Parsec: A parser for Math equations using a lighter, faster and more complete version of muparserx C++ library

Overview

Welcome to the Equation Evaluator repository – a powerful and flexible tool for evaluating a wide range of equations on the fly. Whether it's simple arithmetic or complex calculations involving logarithms and custom functions like concat(), sum(), avg(), mask(), left(), right(), this repository has you covered.

Our goal is to provide a reliable and efficient equation evaluation solution, capable of handling various mathematical and custom functions that can be seamlessly integrated into your existing systems. This README will walk you through the features, capabilities, and potential applications of our Equation Evaluator.

Requirements

1. swig >= 4.0.2
2. cmake

Usage

Add to your Gemfile

gem 'parsecs'

Tests

gem build parsec.gemspec
gem install ./parsecs-VERSION.gem (e.g.: gem install ./parsecs-0.9.3.gem)
ruby -Ilib -Iext/libnativemath test/test_parsec.rb

• Use Ruby version 2.5.1

You can then eval equations in your code

parser = Parsec::Parsec
parser.eval_equation('5 + 1')
parser.eval_equation('(3 + 3) * (5 * 2)')

And also validate the syntax of the equations

parser = Parsec::Parsec
parser.validate_syntax!('4 + 4')               # return => true
parser.validate_syntax!('4 + ')                # raise SyntaxError with message: Unexpected end of expression found at position 4.

parser.validate_syntax!('(4 + 3) + ( 4 + 2)')  # return => true
parser.validate_syntax!('(4 + 3) + ( 4 + 2')   # raise SyntaxError with message: Missing parenthesis.

parser.validate_syntax!('4==4 ? true : false') # return => true
parser.validate_syntax!('4==4 ? true')         # raise SyntaxError with message: If-then-else operator is missing an else clause.
parser.validate_syntax!('4==4 ^ true : false') # raise SyntaxError with message: Misplaced colon at position 12.

Here are examples of equations which are accepted by the parser

parser = Parsec::Parsec

# Simple Math equations
parser.eval_equation('(5 + 1) + (6 - 2)')  # result => 10
parser.eval_equation('4 + 4 * 3')          # result => 16
parser.eval_equation('10.5 / 5.25')        # result => 2
parser.eval_equation('abs(-5)')            # result => 5
parser.eval_equation('sqrt(16) + cbrt(8)') # result => 6
parser.eval_equation('log10(10)')          # result => 1
parser.eval_equation('round(4.4)')         # result => 4
parser.eval_equation('(3^3)^2')            # result => 729
parser.eval_equation('3^(3^(2))')          # result => 19683
parser.eval_equation('10!')                # result => 3628800
parser.eval_equation('string(10)')         # result => "10"

# Complex Math equations
parser.eval_equation('log10(10) + ln(e) + log(10)')       # result => 4.30259
parser.eval_equation('sin(1) + cos(0) + tan(0.15722)')    # result => 2.0
parser.eval_equation('max(1, 2) + min(3, 4) + sum(5, 6)') # result => 16
parser.eval_equation('avg(9, 9.8, 10)')                   # result => 9.6
parser.eval_equation('pow(2, 3)')                         # result => 8
parser.eval_equation('round_decimal(4.559, 2)')           # result => 4.56

# IF THEN ELSE equations
parser.eval_equation('4 > 2 ? "bigger" : "smaller"')    # result => "bigger"
parser.eval_equation('2 == 2 ? true : false')           # result => true
parser.eval_equation('2 != 2 ? true : false')           # result => false
parser.eval_equation('"this" == "this" ? "yes" : "no"') # result => "yes"
parser.eval_equation('"this" != "that" ? "yes" : "no"') # result => "yes"

# Logic equations
parser.eval_equation('true and false')    # result => false
parser.eval_equation('true or false')     # result => true
parser.eval_equation('(3==3) and (3!=3)') # result => false
parser.eval_equation('exp(1) == e')       # result => true

# String equations
parser.eval_equation('length("test string")')     # result => 11
parser.eval_equation('toupper("test string")')    # result => "TEST STRING"
parser.eval_equation('tolower("TEST STRING")')    # result => "test string"
parser.eval_equation('concat("Hello ", "World")') # result => "Hello World"
parser.eval_equation('link("Title", "http://foo.bar")') # result => "<a href="http://foo.bar">Title</a>"
parser.eval_equation('str2number("5")')           # result => 5
parser.eval_equation('left("Hello World", 5)')    # result => "Hello"
parser.eval_equation('right("Hello World", 5)')   # result => "World"
parser.eval_equation('number("5")')               # result => 5

# Date equations (return the difference in days)
parser.eval_equation("current_date()"))                        # result => "2018-10-03"
parser.eval_equation('daysdiff(current_date(), "2018-10-04")') # result => 1
parser.eval_equation('daysdiff("2018-01-01", "2018-12-31")')   # result => 364

# DateTime equations (return the difference in hours)
parser.eval_equation('hoursdiff("2018-01-01", "2018-01-02")')             # result => 24
parser.eval_equation('hoursdiff("2019-02-01T08:00", "2019-02-01T12:00")') # result => 4
parser.eval_equation('hoursdiff("2019-02-01T08:20", "2019-02-01T12:00")') # result => 3.67
parser.eval_equation('hoursdiff("2018-01-01", "2018-01-01")')             # result => 0

# Calculate a string as an equation
parser.eval_equation('calculate("2+2+2*4)"')                                           # result => "12"
parser.eval_equation('calculate("(2+2)*4)"')                                           # result => "16"
parser.eval_equation('calculate("2^4)"')                                               # result => "16"
parser.eval_equation('calculate("sqrt(9))"')                                           # result => "3"
parser.eval_equation('calculate("abs(-50))"')                                          # result => "50"
parser.eval_equation('calculate("round(1.123))"')                                      # result => "1"
parser.eval_equation('calculate("add_days(\"2019-01-01\", 3))"')                       # result => "2019-01-04"
parser.eval_equation('calculate("daysdiff(\"2019-01-01\", \"2019-01-02\"))"')          # result => "1"
parser.eval_equation('calculate("hoursdiff(\"2019-01-01\", \"2019-01-02\"))"')         # result => "24"
parser.eval_equation('calculate("3 > 2 ? \"higher\" : \"lower\")"')                    # result => "higher"
parser.eval_equation('calculate("3 < 2 ? \"higher\" : \"lower\")"')                    # result => "lower"
parser.eval_equation('calculate("concat(\"One \", concat(\"Two\", \" Three\")))"')     # result => "One Two Three"
parser.eval_equation('calculate("\"One\" // \" \" // \"Two\" // \" \" // \"Three\")"') # result => "One Two Three"
parser.eval_equation('calculate("number(calculate(\"1 + 1\")) + 1)"')                  # result => "3"

The following functions can be used

• Math trigonometric functions: sin, cos, tan, sinh, cosh, tanh, asin, acos, atan, asinh, acosh, atanh
• Math logarithm functions: ln, log, log10
• Math standard functions: abs, sqrt, cbrt, pow, exp, round, round_decimal
• Number functions: string
• Math constants: e, pi
• Unlimited number of arguments: min, max, sum, avg
• String functions: concat, length, toupper, tolower, left, right, str2number, number, link
• Complex functions: real, imag, conj, arg, norm
• Array functions: sizeof, eye, ones, zeros
• Date functions: current_date, daysdiff, hoursdiff
• Extra functions: default_value