Map Statements

Note

While this section is up-to-date and complete, it has to be reformated to be easier on the eyes. All UPPERCASE statement names and code should be changed to lowercase.

CLEAR

The CLEAR statement empties a MAP, thus deleting all its contents. The MAP itself is not deleted though, and can still be used and filled with new elements after a CLEAR statement has been executed.

Syntax:

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CLEAR <MAP>

COPY _ TO _

The COPY - TO statement copies all the elements of a MAP with their respective keys to another MAP of the same type. The original MAP is untouched, but the destination MAP is completely overwritten by the contents of the copied MAP and any elements that existed in it prior to the copy are deleted. In other words, the destination MAP is CLEARed before the copy.

Syntax:

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COPY <TEXT-MAP> TO <TEXT-MAP>
COPY <NUMBER-MAP> TO <NUMBER-MAP>

Example:

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DATA:
    foo IS TEXT MAP
    bar IS TEXT MAP
PROCEDURE:
    STORE "Hello there!" IN foo:0
    STORE "How are you?" IN foo:7
    COPY foo TO bar
    DISPLAY bar:0 " " bar:7 CRLF
    # Will display "Hello there! How are you?"

GET KEY COUNT OF _ IN _

The GET KEY COUNT OF - IN statement stores the amount of elements (or, analogously, keys) stored in a MAP into a numeric variable.

Syntax:

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GET KEY COUNT OF <MAP> IN <NUMBER-VAR>

Example:

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DATA:
    foo IS TEXT MAP
    count IS NUMBER
PROCEDURE:
    STORE "Hello there!" IN foo:0
    STORE "How are you?" IN foo:7
    GET KEY COUNT OF foo IN count
    DISPLAY count CRLF
    # Will display 2

GET KEYS OF _ IN _

The GET KEYS OF - IN statement stores all the keys of a MAP into a TEXT LIST. Say you have a MAP with keys 0, "cat" and "dog". The elements these keys point to are not important. Using the GET KEYS OF statement, you can copy the keys of this MAP to a LIST. Thus, the resulting LIST will (for example) have the value 0 at index 0, the value "cat" at index 1 and the value "dog" at index 2. This statement is thus used to find all the keys of a particular MAP.

Syntax:

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GET KEYS OF <MAP> IN <TEXT-LIST>

Example:

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DATA:
    foo IS TEXT MAP
    bar IS TEXT LIST
PROCEDURE:
    STORE "Hello there!" IN foo:0
    STORE "How are you?" IN foo:7
    STORE "I like cats" IN foo:"cat"
    STORE "I love dogs" IN foo:"dog"
    STORE "LDPL is nice" IN foo:3
    GET KEYS OF foo IN bar

At the end of the execution of the previous excerpt of code, the TEXT LIST called bar will contain the values "0", "7", "cat", "dog" and "3" at indexes that are consecutive integers starting at zero.