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Introducing the new 7th programming language

The 7th® programming language is based on the concepts of Charles Henry Moore's "Problem Oriented Language".

Because of its unique interpreting compiler, Forth™ makes programming quite easy and a compiled program – called “word” – is very compact.
The programming language 7th runs as such an interpreting compiler for stability and portability on the JVM.
Beside Forth's major features 7th brings several enhancements, to name some
 • object orientation
 • help function
 • redirecting of program output
 • complex numbers
 • array and array functions
 • pattern matching

The functions of the "Klassenbibliothek" formerly found here are all included in 7th.
7th comes with an complete development system, with an editor and a code beautifier that does syntax highlighting and correct indentation in a very small package.

Comment syntax

To comment out the rest of the line use //
//  Loop through numbers from 1 to 10.000

to show the stack behavior of a word use ( -- )  "-" two times!
: facul  ( n -- facul )

to comment out a part of a line use (* *)
row i @ (* occupied *) 'x' == if

Text inside round braces is interpreted as an algebraic expression ( )

7th IDE – Try Out

7th Try Out Page ***Oracle has announced that Java Applets and WebStart functionality, including the Applet API, the Java plug-in, the Java Applet Viewer, JNLP and Java Web Start are all deprecated in JDK 9 and will be removed in a future release.***
No need to support Web Start on this page any further. You can now download a minimal JRE file with the Seventh.jar 7th IDE contained for Windows.
Or if You have already JavaTM installed in version 11 or newer, You can download the file Seventh.jar separately.

Webstart on Linux

Web Start was a replacement after removing the Applet functionality from the browsers and always some kind of an overkill for deploying the relatively small Seventh.jar 7th IDE program.
You can download and install the open-source JDK's for most popular Linux distributions here:


7th IDE features

object orientation

variable x

0.5 x !

"string" x !

ERR: ”x” expects java.lang.Number — found java.lang.String…

help function

redirecting of program output

ok> help .us

— .us —


prints the user stack


--nope     don't execute the word


--verbose  prints what would happen, when the word is executed


--str      pushes the output as string onto the stack instead of printing


--out      redirects the message to the given file


--append   appends the message to the given file


complex numbers

ok> (3, 4i)

ok> (5, 6i)

ok> *

ok> .s

› (-9, 38i)

array and array functions

ok> 8 int-array numbers

ok> 7 numbers 0 !

ok> numbers .s

› Create…Integer[8]+[7, 0, 0, 0, 0, 0, 0, 0]‹numbers›

pattern matching

find a  /pattern/  ~~

match a /pattern/ =~

ok> "text" /ex/    ~~ .s

› true

ok> "text" /.ex./  =~ .s

› true

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