Individual Contribution Daniel M. Myers
Internet-Draft Monolithic Technologies
Category: Informational June 2001
Expires: December 2001
Procedural Footnote Language
Version 1.0
draft-myers-pfl-02.txt
Status of this Memo
This document is an Internet-Draft and is subject to all provisions
of Section 10 of RFC2026.
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Copyright Notice
Copyright (C) The Internet Society (2001).
Abstract
This document sets out the proper syntax and usage of the Procedural
Footnote Language (PFL) - a system of adding structured footnote
objects to a text file.
Introduction
In the course of composing email or other text documents it may be
desirable to add comments or other notes to clarify a statement when
those additions may not fit the syntax of the statement, or may not
significantly add to the reader's understanding of the statement, and
where the use of a parenthetical comment would adversely affect the
readability of the statement. In such a situation footnotes are one
method of including the additional information with minimal negative
impact.
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1. The PFL Document
A document complying with the PFL 1.0 format consists of plain ASCII
text and is divided into two sections: the BODY and the FOOTNOTES.
1.1 The BODY Section
The BODY section consists of zero or more ASCII characters with an
undefined structure, and containing zero or more footnote
delimiters. A footnote delimiter consists of a positive integer
enclosed in square brackets. As the square bracket is used in PFL
as a delimiter to indicate a footnote, any square brackets in the
body of a document must be "escaped out" by enclosing them in
square brackets. All footnote delimiters in the BODY section must
have a corresponding footnote in the FOOTNOTE section.
Example: This is body text containing a footnote tag[1]
Example: [[]This is body text[1] enclosed in square
brackets.[]]
Footnote delimiters may be marked as being "optional" by enclosing
the number within the square brackets in parentheses. Note that
the corresponding footnote in the FOOTNOTE section does not
contain the parentheses.
Example: This is an optional footnote delimiter[(2)].
1.2 The FOOTNOTES Section
The FOOTNOTES section consists of the PFL document identifier
followed by zero or more footnotes in PFL format. The PFL
document identifier is the text "PFL" followed by the version
number, enclosed in square brackets, on a line by itself. Any
text between the PFL document identifier and the first PFL
footnote is ignored.
Example: [PFL1.0]
The proper syntax of a PFL footnote is a number enclosed by square
brackets followed by a space followed by 1 or more ASCII
characters. There must be no text between the start of the line
and the start of the footnote. As with the body text any square
brackets in the text portion of a PFL footnote must be escaped out
by enclosing them in square brackets. All footnotes in the
FOOTNOTE section must have a corresponding delimiter in the BODY
section. The numbers of the footnotes in the FOOTNOTES section
must be in sequential order and may not skip any values.
Example: [1] Hi Sherry!
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Footnotes may also have one or two optional parameters. A first
parameter will indicate the maximum number of times a footnote is
to be evaluated, with any further delimiters referencing that
footnote being ignored.
Example: The footnote "[1:3] Wubba[1]" would parse as " Wubba
Wubba Wubba"
A second parameter will indicate the minimum index value for the
footnote to be evaluated. The footnote will not be evaluated
before this index is reached. Note that a delimiter referencing
the footnote will advance the index for that footnote, but will
not add to the number of times the footnote has been evaluated
unless the index is greater or equal to the first parameter
Example: The PFL document below ...
[1]
[PFL1.0]
[1:2] Hi ho![1][2]
[2:1:2] It's off to work we go!
[PFLEND]
would evaluate to "Hi ho! Hi ho! It's off to work we go!"
The minimal allowed document in PFL format would be:
[PFL1.0]
The traditional "Hello World" program would be represented in
PFL as:
[1]
[PFL1.0]
[1] Hello World
[PFLEND]
2. Markers
There are a number of optional markers. These markers all take the
form of one or more ASCII characters enclosed in square brackets.
[HS] (honorable salutation) - This marker may occur in either the
BODY or FOOTNOTES sections of a PFL document and is the equivalent
to a delimiter pointing to a footnote that contains the text "Hi
Sherry!". Note that if the [HS] marker appears at the start of a
line in the FOOTNOTES section, it is taken as a special "Hi
Sherry!" footnote and will generate a UFA error if a [HS] marker
does not also appear elsewhere in the document.
[PFLEND] (PFL End of Document) - Indicates the end of the FOOTNOTES
section of a PFL document. This marker may only be used at the
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end of the FOOTNOTES section. All text in a document after
the [PFLEND] marker will be ignored.
[[] ("Escaped" Leading Square Bracket) - used when a open square
bracket is desired anywhere in the document. This marker may not
be used at the start of a line in the FOOTNOTES section of a
document.
[]] ("Escaped" Trailing Square Bracket) - used when a close square
bracket is desired anywhere in the document. This marker may not
be used at the start of a line in the FOOTNOTES section of a
document.
3. Functions
PFL Defines a number of built in functions of a mathematical or
logical nature. Each function is evaluated by the parser. The
functions may be nested as required. Parameters enclosed in angle
brackets are optional.
[ABC] - returns ABCDEFGHIJKLMNOPQRSTUVWXYZ
[ADD:x:y] - returns the value x + y
[AND:condition 1:condition 2] - returns true if both conditions are
true, and false otherwise
[ASCII:hex] - returns the ASCII character for a given hexadecimal
value
[BEEP] - system beep
[DATE] - returns the current date
[FALSE] - returns false
[GT:x:y] - returns true if x is greater than y, and false otherwise
[HEX:character] - returns the hexadecimal value of an ASCII character
[IF:condition:x<:y>] - Evaluates the condition and branches to
footnote x if the result is true, otherwise branches to footnote
y. A footnote used as the condition will always evaluate as true.
[INDEX:x] - returns the number of times that footnote x has been
evaluated by the parser
[IS:x:y] - returns true if x is equal to y, and false otherwise
[LEN:text1] - returns the number of characters in text1
[LT:x:y] - returns true if x is less than y, and false otherwise
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[NOT:condition] - returns true if the condition is false, and false
otherwise
[OR:condition 1:condition 2] - returns true if either condition is
true (or both), and false otherwise
[ORD:x] - returns the ordinal value of x (i.e. "first" for "1",
"second" for "2", etc...)
[RET] - returns a carriage return
[SPACE] - returns a space
[SUB:x:y] - returns the value x - y
[TAB] - returns a tab
[TIME] - returns the current time
[TRUE] - returns true
[USERDATA<:parameter>] - returns various data on the user, if it is
available. If the parameter is omitted then it will return true
if the user data is available, and false otherwise.
[USERDATA:FULLNAME] - returns the full name of the user in the
format "firstname lastname"
[USERDATA:FIRSTNAME] - returns the first name of the user
[USERDATA:LASTNAME] - returns the last name of the user
[USERDATA:INITIAL] - returns the middle initial of the user
[USERDATA:COMPANY] - returns the company name of the user
[USERDATA:STREET] - returns the street address of the user
[USERDATA:CITY] - returns the city of the user
[USERDATA:REGION] - returns the region of the user
[USERDATA:POSTAL] - returns the postal zone of the user
[USERDATA:COUNTRY] - returns the country of the user
[USERDATA:LANGUAGE] - returns the preferred language of the user
[VER] - returns the PFL version of the parser
[XOR:condition 1:condition 2] - returns true if either condition is
true (but not both) , and false otherwise
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[ZEN] - doesn't return anything
4. Possible Errors
The following are potential errors that may be encountered when
parsing a PFL document.
FSE - Footnote Sequence Error: The footnote numbers in the FOOTNOTES
section are not in sequential order.
IFA - Improper Footnote Alert: A footnote was found in the FOOTNOTES
section that was not properly formed.
MDA - Malformed Delimiter Alert: A delimiter was found in either the
BODY or the FOOTNOTES section that was not properly formed.
This may be caused by square brackets that have not been
properly escaped.
MFA - Missing Footnote Alert: There is a delimiter in the BODY
section of the document that has no corresponding footnote in
the FOOTNOTES section.
NOT - Not a PFL Document: No PFL document identifier was found.
TMI - Too Much Information: There was a buffer overflow while
parsing the document, possibly due to a circular reference.
UFA - Unassigned Footnote Alert: There is a footnote in the
FOOTNOTES section of the document that has no corresponding
delimiter in the BODY section.
UPM - Unexpected PFLEND Marker: A [PFLEND] marker was encountered in
the BODY section of the document.
UVN - Unrecognized Version Number: The version of PFL specified in
the PFL document identifier was not recognized by the parser.
5. Security Considerations
This document raises no security issues.
6. Author's Address
Daniel Myers
PO Box 523
Loveland, OH 45140-0523
Phone: +1 513-708-1024
Email: myers@monogames.com
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7. Full Copyright Statement
Copyright (C) The Internet Society (2001). All Rights Reserved
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or any
other Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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