Putting things together
This section contains all commands that put together Logo words or lists, or access elements of Logo words or lists.
FPUT
Prepends an element to its input.
Syntax
FPUT word word
FPUT word list
FPUT list list
Description
FPUT reports the word or list that is created by putting the first input at the beginning of the second input. If both inputs are words, FPUT reports a word; otherwise it reports a list. See also LIST, LPUT, SENTENCE, and WORD.
Example
FPUT “A “BC Result: ABC FPUT 1 23 Result: 123 FPUT “A [GREEN CHEVY] Result: [A GREEN CHEVY] FPUT [NORTH DAKOTA] [NEW HAMPSHIRE] Result: [[NORTH DAKOTA] NEW HAMPSHIRE]
ISEQ
Outputs a list of sequential integers.
Syntax
ISEQ from to
(ISEQ from to increment)
Description
ISEQ outputs a list of the integers from FROM to TO, inclusive. If an increment is given as an optional third input, the integers are created using the given increment; if no increment is given, the increment is 1 if FROM is less than TO, or -1 if FROM is greater than TO. Note that if the increment is not 1 or -1, the TO value may not be part of the list; for example, the output of (ISEQ 1 5 3) would not contain the value 5, because the next value to add would have been 6 instead of 5.
Example
ISEQ 5 10 Result: [5 6 7 8 9 10] ISEQ 10 5 Result: [10 9 8 7 6 5] (ISEQ 5 10 2) Result: [5 7 9]
LIST
Concatenates its inputs to a list.
Syntax
LIST object1 object2
(LIST object1 object2 object3 ...)
Description
LIST reports a list composed of its inputs. The inputs to LIST can be either words or lists. If the inputs to LIST are themselves lists, LIST preserves them as lists. LIST expects two inputs, but can accept more or less if it and all its inputs are enclosed in parentheses. See also FPUT, LPUT, SENTENCE, and WORD.
Example
LIST “NORTH “CAROLINA Result: [NORTH CAROLINA] LIST [TO BE] [OR NOT TO BE] Result: [[TO BE] [OR NOT TO BE]]
LPUT
Appends an element to its input.
Syntax
LPUT word word
LPUT word list
LPUT list list
Description
LPUT reports a new object that is created by placing the first input at the end of the second input. The inputs to LPUT can be either words or lists. If the first input is a list, the second cannot be a word. If both inputs are words, LPUT reports a word. See also LIST, FPUT, SENTENCE, and WORD.
Example
LPUT “ISSIPPI “MISS Result: MISSISSIPPI LPUT [COLORADO] [MISS] Result: [MISS [COLORADO]] LPUT FIRST [X Y Z] [A B C D] Result: [A B C D X]
PARSE
Parses a string and outputs a list.
Syntax
PARSE word
Description
PARSE reads its input and converts it to a list.
The Listener procedure that Logo uses to evaluate user input is roughly written as:
TO LISTENER
RUN PARSE READQUOTE
LISTENER
END
Example
PARSE “|hi world| Result: [HI WORLD] PARSE “|(a b c)| Result: [(A B C)]
RSEQ
Outputs a list of equally spaced rational numbers.
Syntax
RSEQ from to count
Description
RSEQ outputs a list of COUNT equally spaced rational numbers between FROM and TO, inclusive.
Example
RSEQ 4 5 6 Result: [4 4.17 4.33 4.5 4.67 4.83]
SENTENCE
Also: SE
Concatenates its inputs to a list, flattening lists.
Syntax
SENTENCE object1 object2
(SE object1 object2 object3 ...)
Description
SENTENCE reports a list made up of its inputs. SENTENCE expects two inputs, but will accept more if it and all of its inputs are enclosed in parentheses. If the inputs to SENTENCE are lists, their brackets are removed and combined into one list. See also FPUT, LPUT, LIST, and WORD.
Example
SENTENCE “NICEST “MONTH Result: [NICEST MONTH] SENTENCE [APRIL IS THE][NICEST MONTH] Result: [APRIL IS THE NICEST MONTH]
SUBST
Substitutes text in a word or a list.
Syntax
SUBST what with wordorlist
Description
SUBST performs a replacement of text in its arguments. It replaces all occurrences of its first input with its second input inside the word or list given as its third input. If the third input is a list, the replacement is recursive and affects all lists inside the list. If the list element to be replaced is quoted, the replaced text remains quoted. In the same way, leading colons are preserved.
Example
Quotes and colons are preserved.
SUBST “JUNK “NEW [A JUNK BOX] Result: [A NEW BOX] SUBST “? “X “A?B?C Result: AXBXC SUBST “? “MIKE [HELLO ? [HOW ARE YOU ?]] Result: [HELLO MIKE [HOW ARE YOU MIKE]]
WORD
Concatenates its inputs to a word.
Syntax
WORD object1 object2
(WORD object1 object2 object3 ...)
Description
WORD contatenates its inputs, which must not be lists, to a single word.
Example
WORD “NICEST “MONTH Result: NICESTMONTH