formula solver 2/7

 BBS: Inland Empire Archive
Date: 03-13-93 (22:24)             Number: 335
From: QUINN TYLER JACKSON          Refer#: NONE
  To: ALL                           Recvd: NO  
Subj: formula solver 2/7             Conf: (2) Quik_Bas

'>>> Start of page 2.

 '   This function can expand factorials:
 '
 '       3! = 6
 '       0! = 1
 '
 '   3. logical greater than, less than, and equality
 '
 '       5 > 4 = -1 [TRUE]
 '       9 < 1 = 0  [FALSE]
 '
 '   4. nested parenthesis precedence override
 '
 '       5*(2+3) = 25 rather than 13
 '
 '   5. PASCAL style variable assignment (using the ":=" of PASCAL)
 '
 '       variable := 5+3  (assigns the value of 8 to variable)
 '
 '       Note also that variables that have been assigned can be used
 '       within expressions:
 '
 '       newvariable := 3+variable  (assigns 11 to new variable based ' upon
 '                                   variable having an assignment of 8)
 '   So far, variables cannot be reassigned by the same expression they
 '   occur in.  So, the following yeilds a faulty answer:
 '
 '   x := x + 1
 '
 '   6. and more!
 '
 '   I leave it to you to figure out what 6?9 solves to!
 '   This FUNCTION can solve complex equations that mix all parts of the
 '   above!  Try it out!  Break it to pieces!  Smoke it!  It's yours!
 '

CONST ASSIGNMENT = ":="     ' This can be changed to suit your needs
                            ' Using a simple = is possible, since ' logical
                            ' equality is a double == with this parser,
                            ' but the PASCAL standard := is easier to ' deal
                            ' with as an assignment operator for some.


' Operator classes                   PRECEDENCE
'---------------------------------------------------
CONST POWER = "^]?**>><<"           ' FIRST
CONST MULTDIV = "*/\%"              ' SECOND
CONST ADDSUB = "+-"                 ' THIRD
CONST LOGICAL = "<>=&|~>==><==<<>"' FOURTH

CONST OperatorClass = 1
CONST DigitClass = 2
CONST VARMAX = 100

TYPE VariableType
    Nom AS STRING * 30  ' variable name
    Valu AS LONG        ' variable's value
END TYPE

' Variables global to this module...
DIM SHARED VarMem(VARMAX) AS VariableType
DIM SHARED VariPtr AS INTEGER
DIM SHARED OPERATOR$
DIM SHARED expression$
DIM SHARED TOKEN$
DIM SHARED TypeToken
DIM SHARED Ptr AS INTEGER

'>>> Continued on page 3.

--- Maximus/2 2.01wb
 * Origin: The Nibble's Roost, Richmond BC Canada 604-244-8009 (1:153/918)