utily/selectively

Library for creating selections by performing filtering on datasets.

template-library

Template for NPM library.

Selectively Grammar

Symbols

• bool-expr (boolean expression)
• prop (property, identifier (id) or combination of identifiers, e.g. identifier.identifier (id.id))
• id (identifier)
• expr (expression)
• expr-op (expression operator e.g. >, <, >=, <=)
• alg-expr (algebraic expression)
• bin-op (binary operator)

Production Rules

Boolean Rules:

• bool-expr -> prop ":" expr | prop expr-op expr | (bool-expr) | bool-expr "|" bool-expr | bool-expr bool-expr | !bool-expr
• prop -> prop "." id | id
• expr -> prop | string | alg-expr | (expr) | "!"expr | expr "|" expr
• expr-op -> < | > | <= | >=

Algebraic Rules:

• alg-expr -> number | alg-expr bin-op alg-expr | (alg-expr)
• bin-op -> + | - | / | *

Merchant Rules

All id could be id.id.id...

Allowed Strings

id>num  
id<=str  
!(id:str)  
id:(str | str)  
id:((str | str) | str)  
(id<num)  
id:num  
id:!num  
id:!(num | num)  
id:(num | !num)  
id:id  
id>id  
(((id>num)))  
(id>(num))  
id.id:(id.id | str | num) | id.id.id:id.id  
id>num + num  
id<= num + (num * num) / num - num

Disallowed Strings

Open brackets:

(((id>num))

Mix of prop ":" expr and prop expr-op expr

id:(id>num)   

Special Rules

prop expr-op expr

Left-hand side:

Can be ambiguous, e.g. amount, where amount is an identifier which can be found as a property on several properties.

Right-hand side:

Can't be ambiguous, it must refer to a string, number or a unique identifier, e.g. "uniqueIdentifier.amount". An ambiguous identifier will be interpreted as a string. 

What is What?

• 3.14 => number
• identifier | identifier.identifier => property or properties
• unique_identifier.identifier => property
• .identifier => property if the identifier is a property of the base object, otherwise string.
• 1.B2 => string
• card.3d.secure => property
• 20-12-24 => string
• 20 - 12 - 24 => algebraic expression (uses whitespaces around the operators.)
• "20 - 12 - 24" => string. ("" forces an)
• Violation of the rules gives red underlining.