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Description:

eval ex

eval_ex #
A Dart port of https://github.com/uklimaschewski/EvalEx.
EvalEx supports mathematical and boolean expression evaluation, using arbitrary precision.
EvalEx supports functions, variables, and operators and additionally makes it very easy to
add your own custom functions or operators.
EvalEx uses decimal to support arbitrary precision arithmetic.
View package on pub.dev.
Basic example #
void main() {
Expression exp = Expression("2 ^ 4 + 8");
print(exp.eval().toString()); // 24

// With a variable
exp = Expression("a ^ b + c");
// Variables may contain alphanumeric characters, and "_". This can be changed
// by using setVariableCharacters(..) and setFirstVariableCharacters(..) (what chars variable are allowed to start with).
exp.setStringVariable("a", "2");
exp.setStringVariable("b", "4");
exp.setStringVariable("c", "8");
print(exp.eval().toString()); // 24

// With a function
exp = Expression("MAX(-7,8)");
print(exp.eval().toString()); // 8

// Boolean logic
exp = Expression("1>0 && 5 == 5");
print(exp.eval().toString()); // 1

exp = Expression("1>0 && 5 == 4");
print(exp.eval().toString()); // 0
}

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Built-in functions and operators #

Function
Description

+
Addition

-
Subtraction

*
Multiplication

/
Division

%
Modulus

^
Power

&&
Returns 1 if both expressions are true, 0 otherwise

||
Returns 1 if either or both expressions are true, 0 otherwise

>
Returns 1 if the left expression is greater than the right

>=
Returns 1 if the left expression is greater than or equal to the right

<
Returns 1 if the right expression is greater than the left

<=
Returns 1 if the right expression is greater than or equal to the left

=
Returns 1 if the left and right expressions are equal

==
Returns 1 if the left and right expressions are equal

!=
Returns 1 if the left and right expressions are NOT equal

<>
Returns 1 if the left and right expressions are NOT equal

STREQ("str1","str2")
Returns 1 if the literal "str1" is equal to "str2", otherwise returns 0

FACT(int)
Computes the factorial of arg1

NOT(expression)
Returns 1 if arg1 evaluates to 0, otherwise returns 0

IF(cond,exp1,exp2)
Returns exp1 if cond evaluates to 1, otherwise returns exp2

Random()
Returns a random decimal between 0 and 1

SINR(exp)
Evaluates the SIN of exp, assuming exp is in radians

COSR(exp)
Evaluates the COS of exp, assuming exp is in radians

TANR(exp)
Evaluates the TAN of exp, assuming exp is in radians

COTR(exp)
Evaluates the COT of exp, assuming exp is in radians

SECR(exp)
Evaluates the SEC of exp, assuming exp is in radians

CSCR(exp)
Evaluates the CSC of exp, assuming exp is in radians

SIN(exp)
Evaluates the SIN of exp, assuming exp is in degrees

COS(exp)
Evaluates the COS of exp, assuming exp is in degrees

TAN(exp)
Evaluates the TAN of exp, assuming exp is in degrees

COT(exp)
Evaluates the COT of exp, assuming exp is in degrees

SEC(exp)
Evaluates the SEC of exp, assuming exp is in degrees

CSC(exp)
Evaluates the CSC of exp, assuming exp is in degrees

ASINR(exp)
Evaluates the ARCSIN of exp, assuming exp is in radians

ACOSR(exp)
Evaluates the ARCCOS of exp, assuming exp is in radians

ATANR(exp)
Evaluates the ARCTAN of exp, assuming exp is in radians

ACOTR(exp)
Evaluates the ARCCOT of exp, assuming exp is in radians

ATAN2R(exp1, exp1)
Evaluates the ARCTAN between exp1 and exp2, assuming exp1 and exp2 are in radians

ASIN(exp)
Evaluates the ARCSIN of exp, assuming exp is in degrees

ACOS(exp)
Evaluates the ARCCOS of exp, assuming exp is in degrees

ATAN(exp)
Evaluates the ARCTAN of exp, assuming exp is in degrees

ACOT(exp)
Evaluates the ARCCOT of exp, assuming exp is in degrees

ATAN2(exp1, exp1)
Evaluates the ARCTAN between exp1 and exp2, assuming exp1 and exp2 are in degrees

RAD(deg)
Converts deg to radians

DEG(rad)
Converts rad to degrees

MAX(a,b,...)
Returns the maximum value from the provided list of 1 or more expressions

MIN(a,b,...)
Returns the minimum value from the provided list of 1 or more expressions

ABS(exp)
Returns the absolute value of exp

LOG(exp)
Returns the natural logarithm of exp

LOG10(exp)
Returns the log base 10 of exp

ROUND(exp,precision)
Returns exp rounded to precision decimal points

FLOOR(exp)
Returns the floor of exp

CEILING(exp)
Returns the ceiling of exp

SQRT(exp)
Computes the square root of exp

e
Euler's number

PI
Ratio of circle's circumference to diameter

NULL
Alias for null

TRUE or true
Alias for 1

FALSE or false
Alias for 0

Adding custom functions, operators, and variables #
Custom functions, operators, and variables can be defined by adding them in built_ins.dart
Differences from https://github.com/uklimaschewski/EvalEx. #

Hyperbolic functions aren't supported
The SQRT function is currently limited to 64-bit precision
Built in operators/functions/variables are instead defined in built_ins.dart