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Husband\'s Calculator Script Webb  all rights reserved  ©2004

Author  Jann Scheuer
Email: scheuer@coco.ihi.ku.dk
Webpage:
Summary: Two suggestions for infix calculators, a simple and an
advanced one
Instructions: Infix calculators
Two suggestions for infix calculators.
There is not a lot to say about them. Infix notation is silly and
contraintuitive, but programming is fun. Therefore I made them.
The simple one behaves like your husband's average 2$ calculator,
evaluating expressions without consideration to operator hierarchies,
etc. The enter key corresponds to the '=' key.
The advanced one uses an operator hierarchy when evaluating expressions.
It maintains two stacks: The numbers in input expressions are put on
the RPN stack. The operators (and parentheses) are put on a stack
consisting of the RPN variables (i.e. xa through xy, xz is used as a
stack index).
The operator hierarchy is: P > *,/ > +,. This means that
3 + 3 * 2 = 9 (and not 8)
4 + 3 * 2 ^ 2 = 16 (and not 196, ^ meaning power)
An input string like 3 + 3 is not evaluated before enter is pressed
or an additional operator at the same or lower level in the heirarchy
is typed in. Try it, and you'll see what I mean.
It features parentheses too. You can have about 12 open left
parentheses in your expression before the application gets dizzy.
Parentheses syntax and some operator syntax is checked.
Warning: The advanced calculator deletes the RPN stack at the beginning
of each calculation. So do not start the function set with an RPN stack
you want to keep.
If the advanced calculator malfunctions (I do not know why it should,
it is pretty robust, but anyway...) you may try the reset button. It
empties both stacks. (Press "infix", then "reset".)
Code:
RPN.2.a \ Infix simple
[r]xac(/:*::+:P);
[s]UhUeh1>(Cr);
{b}Vv4=0(Cs0Xa)
v#'10'=0(Cs1Xa)
v#'16'=0(Cs2Xa)
v#'22'=0(Cs3Xa)
v#'11'=0(Cs4Xa)
v#'12'=0(Cs)Ud;
"Infix"
"Infix"D'Square calculatorOk'd1;
RPN.2.z \ Infix advanced
{o}0Xz;
[p]c(0:1:1:2:2);
[r]c(P:/:*::+);
[u]xz1+XzxzX@;
[o]xzx@xz1Xz;
[t]xz(xzx@:1n);
[l]xz0V{Ct0(B:v1+Vxz1Xz)}Xzv;
[k]xz0V{Ct0<(B:Co8<(v1+V)}Xzv;
[e]{CtCpCoVCtCpvCu&(CoVCoCrvCu:B)};
[E]Ce{Cl(CoCr:B)};
[f]CuUeUhCkh1>(3Cm.)Ce;
[m]c(D'Right parenthesis excpected!Ok':D'Misplaced parenthesis!Ok':
D'No matching left parenthesis!Ok':D'Misplaced operator!Ok')CcUd;
[M]D'Square calculator?ResetOk'c(D'Operator hierarchy: P>*/>+
\and parentheses!Ok'd1:Cc:);
[a]c(0:4:5:#'10':#'11':#'12':#'16':#'17':#'21':#'22':#'23':44P);
[b]V0Xz{xzCag1v=0(d10B:v>(1B)xz1+Xz}0Xz;
[c]hV{_vd1}0Xz;
{b}Vh(xz!(vCb(Cc)))
v4=0(1Cf:
v#'10'=0(2Cf:
v#'16'=0(3Cf:
v#'22'=0(4Cf:
v#'11'=0(0Cf:
v#'12'=0(UeUh
xzCk(0Cm.)hCk=0(3Cm.)
xz(CE)))))))Ud;
"Infix"
"("hCk=0(8Cu:1Cm);
"Infix"CM;
")"hCk=0(1Cm.)xzCk>!(2Cm.)CECod1;

