README
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Simple bool expressions
A simple yet awesome bool expression language.
Expression
An expression is - usually - in the form of <lhs> <operator> <rhs>.
Logical operators
&&: AND||: OR
Comparison operators
==: equals to!=: not equals to~~: matches (regex)
Fields
The <lhs> and <rhs> can be fields, even both at the same time, or other expressions
For example status == status is a valid expression.
The field syntax is as per buger/jsonparser.
So, you can assert conditions also on nested fields!
Let's say you want to log if the user agent starts starts with some value...
You'd need to traverse the request object, its headers child (another object), and its "User-Agent" child (array).
Sounds difficult. But, it isn't! Express this field as: request>headers>User-Agent>[0].
Values
The <lhs> and <rhs> can be values, of course.
The expressions support the following types for the values: boolean, (raw) string, and numbers (int64, and float64).
The language provides two boolean constants (case-insensitive): true and false.
Constants
This means that <lhs> and <rhs> (whether are they fields or constants) need to be of one of those types.
Operator precedence
In order of evaluation:
()||&&==,!=,~~
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
var Fields []string
var Lang = gval.NewLanguage( gval.InfixShortCircuit("&&", func(lhs interface{}) (interface{}, bool) { return false, lhs == false }), gval.InfixShortCircuit("||", func(lhs interface{}) (interface{}, bool) { return true, lhs == true }), gval.InfixBoolOperator("&&", func(lhs, rhs bool) (interface{}, error) { return lhs && rhs, nil }), gval.InfixBoolOperator("||", func(lhs, rhs bool) (interface{}, error) { return lhs || rhs, nil }), gval.InfixBoolOperator("==", func(lhs, rhs bool) (interface{}, error) { return lhs == rhs, nil }), gval.InfixBoolOperator("!=", func(lhs, rhs bool) (interface{}, error) { return lhs != rhs, nil }), gval.InfixNumberOperator("==", func(lhs, rhs float64) (interface{}, error) { return lhs == rhs, nil }), gval.InfixNumberOperator("!=", func(lhs, rhs float64) (interface{}, error) { return lhs != rhs, nil }), gval.InfixEvalOperator("~~", regEx), gval.InfixOperator("==", func(lhs, rhs interface{}) (interface{}, error) { return reflect.DeepEqual(lhs, rhs), nil }), gval.InfixOperator("!=", func(lhs, rhs interface{}) (interface{}, error) { return !reflect.DeepEqual(lhs, rhs), nil }), gval.PrefixExtension(scanner.Int, parseNumber), gval.PrefixExtension(scanner.Float, parseNumber), gval.PrefixExtension(scanner.RawString, parseString), gval.Constant("true", true), gval.Constant("false", false), gval.Parentheses(), gval.Precedence("||", 20), gval.Precedence("&&", 21), gval.Precedence("==", 40), gval.Precedence("!=", 40), gval.Precedence("~~", 40), gval.PrefixMetaPrefix(scanner.Ident, parseIdent), )
Functions ¶
Types ¶
This section is empty.
Source Files