--- 1/draft-ietf-netmod-artwork-folding-02.txt 2019-05-30 08:13:23.154632363 -0700 +++ 2/draft-ietf-netmod-artwork-folding-03.txt 2019-05-30 08:13:23.202633575 -0700 @@ -1,155 +1,164 @@ NETMOD Working Group K. Watsen Internet-Draft Watsen Networks Intended status: Best Current Practice A. Farrel -Expires: October 8, 2019 Old Dog Consulting +Expires: December 1, 2019 Old Dog Consulting Q. Wu Huawei Technologies - April 6, 2019 + May 30, 2019 Handling Long Lines in Inclusions in Internet-Drafts and RFCs - draft-ietf-netmod-artwork-folding-02 + draft-ietf-netmod-artwork-folding-03 Abstract - This document defines a simple and yet time-proven strategy for - handling long lines in inclusions in internet drafts and RFCs using a - backslash ('\') character to indicate where line-folding has - occurred. The strategy works on any text-based content, but is - primarily intended for a structured sequence of lines rather than for - two-dimensional imagery. The approach produces consistent results, - regardless of the content, that is both self-documenting and enables - automated reconstitution of the original content. + This document defines two strategies for handling long lines in + width-bounded text content. One strategy is based on the historic + use of a single backslash ('\') character to indicate where line- + folding has occurred, with the continuation occurring with the first + non-space (' ') character on the next line. The second strategy + extends the first strategy by adding a second backslash character to + identify where the continuation begins and thereby able to handle + cases not supported by the first strategy. Both strategies use a + self-describing header enabling automated reconstitution of the + original content. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on October 8, 2019. + This Internet-Draft will expire on December 1, 2019. Copyright Notice Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 - 2. Applicability Statement . . . . . . . . . . . . . . . . . . . 3 + 2. Applicability Statement . . . . . . . . . . . . . . . . . . . 4 3. Requirements Language . . . . . . . . . . . . . . . . . . . . 4 4. Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1. Automated Folding of Long Lines in Text Content . . . . . 4 - 4.2. Automated Reconstitution of the Original Text Content . . 4 + 4.2. Automated Reconstitution of the Original Text Content . . 5 5. Limitations . . . . . . . . . . . . . . . . . . . . . . . . . 5 5.1. Not Recommended for Graphical Artwork . . . . . . . . . . 5 5.2. Doesn't Work as Well as Format-Specific Options . . . . . 5 - 6. Two Folding Strategies . . . . . . . . . . . . . . . . . . . 5 + 6. Two Folding Strategies . . . . . . . . . . . . . . . . . . . 6 6.1. Comparison . . . . . . . . . . . . . . . . . . . . . . . 6 6.2. Recommendation . . . . . . . . . . . . . . . . . . . . . 6 7. The Single Backslash Strategy ('\') . . . . . . . . . . . . . 6 7.1. Folded Structure . . . . . . . . . . . . . . . . . . . . 6 - 7.1.1. Header . . . . . . . . . . . . . . . . . . . . . . . 6 + 7.1.1. Header . . . . . . . . . . . . . . . . . . . . . . . 7 7.1.2. Body . . . . . . . . . . . . . . . . . . . . . . . . 7 7.2. Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 7 7.2.1. Folding . . . . . . . . . . . . . . . . . . . . . . . 7 - 7.2.2. Unfolding . . . . . . . . . . . . . . . . . . . . . . 8 + 7.2.2. Unfolding . . . . . . . . . . . . . . . . . . . . . . 9 8. The Double Backslash Strategy ('\\') . . . . . . . . . . . . 9 8.1. Folded Structure . . . . . . . . . . . . . . . . . . . . 9 8.1.1. Header . . . . . . . . . . . . . . . . . . . . . . . 9 - 8.1.2. Body . . . . . . . . . . . . . . . . . . . . . . . . 9 + 8.1.2. Body . . . . . . . . . . . . . . . . . . . . . . . . 10 8.2. Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 10 8.2.1. Folding . . . . . . . . . . . . . . . . . . . . . . . 10 8.2.2. Unfolding . . . . . . . . . . . . . . . . . . . . . . 11 9. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 12 9.1. Example Showing Boundary Conditions . . . . . . . . . . . 12 9.1.1. Using '\' . . . . . . . . . . . . . . . . . . . . . . 12 - 9.1.2. Using '\\' . . . . . . . . . . . . . . . . . . . . . 12 + 9.1.2. Using '\\' . . . . . . . . . . . . . . . . . . . . . 13 9.2. Example Showing Multiple Wraps of a Single Line . . . . . 13 9.2.1. Using '\' . . . . . . . . . . . . . . . . . . . . . . 13 9.2.2. Using '\\' . . . . . . . . . . . . . . . . . . . . . 13 9.3. Example Showing Smart Folding . . . . . . . . . . . . . . 13 - 9.3.1. Using '\' . . . . . . . . . . . . . . . . . . . . . . 13 - 9.3.2. Using '\\' . . . . . . . . . . . . . . . . . . . . . 14 - 10. Security Considerations . . . . . . . . . . . . . . . . . . . 15 + 9.3.1. Using '\' . . . . . . . . . . . . . . . . . . . . . . 14 + 9.3.2. Using '\\' . . . . . . . . . . . . . . . . . . . . . 15 + + 10. Security Considerations . . . . . . . . . . . . . . . . . . . 16 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 12.1. Normative References . . . . . . . . . . . . . . . . . . 16 12.2. Informative References . . . . . . . . . . . . . . . . . 16 - Appendix A. POSIX Shell Script . . . . . . . . . . . . . . . . . 17 - Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 23 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23 + Appendix A. POSIX Shell Script . . . . . . . . . . . . . . . . . 18 + Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 25 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25 1. Introduction [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 limited to 72 characters followed by the character sequence that denotes an end-of-line (EOL). Internet-Drafts and RFCs often include example text or code fragments. Many times the example text or code exceeds the 72 character line-length limit. The `xml2rfc` utility does not attempt to wrap the content of such inclusions, simply issuing a warning whenever lines exceed 69 characters. According to the RFC Editor, there is currently no convention in place for how to handle long lines in such inclusions, other than advising authors to clearly indicate what manipulation has occurred. - This document introduces a simple and yet time-proven strategy for - handling long lines using a backslash ('\') character to indicate - where line-folding has occurred. The strategy works on any text - based inclusion, but is primarily intended for a structured sequence - of lines, such as would be referenced by the element - defined in Section 2.48 of [RFC7991], rather than for two-dimensional - imagery, such as would be referenced by the element defined - in Section 2.5 of [RFC7991]. The approach produces consistent - results, regardless of the content, that is both self-documenting and - enables automated reconstitution of the original content. + This document defines two strategies for handling long lines in + width-bounded text content. One strategy is based on the historic + use of a single backslash ('\') character to indicate where line- + folding has occurred, with the continuation occurring with the first + non-space (' ') character on the next line. The second strategy + extends the first strategy by adding a second backslash character to + identify where the continuation begins and thereby able to handle + cases not supported by the first strategy. Both strategies use a + self-describing header enabling automated reconstitution of the + original content. + + The strategies defined in this document work on any text content, but + are primarily intended for a structured sequence of lines, such as + would be referenced by the element defined in + Section 2.48 of [RFC7991], rather than for two-dimensional imagery, + such as would be referenced by the element defined in + Section 2.5 of [RFC7991]. Note that text files are represented as lines having their first character in column 1, and a line length of N where the last character is in the Nth column and is immediately followed by an end of line character sequence. 2. Applicability Statement - The format and algorithm defined in this document may be used in any - context, whether for IETF documents or in other situations where + The formats and algorithms defined in this document may be used in + any context, whether for IETF documents or in other situations where structured folding is desired. Within the IETF, this work primarily targets the xml2rfc v3 element (Section 2.48 of [RFC7991]) and the xml2rfc v2 element (Section 2.5 of [RFC7749]) that, for lack of a better option, is currently used for both source code and artwork. - This work may be also be used for the xml2rfc v3 element (Section 2.5 of [RFC7991]) but, as described in Section 5.1, it is generally not recommended. 3. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all @@ -173,36 +182,35 @@ effort and errors resulting from manual processing. Similarly, dynamically generated output (e.g., tree diagrams) must also be modified, if necessary, in order for the resulting document to satisfy the line length limits. When needed, this effort again SHOULD be automated to reduce effort and errors resulting from manual processing. 4.2. Automated Reconstitution of the Original Text Content - Automated reconstitution of the original content is needed to support - validation of text-based inclusions extracted from documents. YANG - [RFC7950] modules are already extracted from Internet-Drafts and - validated as part of the draft-submission process. Additionally, - there has been some discussion regarding needing to also validate - instance examples (i.e., XML/JSON documents) contained within - Internet-Drafts ([yang-doctors-thread]). Thus, it SHOULD be possible - to mechanically reconstitute the original text content in order to - utilize such tooling. + Automated reconstitution of the exact original text content is needed + to support validation of text-based content extracted from documents. + + For instance, already YANG [RFC7950] modules are extracted from + Internet-Drafts and validated as part of the draft-submission + process. Additionally, the desire to validate instance examples + (i.e., XML/JSON documents) contained within Internet-Drafts has been + discussed ([yang-doctors-thread]). 5. Limitations 5.1. Not Recommended for Graphical Artwork - While the solution presented in this document will work on any kind - of text-based content, it is most useful on content that represents + While the solution presented in this document works on any kind of + text-based content, it is most useful on content that represents source code (XML, JSON, etc.) or, more generally, on content that has not been laid out in two dimensions (e.g., diagrams). Fundamentally, the issue is whether the text content remains readable once folded. Text content that is unpredictable is especially susceptible to looking bad when folded; falling into this category are most UML diagrams, YANG tree diagrams, and ASCII art in general. It is NOT RECOMMENDED to use the solution presented in this document on graphical artwork. @@ -217,52 +225,47 @@ For instance, both the `pyang` and `yanglint` utilities have the command line option "--tree-line-length" that can be used to indicate a desired maximum line length for when generating tree diagrams [RFC8340]. In another example, some source formats (e.g., YANG [RFC7950]) allow any quoted string to be broken up into substrings separated by a concatenation character (e.g., '+'), any of which can be on a different line. - In yet another example, some languages allow factoring blocks of code - into call outs, such as functions. Using such call outs is - especially helpful when in some deeply-nested code, as they typically - reset the indentation back to the first column. - It is RECOMMENDED that authors do as much as possible within the selected format to avoid long lines. 6. Two Folding Strategies This document defines two nearly identical strategies for folding text-based content. The Single Backslash Strategy ('\'): Uses a backslash ('\') character at the end of the line where folding occurs, and - assumes that the continuation begins at the first non- - whitespace character on the following line. + assumes that the continuation begins at the character that is + not a space character (' ') on the following line. The Double Backslash Strategy ('\\'): Uses a backslash ('\') character at the end of the line where folding occurs, and assumes that the continuation begins after a second backslash ('\') character on the following line. 6.1. Comparison The first strategy produces more readable output, however it is significantly more likely to encounter unfoldable input (e.g., there - is exists a line anywhere in the input ending with a backslash - character, or there exists a long line containing only space and - backslash characters) and, for long lines that can be folded, - automation implementations are likely to encounter scenarios that - will produce errors without special care. + exists a line anywhere in the input ending with a backslash + character, or there exists a long line containing only space + characters) and, for long lines that can be folded, automation + implementations may encounter scenarios that will produce errors + without special care. The second strategy produces less readable output, but is unlikely to encounter unfoldable input, there are no long lines that cannot be folded, and no special care is required for when folding a long line. 6.2. Recommendation It is RECOMMENDED for implementations to first attempt to fold 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 @@ -298,64 +301,68 @@ The character encoding is the same as described in Section 2 of [RFC7994], except that, per [RFC7991], tab characters are prohibited. Lines that have a backslash ('\') occurring as the last character in a line are considered "folded". Really long lines may be folded multiple times. 7.2. Algorithm - This section describes the process for folding and unfolding long - lines when they are encountered in a single instance of text content. - It is assumed that another process inserts/extracts the individual - text content instances to/from an Internet-Draft or RFC. For - example, the `xiax` utility [xiax] does this. + This section describes a process for folding and unfolding long lines + when they are encountered in text content. -7.2.1. Folding + The steps are complete, but implementations MAY achieve the same + result in other ways. - Folding is assumed to be automated although authors may perform the - folding steps manually. + When a larger document contains multiple instances of text content + that may need to be folded or unfolded, another process must insert/ + extract the individual text content instances to/from the larger + document prior to utilizing the algorithms described in this section. + For example, the `xiax` utility [xiax] does this. - Determine the desired maximum line length from input to the automated - line-wrapping process, such as from a command line parameter. If no - value is explicitly specified, the value "69" SHOULD be used. +7.2.1. Folding + + Determine the desired maximum line length from input to the line- + wrapping process, such as from a command line parameter. If no value + is explicitly specified, the value "69" SHOULD be used. 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 45 characters. If the desired maximum line length is less than this minimum, exit (this text-based content cannot be folded). Scan the text content for horizontal tab characters. If any horizontal tab characters appear, either resolve them to space characters or exit, forcing the input provider to convert them to space characters themselves first. - 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 - not need to be folded). + Scan the text content to ensure at least one line exceeds the desired + maximum. If no line exceeds the desired maximum, exit (this text + content does not need to be folded). Scan the text content to ensure no existing lines already end with a backslash ('\') character, as this would lead to an ambiguous result. If such a line is found, exit (this text content cannot be folded). If this text content needs to and can be folded, insert the header described in Section 7.1.1, ensuring that any additional printable characters surrounding the header does 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 exceeds the desired maximum, then fold the line by: 1. Determine where the fold will occur. This location MUST be - before or at the desired maximum column, and MUST NOT precede a - space (' ') character. + before or at the desired maximum column, and MUST NOT be on top + of a space (' ') character. 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 ('\') character followed by the end of line character sequence. 3. On the following line, insert any number of space (' ') characters. The result of the previous operation is that the next line starts with an arbitrary number of space (' ') characters, followed by the character that was previously occupying the position where the fold @@ -364,24 +371,20 @@ Continue in this manner until reaching the end of the text content. Note that this algorithm naturally addresses the case where the remainder of a folded line is still longer than the desired maximum, and hence needs to be folded again, ad infinitum. The process described in this section is illustrated by the "fold_it_1()" function in Appendix A. 7.2.2. Unfolding - All unfolding is assumed to be automated, although a reader will - mentally perform the act of unfolding the text to understand the true - nature of the original text content. - Scan the beginning of the text content for the header described in Section 7.1.1. If the header is not present, starting on the first line of the text content, exit (this text contents does not need to be unfolded). Remove the 2-line header from the text content. For each line in the text content, from top-to-bottom, if the line has a backslash ('\') character immediately followed by the end of line character sequence, then the line can be unfolded. Remove the @@ -426,62 +429,68 @@ Lines that have a backslash ('\') occurring as the last character in a line immediately followed by the end of line character sequence, when the subsequent line starts with a backslash ('\') as the first non-space (' ') character, are considered "folded". Really long lines may be folded multiple times. 8.2. Algorithm - This section describes the process for folding and unfolding long - lines when they are encountered in a single instance of text content. - It is assumed that another process inserts/extracts the individual - text content instances to/from an Internet-Draft or RFC. For - example, the `xiax` utility [xiax] does this. + This section describes a process for folding and unfolding long lines + when they are encountered in text content. -8.2.1. Folding + The steps are complete, but implementations MAY achieve the same + result in other ways. - Folding is assumed to be automated, although authors may perform the - folding steps manually. + When a larger document contains multiple instances of text content + that may need to be folded or unfolded, another process must insert/ + extract the individual text content instances to/from the larger + document prior to utilizing the algorithms described in this section. + For example, the `xiax` utility [xiax] does this. - Determine the desired maximum line length from input to the automated - line-wrapping process, such as from a command line parameter. If no - value is explicitly specified, the value "69" SHOULD be used. +8.2.1. Folding + + Determine the desired maximum line length from input to the line- + wrapping process, such as from a command line parameter. If no value + is explicitly specified, the value "69" SHOULD be used. 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 cannot be folded). Scan the text content for horizontal tab characters. If any horizontal tab characters appear, either resolve them to space characters or exit, forcing the input provider to convert them to space characters themselves first. 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 not need to be folded). Scan the text content to ensure no existing lines already end with a backslash ('\') character while the subsequent line starts with a backslash ('\') character as the first non-space (' ') character, as - this would lead to an ambiguous result. If such a line is found, - exit (this text content cannot be folded). + 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 + for forced folding (folding even though unnecessary). If the folding + implementation doesn't support forced foldings, it MUST exit. If this text content needs to and can be folded, insert the header described in Section 8.1.1, ensuring that any additional printable characters surrounding the header does 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 - exceeds the desired maximum, then fold the line by: + exceeds the desired maximum, or requires a forced folding, then fold + the line by: 1. Determine where the fold will occur. This location MUST be before or at the desired maximum column. 2. At the location where the fold is to occur, insert a first backslash ('\') character followed by the end of line character sequence. 3. On the following line, insert any number of space (' ') characters followed by a second backslash ('\') character. @@ -494,24 +503,20 @@ Continue in this manner until reaching the end of the text content. Note that this algorithm naturally addresses the case where the remainder of a folded line is still longer than the desired maximum, and hence needs to be folded again, ad infinitum. The process described in this section is illustrated by the "fold_it_2()" function in Appendix A. 8.2.2. Unfolding - All unfolding is assumed to be automated although a reader will - mentally perform the act of unfolding the text to understand the true - nature of the original text content. - Scan the beginning of the text content for the header described in Section 8.1.1. If the header is not present, starting on the first line of the text content, exit (this text content does not need to be unfolded). Remove the 2-line header from the text content. For each line in the text content, from top-to-bottom, if the line has a backslash ('\') character immediately followed by the end of line character sequence, and if the next line has a backslash ('\') @@ -746,22 +751,53 @@ . [yang-doctors-thread] "[yang-doctors] automating yang doctor reviews", . Appendix A. POSIX Shell Script This non-normative appendix section includes a shell script that can - both fold and unfold text content. Note that this script is applied - only to single text content instances. + both fold and unfold text content using both the single and double + backslash strategies described in Section 7 and Section 8 + respectively. + + This script is intended to be applied to a single text content + instance. If it is desired to fold or unfold test content instances + within a larger document (e.g., an Internet draft or RFC), then + another tool must be used to extract the content from the larger + document before utilizing this script. + + For readability purposes, this script forces the minimally supported + line length to be eight characters longer than the raw header text + defined in Section 7.1.1 and Section 8.1.1 so as to ensure that the + header can be wrapped by a space (' ') character and three equal + ('=') characters on each side of the raw header text. + + This script does not implement the "forced folding" logic described + in Section 8.2.1. In such cases the script will exit with the + message: + + Error: infile has a line ending with a '\\' character + followed by a '\\' character as the first non-space + character on the next line. This file cannot be folded. + + Shell-level end-of-line backslash ('\') characters have been + purposely added to the script so as to ensure that the script is + itself not folded in this document, thus simplify the ability to + copy/paste the script for local use. As should be evident by the + lack of the mandatory header described in Section 7.1.1, these + backslashes do not designate a folded line, such as described in + Section 7. + + #!/bin/bash --posix # must be `bash` (not `sh`) print_usage() { echo echo "Folds the text file, only if needed, at the specified" echo "column, according to BCP XX." echo echo "Usage: $0 [-s ] [-c ] [-r] -i " echo " -o " @@ -782,46 +818,46 @@ strategy=0 # auto debug=0 reversed=0 infile="" outfile="" maxcol=69 # default, may be overridden by param hdr_txt_1="NOTE: '\\' line wrapping per BCP XX (RFC XXXX)" hdr_txt_2="NOTE: '\\\\' line wrapping per BCP XX (RFC XXXX)" equal_chars="==============================================" space_chars=" " + temp_dir="" fold_it_1() { # ensure input file doesn't contain the fold-sequence already pcregrep -M "\\\\\n" $infile >> /dev/null 2>&1 if [ $? -eq 0 ]; then echo - echo "Error1: infile $infile has a line ending with a '\\'" + echo "Error: infile $infile has a line ending with a '\\'" echo "character. This file cannot be folded." echo return 1 fi # stash some vars testcol=`expr "$maxcol" + 1` foldcol=`expr "$maxcol" - 1` # for the inserted '\' char # ensure input file doesn't contain whitespace on the fold column grep "^.\{$foldcol\} " $infile >> /dev/null 2>&1 if [ $? -eq 0 ]; then echo - echo "Error: infile has a space character occuring after the" + echo "Error: infile has a space character occuring on the" echo "folding column. This file cannot be folded." echo return 1 fi - # center header text length=`expr ${#hdr_txt_1} + 2` left_sp=`expr \( "$maxcol" - "$length" \) / 2` right_sp=`expr "$maxcol" - "$length" - "$left_sp"` header=`printf "%.*s %s %.*s" "$left_sp" "$equal_chars"\ "$hdr_txt_1" "$right_sp" "$equal_chars"` # generate outfile echo "$header" > $outfile echo "" >> $outfile @@ -825,56 +861,61 @@ # generate outfile echo "$header" > $outfile echo "" >> $outfile gsed "/.\{$testcol\}/s/\(.\{$foldcol\}\)/\1\\\\\n/g"\ < $infile >> $outfile return 0 } fold_it_2() { + if [ "$temp_dir" == "" ]; then + temp_dir=`mktemp -d` + fi + # ensure input file doesn't contain the fold-sequence already pcregrep -M "\\\\\n[\ ]*\\\\" $infile >> /dev/null 2>&1 if [ $? -eq 0 ]; then echo - echo "Error2: infile has a line ending with a '\\' character" + echo "Error: infile has a line ending with a '\\' character" echo "followed by a '\\' character as the first non-space" echo "character on the next line. This file cannot be folded." echo return 1 fi # center header text length=`expr ${#hdr_txt_2} + 2` left_sp=`expr \( "$maxcol" - "$length" \) / 2` right_sp=`expr "$maxcol" - "$length" - "$left_sp"` header=`printf "%.*s %s %.*s" "$left_sp" "$equal_chars"\ "$hdr_txt_2" "$right_sp" "$equal_chars"` # fold using recursive passes ('g' used in fold_it_1 didn't work) if [ -z "$1" ]; then # init recursive env - cp $infile /tmp/wip + cp $infile $temp_dir/wip fi testcol=`expr "$maxcol" + 1` foldcol=`expr "$maxcol" - 1` # for the inserted '\' char - gsed "/.\{$testcol\}/s/\(.\{$foldcol\}\)/\1\\\\\n\\\\/" < /tmp/wip\ - >> /tmp/wip2 - diff /tmp/wip /tmp/wip2 > /dev/null 2>&1 + gsed "/.\{$testcol\}/s/\(.\{$foldcol\}\)/\1\\\\\n\\\\/" \ + < $temp_dir/wip >> $temp_dir/wip2 + + diff $temp_dir/wip $temp_dir/wip2 > /dev/null 2>&1 if [ $? -eq 1 ]; then - mv /tmp/wip2 /tmp/wip + mv $temp_dir/wip2 $temp_dir/wip fold_it_2 "recursing" else echo "$header" > $outfile echo "" >> $outfile - cat /tmp/wip2 >> $outfile - rm /tmp/wip* + cat $temp_dir/wip2 >> $outfile + rm -rf $temp_dir fi return 0 } fold_it() { # ensure input file doesn't contain a TAB grep $'\t' $infile >> /dev/null 2>&1 if [ $? -eq 0 ]; then echo echo "Error: infile contains a TAB character, which is not" @@ -903,40 +945,45 @@ fi fold_it_1 if [ $? -ne 0 ]; then fold_it_2 return $? fi return 0 } unfold_it_1() { + temp_dir=`mktemp -d` + # output all but the first two lines (the header) to wip file - awk "NR>2" $infile > /tmp/wip + awk "NR>2" $infile > $temp_dir/wip # unfold wip file - gsed ":x; /.*\\\\$/N; s/\\\\\n[ ]*//; tx" /tmp/wip > $outfile + gsed ":x; /.*\\\\$/N; s/\\\\\n[ ]*//; tx" $temp_dir/wip > $outfile # clean up and return - rm /tmp/wip + rm -rf $temp_dir return 0 } unfold_it_2() { + temp_dir=`mktemp -d` + # output all but the first two lines (the header) to wip file - awk "NR>2" $infile > /tmp/wip + awk "NR>2" $infile > $temp_dir/wip # unfold wip file - gsed ":x; /.*\\\\$/N; s/\\\\\n[ ]*\\\\//; tx" /tmp/wip > $outfile + gsed ":x; /.*\\\\$/N; s/\\\\\n[ ]*\\\\//; tx" $temp_dir/wip \ + > $outfile # clean up and return - rm /tmp/wip + rm -rf $temp_dir return 0 } unfold_it() { # check if file needs unfolding line=`head -n 1 $infile` result=`echo $line | fgrep "$hdr_txt_1"` if [ $? -eq 0 ]; then unfold_it_1 return $? @@ -1031,32 +1076,36 @@ fi } main() { if [ "$#" == "0" ]; then print_usage exit 1 fi process_input $@ + if [[ $reversed -eq 0 ]]; then fold_it code=$? else unfold_it code=$? fi exit $code + } main "$@" + + Acknowledgements The authors thank the following folks for their various contributions (sorted by first name): Benoit Claise, Gianmarco Bruno, Italo Busi, Joel Jaeggli, Jonathan Hansford, Lou Berger, Martin Bjorklund, and Rob Wilton. The authors additionally thank the RFC Editor for confirming that there is no set convention today for handling long lines in artwork/ sourcecode inclusions.