FORTH - ponyatov/orth GitHub Wiki

FORTH

was selected as a command language

due to its simplicity in syntax and implementation

FORTH has a long history in this role from 1968, and it is indomitable as tiny CLI command shell:

extra simple internals
no syntax in fact (dumb lexer can be written in a few machine commands)
require very small resources, can work in a few Kb of RAM and the same quantities of runtime code in ROM
portability: you can rewrite working system from scratch in a weekend

But it has serious drawbacks kicks out FORTH from commercial development:

no system protection: you can do errors on the stack, and data can be written in a random place in memory; OS will drop whole your program by segfault, and this the best case comparing to data corruption by unpredictable disk write or trash requests to DBMS
low-level stack shaking: DUP SWAP smeared out all over the code, +1 step to code unreadability
there is no fool protection in language: no type checking or memory protection barriers, you can write anything to any place in memory; as FORTH mainly targetted for an interactive session, this makes the system in common unstable and error-prone (it's the price of implementation simplicity)
community dissipation due to creeping dialect nature: language itself is atomic, but you can get syntax wars even in a single tiny developing team due to preferences in the order of the parameters on the stack or string format (single object pointer in '84 vs addr/len pair in '94 standards)
language primitivity together with the poverty of stdlib: you must reimplement from scratch everything available out of the shelf in other languages (implementations)

To get the first feel, look into Starting FORTH by Leo Brodie. This is good intro book available online for free. Don't dive too deep, we'll use some non-standard dialect based on objects (it can resemble Factor language). Just become friendly with concatenative programming using a stack and making simple definitions.

appalling nonstandardity

ANS'Forth diy. Really, did you anytime see (not hear) about some software system written in Forth and still in use today? Standardization is good for efforts reuse, but it did not help Forth survive. And inside-outed IF was not engraved on stone tablets given as by the Godly Chuck. The root idea of FORTH was simplicity+flexibility. Chuck Moore itself jumped out into something alien-given like Color Forth...colorblinds were bewildered.

Dialects are bad for developers teams, it exfoliates community. Oops, are they exist, these teams?! Keep free if you can control it.