19 releases (1 stable)

1.0.0	Dec 29, 2023
0.12.0	Jun 17, 2023
0.11.0	Jun 12, 2023
0.9.0	Feb 6, 2023
0.1.2	Mar 15, 2022

#811 in Parser implementations

121 downloads per month

MIT/Apache

130KB
3K SLoC

ksql

Is a JSON data expression lexer, parser, cli and library.

How to install CLI

~ cargo install ksql

Usage

use ksql::parser::{Parser, Value};
use std::error::Error;

fn main() -> Result<(), Box<dyn Error>>{
    let src = r#"{"name":"MyCompany", "properties":{"employees": 50}"#.as_bytes();
    let expression = ".properties.employees > 20";
    let ex = Parser::parse(expression.as_bytes())?;
    let result = ex.calculate(src)?;
    assert_eq!(Value::Bool(true), result);
    Ok(())
}

CLI Usage

~ ksql '(.field1 + 1) /2' '{"field1": 1}'
or
echo '{"field1": 1}' | ksql '(.field1 + 1) /2'

Expressions

Expressions support most mathematical and string expressions see below for details:

Syntax & Rules

Token	Example	Syntax Rules
`Equals`	`==`	supports both `==` and `=`.
`Add`	`+`	N/A
`Subtract`	`-`	N/A
`Multiply`	`*`	N/A
`Divide`	`/`	N/A
`Gt`	`>`	N/A
`Gte`	`>=`	N/A
`Lt`	`<`	N/A
`Lte`	`<=`	N/A
`OpenParen`	`(`	N/A
`CloseParen`	`)`	N/A
`OpenBracket`	`[`	N/A
`CloseBracket`	`]`	N/A
`Comma`	`,`	N/A
`QuotedString`	`"sample text"`	Must start and end with an unescaped `"` character
`Number`	`123.45`	Must start and end with a space or '+' or '-' when hard coded value in expression and supports `0-9 +- e` characters for numbers and exponent notation.
`BooleanTrue`	`true`	Accepts `true` as a boolean only.
`BooleanFalse`	`false`	Accepts `false` as a boolean only.
`SelectorPath`	`.selector_path`	Starts with a `.` and ends with whitespace blank space. This crate currently uses gjson and so the full gjson syntax for identifiers is supported.
`And`	`&&`	N/A
`Not`	`!`	Must be before Boolean identifier or expression or be followed by an operation
`Or`	`\|\|`	N/A
`Contains`	`CONTAINS`	Ends with whitespace blank space.
`ContainsAny`	`CONTAINS_ANY`	Ends with whitespace blank space.
`ContainsAll`	`CONTAINS_ALL`	Ends with whitespace blank space.
`In`	`IN`	Ends with whitespace blank space.
`Between`	`BETWEEN`	Starts & ends with whitespace blank space. example `1 BETWEEN 0 10`
`StartsWith`	`STARTSWITH`	Ends with whitespace blank space.
`EndsWith`	`ENDSWITH`	Ends with whitespace blank space.
`NULL`	`NULL`	N/A
`Coerce`	`COERCE`	Coerces one data type into another using in combination with 'Identifier'. Syntax is `COERCE <expression> _identifer_`.
`Identifier`	`_identifier_`	Starts and end with an `_` used with 'COERCE' to cast data types, see table below with supported values. You can combine multiple coercions if separated by a COMMA.
`Colon`	`:`	N/A

COERCE Types

Type	Description
`_datetime_`	This attempts to convert the type into a DateTime.
`_lowercase_`	This converts the text into lowercase.
`_uppercase_`	This converts the text into uppercase.
`_title_`	This converts the text into title case, when the first letter is capitalized but the rest lower cased.
`_string_`	This converts the value into a string and supports the Value's String, Number, Bool, DateTime with nanosecond precision.
`_number_`	This converts the value into an f64 number and supports the Value's Null, String, Number, Bool and DateTime.
`_substr_[n:n]`	This allows taking a substring of a string value. this returns Null if no match at specified indices exits.

License

^{Licensed under either of Apache License, Version
2.0 or MIT license at your option.}
_{Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in Proteus by you, as defined in the Apache-2.0 license, shall be
dual licensed as above, without any additional terms or conditions.}

Dependencies

~7MB
~75K SLoC