Package cs2110

Class RpnCalc

java.lang.Object

cs2110.RpnCalc

public class RpnCalc
extends Object

An interactive calculator for evaluating expressions represented in Reverse Polish Notation.

Constructor Summary

Constructors

Constructor	Description
RpnCalc()	Create a new calculator object with no variables set and an initial expression of "0" that understands the core math functions defined in `UnaryFunction`.

Method Summary

Modifier and Type	Method	Description
void	dispatchCommand(Scanner scanner)	Consume the first token in `scanner`, interpret it as a command name, and execute the appropriate command handler.
void	doClear(Scanner scanner)	Parse remaining arguments in `scanner` and perform the "clear" command to clear all variable assignments in this calculator instance.
void	doDef(Scanner scanner)	Parse remaining arguments in `scanner` and perform the "def" command to define a new function equivalent to the current expression.
void	doDefs(Scanner scanner)	Parse remaining arguments in `scanner` and perform the "defs" command to print all function definitions in this calculator instance.
void	doDeps(Scanner scanner)	Perform the "deps" command to print the names of variables that the current expression depends on.
void	doEval(Scanner scanner)	Perform the "eval" command to evaluate the current expression and print the result.
void	doHelp(Scanner scanner)	Print the commands understood by this calculator, their arguments (in angle brackets, with additional square brackets around optional arguments), and a brief description of the commands' effects.
void	doInfix(Scanner scanner)	Perform the "infix" command to print the current expression in infix notation.
void	doOpcount(Scanner scanner)	Perform the "opcount" command to print the number of operations required to evaluate the current expression.
void	doOptimize(Scanner scanner)	Perform the "optimize" command to replace the current expression with its optimized form, propagating constant subexpressions based on the current variable assignments.
void	doPostfix(Scanner scanner)	Perform the "postifx" command to print the current expression in postfix (RPN) notation.
void	doSet(Scanner scanner)	Parse remaining arguments in `scanner` and perform the "set" command to assign a value to a variable in this calculator instance.
void	doTabulate(Scanner scanner)	Parse remaining arguments in `scanner` and perform the "tabulate" command to evaluate the current expression at a range of abscissa and print each abscissa and ordinate value.
void	doUnset(Scanner scanner)	Parse remaining arguments in `scanner` and perform the "unset" command to unassign a value from a variable in this calculator instance.
void	doVars(Scanner scanner)	Parse remaining arguments in `scanner` and perform the "vars" command to print all variable assignments in this calculator instance.
boolean	exitRequested()	Return whether the user has issued an 'exit' command.
static void	main(String[] args)	Run an interactive calculator application.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

RpnCalc

public RpnCalc()

Create a new calculator object with no variables set and an initial expression of "0" that understands the core math functions defined in `UnaryFunction`.

Method Details

dispatchCommand

public void dispatchCommand(Scanner scanner)

Consume the first token in `scanner`, interpret it as a command name, and execute the appropriate command handler. Do nothing if `scanner` has no tokens. If the command name is not recognized, print an error message.

exitRequested

public boolean exitRequested()

Return whether the user has issued an 'exit' command.

doHelp

public void doHelp(Scanner scanner)

Print the commands understood by this calculator, their arguments (in angle brackets, with additional square brackets around optional arguments), and a brief description of the commands' effects. Arguments passed in `scanner` are currently ignored.

doSet

public void doSet(Scanner scanner)

Parse remaining arguments in `scanner` and perform the "set" command to assign a value to a variable in this calculator instance. Prints usage to `System.err` and returns if improper arguments are passed.

doUnset

public void doUnset(Scanner scanner)

Parse remaining arguments in `scanner` and perform the "unset" command to unassign a value from a variable in this calculator instance. Prints usage to `System.err` and returns if improper arguments are passed.

doClear

public void doClear(Scanner scanner)

Parse remaining arguments in `scanner` and perform the "clear" command to clear all variable assignments in this calculator instance. Prints usage to `System.err` and returns if improper arguments are passed.

doVars

public void doVars(Scanner scanner)

Parse remaining arguments in `scanner` and perform the "vars" command to print all variable assignments in this calculator instance. Prints usage to `System.err` and returns if improper arguments are passed.

doDefs

public void doDefs(Scanner scanner)

Parse remaining arguments in `scanner` and perform the "defs" command to print all function definitions in this calculator instance. Prints usage to `System.err` and returns if improper arguments are passed.

doEval

public void doEval(Scanner scanner)

Perform the "eval" command to evaluate the current expression and print the result. If arguments are provided in `scanner`, parse them as an RPN expression and update the current expression. Prints to `System.err` and returns if expression cannot be parsed or depends on variables that have not been assigned a value.

doInfix

public void doInfix(Scanner scanner)

Perform the "infix" command to print the current expression in infix notation. If arguments are provided in `scanner`, parse them as an RPN expression and update the current expression. Prints to `System.err` and returns if expression cannot be parsed.

doPostfix

public void doPostfix(Scanner scanner)

Perform the "postifx" command to print the current expression in postfix (RPN) notation. If arguments are provided in `scanner`, parse them as an RPN expression and update the current expression. Prints to `System.err` and returns if expression cannot be parsed.

doDeps

public void doDeps(Scanner scanner)

Perform the "deps" command to print the names of variables that the current expression depends on. If arguments are provided in `scanner`, parse them as an RPN expression and update the current expression. Prints to `System.err` and returns if expression cannot be parsed.

doOpcount

public void doOpcount(Scanner scanner)

Perform the "opcount" command to print the number of operations required to evaluate the current expression. If arguments are provided in `scanner`, parse them as an RPN expression and update the current expression. Prints to `System.err` and returns if expression cannot be parsed.

doOptimize

public void doOptimize(Scanner scanner)

Perform the "optimize" command to replace the current expression with its optimized form, propagating constant subexpressions based on the current variable assignments. If arguments are provided in `scanner`, parse them as an RPN expression and update the current expression. Prints to `System.err` and returns if expression cannot be parsed.

doTabulate

public void doTabulate(Scanner scanner)

Parse remaining arguments in `scanner` and perform the "tabulate" command to evaluate the current expression at a range of abscissa and print each abscissa and ordinate value. The required arguments are:

1. var: The name of the abscissa variable
2. lo: The minimum value of the abscissa (floating-point number)
3. hi: The maximum value of the abscissa (floating-point number)
4. n: The number of abscissa to sample at (integer)

If additional arguments are provided in `scanner`, parse them as an RPN expression and update the current expression.

The `n` sampled abscissa are evenly spaced between `lo` and `hi`. After executing this command,`var` should be assigned the value `hi`. Prints to `System.err` and returns if improper arguments are passed, if expression cannot be parsed, or if expression depends on variables that have not been assigned a value.

doDef

public void doDef(Scanner scanner)

Parse remaining arguments in `scanner` and perform the "def" command to define a new function equivalent to the current expression. The required arguments are:

1. name: The name of the function to define
2. var: The name of the variable to serve as the function's argument

If additional arguments are provided in `scanner`, parse them as an RPN expression and update the current expression.

Prints to `System.err` and returns if improper arguments are passed, if expression cannot be parsed, if expression depends on variables other than var, or if a function named `name` has already been defined (in the latter two cases, the current expression is still updated).

main

public static void main(String[] args)

Run an interactive calculator application. If a program argument is provided, commands are read from a file rather than `System.in`.