Calculator

By RcCookie

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A simple command-line calculator with support for several features:

• Basic arithmetics (+-*/^!)
• Fraction expressions and calculations
• Implicit multiplication (omit multiplication sign, i.e. 2(3+4) = 2*(3+4)
• Comparisons (< <= = >= >) returning 0 or 1
• Vectors: Declare with brackets, split arguments with commas, i.e. [1,2,3]
• Function calls as usual, i.e. f(2). List default functions using \vars
• Variable declarations: declare using :=, i.e. x := 42
• Function declarations: declare using :=, i.e. f(x) := 2x
• Anonymous function declarations aka lambdas: declare using ->, i.e. f := x -> 2x
• First class functions: functions (particularly lambdas) may be passed to other functions
• Function arithmetics: operating on functions like numbers will create derived functions
• Function compositions: Using f(g) or f g defines the composition "f after g"
• Convert degrees to radians when writing ° symbol, i.e. 180° -> pi (may not be supported due to some terminals not properly parsing '°' character)
• Convert percentage to normal number when writing % symbol, i.e. 10% -> 1/10
• Load packages of constants and formulas using \load <name>, i.e. \load physics
• Force decimal or fraction rendering for the last result using \dec / \frac
• Output more decimal places from the last result using \more
• Use the variable ans to refer to the previous result, or operate as if it was at the front of the expression
• Set the variable precision to set the approximate decimal number precision (>1)
• Set the variable scientific to something other than 0 to enable scientific notation output
• Set the variable exit to a desired value to set the exit code of the program, exit with \exit

The API to parse math expressions can also be used without the calculator.

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Currently requires Java 18 with flag --enable-preview. Switch pattern matching is pretty convenient for this kind of stuff :)

For executing on Windows, you should first set the console charset to Windows-1512 for ² and similar to work. Then, start the program with the additional flag -Dfile.encoding=windows-1512. For conveniance, you may create a cmd file:

@echo off
chcp 1512
java -jar --enable-preview -Dfile.encoding=1512 "<path to jar>"