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2.1 Constructors 2.2 Data Selectors 2.3 Data Mutators 2.4 Predicates 2.5 Queries
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word list sentence fput lput array mdarray listtoarray arraytolist combine reverse gensym
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WORD word1 word2 (WORD word1 word2 word3 ...) |
outputs a word formed by concatenating its inputs.
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LIST thing1 thing2 (LIST thing1 thing2 thing3 ...) |
outputs a list whose members are its inputs, which can be any Logo datum (word, list, or array).
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SENTENCE thing1 thing2 SE thing1 thing2 (SENTENCE thing1 thing2 thing3 ...) (SE thing1 thing2 thing3 ...) |
outputs a list whose members are its inputs, if those inputs are not lists, or the members of its inputs, if those inputs are lists.
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FPUT thing list |
outputs a list equal to its second input with one extra member, the first input, at the beginning.
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LPUT thing list |
outputs a list equal to its second input with one extra member, the first input, at the end.
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ARRAY size (ARRAY size origin) |
outputs an array of size
members (must be a positive integer), each of
which initially is an empty list. Array members can be selected with
ITEM and changed with SETITEM. The first member of the array is member
number 1 unless an origin
input (must be an integer) is given, in
which case the first member of the array has that number as its index.
(Typically 0 is used as the origin if anything.) Arrays are printed by
PRINT and friends, and can be typed in, inside curly braces; indicate an
origin with {a b c}@0.
See section item , setitem , print .
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MDARRAY sizelist (library procedure) (MDARRAY sizelist origin) |
outputs a multi-dimensional array. The first input must be a list of one or more positive integers. The second input, if present, must be a single integer that applies to every dimension of the array.
Ex: (MDARRAY [3 5] 0) outputs a two-dimensional array whose members range from [0 0] to [2 4].
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LISTTOARRAY list (LISTTOARRAY list origin) |
outputs an array of the same size as the input list, whose members are the members of the input list.
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ARRAYTOLIST array |
outputs a list whose members are the members of the input array. The first member of the output is the first member of the array, regardless of the array's origin.
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COMBINE thing1 thing2 (library procedure) |
if thing2 is a word, outputs WORD thing1 thing2. If thing2 is a list, outputs FPUT thing1 thing2.
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REVERSE list (library procedure) |
outputs a list whose members are the members of the input list, in reverse order.
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GENSYM (library procedure) |
outputs a unique word each time it's invoked. The words are of the form G1, G2, etc.
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first firsts last butfirst butfirsts butlast item mditem pick remove remdup quoted
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FIRST thing |
if the input is a word, outputs the first character of the word. If the input is a list, outputs the first member of the list. If the input is an array, outputs the origin of the array (that is, the INDEX OF the first member of the array).
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FIRSTS list |
outputs a list containing the FIRST of each member of the input list. It is an error if any member of the input list is empty. (The input itself may be empty, in which case the output is also empty.) This could be written as
to firsts :list output map "first :list end |
but is provided as a primitive in order to speed up the iteration tools MAP, MAP.SE, and FOREACH.
to transpose :matrix if emptyp first :matrix [op []] op fput firsts :matrix transpose bfs :matrix end |
See section map , map.se , foreach
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LAST wordorlist |
if the input is a word, outputs the last character of the word. If the input is a list, outputs the last member of the list.
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BUTFIRST wordorlist BF wordorlist |
if the input is a word, outputs a word containing all but the first character of the input. If the input is a list, outputs a list containing all but the first member of the input.
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BUTFIRSTS list BFS list |
outputs a list containing the BUTFIRST of each member of the input list. It is an error if any member of the input list is empty or an array. (The input itself may be empty, in which case the output is also empty.) This could be written as
to butfirsts :list output map "butfirst :list end |
but is provided as a primitive in order to speed up the iteration tools MAP, MAP.SE, and FOREACH.
See section map , map.se , foreach
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BUTLAST wordorlist BL wordorlist |
if the input is a word, outputs a word containing all but the last character of the input. If the input is a list, outputs a list containing all but the last member of the input.
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ITEM index thing |
if the thing
is a word, outputs the index
th character of the word.
If the thing
is a list, outputs the index
th member of the list. If
the thing
is an array, outputs the index
th member of the array.
Index
starts at 1 for words and lists; the starting index of an array
is specified when the array is created.
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MDITEM indexlist array (library procedure) |
outputs the member of the multidimensional array
selected by the list
of numbers indexlist
.
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PICK list (library procedure) |
outputs a randomly chosen member of the input list.
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REMOVE thing list (library procedure) |
outputs a copy of list
with every member equal to thing
removed.
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REMDUP list (library procedure) |
outputs a copy of list
with duplicate members removed. If two or more
members of the input are equal, the rightmost of those members is the
one that remains in the output.
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QUOTED thing (library procedure) |
outputs its input, if a list; outputs its input with a quotation mark prepended, if a word.
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setitem mdsetitem .setfirst SETFIRST .setbf SETBF .setitem SETITEM push pop queue dequeue
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SETITEM index array value |
command. Replaces the index
th member of array
with the new value
.
Ensures that the resulting array is not circular, i.e., value
may not
be a list or array that contains array
.
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MDSETITEM indexlist array value (library procedure) |
command. Replaces the member of array
chosen by indexlist
with the
new value
.
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.SETFIRST list value |
command. Changes the first member of list
to be value
.
WARNING: Primitives whose names start with a period are DANGEROUS. Their use by non-experts is not recommended. The use of .SETFIRST can lead to circular list structures, which will get some Logo primitives into infinite loops; unexpected changes to other data structures that share storage with the list being modified; and the loss of memory if a circular structure is released.
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.SETBF list value |
command. Changes the butfirst of list
to be value
.
WARNING: Primitives whose names start with a period are DANGEROUS.
Their use by non-experts is not recommended. The use of .SETBF can lead
to circular list structures, which will get some Logo primitives into
infinite loops; unexpected changes to other data structures that share
storage with the list being modified; Logo crashes and coredumps if the
butfirst of a list is not itself a list; and the loss of memory if a
circular structure is released.
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.SETITEM index array value |
command. Changes the index
th member of array
to be value
, like
SETITEM, but without checking for circularity.
WARNING: Primitives whose names start with a period are DANGEROUS. Their use by non-experts is not recommended. The use of .SETITEM can lead to circular arrays, which will get some Logo primitives into infinite loops; and the loss of memory if a circular structure is released.
See section setitem.
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PUSH stackname thing (library procedure) |
command. Adds the thing
to the stack that is the value of the
variable whose name is stackname
. This variable must have a list as
its value; the initial value should be the empty list. New members are
added at the front of the list.
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POP stackname (library procedure) |
outputs the most recently PUSHed member of the stack that is the value
of the variable whose name is stackname
and removes that member from
the stack.
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QUEUE queuename thing (library procedure) |
command. Adds the thing
to the queue that is the value of the
variable whose name is queuename
. This variable must have a list as
its value; the initial value should be the empty list. New members are
added at the back of the list.
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DEQUEUE queuename (library procedure) |
outputs the least recently QUEUEd member of the queue that is the value
of the variable whose name is queuename
and removes that member from
the queue.
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wordp listp arrayp emptyp equalp beforep .eq EQ memberp substringp numberp backslashedp
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WORDP thing WORD? thing |
outputs TRUE if the input is a word, FALSE otherwise.
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LISTP thing LIST? thing |
outputs TRUE if the input is a list, FALSE otherwise.
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ARRAYP thing ARRAY? thing |
outputs TRUE if the input is an array, FALSE otherwise.
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EMPTYP thing EMPTY? thing |
outputs TRUE if the input is the empty word or the empty list, FALSE otherwise.
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EQUALP thing1 thing2 EQUAL? thing1 thing2 thing1 = thing2 |
outputs TRUE if the inputs are equal, FALSE otherwise. Two numbers are equal if they have the same numeric value. Two non-numeric words are equal if they contain the same characters in the same order. If there is a variable named CASEIGNOREDP whose value is TRUE, then an upper case letter is considered the same as the corresponding lower case letter. (This is the case by default.) Two lists are equal if their members are equal. An array is only equal to itself; two separately created arrays are never equal even if their members are equal. (It is important to be able to know if two expressions have the same array as their value because arrays are mutable; if, for example, two variables have the same array as their values then performing SETITEM on one of them will also change the other.)
See section caseignoredp , setitem
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BEFOREP word1 word2 BEFORE? word1 word2 |
outputs TRUE if word1 comes before word2 in ASCII collating sequence (for words of letters, in alphabetical order). Case-sensitivity is determined by the value of CASEIGNOREDP. Note that if the inputs are numbers, the result may not be the same as with LESSP; for example, BEFOREP 3 12 is false because 3 collates after 1.
See section caseignoredp , lessp
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.EQ thing1 thing2 |
outputs TRUE if its two inputs are the same datum, so that applying a mutator to one will change the other as well. Outputs FALSE otherwise, even if the inputs are equal in value.
WARNING: Primitives whose names start with a period are DANGEROUS. Their use by non-experts is not recommended. The use of mutators can lead to circular data structures, infinite loops, or Logo crashes.
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MEMBERP thing1 thing2 MEMBER? thing1 thing2 |
if thing2
is a list or an array, outputs TRUE if thing1
is EQUALP to
a member of thing2
, FALSE otherwise. If thing2
is a word, outputs
TRUE if thing1
is a one-character word EQUALP to a character of
thing2
, FALSE otherwise.
See section equalp .
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SUBSTRINGP thing1 thing2 SUBSTRING? thing1 thing2 |
if thing1
or thing2
is a list or an array, outputs FALSE. If
thing2
is a word, outputs TRUE if thing1
is EQUALP to a substring of
thing2
, FALSE otherwise.
See section equalp .
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NUMBERP thing NUMBER? thing |
outputs TRUE if the input is a number, FALSE otherwise.
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BACKSLASHEDP char BACKSLASHED? char |
outputs TRUE if the input character was originally entered into Logo with a backslash (\) before it or within vertical bars (|) to prevent its usual special syntactic meaning, FALSE otherwise. (Outputs TRUE only if the character is a backslashed space, tab, newline, or one of ()[]+-*/=<>":;\~?| )
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count ascii rawascii char member lowercase uppercase standout parse runparse
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COUNT thing |
outputs the number of characters in the input, if the input is a word; outputs the number of members in the input, if it is a list or an array. (For an array, this may or may not be the index of the last member, depending on the array's origin.)
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ASCII char |
outputs the integer (between 0 and 255) that represents the input character in the ASCII code. Interprets control characters as representing backslashed punctuation, and returns the character code for the corresponding punctuation character without backslash. (Compare RAWASCII.)
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RAWASCII char |
outputs the integer (between 0 and 255) that represents the input character in the ASCII code. Interprets control characters as representing themselves. To find out the ASCII code of an arbitrary keystroke, use RAWASCII RC.
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CHAR int |
outputs the character represented in the ASCII code by the input, which must be an integer between 0 and 255.
See section ascii .
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MEMBER thing1 thing2 |
if thing2
is a word or list and if MEMBERP with these inputs would
output TRUE, outputs the portion of thing2
from the first instance of
thing1
to the end. If MEMBERP would output FALSE, outputs the empty
word or list according to the type of thing2
. It is an error for
thing2
to be an array.
See section memberp .
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LOWERCASE word |
outputs a copy of the input word, but with all uppercase letters changed to the corresponding lowercase letter.
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UPPERCASE word |
outputs a copy of the input word, but with all lowercase letters changed to the corresponding uppercase letter.
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STANDOUT thing |
outputs a word that, when printed, will appear like the input but displayed in standout mode (boldface, reverse video, or whatever your terminal does for standout). The word contains terminal-specific magic characters at the beginning and end; in between is the printed form (as if displayed using TYPE) of the input. The output is always a word, even if the input is of some other type, but it may include spaces and other formatting characters. Note: a word output by STANDOUT while Logo is running on one terminal will probably not have the desired effect if printed on another type of terminal.
On the Macintosh, the way that standout works is incompatible with the use of characters whose ASCII code is greater than 127. Therefore, you have a choice to make: The instruction
CANINVERSE 0 |
CANINVERSE 1 |
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PARSE word |
outputs the list that would result if the input word were entered in response to a READLIST operation. That is, PARSE READWORD has the same value as READLIST for the same characters read.
See section readlist , readword
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RUNPARSE wordorlist |
outputs the list that would result if the input word or list were entered as an instruction line; characters such as infix operators and parentheses are separate members of the output. Note that sublists of a runparsed list are not themselves runparsed.
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