Natural is a fourth-generation programming language from Software AG. It is largely used for building databases output in plain text form, for example.* Hello World in NATURAL WRITE 'Hello World!' END
It has the
ESCAPE TOP flow control instruction, which is similar to
continue in C, C++, Java and several other languages, except that it also works within subroutines to both return from the routine and then continue the calling statement's processing loop.
continue, it avoids large amounts of indentation levels when using nested instruction blocks inside any loop.
Example with ESCAPE TOP:DEFINE DATA LOCAL 1 I (N3) /* 3 digits without decimals END-DEFINE FOR I = 2 TO 100 IF (I / 2 * 2) = I AND I > 2 WRITE 'Number' I 'is divisible by 2' ESCAPE TOP END-IF IF (I / 3 * 3) = I AND I > 3 WRITE 'Number' I 'is divisible by 3' ESCAPE TOP END-IF IF (I / 5 * 5) = I AND I > 5 WRITE 'Number' I 'is divisible by 5' ESCAPE TOP END-IF IF (I / 7 * 7) = I AND I > 7 WRITE 'Number' I 'is divisible by 7' ESCAPE TOP END-IF IF (I / 11 * 11) = I AND I > 11 WRITE 'Number' I 'is divisible by 11' ESCAPE TOP END-IF WRITE 'Number' I 'is prime' END-FOR END
The levels of indentation can be automatically adjusted with the STRUCT command in the Natural Editor.
The same example, without ESCAPE TOP:DEFINE DATA LOCAL 1 I (N3) /* 3 digits without decimals END-DEFINE FOR I = 2 TO 100 IF (I / 2 * 2) = I AND I > 2 WRITE 'Number' I 'is divisible by 2' ELSE IF (I / 3 * 3) = I AND I > 3 WRITE 'Number' I 'is divisible by 3' ELSE IF (I / 5 * 5) = I AND I > 5 WRITE 'Number' I 'is divisible by 5' ELSE IF (I / 7 * 7) = I AND I > 7 WRITE 'Number' I 'is divisible by 7' ELSE IF (I / 11 * 11) = I AND I > 11 WRITE 'Number' I 'is divisible by 11' ELSE WRITE 'Number' I 'is prime' END-IF END-IF END-IF END-IF END-IF END-FOR END
Another powerful flow control instruction command is the
ESCAPE BOTTOM, which is similar to
ESCAPE TOP except that it continues the processing from end of the calling statement's processing loop. Example with ESCAPE BOTTOM:
One trait that sets Natural apart from most other languages is its rich syntax. For example, many languages have a simple switch case statement that can be used to replace nested IF statements pertaining to a single variable; in C-like languages, it is prone to logic errors since it is necessary to BREAK out of the statement programatically. Natural has a much cleaner/richer DECIDE statement which is easier to understand and code. Here is an example:DECIDE ON FIRST VALUE MARITAL-STATUS VALUE 'M' DESC := 'Married' VALUE 'D' DESC := 'Divorced' VALUE 'W' DESC := 'Widowed' ANY ONCE-MARRIED := TRUE NONE DESC := 'Single' END-DECIDE
Famous quotes containing the word natural:
“The problem of the novelist who wishes to write about a mans encounter with God is how he shall make the experiencewhich is both natural and supernaturalunderstandable, and credible, to his reader. In any age this would be a problem, but in our own, it is a well- nigh insurmountable one. Todays audience is one in which religious feeling has become, if not atrophied, at least vaporous and sentimental.”
—Flannery OConnor (19251964)
“Parents fear lest the natural love of their children may fade away. What kind of nature is that which is subject to decay? Custom is a second nature which destroys the former. But what is nature? For is custom not natural? I am much afraid that nature is itself only a first custom, as custom is a second nature.”
—Blaise Pascal (16231662)
“She atoned for want of devotion to God, by devotion to man. She had a womans natural tendency towards asceticism, self-extinction, self-abnegation.”
—Henry Brooks Adams (18381918)