The Compiler Language With No Pronounceable Acronym ( INTERCAL ) is an esoteric programming language that was created as a parody by Don Woods and James M. Lyon [ ru ] , two Princeton University students, in 1972. It satirizes aspects of the various programming languages at the time, as well as the proliferation of proposed language constructs and notations in the 1960s.
97-446: There are two maintained implementations of INTERCAL dialects: C-INTERCAL (created in 1990), maintained by Eric S. Raymond and Alex Smith, and CLC-INTERCAL, maintained by Claudio Calvelli. According to the original manual by the authors, The full name of the compiler is "Compiler Language With No Pronounceable Acronym", which is, for obvious reasons, abbreviated "INTERCAL". The original Princeton implementation used punched cards and
194-493: A . , called a "spot"), the 32-bit integer ( : , a "twospot"), the array of 16-bit integers ( , , a "tail"), and the array of 32-bit integers ( ; , a "hybrid"). There are 65535 available variables of each type, numbered from .1 to .65535 for 16-bit integers, for instance. However, each of these variables has its own stack on which it can be pushed and popped (STASHed and RETRIEVEd, in INTERCAL terminology), increasing
291-408: A gun rights advocate. He has endorsed the open source firearms organization Defense Distributed , calling them "friends of freedom" and writing "I approve of any development that makes it more difficult for governments and criminals to monopolize the use of force. As 3D printers become less expensive and more ubiquitous, this could be a major step in the right direction." In 2015, Raymond accused
388-467: A scalar variable. Constants can also be used, and are represented by a # ("mesh") followed by the constant itself, written as a decimal number; only integer constants from 0 to 65535 are supported. There are only five operators in INTERCAL-72. Implementations vary in which characters represent which operation, and many accept more than one character, so more than one possibility is given for many of
485-525: A shift function (like in ITA2 ), which would allow more than 64 codes to be represented by a six-bit code . In a shifted code, some character codes determine choices between options for the following character codes. It allows compact encoding, but is less reliable for data transmission , as an error in transmitting the shift code typically makes a long part of the transmission unreadable. The standards committee decided against shifting, and so ASCII required at least
582-501: A "secure, hardened replacement" for the Unix utility NTP . Raymond has written numerous open-source tools, including cvs-fast-export, a tool for exporting CVS repositories to Git fast-import streams, and "reposurgeon", a tool for exporting SVN repositories. Raymond coined an aphorism he dubbed Linus's law , inspired by Linus Torvalds : "Given enough eyeballs, all bugs are shallow". It first appeared in his book The Cathedral and
679-537: A "statement identifier"; in INTERCAL-72, this can be DO , PLEASE , or PLEASE DO , all of which mean the same to the program (but using one of these too heavily causes the program to be rejected, an undocumented feature in INTERCAL-72 that was mentioned in the C-INTERCAL manual), or an inverted form (with NOT or N'T appended to the identifier). Backtracking INTERCAL, a modern variant, also allows variants using MAYBE (possibly combined with PLEASE or DO) as
776-429: A 2007 mailing list post that as a matter of policy, the development team preferred more incremental changes. ) Raymond's 2003 book The Art of Unix Programming discusses user tools for programming and other tasks. Some versions of NetHack still include Raymond's guide. He has also contributed code and content to the free software video game The Battle for Wesnoth . Raymond is the main developer of NTPsec ,
873-485: A 2008 essay, he defended programmers' right to issue work under proprietary licenses: "I think that if a programmer wants to write a program and sell it, it's neither my business nor anyone else's but his customer's what the terms of sale are." In the same essay he said that the "logic of the system" puts developers into "dysfunctional roles", with bad code the result. Raymond is a member of the Libertarian Party and
970-522: A BS (backspace). Instead, there was a key marked RUB OUT that sent code 127 (DEL). The purpose of this key was to erase mistakes in a manually-input paper tape: the operator had to push a button on the tape punch to back it up, then type the rubout, which punched all holes and replaced the mistake with a character that was intended to be ignored. Teletypes were commonly used with the less-expensive computers from Digital Equipment Corporation (DEC); these systems had to use what keys were available, and thus
1067-534: A Microsoft document expressing worry about the quality of rival open-source software. He named this document, together with others subsequently leaked, " The Halloween Documents ". Between 2000 and 2002, he created Configuration Menu Language 2 (CML2), a source code configuration system; while originally intended for the Linux operating system , it was rejected by kernel developers. (Raymond attributed this rejection to "kernel list politics", but Linus Torvalds said in
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#17330938714471164-458: A character count followed by the characters of the line and which used EBCDIC rather than ASCII encoding. The Telnet protocol defined an ASCII "Network Virtual Terminal" (NVT), so that connections between hosts with different line-ending conventions and character sets could be supported by transmitting a standard text format over the network. Telnet used ASCII along with CR-LF line endings, and software using other conventions would translate between
1261-452: A fictional video game console created by British indie game developer Nitrome , has games which are programmed in INTERCAL. Eric S. Raymond Eric Steven Raymond (born December 4, 1957), often referred to as ESR , is an American software developer , open-source software advocate, and author of the 1997 essay and 1999 book The Cathedral and the Bazaar . He wrote a guidebook for
1358-491: A line terminator. The tty driver would handle the LF to CRLF conversion on output so files can be directly printed to terminal, and NL (newline) is often used to refer to CRLF in UNIX documents. Unix and Unix-like systems, and Amiga systems, adopted this convention from Multics. On the other hand, the original Macintosh OS , Apple DOS , and ProDOS used carriage return (CR) alone as
1455-600: A line terminator; however, since Apple later replaced these obsolete operating systems with their Unix-based macOS (formerly named OS X) operating system, they now use line feed (LF) as well. The Radio Shack TRS-80 also used a lone CR to terminate lines. Computers attached to the ARPANET included machines running operating systems such as TOPS-10 and TENEX using CR-LF line endings; machines running operating systems such as Multics using LF line endings; and machines running operating systems such as OS/360 that represented lines as
1552-566: A number of public disputes with other figures in the free software movement . As head of the Open Source Initiative, he argued that advocates should focus on the potential for better products. The "very seductive" moral and ethical rhetoric of Richard Stallman and the Free Software Foundation fails, he said, "not because his principles are wrong, but because that kind of language ... simply does not persuade anybody". In
1649-557: A random black male behaving suspiciously who might be in the critical age range as though he is an near-imminent lethal threat, are being rational, not racist." A progressive campaign, "The Great Slate", was successful in raising funds for candidates in part by asking for contributions from tech workers in return for not posting similar quotes by Raymond. Matasano Security employee and Great Slate fundraiser Thomas Ptacek said, "I've been torturing Twitter with lurid Eric S. Raymond quotes for years. Every time I do, 20 people beg me to stop." It
1746-591: A reserved device control (DC0), synchronous idle (SYNC), and acknowledge (ACK). These were positioned to maximize the Hamming distance between their bit patterns. ASCII-code order is also called ASCIIbetical order. Collation of data is sometimes done in this order rather than "standard" alphabetical order ( collating sequence ). The main deviations in ASCII order are: An intermediate order converts uppercase letters to lowercase before comparing ASCII values. ASCII reserves
1843-541: A reserved meaning. Over time this interpretation has been co-opted and has eventually been changed. In modern usage, an ESC sent to the terminal usually indicates the start of a command sequence, which can be used to address the cursor, scroll a region, set/query various terminal properties, and more. They are usually in the form of a so-called " ANSI escape code " (often starting with a " Control Sequence Introducer ", "CSI", " ESC [ ") from ECMA-48 (1972) and its successors. Some escape sequences do not have introducers, like
1940-404: A seven-bit code. The committee considered an eight-bit code, since eight bits ( octets ) would allow two four-bit patterns to efficiently encode two digits with binary-coded decimal . However, it would require all data transmission to send eight bits when seven could suffice. The committee voted to use a seven-bit code to minimize costs associated with data transmission. Since perforated tape at
2037-416: A statement identifier, which introduces a choice-point. Before the identifier, an optional line number (an integer enclosed in parentheses) can be given; after the identifier, a percent chance of the line executing can be given in the format %50 , which defaults to 100%. In INTERCAL-72, the main control structures are NEXT, RESUME, and FORGET. DO ( line ) NEXT branches to the line specified, remembering
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#17330938714472134-399: A terminal. Some operating systems such as CP/M tracked file length only in units of disk blocks, and used control-Z to mark the end of the actual text in the file. For these reasons, EOF, or end-of-file , was used colloquially and conventionally as a three-letter acronym for control-Z instead of SUBstitute. The end-of-text character ( ETX ), also known as control-C , was inappropriate for
2231-446: A variety of reasons, while using control-Z as the control character to end a file is analogous to the letter Z's position at the end of the alphabet, and serves as a very convenient mnemonic aid . A historically common and still prevalent convention uses the ETX character convention to interrupt and halt a program via an input data stream, usually from a keyboard. The Unix terminal driver uses
2328-731: Is 0101 in binary). Many of the non-alphanumeric characters were positioned to correspond to their shifted position on typewriters; an important subtlety is that these were based on mechanical typewriters, not electric typewriters. Mechanical typewriters followed the de facto standard set by the Remington No. 2 (1878), the first typewriter with a shift key, and the shifted values of 23456789- were "#$ %_&'() – early typewriters omitted 0 and 1 , using O (capital letter o ) and l (lowercase letter L ) instead, but 1! and 0) pairs became standard once 0 and 1 became common. Thus, in ASCII !"#$ % were placed in
2425-410: Is Threaded Intercal, which extends the functionality of COME FROM to support multithreading . CLC-INTERCAL has a library called INTERNET for networking functionality including being an INTERCAL server, and also includes features such as Quantum Intercal, which enables multi-value calculations in a way purportedly ready for the first quantum computers . In early 2017 a .NET Implementation targeting
2522-454: Is entirely a coincidence since 0.06 is not being developed) * The fractional part of a perversion number can be integer or floating point, with a similar meaning for the parts. The current pre-escape is 1.-94.-2 which means "2 pre-pre-escapes to go before pre-escape 1.-94". INTERCAL was intended to be completely different from all other computer languages. Common operations in other languages have cryptic and redundant syntax in INTERCAL. From
2619-606: Is estimated that, as of March 2018, over $ 30,000 has been raised in this way. Raymond describes himself as neo-pagan . ASCII ASCII ( / ˈ æ s k iː / ASS -kee ), an acronym for American Standard Code for Information Interchange , is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment , and other devices. ASCII has just 128 code points , of which only 95 are printable characters , which severely limit its scope. The set of available punctuation had significant impact on
2716-417: Is from standard programming languages. In C , it could read as follows: The equivalent program in C-INTERCAL is longer and harder to read: The original Woods–Lyon INTERCAL was very limited in its input/output capabilities: the only acceptable input were numbers with the digits spelled out, and the only output was an extended version of Roman numerals . The C-INTERCAL reimplementation, being available on
2813-622: Is in INTERCAL a left-arrow, <- , made up of an "angle" and a "worm", obviously read as "gets". Input (using the WRITE IN instruction) and output (using the READ OUT instruction) do not use the usual formats; in INTERCAL-72, WRITE IN inputs a number written out as digits in English (such as SIX FIVE FIVE THREE FIVE), and READ OUT outputs it in "butchered" Roman numerals . More recent versions have their own I/O systems. Comments can be achieved by using
2910-427: Is replaced by a second control-S to resume output. The 33 ASR also could be configured to employ control-R (DC2) and control-T (DC4) to start and stop the tape punch; on some units equipped with this function, the corresponding control character lettering on the keycap above the letter was TAPE and TAPE respectively. The Teletype could not move its typehead backwards, so it did not have a key on its keyboard to send
3007-404: Is the newline problem on various operating systems . Teletype machines required that a line of text be terminated with both "carriage return" (which moves the printhead to the beginning of the line) and "line feed" (which advances the paper one line without moving the printhead). The name "carriage return" comes from the fact that on a manual typewriter the carriage holding the paper moves while
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3104-457: Is the least significant bit of the result). There is no operator precedence; grouping marks must be used to disambiguate the precedence where it would otherwise be ambiguous (the grouping marks available are ' ("spark"), which matches another spark, and " ("rabbit ears"), which matches another rabbit ears; the programmer is responsible for using these in such a way that they make the expression unambiguous). INTERCAL statements all start with
3201-470: The .NET Framework appeared on GitHub . This implementation supports the creation of standalone binary libraries and interop with other programming languages. In the article "A Box, Darkly: Obfuscation, Weird Languages, and Code Aesthetics", INTERCAL is described under the heading "Abandon all sanity, ye who enter here: INTERCAL". The compiler and commenting strategy are among the "weird" features described: The compiler, appropriately named "ick", continues
3298-483: The Ada Initiative and other women in tech groups of attempting to entrap male open source leaders and accuse them of rape, saying "Try to avoid even being alone, ever, because there is a chance that a 'women in tech' advocacy group is going to try to collect your scalp." Raymond has claimed that "Gays experimented with unfettered promiscuity in the 1970s and got AIDS as a consequence", and that "Police who react to
3395-486: The Comité Consultatif International Téléphonique et Télégraphique (CCITT) International Telegraph Alphabet No. 2 (ITA2) standard of 1932, FIELDATA (1956 ), and early EBCDIC (1963), more than 64 codes were required for ASCII. ITA2 was in turn based on Baudot code , the 5-bit telegraph code Émile Baudot invented in 1870 and patented in 1874. The committee debated the possibility of
3492-501: The EBCDIC character set. To allow INTERCAL to run on computers using ASCII , substitutions for two characters had to be made: $ substituted for ¢ as the mingle operator, "represent[ing] the increasing cost of software in relation to hardware", and ? was substituted for ⊻ as the unary exclusive-or operator to "correctly express the average person's reaction on first encountering exclusive-or". In recent versions of C-INTERCAL,
3589-529: The Jargon File had not been maintained since about 1983, he adopted it, but not without criticism; Paul Dourish maintains an archived original version of the Jargon File, because, he says, Raymond's updates "essentially destroyed what held it together." In 1996, Raymond took over development of the open-source email software "popclient", renaming it to Fetchmail . Soon after this experience, in 1997, he wrote
3686-576: The Open Source Initiative (OSI) in 1998, taking on the self-appointed role of ambassador of open source to the press, business and public. He remains active in OSI, but stepped down as president of the initiative in February 2005. In early March 2020, he was removed from two Open Source Initiative mailing lists due to posts that violated the OSI's Code of Conduct. In 1998, Raymond received and published
3783-648: The Roguelike game NetHack . In the 1990s, he edited and updated the Jargon File , published as The New Hacker's Dictionary . Raymond was born in Boston, Massachusetts in 1957, and lived in Venezuela as a child. His family moved to Pennsylvania in 1971. He developed cerebral palsy at birth; his weakened physical condition motivated him to go into computing. Raymond began his programming career writing proprietary software , between 1980 and 1985. In 1990, noting that
3880-618: The Teletype Model 33 , which used the left-shifted layout corresponding to ASCII, differently from traditional mechanical typewriters. Electric typewriters, notably the IBM Selectric (1961), used a somewhat different layout that has become de facto standard on computers – following the IBM PC (1981), especially Model M (1984) – and thus shift values for symbols on modern keyboards do not correspond as closely to
3977-697: The United States Federal Government support ASCII, stating: I have also approved recommendations of the Secretary of Commerce [ Luther H. Hodges ] regarding standards for recording the Standard Code for Information Interchange on magnetic tapes and paper tapes when they are used in computer operations. All computers and related equipment configurations brought into the Federal Government inventory on and after July 1, 1969, must have
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4074-667: The carriage return , line feed , and tab codes. For example, lowercase i would be represented in the ASCII encoding by binary 1101001 = hexadecimal 69 ( i is the ninth letter) = decimal 105. Despite being an American standard, ASCII does not have a code point for the cent (¢). It also does not support English terms with diacritical marks such as résumé and jalapeño , or proper nouns with diacritical marks such as Beyoncé (although on certain devices characters could be combined with punctuation such as Tilde (~) and Backtick (`) to approximate such characters.) The American Standard Code for Information Interchange (ASCII)
4171-641: The "Reset to Initial State", "RIS" command " ESC c ". In contrast, an ESC read from the terminal is most often used as an out-of-band character used to terminate an operation or special mode, as in the TECO and vi text editors . In graphical user interface (GUI) and windowing systems, ESC generally causes an application to abort its current operation or to exit (terminate) altogether. The inherent ambiguity of many control characters, combined with their historical usage, created problems when transferring "plain text" files between systems. The best example of this
4268-574: The "help" prefix command in GNU Emacs . Many more of the control characters have been assigned meanings quite different from their original ones. The "escape" character (ESC, code 27), for example, was intended originally to allow sending of other control characters as literals instead of invoking their meaning, an "escape sequence". This is the same meaning of "escape" encountered in URL encodings, C language strings, and other systems where certain characters have
4365-401: The "line feed" function (which causes a printer to advance its paper), and character 8 represents " backspace ". RFC 2822 refers to control characters that do not include carriage return, line feed or white space as non-whitespace control characters. Except for the control characters that prescribe elementary line-oriented formatting, ASCII does not define any mechanism for describing
4462-419: The ASCII chart in this article. Ninety-five of the encoded characters are printable: these include the digits 0 to 9 , lowercase letters a to z , uppercase letters A to Z , and punctuation symbols . In addition, the original ASCII specification included 33 non-printing control codes which originated with Teletype models ; most of these are now obsolete, although a few are still commonly used, such as
4559-676: The ASCII table as earlier keyboards did. The /? pair also dates to the No. 2, and the ,< .> pairs were used on some keyboards (others, including the No. 2, did not shift , (comma) or . (full stop) so they could be used in uppercase without unshifting). However, ASCII split the ;: pair (dating to No. 2), and rearranged mathematical symbols (varied conventions, commonly -* =+ ) to :* ;+ -= . Some then-common typewriter characters were not included, notably ½ ¼ ¢ , while ^ ` ~ were included as diacritics for international use, and < > for mathematical use, together with
4656-535: The Bazaar . Raymond has refused to speculate on whether the "bazaar" development model could be applied to works such as books and music, saying that he does not want to "weaken the winning argument for open-sourcing software by tying it to a potential loser". Raymond claims his method of promoting open-source software has been effective because he has used "a strategy of making rational, technical, utility-maximization arguments in which I explicitly disclaimed having any normative or moralizing agenda." Raymond has had
4753-467: The DEL character was assigned to erase the previous character. Because of this, DEC video terminals (by default) sent the DEL character for the key marked "Backspace" while the separate key marked "Delete" sent an escape sequence ; many other competing terminals sent a BS character for the backspace key. The early Unix tty drivers, unlike some modern implementations, allowed only one character to be set to erase
4850-541: The IGNORE and REMEMBER instructions on variables (which cause writes to the variable to be silently ignored and to take effect again, so that instructions can be disabled by causing them to have no effect), and the ABSTAIN and REINSTATE instructions on lines or on types of statement, causing the lines to have no effect or to have an effect again respectively. The traditional "Hello, world!" program demonstrates how different INTERCAL
4947-615: The INTERCAL Reference Manual: It is a well-known and oft-demonstrated fact that a person whose work is incomprehensible is held in high esteem. For example, if one were to state that the simplest way to store a value of 65536 in a 32-bit INTERCAL variable is: any sensible programmer would say that that was absurd. Since this is indeed the simplest method, the programmer would be made to look foolish in front of his boss, who would of course happen to turn up, as bosses are expected to do. The effect would be no less devastating for
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#17330938714475044-415: The INTERCAL compiler as a dominatrix: If PLEASE was not encountered often enough, the program would be rejected; that is, ignored without explanation by the compiler. Too often and it would still be rejected, this time for sniveling. Combined with other words that are rarely used in programming languages but appear as statements in INTERCAL, the code reads like someone pleading. The Nitrome Enjoyment System,
5141-682: The Internet, has made the language more popular with devotees of esoteric programming languages. The C-INTERCAL dialect has a few differences from original INTERCAL and introduced a few new features, such as a COME FROM statement and a means of doing text I/O based on the Turing Text Model. The authors of C-INTERCAL also created the TriINTERCAL variant, based on the Ternary numeral system and generalizing INTERCAL's set of operators. A more recent variant
5238-462: The Teletype Model 33 machine assignments for codes 17 (control-Q, DC1, also known as XON), 19 (control-S, DC3, also known as XOFF), and 127 ( delete ) became de facto standards. The Model 33 was also notable for taking the description of control-G (code 7, BEL, meaning audibly alert the operator) literally, as the unit contained an actual bell which it rang when it received a BEL character. Because
5335-407: The bits of its first operand that correspond to "1" bits of its second operand and removes the bits that correspond to "0" bits, shifting towards the least significant bit and padding with zeroes (so 51 (1 1 0 0 1 1 in binary) SELECT 21 (10101 in binary) is 5 ( 101 in binary)); MINGLE alternates bits from its first and second operands (in such a way that the least significant bit of its second operand
5432-546: The call stack and jumps to the last line remembered. C-INTERCAL also provides the COME FROM instruction, written DO COME FROM ( line ) ; CLC-INTERCAL and the most recent C-INTERCAL versions also provide computed COME FROM ( DO COME FROM expression ) and NEXT FROM, which is like COME FROM but also saves a return address on the NEXT STACK. Alternative ways to affect program flow, originally available in INTERCAL-72, are to use
5529-585: The change into its draft standard. The X3.2.4 task group voted its approval for the change to ASCII at its May 1963 meeting. Locating the lowercase letters in sticks 6 and 7 caused the characters to differ in bit pattern from the upper case by a single bit, which simplified case-insensitive character matching and the construction of keyboards and printers. The X3 committee made other changes, including other new characters (the brace and vertical bar characters), renaming some control characters (SOM became start of header (SOH)) and moving or removing others (RU
5626-493: The concept of "carriage return" was meaningless. IBM's PC DOS (also marketed as MS-DOS by Microsoft) inherited the convention by virtue of being loosely based on CP/M, and Windows in turn inherited it from MS-DOS. Requiring two characters to mark the end of a line introduces unnecessary complexity and ambiguity as to how to interpret each character when encountered by itself. To simplify matters, plain text data streams, including files, on Multics used line feed (LF) alone as
5723-524: The convention was so well established that backward compatibility necessitated continuing to follow it. When Gary Kildall created CP/M , he was inspired by some of the command line interface conventions used in DEC's RT-11 operating system. Until the introduction of PC DOS in 1981, IBM had no influence in this because their 1970s operating systems used EBCDIC encoding instead of ASCII, and they were oriented toward punch-card input and line printer output on which
5820-659: The earlier five-bit ITA2 , which was also used by the competing Telex teleprinter system. Bob Bemer introduced features such as the escape sequence . His British colleague Hugh McGregor Ross helped to popularize this work – according to Bemer, "so much so that the code that was to become ASCII was first called the Bemer–Ross Code in Europe". Because of his extensive work on ASCII, Bemer has been called "the father of ASCII". On March 11, 1968, US President Lyndon B. Johnson mandated that all computers purchased by
5917-576: The earlier teleprinter encoding systems. Like other character encodings , ASCII specifies a correspondence between digital bit patterns and character symbols (i.e. graphemes and control characters ). This allows digital devices to communicate with each other and to process, store, and communicate character-oriented information such as written language. Before ASCII was developed, the encodings in use included 26 alphabetic characters, 10 numerical digits , and from 11 to 25 special graphic symbols. To include all these, and control characters compatible with
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#17330938714476014-497: The end-of-transmission character ( EOT ), also known as control-D, to indicate the end of a data stream. In the C programming language , and in Unix conventions, the null character is used to terminate text strings ; such null-terminated strings can be known in abbreviation as ASCIZ or ASCIIZ, where here Z stands for "zero". Other representations might be used by specialist equipment, for example ISO 2047 graphics or hexadecimal numbers. Codes 20 hex to 7E hex , known as
6111-542: The error message says this; if it appears too often, the program could be rejected as excessively polite. Although this feature existed in the original INTERCAL compiler, it was undocumented. Despite the language's intentionally obtuse and wordy syntax, INTERCAL is nevertheless Turing-complete : given enough memory, INTERCAL can solve any problem that a Universal Turing machine can solve. Most implementations of INTERCAL do this very slowly, however. A Sieve of Eratosthenes benchmark, computing all prime numbers less than 65536,
6208-618: The essay " The Cathedral and the Bazaar ", detailing his thoughts on open-source software development and why it should be done as openly as possible (the "bazaar" approach). The essay was based in part on his experience in developing Fetchmail. He first presented his thesis at the annual Linux Kongress on May 27, 1997. He later expanded the essay into a book, The Cathedral and the Bazaar: Musings on Linux and Open Source by an Accidental Revolutionary , in 1999. The essay has been widely cited. The internal white paper by Frank Hecker that led to
6305-624: The first 32 code points (numbers 0–31 decimal) and the last one (number 127 decimal) for control characters . These are codes intended to control peripheral devices (such as printers ), or to provide meta-information about data streams, such as those stored on magnetic tape. Despite their name, these code points do not represent printable characters (i.e. they are not characters at all, but signals). For debugging purposes, "placeholder" symbols (such as those given in ISO 2047 and its predecessors) are assigned to them. For example, character 0x0A represents
6402-400: The inverted statement identifiers involving NOT or N'T; these cause lines to be initially ABSTAINed from so that they have no effect. (A line can be ABSTAINed from even if it does not have valid syntax; syntax errors happen at runtime, and only then when the line is un-ABSTAINed.) INTERCAL-72 (the original version of INTERCAL) had only four data types : the 16- bit integer (represented with
6499-448: The keytop for the O key also showed a left-arrow symbol (from ASCII-1963, which had this character instead of underscore ), a noncompliant use of code 15 (control-O, shift in) interpreted as "delete previous character" was also adopted by many early timesharing systems but eventually became neglected. When a Teletype 33 ASR equipped with the automatic paper tape reader received a control-S (XOFF, an abbreviation for transmit off), it caused
6596-776: The local conventions and the NVT. The File Transfer Protocol adopted the Telnet protocol, including use of the Network Virtual Terminal, for use when transmitting commands and transferring data in the default ASCII mode. This adds complexity to implementations of those protocols, and to other network protocols, such as those used for E-mail and the World Wide Web, on systems not using the NVT's CR-LF line-ending convention. The PDP-6 monitor, and its PDP-10 successor TOPS-10, used control-Z (SUB) as an end-of-file indication for input from
6693-459: The next line that would be executed if it weren't for the NEXT on a call stack (other identifiers than DO can be used on any statement, DO is given as an example); DO FORGET expression removes expression entries from the top of the call stack (this is useful to avoid the error that otherwise happens when there are more than 80 entries), and DO RESUME expression removes expression entries from
6790-493: The older operators are supported as alternatives; INTERCAL programs may now be encoded in ASCII , Latin-1 , or UTF-8 . C-INTERCAL swaps the major and minor version numbers, compared to tradition. The HISTORY file shows releases starting at version 0.3 and as of May 2020 having progressed to 0.31, but containing 1.26 between 0.26 and 0.27. CLC-INTERCAL version numbering scheme was traditional until version 0.06, when it changed to
6887-420: The operators. Contrary to most other languages, AND, OR, and XOR are unary operators, which work on consecutive bits of their argument; the most significant bit of the result is the operator applied to the least significant and most significant bits of the input, the second-most-significant bit of the result is the operator applied to the most and second-most significant bits, the third-most-significant bit of
6984-477: The parody. Anything the compiler can't understand, which in a normal language would result in a compilation error, is just skipped. This "forgiving" feature makes finding bugs very difficult; it also introduces a unique system for adding program comments. The programmer merely inserts non-compileable text anywhere in the program, being careful not to accidentally embed a bit of valid code in the middle of their comment. In "Technomasochism", Lev Bratishenko characterizes
7081-522: The possible complexity of data structures. More modern versions of INTERCAL have by and large kept the same data structures, with appropriate modifications; TriINTERCAL, which modifies the radix with which numbers are represented, can use a 10- trit type rather than a 16-bit type, and CLC-INTERCAL implements many of its own data structures, such as "classes and lectures", by making the basic data types store more information rather than adding new types. Arrays are dimensioned by assigning to them as if they were
7178-452: The previous character in canonical input processing (where a very simple line editor is available); this could be set to BS or DEL, but not both, resulting in recurring situations of ambiguity where users had to decide depending on what terminal they were using ( shells that allow line editing, such as ksh , bash , and zsh , understand both). The assumption that no key sent a BS character allowed Ctrl+H to be used for other purposes, such as
7275-515: The previous section. Code 7F hex corresponds to the non-printable "delete" (DEL) control character and is therefore omitted from this chart; it is covered in the previous section's chart. Earlier versions of ASCII used the up arrow instead of the caret (5E hex ) and the left arrow instead of the underscore (5F hex ). ASCII was first used commercially during 1963 as a seven-bit teleprinter code for American Telephone & Telegraph 's TWX (TeletypeWriter eXchange) network. TWX originally used
7372-413: The printable characters, represent letters, digits, punctuation marks , and a few miscellaneous symbols. There are 95 printable characters in total. Code 20 hex , the "space" character, denotes the space between words, as produced by the space bar of a keyboard. Since the space character is considered an invisible graphic (rather than a control character) it is listed in the table below instead of in
7469-413: The programmer having been correct. INTERCAL has many other features designed to make it even more aesthetically unpleasing to the programmer: it uses statements such as "READ OUT", "IGNORE", "FORGET", and modifiers such as "PLEASE". This last keyword provides two reasons for the program's rejection by the compiler: if "PLEASE" does not appear often enough, the program is considered insufficiently polite, and
7566-444: The proposed Bell code and ASCII were both ordered for more convenient sorting (i.e., alphabetization) of lists and added features for devices other than teleprinters. The use of ASCII format for Network Interchange was described in 1969. That document was formally elevated to an Internet Standard in 2015. Originally based on the (modern) English alphabet , ASCII encodes 128 specified characters into seven-bit integers as shown by
7663-454: The release of the Mozilla (then Netscape ) source code in 1998 cited The Cathedral and the Bazaar as "independent validation" of ideas proposed by Eric Hahn and Jamie Zawinski . Hahn would later describe the 1999 book as "clearly influential". From the late 1990s onward, due in part to the popularity of his essay, Raymond became a prominent voice in the open source movement. He co-founded
7760-432: The result is the operator applied to the second-most and third-most bits, and so on. The operator is placed between the punctuation mark specifying a variable name or constant and the number that specifies which variable it is, or just inside grouping marks (i.e. one character later than it would be in programming languages like C .) SELECT and INTERLEAVE (which is also known as MINGLE) are infix binary operators; SELECT takes
7857-516: The same reason, many special signs commonly used as separators were placed before digits. The committee decided it was important to support uppercase 64-character alphabets , and chose to pattern ASCII so it could be reduced easily to a usable 64-character set of graphic codes, as was done in the DEC SIXBIT code (1963). Lowercase letters were therefore not interleaved with uppercase . To keep options available for lowercase letters and other graphics,
7954-455: The scheme documented in the README file, which says: * The term "version" has been replaced by "perversion" for correctness * The perversion number consists of a floating-point number with independent signs for the integer and fractional part. Negative fractions indicate pre-escapes (so 1.-94 means "94 pre-escapes to go before 1.00". Or you can just add the numbers together and get 0.06, which
8051-494: The second stick, positions 1–5, corresponding to the digits 1–5 in the adjacent stick. The parentheses could not correspond to 9 and 0 , however, because the place corresponding to 0 was taken by the space character. This was accommodated by removing _ (underscore) from 6 and shifting the remaining characters, which corresponded to many European typewriters that placed the parentheses with 8 and 9 . This discrepancy from typewriters led to bit-paired keyboards , notably
8148-534: The simple line characters \ | (in addition to common / ). The @ symbol was not used in continental Europe and the committee expected it would be replaced by an accented À in the French variation, so the @ was placed in position 40 hex , right before the letter A. The control codes felt essential for data transmission were the start of message (SOM), end of address (EOA), end of message (EOM), end of transmission (EOT), "who are you?" (WRU), "are you?" (RU),
8245-402: The special and numeric codes were arranged before the letters, and the letter A was placed in position 41 hex to match the draft of the corresponding British standard. The digits 0–9 are prefixed with 011, but the remaining 4 bits correspond to their respective values in binary, making conversion with binary-coded decimal straightforward (for example, 5 in encoded to 011 0101 , where 5
8342-425: The standard is unclear about the meaning of "delete". Probably the most influential single device affecting the interpretation of these characters was the Teletype Model 33 ASR, which was a printing terminal with an available paper tape reader/punch option. Paper tape was a very popular medium for long-term program storage until the 1980s, less costly and in some ways less fragile than magnetic tape. In particular,
8439-440: The structure or appearance of text within a document. Other schemes, such as markup languages , address page and document layout and formatting. The original ASCII standard used only short descriptive phrases for each control character. The ambiguity this caused was sometimes intentional, for example where a character would be used slightly differently on a terminal link than on a data stream , and sometimes accidental, for example
8536-511: The syntax of computer languages and text markup. ASCII hugely influenced the design of character sets used by modern computers, including Unicode which has over a million code points, but the first 128 of these are the same as ASCII. The Internet Assigned Numbers Authority (IANA) prefers the name US-ASCII for this character encoding. ASCII is one of the IEEE milestones . ASCII was developed in part from telegraph code . Its first commercial use
8633-441: The tape reader to stop; receiving control-Q (XON, transmit on) caused the tape reader to resume. This so-called flow control technique became adopted by several early computer operating systems as a "handshaking" signal warning a sender to stop transmission because of impending buffer overflow ; it persists to this day in many systems as a manual output control technique. On some systems, control-S retains its meaning, but control-Q
8730-600: The time could record eight bits in one position, it also allowed for a parity bit for error checking if desired. Eight-bit machines (with octets as the native data type) that did not use parity checking typically set the eighth bit to 0. The code itself was patterned so that most control codes were together and all graphic codes were together, for ease of identification. The first two so-called ASCII sticks (32 positions) were reserved for control characters. The "space" character had to come before graphics to make sorting easier, so it became position 20 hex ; for
8827-447: The typebars that strike the ribbon remain stationary. The entire carriage had to be pushed (returned) to the right in order to position the paper for the next line. DEC operating systems ( OS/8 , RT-11 , RSX-11 , RSTS , TOPS-10 , etc.) used both characters to mark the end of a line so that the console device (originally Teletype machines) would work. By the time so-called "glass TTYs" (later called CRTs or "dumb terminals") came along,
8924-451: Was decided that the INTERCAL manual should contain some other type of removable organ." The INTERCAL manual gives unusual names to all non-alphanumeric ASCII characters: single and double quotes are 'sparks' and "rabbit ears" respectively. (The exception is the ampersand : as the Jargon File states, "what could be sillier?") The assignment operator, represented as an equals sign (INTERCAL's "half mesh") in many other programming languages,
9021-704: Was developed under the auspices of a committee of the American Standards Association (ASA), called the X3 committee, by its X3.2 (later X3L2) subcommittee, and later by that subcommittee's X3.2.4 working group (now INCITS ). The ASA later became the United States of America Standards Institute (USASI) and ultimately became the American National Standards Institute (ANSI). With the other special characters and control codes filled in, ASCII
9118-554: Was in the Teletype Model 33 and the Teletype Model 35 as a seven- bit teleprinter code promoted by Bell data services. Work on the ASCII standard began in May 1961, with the first meeting of the American Standards Association's (ASA) (now the American National Standards Institute or ANSI) X3.2 subcommittee. The first edition of the standard was published in 1963, underwent a major revision during 1967, and experienced its most recent update during 1986. Compared to earlier telegraph codes,
9215-676: Was published as ASA X3.4-1963, leaving 28 code positions without any assigned meaning, reserved for future standardization, and one unassigned control code. There was some debate at the time whether there should be more control characters rather than the lowercase alphabet. The indecision did not last long: during May 1963 the CCITT Working Party on the New Telegraph Alphabet proposed to assign lowercase characters to sticks 6 and 7, and International Organization for Standardization TC 97 SC 2 voted during October to incorporate
9312-450: Was removed). ASCII was subsequently updated as USAS X3.4-1967, then USAS X3.4-1968, ANSI X3.4-1977, and finally, ANSI X3.4-1986. In the X3.15 standard, the X3 committee also addressed how ASCII should be transmitted ( least significant bit first) and recorded on perforated tape. They proposed a 9-track standard for magnetic tape and attempted to deal with some punched card formats. The X3.2 subcommittee designed ASCII based on
9409-500: Was tested on a Sun SPARCstation 1 in 1992. In C, it took less than half a second; the same program in INTERCAL took over seventeen hours. The INTERCAL Reference Manual contains many paradoxical, nonsensical, or otherwise humorous instructions: Caution! Under no circumstances confuse the mesh with the interleave operator, except under confusing circumstances! The manual also contains a " tonsil ", as explained in this footnote: "4) Since all other reference manuals have appendices, it
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