Reva has built-in help, which is mostly complete (NOTE: should you find inadequacies, please report them!)
There are several help-related words inside Reva, help help/. They are used like this:
help help <i>someword</i> help/ <i>someword</i>
help without arguments gives a short usage message. help word looks for the word word in the help database. If it is present there, it will show the help text associated with it as well as some other pertinent information. If there is more than one matching word, all matching words and their help will be shown.
help/ word looks for word, matching partially both the names of words and their descriptions. The result will be a list of all words which either match word, or have word in the description somewhere.
Example help will look like:
dup ( a -- a a ) 'inline Context: ~ Source in: src/reva.f Duplicate the top stack item SEE ALSO: (s0) -2nip -rot -swap .rs .s 2drop 2dup 2nip 2over 2swap 3drop 3dup 4dup ?dup depth drop nip over pick put rdepth rot s0 stack-ops swap tuck
The first line gives the "stack effect diagram" of the word. That is, what its inputs and outputs are. The next bit (after the closing parenthesis) is the class to which the word belongs.
The next line shows in which context the word can be found. That context must be in the search list when trying to use the word (from the interpreter: once the word has been compiled, it makes no difference what the search list state is).
The third line shows the source file in which the word was defined.
Then comes the description of the action of the word, its side-effects and any caveats or examples.
Finally, a list of related words. They may be fairly distantly related, and some words which you would think should be in the list may not appear.
Special help: There are certain special help topics, which help by itself will tell you about. For example, help libraries will display a list of all the libraries the Reva system knew about when the help was created.
Asking for help on a library will display all words in the library for which help was defined.
Asking for help on a context will display all words in the context for which help was defined.
Languages other than English
Reva's help system also supports languages other than English. At present, only German help is defined (and it is incomplete relative to the English help).
Accessing help in other languages is simple. If you define the 'REVALANG' environment variable and give it the two-letter language code for the help language you prefer, Reva will give you help in that language if it exists. If it doesn't, Reva will give you the English language help -- on the theory that some help is better than none.
Currently available help languages (besides English):
- de -- German