easy-path-expressions
v3.1.0
Published
Easy-path-expressions is a syntax parser that converts basic mathematical expressions into FHIRPath notation.
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Easy Path Expressions
Easy-path-expressions is a syntax parser that converts basic mathematical expressions into FHIRPath notation.
Local Installation
npm install
To test that easy-path-expressions is working correctly:
npm test
Usage
import * as easyPathExpressions from 'easy-path-expressions';
easyPathExpressions.fhirConvert("(a+b)^2", ["a", "b"]); // returns ($a+$b).power(2)
easyPathExpressions.fhirConvert("CEILING(a*b)", ["a", "b"]); // returns ($a*$b).ceiling()
fhirConvert is the main function of easy-path-expressions, which validates and converts an inputted expression to fhirpath. fhirConvert will also return null if the expression fails validation.
fhirConvert takes in two inputs: the mathematical expression for conversion and an array of usable variables. The format is as follows:
fhirConvert([expression], [vars])
Basic syntax expressions utilize traditional operators and function statements. Expressions can be written using variable names, mathematical operators, and various functions. The syntax guide is bellow.
Syntax Guide
USABLE OPERATORS: +, -, *, /, ^, **, !=, !~, >=, <=, =, &&, ||, xor, and, or, implies
USABLE FUNCTIONS: CEILING(), FLOOR(), ABS(), LOG(), TRUNCATE(), EXP(), SQRT(), LN(), NOT(), LENGTH()
- Usage: CEILING([expression]), FLOOR([expression]), etc.
LOG()
- Usage: LOG([Base], [Value])
USABLE VARIABLES: Any string of letters and numbers differing from the aforementioned functions.
EXAMPLE EXPRESSIONS (vars: [a, b, c]): 2+2 (a+b)^3 CEILING(LOG(2, 17)) TRUNCATE(ABS(-3.3)) + SQRT(LN(a+b+c))
EXAMPLE OUTPUTS:
INPUT: fhirConvert("2+2", ["a", "b", "c", "d"]) OUTPUT: "2+2"
INPUT: fhirConvert("(a+b)^3", ["a", "b", "c", "d"]) OUTPUT: "((%a+%b).power(3))"
INPUT: fhirConvert("CEILING(LOG(2, 17))", ["a", "b", "c", "d"]) OUTPUT: "((17.log(2)).ceiling())"
INPUT: fhirConvert("TRUNCATE(ABS(-3.3))+SQRT(LN(a+b+c))", ["a", "b", "c", "d"]) OUTPUT: "((-3.3).abs()).truncate()+((%a+%b+%c).ln()).sqrt()"