I will be presenting 4th.CoSy at Ray Cannon's
APL Moot in Surrey England the weekend of August 18

#4th.CoSy
The main focus of this note is to describe progress on the creation of 4th.CoSy . I will be presenting my work so far at the APL "Moot" in Surrey England the weekend of August 18 . So those of you not interested in the teky stuff just skip to Liberty . I will be spending a couple of days in NYC on the way out and Chicago and the farm in Illinois on the way back .

4th.CoSy is melding the most powerful languages at the two ends of the spectrum from machine to man . At the hardware end 4th.CoSy is built in Ron Aaron's new , but rooted in tradition , Reva FORTH . On the human end , is the winnowed product of my decades of creating and living in APL based environments . In a real sense , 4th.CoSy is a new and powerful generation of computing language .

Software creation is among the "everything" the web has changed . Open source code has won major market share for all web utilities . I , for instance , along with millions , use Mozilla browser and email ; all my hosted websites run on Linux ; they use facilities like PHPbb or PunBB bulletin boards , PHPlist mail manager , all these running in MySQL data base . Pov-Ray spectacularly renders the images of my glass tables . These are all open freeware programs . Reva itself is build using a free assembler , FASM .

In language development particularly , a small group of brilliant programmers literally around the globe can and often does outperform what is possible in a proprietary company . My own path from a well regarded proprietary FORTH to the much more nimble Reva is a case in point . With open code and global support even by a small ( but brilliant ) community , use of new and powerful language can be a cost effective but safe business decision .

APL and FORTH are both language families which have identifiable fundamental philosophical goals . APL's ultimate goal is to provide the most powerful succinct vocabulary for expressing finite algorithms . It's roots are in the notation of matrix algebra and applied mathematics . FORTH's goal is to provide the minimal extensible language , ie , a minimal dictionary which provides a vocabulary capable of adding new definitions to itself . That minimality extends to the syntax which is simply to execute the definition of each word as it is encountered .

In both languages the act of programming is the act of constructing vocabularies to deal with the subject of interest . Thus constructing APL in FORTH consists first of creating the many words encapsulating the array abstractions of APL . Since both languages are interactive , that means making an environment with much of the power of APL available in the FORTH static memory milieu . Thus 4th.CoSy provides first of all a sort of an "APL construction set" which provides a platform for implementing and testing various ideas one may have about syntax and vocabulary .

Reva FORTH
FORTH is perhaps an even more under appreciated language than APL . Ken Iverson the creator of APL received the ACM Turing Award , computing's Nobel , in 1979 ; it is unconscionable that Charles Moore , the creator of FORTH has yet to receive his . I tend to categorize programming languages under 4 archetypes , in approximate historical order : ALGOL , LISP , APL , FORTH . Almost all common languages from COBOL to C to Java fall under the ALGOL category .

There are a number of original and unique aspects of FORTH :

• As mentioned above , FORTH has the simplest possible syntax . any non-blank string of characters separated by a blank is a valid name . Interpretation consists of starting at the beginning of a line , parsing up to the first space and looking up the word in the dictionary of existing words .

• FORTH is a stack based language . LIFO "last in first out" stacks are fundamental in any modern computer and language design . FORTH uses 2 stacks . When a word B is encountered in the execution of the definition of a word A , word A is pushed on a return stack so when execution of word B is completed , it can resume execution of word A . Data is passed from word to word by pushing it on a data stack where it is found by the next word being executed . The purity of this structure is starting to become recognized as the exemplar of concatinative languages .

• More than any other language , FORTH recognizes that languages are not simply a horizon of immutable definitions . Rather , words are built upon previously ( some simultaneously ) defined words . The existence of the higher level definitions does not obviate the potential utility of the component concepts . For instance , it is very common to have a word , for instance , create , which parses the next word in the input and makes a new entry in the dictionary for it . It's definition will be essentially   parsews (create)   where parsews parses the next word and returns it's address and length , and (create) is the same as create but expects the address and length of a character string .

• Compilation in FORTH , the process of adding words to the dictionary is very sophisticated and subtle . I won't go into it further , but suffice it to say you have total control over what happens while a word is being defined versus when it is executed in the course of interpretation . This provides great power but also potential "gotcha"s .

APL
I'll say less about APL because I've written much more about it elsewhere , and The APLers I'm going to be "moot"ing with already are experts in it . The power of APLs lie mainly in a compact vocabulary of sophisticated verbs which act on very regular but extremely general data structures . The basic data structure is dynamic reference counted lists of lists with the leaves themselves generally being homogeneous byte , integer , or float lists . I intend to be the simplest , yet among the most powerful APLs . I am implementing a number of concepts from Arthur Whitney's   K   but not his syntax which will basically be APL's infix ( "noun verb noun" , eg , 1 + 2 and "noun verb adverb noun" , eg , 5 drop each list ) but determined largely by the words themselves rather than being table driven . The flexibility of the interpretive FORTH environment makes experimentation on such matters feasible .
One innovation I've made which I find quite successful is modulo indexing which eliminates such notions as "scalar extension" - APLers know what I'm talking about .

There is much more to be said , but bottom line , if you can make it to Surrey the latter part of August , you'll be able to see an offspring of two of the great lines of computing language , and the ground work for the next generation executive note-computing environment .