NATURAL

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.

Like 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:

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 BOTTOM END-IF IF (I / 3 * 3) = I AND I > 3 WRITE 'Number' I 'is divisible by 3' ESCAPE BOTTOM END-IF IF (I / 5 * 5) = I AND I > 5 WRITE 'Number' I 'is divisible by 5' ESCAPE BOTTOM END-IF IF (I / 7 * 7) = I AND I > 7 WRITE 'Number' I 'is divisible by 7' ESCAPE BOTTOM END-IF IF (I / 11 * 11) = I AND I > 11 WRITE 'Number' I 'is divisible by 11' ESCAPE BOTTOM END-IF WRITE 'Number' I 'is prime' END-FOR END

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

Other articles related to "natural":

Economy Of Ukraine - Natural Resources
... Ukraine is relatively rich in natural resources, particularly in mineral deposits ... Although oil and natural gas reserves in the country are largely exhausted, it has other important energy sources, such as coal, hydroelectricity and nuclear fuel raw materials ...
Fossil Fuel - Origin
... Petroleum and natural gas are formed by the anaerobic decomposition of remains of organisms including phytoplankton and zooplankton that settled to the sea (or lake) bottom in large ... Some fuels like natural gas, for instance, contain only very low boiling, gaseous components ... plants also form type III kerogen, a source of natural gas ...
Natural Capital
... Natural capital is the extension of the economic notion of capital (manufactured means of production) to goods and services relating to the natural environment ... Natural capital is thus the stock of natural ecosystems that yields a flow of valuable ecosystem goods or services into the future ... Natural capital may also provide services like recycling wastes or water catchment and erosion control ...
Humanae Vitae - Summary - Appeal To Natural Law and Conclusion
... Public authorities should oppose laws which undermine natural law scientists should further study effective methods of natural birth control doctors should further familiarize themselves with this ...
Economy Of Turkey - External Trade and Investment
32% has been invested in Russia, primarily in the natural resources and construction sector, and 46% in Turkey’s Black Sea neighbours, Bulgaria and Romania ... rose to $162.1 billion, mostly due to the rising demand for energy resources like natural gas and crude oil ... Share of natural gas decreased from 74% in 1980 to 30% in 1990 and 12% in 2005 ...

Famous quotes containing the word natural:

    If the most significant characteristic of man is the complex of biological needs he shares with all members of his species, then the best lives for the writer to observe are those in which the role of natural necessity is clearest, namely, the lives of the very poor.
    —W.H. (Wystan Hugh)

    Of all natural forces, vitality is the incommunicable one.... Vitality never “takes.” You have it or you haven’t it, like health or brown eyes or a baritone voice.
    F. Scott Fitzgerald (1896–1940)

    The natural flights of the human mind are not from pleasure to pleasure, but from hope to hope.
    Samuel Johnson (1709–1784)