Queries
Test data or data contents.
COUNT
Counts the number of items in its input; one input.
Syntax
COUNT word
COUNT list
Description
COUNT reports the number of elements in its input. If its input is a word, COUNT reports the number of characters. If the input is a list, COUNT reports the number of elements in the list.
Examples
COUNT “ELEMENTARY Result: 10 COUNT [ELEMENTARY] Result: 1 COUNT [[MT. WASHINGTON] [MT. RAINIER] [MAUNA LOA]] Result: 3
DEFINED?
Also: DEFINEDP
Checks whether a procedure is defined; one input.
Syntax
DEFINED? name
Description
DEFINED? reports TRUE if the input is a name of a primitive procedure or a user-defined procedure; otherwise it reports FALSE. Compare with PROCEDURE?, which reports TRUE only if the input is a user-defined procedure, and PRIMITIVE?, which reports TRUE only if the input is a built-in command.
Examples
DEFINED? “FORWARD Result: TRUE
EMPTY?
Also: EMPTYP
Checks whether a name is empty; one input.
Syntax
EMPTY? word
EMPTY? list
Description
| EMPTY? reports TRUE if the input is the empty word (“ | ) or the empty list ([]); otherwise, it reports FALSE. |
Examples
MAKE “FRUIT “|| EMPTY? :FRUIT Result: TRUE MAKE “FRUIT [PAPAYA] EMPTY? :FRUIT Result: FALSE
LIST?
Also: LISTP
Checks for its input being a list; one input.
Syntax
LIST? object
Description
LIST? reports TRUE if its input is a list; otherwise, it reports FALSE. See also TYPEOF, NUMBER? and WORD?.
Examples
LIST? [GREEN BLUE] Result: TRUE LIST? “GREEN Result: FALSE LIST? [] Result: TRUE
MACRO?
Also: MACROP
Checks its input for being a macro; one input.
Syntax
MACRO? word
Description
MACRO? reports TRUE if the input word is the name of a Logo macro; otherwise, it reports FALSE. Compare with DEFINED?, which reports TRUE for both primitives and procedures, and PROCEDURE?, which reports FALSE for primitives and TRUE for user-defined procedures. All these commands report similarly for both buried and unburied procedures. See also .MACRO and .DEFMACRO for more information about macros.
Examples
MACRO? “FD Result: FALSE DEFINED? “FD Result: TRUE
MEMBER?
Also: MEMBERP
Checks if an object is part of another object; two inputs.
Syntax
MEMBER? word-or-list word-or-list
Description
MEMBER? reports TRUE if the first input is an element of the second input; otherwise it reports FALSE.
If the second input is a list, MEMBER? compares each element of the list. It does not scan any sublists.
If you need the item number of an object inside another object, use ITEM.
Examples
MEMBER? “A “ABC Result: TRUE MEMBER? [INSIDE] [A [B [INSIDE] C] D] Result: FALSE
NAME?
Also: NAMEP
Checks whether its input is assigned a value; one input.
Syntax
NAME? name
Description
NAME? reports TRUE if the input is a name of a variable; otherwise; it reports FALSE. See also TYPEOF, LIST?, NUMBER?, and WORD?.
Examples
ERASE “ANIMAL NAME? “ANIMAL Result: FALSE MAKE “ANIMAL “CAT NAME? “ANIMAL Result: TRUE
NUMBER?
Also: NUMBERP
Checks its input for being a number; one input.
Syntax
NUMBER? object
Description
NUMBER? reports TRUE if its input is a number; otherwise it reports FALSE. Note that Logo treats quoted numbers or numbers that have been put together as numbers as well. See also LIST?, NAME?, and WORD?.
Examples
NUMBER? WORD “4 “1 Result: TRUE NUMBER? 41 Result: TRUE NUMBER? [41] Result: FALSE NUMBER? FIRST [41] Result: TRUE NUMBER? 4.1 Result: TRUE
PLIST?
Also: PLISTP
Checks its input for containing a property list; one input.
Syntax
PLIST? word
Description
PLIST? outputs TRUE if a property list exists under the given name, FALSE otherwise.
Examples
PLIST “A Result: FALSE PPROP “A “B “C PLIST? “A Result: TRUE
PRIMITIVE?
Also: PRIMITIVEP
Checks its input for being a built-in procedure or macro; one input.
Syntax
PRIMITIVE? word
Description
PRIMITIVE? reports TRUE if the input word is the name of a built-in Logo command or macro; otherwise, it reports FALSE. User-defined procedures or macros are not considered primitives; hence PRIMITIVE? reports FALSE when given their names as input. Compare with DEFINED?, which reports TRUE for both primitives, macros and procedures, and PROCEDURE?, which reports FALSE for primitives and TRUE for user-defined procedures and macros. All these commands report similarly for both buried and unburied procedures and macros. Remember that a macro is a special form of a procedure, see .MACRO for details.
Examples
PRIMITIVE? “FD Result: TRUE PROCEDURE? “FD Result: FALSE DEFINED? “FD Result: TRUE
PROCEDURE?
Also: PROCEDUREP
Checks its input for being a user-defined procedure; one input.
Syntax
PROCEDURE? word
Description
PROCEDURE? reports TRUE if the input word is the name of a user-defined Logo procedure; otherwise, it reports FALSE. Compare with DEFINED?, which reports TRUE for both primitives and procedures, and PRIMITIVE?, which reports TRUE for primitives and FALSE for user-defined procedures. All these commands report similarly for both buried and unburied procedures.
Examples
TO SAY.HELLO PRINT “HELLO END SAY.HELLO defined PRIMITIVE? “SAY.HELLO Result: FALSE PROCEDURE? “SAY.HELLO Result: TRUE DEFINED? “SAY.HELLO Result: TRUE
WORD?
Also: WORDP
Checks its input for being a word; one input.
Syntax
WORD? object
Description
WORD? reports TRUE if its input is a word; otherwise it reports FALSE. See also LIST?, NAME?, and NUMBER?.
Examples
WORD? 123 Result: TRUE WORD? “FD Result: TRUE WORD? [FD] Result: FALSE
EQUAL?
Also: EQUALP, .EQ
Tests its inputs for equality; two inputs.
Syntax
.EQ object object
Description
EQUAL? compares two objects. If they are equal, the output is TRUE; otherwise it is FALSE. The infix operator = does the same for a left and rignt input.
The value of the :EPSILON variable determines how the equality operator compares two numbers. See :EPSILON for details.
Examples
.EQ 5 5 Result: TRUE EQUAL? [6] [6] Result: TRUE EQUAL? 6 [6] Result: FALSE
GREATEREQUAL?
Also: .GE, GREATEREQUALP
Tests if its first input is greater than or equal to its second input; two inputs.
Syntax
.GE word word
Description
GREATEREQUAL? compares two words. If the first word is greater than or equal to the second word, the output is TRUE; otherwise, it is FALSE. The infix operator >= does the same for a left and rignt input.
Examples
GREATEREQUAL? 4 5 Result: FALSE .GE 5 5 Result: TRUE
GREATER?
Also: .GT, GREATERP
Tests if its first input is greater than its second input; two inputs.
Syntax
.GT word word
Description
GREATER? compares two words. If the first word is greater than the second word, the output is TRUE; otherwise it is FALSE. The infix operator > does the same for a left and rignt input.
Examples
.GT 5 5 Result: FALSE
LESSEQUAL?
Also: .LE, LESSEQUALP
Tests if its first input is less than or equal to its second input; two inputs.
Syntax
.LE word word
Description
LESSEQUAL? compares two words. If the first word is less than or equal to the second word, the output is TRUE; otherwise it is FALSE. The infix operator <= does the same for a left and rignt input.
Examples
.LE 4 5 Result: TRUE .LE 5 5 Result: TRUE
LESS?
Also: .LT, LESSP
Tests if its first input is less than its second input; two inputs.
Syntax
.LT number number
Description
LESS? compares two words. If the first word is less than the second word, the output is TRUE; otherwise it is FALSE. The infix operator < does the same for a left and rignt input.
Examples
.LT 4 5 Result: TRUE .LT 5 5 Result: FALSE
NOTEQUAL?
Also: .NE, NOT.EQUAL?, NOTEQUALP, NOT.EQUALP
Tests its inputs for inequality; two inputs.
Syntax
NOTEQUAL? object object
Description
NOTEQUAL? reports TRUE if its two inputs are not equal; otherwise it reports FALSE. Its inputs may be numbers, words, or lists. The infix operator != does the same for a left and rignt input.
The value of the :EPSILON variable determines how the inequality operator compares two numbers. See :EPSILON for details.
Examples
NOTEQUAL? 6 6 Result: FALSE NOTEQUAL? 6 66 Result: TRUE NOTEQUAL? “AZURE “AZURE Result: FALSE NOTEQUAL? [SPRING GREEN] [SPRING GREEN] Result: FALSE NOTEQUAL? “AZURE [AZURE] Result: TRUE