.TH BFSH 1 "" "v.69" "BrainF* SHell"
.SH NAME
BFSH \- An interactive command line shell for the Brainf* language
.SH SYNOPSIS
.B bfsh [-a] [-l TAPELENGTH] [-s]
.SH DESCRIPTION
BFSH is a command line shell that repeatedly accepts and evaluates user input as Brainf* source code. The shell allows users to input Brainf* source code, comments, and macro procedures.
.SH USAGE
Usage of BFSH is rather straight-forward, for the most part. The user may provide Brainf* source through keyboard input and bind names to text as procedures, allowing for a level of abstraction. The shell also makes use of the GNU readline library for usage of simple history functions and a peristent history file. When a given line of input ends with an opened loop, '[', a subprompt begins, delaying interpretation of all input. This subprompt is ended when the first character of the line is ']' , and interpretation resumes. Currently, nested loops may allow for undefined behavior when using this subprompt scheme. The shell will exit on ^D.
.SH MACROS
In accordance with proper Brainf* interpretation, all non-BF operations are considered comments and not evaluated. Any 'comments' separated from other code by spaces may be used to define or call macro'd procedures. If the section of code is not a named procedure, it is processed as normal Brainf*. Macros can be defined as [NAME=PROCEDURE], where NAME and PROCEDURE may be any combination of Brainf* operations and other characters, ended with a space. NAME itself may even contain Brainf* operations, though they won't be treated as such when used as a procedure; +=- is entirely valid. BFSH also comes with a few predefined macros to play with.
.SH MACRO EXAMPLES
.B add (predefined)
		    ,>, [-<+>] .<.
.sp
.B pushLeftOne (predefined)
	 [-<+>]
.sp
.B pushRightOne (predefined)
	[->+<]
.sp
.B Output 2
				  +++ minus=- minus \&.
.sp
.B Redefine minus
			 minus=+++[-]