Expression format accepted by bool:
<equation> = <token> = <expr>;
<expr> = <expr> <opr> <expr> | (<expr>) | <not> <expr> |
<expr> | <token> | <constant>
<not> = '!' | '~' | '/'
<constant> = '1' | '0'
<token> = <alpha>[<alphanum>[<alphanum>...]]
<alpha> = 'a' .. 'z' | 'A' .. 'Z'
<alphanum> = <alpha> | '0' .. '9'
<opr> = '|' | '+' | '*' | '&' | '^'
Operator Operation
-------- ---------
'+' OR
'|' OR
'*' AND
'&' AND
'/' NOT
'!' NOT
'~' NOT
'^' XOR
The following are two examples of valid equations:
o1= /i5 * (i4 * (i3 + /i3 * i2)) + i5; o2= !i5 & (i4 & (i3 | !i3 & i2)) | i5;
These expressions are identical.
Operators have higher precedence as you move left in the equation. Precedence may be forced by using parentheses. Expressions within parentheses are evaluated before those outside of parentheses. For example:
e1= x + y * z = (x + y) * z; [output of x OR y AND'ed with z] e2= x + (y * z) = y * z + x; [output of y AND z OR'ed with x]
Tokens are either inputs to an equation or equation identifiers. Tokens must start with an alphabetic character or an underscore. Subsequent characters may include numerics. Tokens may be any length but only the first thirty-one characters or so are significant.
Equation identifiers are handled independently of inputs, so you may have an equation identifier of the same name as an input.
Comments may be included in the file; they are any characters surrounded by '[' and
Errors in source files will be reported when they are discovered and bool will stop evaluating the file. Usually a relevant error message will be printed.
-DEBUG causes bool to print out additional information on how an equation was parsed. This includes all parentheses (including implicit parentheses) and errors if there were any.
-noprint suppresses the printing of the source file while it's being read.
All files passed to bool should end in .b or they will be rejected by bool. This was done to make it harder to pass garbage to bool.
Any problems you have with bool should be sent to madd@bucsf.bu.edu. Bool has built in problem checking -- if it discovers an inconsistency, it will print out a big irritating message to let you know. While debugging bool this message never once appeared, so I don't expect that it will. If it does, report it to me immediately and include the source file that caused the error.
In case you may be wondering what a boolean equation array evaluator is useful for, here's why I made it. A friend of mine, who works for a relatively large company that produces a lot of electronic equipment, needed some way to determine every possible output from a series of inputs to a PAL chip. With 20 inputs and outputs, this is a pain to do by hand. So he inquired if I could make an evaluator and here it is.
If you make changes to the source code, please follow the instructions in the copyright. I'd be interested in any improvements or bug fixes you might make.
jim frost madd@bucsb.bu.edu
(c) copyright 1987 jim frost all rights reservedthis program is copyrighted material. the author gives permission to duplicate and redistribute this program provided the following conditions are met:
- this copyright notice is not removed.
- all duplicate copies or distributions contain full source
and documentation, including copyright notices.
- duplicate copies or distributions outside a single site are
original distributions without modifications. (this is to keep
bastardized versions from showing up all over thie place.)
this program source may be modified provided the following conditions are met:
- modified source is not distributed to other sites.
- modifications (including, but not limited to, bug fixes) are
sent to the author if the modifications are to be distributed.
no modified source is to be distributed unless done so by the
author.
no warranty, either express or implied, is given for this program. the author makes no guarantees of fitness for any use of this program. the author is not responsible for damages resulting from the use of this program for any purpose.
'site' refers to one or more computers under a single management. 'author' refers to the copyright holder, jim frost. 'source' refers to all files related to this program.
basically this notice is to keep me out of trouble should anything go wrong (i really *do* test these things though) and to make sure that the distribution of code is centralized. makes bug fixes and enhancements much easier.
thank you for your attention to this copyright notice. if everyone ollows this, you may find this a useful tool that is pretty well supported.
sample?.b - sample source files
None so far.