Henceforth

This is Henceforth, a simple interpreter for a Forth-like stack-based language.

Installation

For compiling from the source, clone this repository and then run

cd ${HF_DIR} && cmake . && make

where ${HF_DIR} is the path to the cloned directory. The binary will then be compiled to ./henceforth

Usage

henceforth [-e] [file.fth ...]

Henceforth accepts any number of file names as arguments. It interprets all the files specified in order and then opens an interactive user shell on standard input. The interactive shell will not be spawned if the user supplies the -e option.

Supported commands

Henceforth supports the following words from the Forth CORE dictionary:

+, -, *, /, MOD, /MOD, RSHIFT, LSHIFT
1+, 1-, 2*, 2/, 0=, 0<
TRUE, FALSE
<, >, =, <>, MAX, MIN, WITHIN
AND, OR, XOR, NEGATE, INVERT
DUP, DROP, ., CR, SWAP, OVER, ROT, DEPTH
:, ;, \, (

In addition, Henceforth supports the following Forth words exclusively in the compilation environment:

IF, ELSE, THEN, BEGIN, WHILE, REPEAT, AGAIN
DO, ?DO, LOOP, +LOOP, LEAVE, UNLOOP, I, J
.", RECURSE, EXIT

To find out more about the usage of the words listed above, see the Forth standard website.

Differences from the Forth standard

While Henceforth generally tries to adhere to the Forth standard, there are a few notable exceptions:

Henceforth only supports signed integers as a data type. No other data types are available for use on the stack. (Technically, flags and do-sys are emulated using signed integers.)
Other than \ and (, Henceforth doesn't support immediate words at the moment.

Developer documentation

Documentation for developers is available both as part of the source code itself and in the Wiki.

lunakv / henceforth