate		utilities have the command line option "--tree-line-length" that can
	a desired maximum line length for when generating tree diagrams		be used to indicate a desired maximum line length for when generating
	[RFC8340].		tree diagrams [RFC8340].
	In another example, some source formats (e.g., YANG [RFC7950]) allow		In another example, some source formats (e.g., YANG [RFC7950]) allow
	any quoted string to be broken up into substrings separated by a		any quoted string to be broken up into substrings separated by a
	concatenation character (e.g., '+'), any of which can be on a		concatenation character (e.g., '+'), any of which can be on a
	different line.		different line.
	It is RECOMMENDED that authors do as much as possible within the		It is RECOMMENDED that authors do as much as possible within the
	selected format to avoid long lines.		selected format to avoid long lines.
	6. Two Folding Strategies		6. Two Folding Strategies
	This document defines two nearly identical strategies for folding		This document defines two nearly identical strategies for folding
	text-based content.		text-based content.
	The Single Backslash Strategy ('\'): Uses a backslash ('\')		The Single Backslash Strategy ('\'): Uses a backslash ('\')
	character at the end of the line where folding occurs, and		character at the end of the line where folding occurs, and
	assumes that the continuation begins at the character that is		assumes that the continuation begins at the first character
	not a space character (' ') on the following line.		that is not a space character (' ') on the following line.
	The Double Backslash Strategy ('\\'): Uses a backslash ('\')		The Double Backslash Strategy ('\\'): Uses a backslash ('\')
	character at the end of the line where folding occurs, and		character at the end of the line where folding occurs, and
	assumes that the continuation begins after a second backslash		assumes that the continuation begins after a second backslash
	('\') character on the following line.		('\') character on the following line.
	6.1. Comparison		6.1. Comparison
	The first strategy produces more readable output, however it is		The first strategy produces more readable output, however it is
	significantly more likely to encounter unfoldable input (e.g., there		significantly more likely to encounter unfoldable input (e.g., a long
	exists a line anywhere in the input ending with a backslash		line containing only space characters) and, for long lines that can
	character, or there exists a long line containing only space		be folded, automation implementations may encounter scenarios that
	characters) and, for long lines that can be folded, automation		will produce errors without special care.
	implementations may encounter scenarios that will produce errors
	without special care.
	The second strategy produces less readable output, but is unlikely to		The second strategy produces less readable output, but is unlikely to
	encounter unfoldable input, there are no long lines that cannot be		encounter unfoldable input, there are no long lines that cannot be
	folded, and no special care is required for when folding a long line.		folded, and no special care is required for when folding a long line.
	6.2. Recommendation		6.2. Recommendation
	It is RECOMMENDED for implementations to first attempt to fold		It is RECOMMENDED for implementations to first attempt to fold
	content using the single backslash strategy and, only in the unlikely		content using the single backslash strategy and, only in the unlikely
	event that it cannot fold the input or the folding logic is unable to		event that it cannot fold the input or the folding logic is unable to
	skipping to change at page 7, line 9 ¶		skipping to change at page 7, line 5 ¶
	7.1. Folded Structure		7.1. Folded Structure
	Text content that has been folded as specified by this strategy MUST		Text content that has been folded as specified by this strategy MUST
	adhere to the following structure.		adhere to the following structure.
	7.1.1. Header		7.1.1. Header
	The header is two lines long.		The header is two lines long.
	The first line is the following 45-character string that MAY be		The first line is the following 46-character string that MAY be
	surrounded by any number of printable characters. This first line		surrounded by any number of printable characters. This first line
	cannot itself be folded.		cannot itself be folded.
	NOTE: '\' line wrapping per BCP XX (RFC XXXX)		NOTE: '\' line wrapping per BCP XXX (RFC XXXX)
	[Note to RFC Editor: Please replace XX and XXXX with the numbers		[Note to RFC Editor: Please replace XXX and XXXX with the numbers
	assigned to this document and delete this note. Please make this		assigned to this document and delete this note. Please make this
	change in multiple places in this document.]		change in multiple places in this document.]
	The second line is a blank line. This line provides visual		The second line is a empty line, containing only the end-of-line
	separation for readability.		character sequence. This line provides visual separation for
			readability.
	7.1.2. Body		7.1.2. Body
	The character encoding is the same as described in Section 2 of		The character encoding is the same as described in Section 2 of
	[RFC7994], except that, per [RFC7991], tab characters are prohibited.		[RFC7994], except that, per [RFC7991], tab characters are prohibited.
	Lines that have a backslash ('\') occurring as the last character in		Lines that have a backslash ('\') occurring as the last character in
	a line are considered "folded".		a line are considered "folded".
	Really long lines may be folded multiple times.		Really long lines may be folded multiple times.
	skipping to change at page 8, line 6 ¶		skipping to change at page 7, line 50 ¶
	document prior to utilizing the algorithms described in this section.		document prior to utilizing the algorithms described in this section.
	For example, the `xiax` utility [xiax] does this.		For example, the `xiax` utility [xiax] does this.
	7.2.1. Folding		7.2.1. Folding
	Determine the desired maximum line length from input to the line-		Determine the desired maximum line length from input to the line-
	wrapping process, such as from a command line parameter. If no value		wrapping process, such as from a command line parameter. If no value
	is explicitly specified, the value "69" SHOULD be used.		is explicitly specified, the value "69" SHOULD be used.
	Ensure that the desired maximum line length is not less than the		Ensure that the desired maximum line length is not less than the
	minimum header, which is 45 characters. If the desired maximum line		minimum header, which is 46 characters. If the desired maximum line
	length is less than this minimum, exit (this text-based content		length is less than this minimum, exit (this text-based content
	cannot be folded).		cannot be folded).
	Scan the text content for horizontal tab characters. If any		Scan the text content for horizontal tab characters. If any
	horizontal tab characters appear, either resolve them to space		horizontal tab characters appear, either resolve them to space
	characters or exit, forcing the input provider to convert them to		characters or exit, forcing the input provider to convert them to
	space characters themselves first.		space characters themselves first.
	Scan the text content to ensure at least one line exceeds the desired		Scan the text content to ensure at least one line exceeds the desired
	maximum. If no line exceeds the desired maximum, exit (this text		maximum. If no line exceeds the desired maximum, exit (this text
	content does not need to be folded).		content does not need to be folded).
	Scan the text content to ensure no existing lines already end with a		Scan the text content to ensure no existing lines already end with a
	backslash ('\') character, as this would lead to an ambiguous result.		backslash ('\') character, as this could lead to an ambiguous result.
	If such a line is found, and its width is less than the desired		If such a line is found, and its width is less than the desired
	maximum, then it SHOULD be flagged for forced folding (folding even		maximum, then it SHOULD be flagged for forced folding (folding even
	though unnecessary). If the folding implementation doesn't support		though unnecessary). If the folding implementation doesn't support
	forced foldings, it MUST exit.		forced foldings, it MUST exit.
	If this text content needs to and can be folded, insert the header		If this text content needs to and can be folded, insert the header
	described in Section 7.1.1, ensuring that any additional printable		described in Section 7.1.1, ensuring that any additional printable
	characters surrounding the header does not result in a line exceeding		characters surrounding the header do not result in a line exceeding
	the desired maximum.		the desired maximum.
	For each line in the text content, from top-to-bottom, if the line		For each line in the text content, from top-to-bottom, if the line
	exceeds the desired maximum, or requires a forced folding, then fold		exceeds the desired maximum, or requires a forced folding, then fold
	the line by:		the line by:
	1. Determine where the fold will occur. This location MUST be		1. Determine where the fold will occur. This location MUST be
	before or at the desired maximum column, and MUST NOT be chosen		before or at the desired maximum column, and MUST NOT be chosen
	such that the character immediately after the fold is a space ('		such that the character immediately after the fold is a space ('
	') character. If no such location can be found, then exit (this		') character. For forced foldings, the location is between the
	text content cannot be folded).		'\' and the end of line sequence. If no such location can be
			found, then exit (this text content cannot be folded).
	2. At the location where the fold is to occur, insert a backslash		2. At the location where the fold is to occur, insert a backslash
	('\') character followed by the end of line character sequence.		('\') character followed by the end of line character sequence.
	3. On the following line, insert any number of space (' ')		3. On the following line, insert any number of space (' ')
	characters.		characters.
	The result of the previous operation is that the next line starts		The result of the previous operation is that the next line starts
	with an arbitrary number of space (' ') characters, followed by the		with an arbitrary number of space (' ') characters, followed by the
	character that was previously occupying the position where the fold		character that was previously occupying the position where the fold
	skipping to change at page 9, line 46 ¶		skipping to change at page 9, line 41 ¶
	8.1. Folded Structure		8.1. Folded Structure
	Text content that has been folded as specified by this strategy MUST		Text content that has been folded as specified by this strategy MUST
	adhere to the following structure.		adhere to the following structure.
	8.1.1. Header		8.1.1. Header
	The header is two lines long.		The header is two lines long.
	The first line is the following 46-character string that MAY be		The first line is the following 47-character string that MAY be
	surrounded by any number of printable characters. This first line		surrounded by any number of printable characters. This first line
	cannot itself be folded.		cannot itself be folded.
	NOTE: '\\' line wrapping per BCP XX (RFC XXXX)		NOTE: '\\' line wrapping per BCP XXX (RFC XXXX)
	[Note to RFC Editor: Please replace XX and XXXX with the numbers		[Note to RFC Editor: Please replace XXX and XXXX with the numbers
	assigned to this document and delete this note. Please make this		assigned to this document and delete this note. Please make this
	change in multiple places in this document.]		change in multiple places in this document.]
			The second line is a empty line, containing only the end-of-line
	The second line is a blank line. This line provides visual		character sequence. This line provides visual separation for
	separation for readability.		readability.
	8.1.2. Body		8.1.2. Body
	The character encoding is the same as described in Section 2 of		The character encoding is the same as described in Section 2 of
	[RFC7994], except that, per [RFC7991], tab characters are prohibited.		[RFC7994], except that, per [RFC7991], tab characters are prohibited.
	Lines that have a backslash ('\') occurring as the last character in		Lines that have a backslash ('\') occurring as the last character in
	a line immediately followed by the end of line character sequence,		a line immediately followed by the end of line character sequence,
	when the subsequent line starts with a backslash ('\') as the first		when the subsequent line starts with a backslash ('\') as the first
	non-space (' ') character, are considered "folded".		non-space (' ') character, are considered "folded".
	skipping to change at page 10, line 47 ¶		skipping to change at page 10, line 41 ¶
	document prior to utilizing the algorithms described in this section.		document prior to utilizing the algorithms described in this section.
	For example, the `xiax` utility [xiax] does this.		For example, the `xiax` utility [xiax] does this.
	8.2.1. Folding		8.2.1. Folding
	Determine the desired maximum line length from input to the line-		Determine the desired maximum line length from input to the line-
	wrapping process, such as from a command line parameter. If no value		wrapping process, such as from a command line parameter. If no value
	is explicitly specified, the value "69" SHOULD be used.		is explicitly specified, the value "69" SHOULD be used.
	Ensure that the desired maximum line length is not less than the		Ensure that the desired maximum line length is not less than the
	minimum header, which is 46 characters. If the desired maximum line		minimum header, which is 47 characters. If the desired maximum line
	length is less than this minimum, exit (this text-based content		length is less than this minimum, exit (this text-based content
	cannot be folded).		cannot be folded).
	Scan the text content for horizontal tab characters. If any		Scan the text content for horizontal tab characters. If any
	horizontal tab characters appear, either resolve them to space		horizontal tab characters appear, either resolve them to space
	characters or exit, forcing the input provider to convert them to		characters or exit, forcing the input provider to convert them to
	space characters themselves first.		space characters themselves first.
	Scan the text content to see if any line exceeds the desired maximum.		Scan the text content to see if any line exceeds the desired maximum.
	If no line exceeds the desired maximum, exit (this text content does		If no line exceeds the desired maximum, exit (this text content does
	skipping to change at page 11, line 21 ¶		skipping to change at page 11, line 19 ¶
	Scan the text content to ensure no existing lines already end with a		Scan the text content to ensure no existing lines already end with a
	backslash ('\') character while the subsequent line starts with a		backslash ('\') character while the subsequent line starts with a
	backslash ('\') character as the first non-space (' ') character, as		backslash ('\') character as the first non-space (' ') character, as
	this could lead to an ambiguous result. If such a line is found, and		this could lead to an ambiguous result. If such a line is found, and
	its width is less than the desired maximum, then it SHOULD be flagged		its width is less than the desired maximum, then it SHOULD be flagged
	for forced folding (folding even though unnecessary). If the folding		for forced folding (folding even though unnecessary). If the folding
	implementation doesn't support forced foldings, it MUST exit.		implementation doesn't support forced foldings, it MUST exit.
	If this text content needs to and can be folded, insert the header		If this text content needs to and can be folded, insert the header
	described in Section 8.1.1, ensuring that any additional printable		described in Section 8.1.1, ensuring that any additional printable
	characters surrounding the header does not result in a line exceeding		characters surrounding the header do not result in a line exceeding
	the desired maximum.		the desired maximum.
	For each line in the text content, from top-to-bottom, if the line		For each line in the text content, from top-to-bottom, if the line
	exceeds the desired maximum, or requires a forced folding, then fold		exceeds the desired maximum, or requires a forced folding, then fold
	the line by:		the line by:
	1. Determine where the fold will occur. This location MUST be		1. Determine where the fold will occur. This location MUST be
	before or at the desired maximum column.		before or at the desired maximum column. For forced foldings,
			the location is between the '\' and the end of line sequence on
			the first line.
	2. At the location where the fold is to occur, insert a first		2. At the location where the fold is to occur, insert a first
	backslash ('\') character followed by the end of line character		backslash ('\') character followed by the end of line character
	sequence.		sequence.
	3. On the following line, insert any number of space (' ')		3. On the following line, insert any number of space (' ')
	characters followed by a second backslash ('\') character.		characters followed by a second backslash ('\') character.
	The result of the previous operation is that the next line starts		The result of the previous operation is that the next line starts
	with an arbitrary number of space (' ') characters, followed by a		with an arbitrary number of space (' ') characters, followed by a
	skipping to change at page 13, line 4 ¶		skipping to change at page 13, line 4 ¶
	be folded. Alas, only the results can be provided.		be folded. Alas, only the results can be provided.
	9.1. Example Showing Boundary Conditions		9.1. Example Showing Boundary Conditions
	This example illustrates boundary condition. The input contains		This example illustrates boundary condition. The input contains
	seven lines, each line one character longer than the previous line.		seven lines, each line one character longer than the previous line.
	Numbers for counting purposes. The default desired maximum column		Numbers for counting purposes. The default desired maximum column
	value "69" is used.		value "69" is used.
	9.1.1. Using '\'		9.1.1. Using '\'
	=========== NOTE: '\' line wrapping per BCP XX (RFC XXXX) ===========		========== NOTE: '\' line wrapping per BCP XXX (RFC XXXX) ===========
	123456789012345678901234567890123456789012345678901234567890123456		123456789012345678901234567890123456789012345678901234567890123456
	1234567890123456789012345678901234567890123456789012345678901234567		1234567890123456789012345678901234567890123456789012345678901234567
	12345678901234567890123456789012345678901234567890123456789012345678		12345678901234567890123456789012345678901234567890123456789012345678
	123456789012345678901234567890123456789012345678901234567890123456789		123456789012345678901234567890123456789012345678901234567890123456789
	12345678901234567890123456789012345678901234567890123456789012345678\		12345678901234567890123456789012345678901234567890123456789012345678\
	90		90
	12345678901234567890123456789012345678901234567890123456789012345678\		12345678901234567890123456789012345678901234567890123456789012345678\
	901		901
	12345678901234567890123456789012345678901234567890123456789012345678\		12345678901234567890123456789012345678901234567890123456789012345678\
	9012		9012
	9.1.2. Using '\\'		9.1.2. Using '\\'
	========== NOTE: '\\' line wrapping per BCP XX (RFC XXXX) ===========		========== NOTE: '\\' line wrapping per BCP XXX (RFC XXXX) ==========
	123456789012345678901234567890123456789012345678901234567890123456		123456789012345678901234567890123456789012345678901234567890123456
	1234567890123456789012345678901234567890123456789012345678901234567		1234567890123456789012345678901234567890123456789012345678901234567
	12345678901234567890123456789012345678901234567890123456789012345678		12345678901234567890123456789012345678901234567890123456789012345678
	123456789012345678901234567890123456789012345678901234567890123456789		123456789012345678901234567890123456789012345678901234567890123456789
	12345678901234567890123456789012345678901234567890123456789012345678\		12345678901234567890123456789012345678901234567890123456789012345678\
	\90		\90
	12345678901234567890123456789012345678901234567890123456789012345678\		12345678901234567890123456789012345678901234567890123456789012345678\
	\901		\901
	12345678901234567890123456789012345678901234567890123456789012345678\		12345678901234567890123456789012345678901234567890123456789012345678\
	skipping to change at page 13, line 41 ¶		skipping to change at page 13, line 41 ¶
	9.2. Example Showing Multiple Wraps of a Single Line		9.2. Example Showing Multiple Wraps of a Single Line
	This example illustrates what happens when very long line needs to be		This example illustrates what happens when very long line needs to be
	folded multiple times. The input contains one line containing 280		folded multiple times. The input contains one line containing 280
	characters. Numbers for counting purposes. The default desired		characters. Numbers for counting purposes. The default desired
	maximum column value "69" is used.		maximum column value "69" is used.
	9.2.1. Using '\'		9.2.1. Using '\'
	=========== NOTE: '\' line wrapping per BCP XX (RFC XXXX) ===========		========== NOTE: '\' line wrapping per BCP XXX (RFC XXXX) ===========
	12345678901234567890123456789012345678901234567890123456789012345678\		12345678901234567890123456789012345678901234567890123456789012345678\
	90123456789012345678901234567890123456789012345678901234567890123456\		90123456789012345678901234567890123456789012345678901234567890123456\
	78901234567890123456789012345678901234567890123456789012345678901234\		78901234567890123456789012345678901234567890123456789012345678901234\
	56789012345678901234567890123456789012345678901234567890123456789012\		56789012345678901234567890123456789012345678901234567890123456789012\
	34567890		34567890
	9.2.2. Using '\\'		9.2.2. Using '\\'
	========== NOTE: '\\' line wrapping per BCP XX (RFC XXXX) ===========		========== NOTE: '\\' line wrapping per BCP XXX (RFC XXXX) ==========
	12345678901234567890123456789012345678901234567890123456789012345678\		12345678901234567890123456789012345678901234567890123456789012345678\
	\9012345678901234567890123456789012345678901234567890123456789012345\		\9012345678901234567890123456789012345678901234567890123456789012345\
	\6789012345678901234567890123456789012345678901234567890123456789012\		\6789012345678901234567890123456789012345678901234567890123456789012\
	\3456789012345678901234567890123456789012345678901234567890123456789\		\3456789012345678901234567890123456789012345678901234567890123456789\
	\01234567890		\01234567890
	9.3. Example Showing "Smart" Folding		9.3. Example Showing "Smart" Folding
	This example illustrates how readability can be improved via "smart"		This example illustrates how readability can be improved via "smart"
	skipping to change at page 14, line 29 ¶		skipping to change at page 14, line 29 ¶
	format-specific indentations are used.		format-specific indentations are used.
	The text content was manually folded, since the script in the		The text content was manually folded, since the script in the
	appendix does not implement smart folding.		appendix does not implement smart folding.
	Note that the headers are surrounded by different printable		Note that the headers are surrounded by different printable
	characters than shown in the script-generated examples.		characters than shown in the script-generated examples.
	9.3.1. Using '\'		9.3.1. Using '\'
	[NOTE: '\' line wrapping per BCP XX (RFC XXXX)]		[NOTE: '\' line wrapping per BCP XXX (RFC XXXX)]
	<yang-library		<yang-library
	xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-library"		xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-library"
	xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">		xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
	<module-set>		<module-set>
	<name>config-modules</name>		<name>config-modules</name>
	<module>		<module>
	<name>ietf-interfaces</name>		<name>ietf-interfaces</name>
	<revision>2018-02-20</revision>		<revision>2018-02-20</revision>
	skipping to change at page 15, line 5 ¶		skipping to change at page 15, line 5 ¶
	</namespace>		</namespace>
	</module>		</module>
	...		...
	</module-set>		</module-set>
	...		...
	</yang-library>		</yang-library>
	Below is the equivalent to the above, but it was folded using the		Below is the equivalent to the above, but it was folded using the
	script in the appendix.		script in the appendix.
	=========== NOTE: '\' line wrapping per BCP XX (RFC XXXX) ===========		========== NOTE: '\' line wrapping per BCP XXX (RFC XXXX) ===========
	<yang-library		<yang-library
	xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-library"		xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-library"
	xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">		xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
	<module-set>		<module-set>
	<name>config-modules</name>		<name>config-modules</name>
	<module>		<module>
	<name>ietf-interfaces</name>		<name>ietf-interfaces</name>
	<revision>2018-02-20</revision>		<revision>2018-02-20</revision>
	<namespace>urn:ietf:params:xml:ns:yang:ietf-interfaces</namesp\		<namespace>urn:ietf:params:xml:ns:yang:ietf-interfaces</namesp\
	ace>		ace>
	</module>		</module>
	...		...
	</module-set>		</module-set>
	...		...
	</yang-library>		</yang-library>
	9.3.2. Using '\\'		9.3.2. Using '\\'
	[NOTE: '\\' line wrapping per BCP XX (RFC XXXX)]		[NOTE: '\\' line wrapping per BCP XXX (RFC XXXX)]
	<yang-library		<yang-library
	xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-library"		xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-library"
	xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">		xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
	<module-set>		<module-set>
	<name>config-modules</name>		<name>config-modules</name>
	<module>		<module>
	<name>ietf-interfaces</name>		<name>ietf-interfaces</name>
	<revision>2018-02-20</revision>		<revision>2018-02-20</revision>
	skipping to change at page 16, line 5 ¶		skipping to change at page 16, line 5 ¶
	\</namespace>		\</namespace>
	</module>		</module>
	...		...
	</module-set>		</module-set>
	...		...
	</yang-library>		</yang-library>
	Below is the equivalent to the above, but it was folded using the		Below is the equivalent to the above, but it was folded using the
	script in the appendix.		script in the appendix.
	========== NOTE: '\\' line wrapping per BCP XX (RFC XXXX) ===========		========== NOTE: '\\' line wrapping per BCP XXX (RFC XXXX) ==========
	<yang-library		<yang-library
	xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-library"		xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-library"
	xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">		xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
	<module-set>		<module-set>
	<name>config-modules</name>		<name>config-modules</name>
	<module>		<module>
	<name>ietf-interfaces</name>		<name>ietf-interfaces</name>
	<revision>2018-02-20</revision>		<revision>2018-02-20</revision>
	skipping to change at page 17, line 7 ¶		skipping to change at page 17, line 7 ¶
	The samples below were manually folded, since the script in the		The samples below were manually folded, since the script in the
	appendix does not implement forced folding.		appendix does not implement forced folding.
	Note that the headers are prefixed by a pound ('#') character, rather		Note that the headers are prefixed by a pound ('#') character, rather
	than surrounded by equal ('=') characters as shown in the script-		than surrounded by equal ('=') characters as shown in the script-
	generated examples.		generated examples.
	9.4.1. Using '\'		9.4.1. Using '\'
	# NOTE: '\' line wrapping per BCP XX (RFC XXXX)		# NOTE: '\' line wrapping per BCP XXX (RFC XXXX)
	The following line exceeds a 68-char max, thus demands folding		The following line exceeds a 68-char max, thus demands folding
	1234567890123456789012345678901234567890123456789012345678901234567\		1234567890123456789012345678901234567890123456789012345678901234567\
	89		89
	This line ends with a backslash \\		This line ends with a backslash \\
	This line ends with a backslash \\		This line ends with a backslash \\
	\ This line begins with a backslash		\ This line begins with a backslash
	Following is an indented 3x3 block of backslashes:		Following is an indented 3x3 block of backslashes:
	\\\\		\\\\
	\\\\		\\\\
	\\\		\\\
	9.4.2. Using '\\'		9.4.2. Using '\\'
	# NOTE: '\\' line wrapping per BCP XX (RFC XXXX)		# NOTE: '\\' line wrapping per BCP XXX (RFC XXXX)
	The following line exceeds a 68-char max, thus demands folding		The following line exceeds a 68-char max, thus demands folding
	1234567890123456789012345678901234567890123456789012345678901234567\		1234567890123456789012345678901234567890123456789012345678901234567\
	\89		\89
	This line ends with a backslash \		This line ends with a backslash \
	This line ends with a backslash \\		This line ends with a backslash \\
	\		\
	\ This line begins with a backslash		\ This line begins with a backslash
	skipping to change at page 18, line 24 ¶		skipping to change at page 18, line 24 ¶
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
	2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,		2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
	May 2017, <https://www.rfc-editor.org/info/rfc8174>.		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	12.2. Informative References		12.2. Informative References
			[pyang] "An extensible YANG (RFC 6020/7950) validator.",
			<https://pypi.org/project/pyang/>.
	[RFC7749] Reschke, J., "The "xml2rfc" Version 2 Vocabulary",		[RFC7749] Reschke, J., "The "xml2rfc" Version 2 Vocabulary",
	RFC 7749, DOI 10.17487/RFC7749, February 2016,		RFC 7749, DOI 10.17487/RFC7749, February 2016,
	<https://www.rfc-editor.org/info/rfc7749>.		<https://www.rfc-editor.org/info/rfc7749>.
	[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",		[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
	RFC 7950, DOI 10.17487/RFC7950, August 2016,		RFC 7950, DOI 10.17487/RFC7950, August 2016,
	<https://www.rfc-editor.org/info/rfc7950>.		<https://www.rfc-editor.org/info/rfc7950>.
	[RFC7991] Hoffman, P., "The "xml2rfc" Version 3 Vocabulary",		[RFC7991] Hoffman, P., "The "xml2rfc" Version 3 Vocabulary",
	RFC 7991, DOI 10.17487/RFC7991, December 2016,		RFC 7991, DOI 10.17487/RFC7991, December 2016,
	skipping to change at page 19, line 5 ¶		skipping to change at page 19, line 10 ¶
	<https://www.rfc-editor.org/info/rfc8340>.		<https://www.rfc-editor.org/info/rfc8340>.
	[xiax] "The `xiax` Python Package",		[xiax] "The `xiax` Python Package",
	<https://pypi.org/project/xiax/>.		<https://pypi.org/project/xiax/>.
	[yang-doctors-thread]		[yang-doctors-thread]
	"[yang-doctors] automating yang doctor reviews",		"[yang-doctors] automating yang doctor reviews",
	<https://mailarchive.ietf.org/arch/msg/yang-doctors/		<https://mailarchive.ietf.org/arch/msg/yang-doctors/
	DCfBqgfZPAD7afzeDFlQ1Xm2X3g>.		DCfBqgfZPAD7afzeDFlQ1Xm2X3g>.
			[yanglint]
			"A feature-rich tool for validation and conversion of the
			schemas and YANG modeled data.",
			<https://github.com/CESNET/libyang#yanglint>.
	Appendix A. POSIX Shell Script: rfcfold		Appendix A. POSIX Shell Script: rfcfold
	This non-normative appendix section includes a shell script that can		This non-normative appendix section includes a shell script that can
	both fold and unfold text content using both the single and double		both fold and unfold text content using both the single and double
	backslash strategies described in Section 7 and Section 8		backslash strategies described in Section 7 and Section 8
	respectively.		respectively.
	This script is intended to be applied to a single text content		This script is intended to be applied to a single text content
	instance. If it is desired to fold or unfold text content instances		instance. If it is desired to fold or unfold text content instances
	within a larger document (e.g., an Internet draft or RFC), then		within a larger document (e.g., an Internet draft or RFC), then
	skipping to change at page 19, line 32 ¶		skipping to change at page 20, line 32 ¶
	('=') characters on each side of the raw header text.		('=') characters on each side of the raw header text.
	This script does not implement the whitespace-avoidance logic		This script does not implement the whitespace-avoidance logic
	described in Section 7.2.1. In such case, the script will exit with		described in Section 7.2.1. In such case, the script will exit with
	one of the following message:		one of the following message:
	Error: infile has a space character occuring on the		Error: infile has a space character occuring on the
	folding column. This file cannot be folded using the		folding column. This file cannot be folded using the
	'\' strategy.		'\' strategy.
	This script does not implement the "forced folding" logic described		While this script can unfold input that contains forced foldings, it
	in Section 7.2.1 or Section 8.2.1. In such cases the script will		unable to fold files that would require forced foldings. Forced
	exit with one of the following message:		folding is described in Section 7.2.1 and Section 8.2.1. When being
			asked to fold a file that would require forced folding, the script
			will instead exit with one of the following messages:
	Error: infile has a line ending with a '\' character		Error: infile has a line ending with a '\' character.
	This file cannot be folded using the '\' strategy.		This file cannot be folded using the '\' strategy without
			there being false positives produced in the unfolding
			(i.e., this script does not attempt to proactively
			force-fold such lines, as described in RFC XXXX).
	Error: infile has a line ending with a '\' character		Error: infile has a line ending with a '\' character
	followed by a '\' character as the first non-space		followed by a '\' character as the first non-space
	character on the next line. This script cannot fold		character on the next line. This script cannot fold
	this file using '\\' strategy without there being		this file using '\\' strategy without there being
	false positives produced in the unfolding (i.e., this		false positives produced in the unfolding (i.e., this
	script does not attempt to proactively force-fold such		script does not attempt to proactively force-fold such
	lines, as described in RFC XXXX).		lines, as described in RFC XXXX).
	Shell-level end-of-line backslash ('\') characters have been		Shell-level end-of-line backslash ('\') characters have been
	skipping to change at page 20, line 51 ¶		skipping to change at page 22, line 8 ¶
	# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES		# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
	# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR		# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
	# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)		# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,		# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)		# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF		# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
	# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.		# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	print_usage() {		print_usage() {
	printf "\n"		printf "\n"
	printf "Folds or unfolds the input text file according to BCP XX"		printf "Folds or unfolds the input text file according to BCP XXX"
	printf " (RFC XXXX).\n"		printf " (RFC XXXX).\n"
	printf "\n"		printf "\n"
	printf "Usage: rfcfold [-s <strategy>] [-c <col>] [-r] -i <infile>"		printf "Usage: rfcfold [-s <strategy>] [-c <col>] [-r] -i <infile>"
	printf " -o <outfile>\n"		printf " -o <outfile>\n"
	printf "\n"		printf "\n"
	printf " -s: strategy to use, '1' or '2' (default: try 1,"		printf " -s: strategy to use, '1' or '2' (default: try 1,"
	printf " else 2)\n"		printf " else 2)\n"
	printf " -c: column to fold on (default: 69)\n"		printf " -c: column to fold on (default: 69)\n"
	printf " -r: reverses the operation\n"		printf " -r: reverses the operation\n"
	printf " -i: the input filename\n"		printf " -i: the input filename\n"
	skipping to change at page 21, line 31 ¶		skipping to change at page 22, line 36 ¶
	}		}
	# global vars, do not edit		# global vars, do not edit
	strategy=0 # auto		strategy=0 # auto
	debug=0		debug=0
	quiet=0		quiet=0
	reversed=0		reversed=0
	infile=""		infile=""
	outfile=""		outfile=""
	maxcol=69 # default, may be overridden by param		maxcol=69 # default, may be overridden by param
	hdr_txt_1="NOTE: '\\' line wrapping per BCP XX (RFC XXXX)"		hdr_txt_1="NOTE: '\\' line wrapping per BCP XXX (RFC XXXX)"
	hdr_txt_2="NOTE: '\\\\' line wrapping per BCP XX (RFC XXXX)"		hdr_txt_2="NOTE: '\\\\' line wrapping per BCP XXX (RFC XXXX)"
	equal_chars="======================================================="		equal_chars="======================================================="
	space_chars=" "		space_chars=" "
	temp_dir=""		temp_dir=""
	# determine name of [g]sed binary		# determine name of [g]sed binary
	type gsed > /dev/null 2>&1 && SED=gsed || SED=sed		type gsed > /dev/null 2>&1 && SED=gsed || SED=sed
	# warn if a non-GNU sed utility is used		# warn if a non-GNU sed utility is used
	"$SED" --version < /dev/null 2> /dev/null \		"$SED" --version < /dev/null 2> /dev/null \
	| grep GNU >/dev/null 2>&1 || echo 'Warning: not using GNU `sed`.'		| grep GNU >/dev/null 2>&1 || \
			echo 'Warning: not using GNU `sed` (likely cause if an error occurs)'
	# verify the availability of pcregrep		# verify the availability of pcregrep
	type pcregrep > /dev/null 2>&1 || {		type pcregrep > /dev/null 2>&1 || {
	echo 'Error: missing utility `pcregrep`'		printf '\nError: missing utility `pcregrep`\n'
	exit 1		exit 1
	}		}
	cleanup() {		cleanup() {
	rm -rf "$temp_dir"		rm -rf "$temp_dir"
	}		}
	trap 'cleanup' EXIT		trap 'cleanup' EXIT
	fold_it_1() {		fold_it_1() {
	# ensure input file doesn't contain the fold-sequence already		# ensure input file doesn't contain the fold-sequence already
	pcregrep -M "\\\\\n" $infile >> /dev/null 2>&1		pcregrep -M "\\\\\n" $infile >> /dev/null 2>&1
	if [[ $? -eq 0 ]]; then		if [[ $? -eq 0 ]]; then
	if [[ $quiet -eq 0 ]]; then		if [[ $quiet -eq 0 ]]; then
	echo		echo
	echo "Error: infile $infile has a line ending with a '\\'"		echo "Error: infile $infile has a line ending with a '\\'"
	skipping to change at page 22, line 16 ¶		skipping to change at page 23, line 21 ¶
	trap 'cleanup' EXIT		trap 'cleanup' EXIT
	fold_it_1() {		fold_it_1() {
	# ensure input file doesn't contain the fold-sequence already		# ensure input file doesn't contain the fold-sequence already
	pcregrep -M "\\\\\n" $infile >> /dev/null 2>&1		pcregrep -M "\\\\\n" $infile >> /dev/null 2>&1
	if [[ $? -eq 0 ]]; then		if [[ $? -eq 0 ]]; then
	if [[ $quiet -eq 0 ]]; then		if [[ $quiet -eq 0 ]]; then
	echo		echo
	echo "Error: infile $infile has a line ending with a '\\'"		echo "Error: infile $infile has a line ending with a '\\'"
	echo "character. This file cannot be folded using the '\\'"		echo "character. This file cannot be folded using the '\\'"
	echo "strategy."		echo "strategy without there being false positives produced"
			echo "in the unfolding (i.e., this script does not attempt"
			echo "to proactively force-fold such lines, as described"
			echo "in RFC XXXX)."
	echo		echo
	fi		fi
	return 1		return 1
	fi		fi
	# where to fold		# where to fold
	foldcol=`expr "$maxcol" - 1` # for the inserted '\' char		foldcol=`expr "$maxcol" - 1` # for the inserted '\' char
	# ensure input file doesn't contain whitespace on the fold column		# ensure input file doesn't contain whitespace on the fold column
	grep "^.\{$foldcol\} " $infile >> /dev/null 2>&1		grep "^.\{$foldcol\} " $infile >> /dev/null 2>&1
	skipping to change at page 25, line 24 ¶		skipping to change at page 26, line 31 ¶
	# unfold wip file		# unfold wip file
	"$SED" '{H;$!d};x;s/^\n//;s/\\\n *\\//g' $temp_dir/wip > $outfile		"$SED" '{H;$!d};x;s/^\n//;s/\\\n *\\//g' $temp_dir/wip > $outfile
	return 0		return 0
	}		}
	unfold_it() {		unfold_it() {
	# check if file needs unfolding		# check if file needs unfolding
	line=`head -n 1 $infile`		line=`head -n 1 $infile`
			line2=`$SED -n '2p' $infile`
	result=`echo $line | fgrep "$hdr_txt_1"`		result=`echo $line | fgrep "$hdr_txt_1"`
	if [ $? -eq 0 ]; then		if [ $? -eq 0 ]; then
			if [ -n "$line2" ]; then
			if [[ $quiet -eq 0 ]]; then
			echo "Error: the second line is not empty."
			fi
			return 1
			fi
	unfold_it_1		unfold_it_1
	return $?		return $?
	fi		fi
	result=`echo $line | fgrep "$hdr_txt_2"`		result=`echo $line | fgrep "$hdr_txt_2"`
	if [ $? -eq 0 ]; then		if [ $? -eq 0 ]; then
			if [ -n "$line2" ]; then
			if [[ $quiet -eq 0 ]]; then
			echo "Error: the second line is not empty."
			fi
			return 1
			fi
	unfold_it_2		unfold_it_2
	return $?		return $?
	fi		fi
	if [[ $debug -eq 1 ]]; then		if [[ $debug -eq 1 ]]; then
	echo "nothing to do"		echo "nothing to do"
	fi		fi
	cp $infile $outfile		cp $infile $outfile
	return -1		return -1
	}		}
	process_input() {		process_input() {
	while [ "$1" != "" ]; do		while [ "$1" != "" ]; do
	if [ "$1" == "-h" -o "$1" == "--help" ]; then		if [ "$1" == "-h" -o "$1" == "--help" ]; then
	print_usage		print_usage
	exit 1		exit 0
	fi		fi
	if [ "$1" == "-d" ]; then		if [ "$1" == "-d" ]; then
	debug=1		debug=1
	fi		fi
	if [ "$1" == "-q" ]; then		if [ "$1" == "-q" ]; then
	quiet=1		quiet=1
	fi		fi
	if [ "$1" == "-s" ]; then		if [ "$1" == "-s" ]; then
	strategy="$2"		strategy="$2"
	shift		shift
	fi		fi
	if [ "$1" == "-c" ]; then		if [ "$1" == "-c" ]; then
	maxcol="$2"		maxcol="$2"
	shift		shift
	fi		fi
	if [ "$1" == "-r" ]; then		if [ "$1" == "-r" ]; then
End of changes. 50 change blocks.
	65 lines changed or deleted		95 lines changed or added
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