Cillogical 1.0.0

(c)illogical

A micro conditional engine used to parse the logical and comparison expressions, evaluate an expression in data context, and provide access to a text form of the given expression.

Revision: Aug 1, 2024.

Other implementations:

• TS/JS
• GO
• Python

About

This project has been developed to provide C// implementation of spaceavocado/illogical.

Table of Content

---

• (c)illogical
  • About
• Basic Usage
  • Evaluate
  • Statement
  • Parse
  • IEvaluable
    • Simplify
    • Serialize
• Working with Expressions
  • Evaluation Data Context
    • Accessing Array Element:
    • Accessing Array Element via Reference:
    • Nested Referencing
    • Composite Reference Key
    • Data Type Casting
  • Operand Types
    • Value
    • Reference
    • Collection
  • Comparison Expressions
    • Equal
    • Not Equal
    • Greater Than
    • Greater Than or Equal
    • Less Than
    • Less Than or Equal
    • In
    • Not In
    • Prefix
    • Suffix
    • Overlap
    • None
    • Present
  • Logical Expressions
    • And
    • Or
    • Nor
    • Xor
    • Not
• Engine Options
  • Reference Serialize Options
    • From
    • To
  • Collection Serialize Options
    • Escape Character
  • Simplify Options
    • Ignored Paths
    • Ignored Paths RegEx
  • Operator Mapping
• Contributing
• License

---

Basic Usage

using Cillogical;

// Create a new instance of the engine
var illogical = new Illogical();

// Evaluate an expression
illogical.Evaluate(new object[] { "==", 1, 1 }, null);

For advanced usage, please Engine Options.

Evaluate

Evaluate comparison or logical expression:

illogical.Evaluate(Comparison Expression or Logical Expression, Evaluation Data Context) ⇒ bool

Example

var context = new Dictionary<string, object?>
{
  { "name", "peter" }
};

// Comparison expression
illogical.Evaluate(new object[]{"==", 5, 5}, context);
illogical.Evaluate(new object[]{"==", "circle", "circle"}, context);
illogical.Evaluate(new object[]{"==", true, true }, context);
illogical.Evaluate(new object[]{"==", "$name", "peter"}, context);
illogical.Evaluate(new object[]{"NULL", "$RefA"}, context);

// Logical expression
illogical.Evaluate(new object[] {
  "AND",
  new object[] { "==", 5, 5 },
  new object[] { "==", 10, 10 }
}, context);

illogical.Evaluate(new object[] {
  "AND",
  new object[] { "==", "circle", "circle" },
  new object[] { "==", 10, 10 }
}, context);

illogical.Evaluate(new object[] {
  "OR",
  new object[] { "==", "$name", "peter" },
  new object[] { "==", 5, 10 }
}, context);

Statement

Get expression string representation:

illogical.Statement(Comparison Expression or Logical Expression) ⇒ str

Example

// Comparison expression

illogical.Statement(new object[] { "==", 5, 5 }); // (5 == 5)
illogical.Statement(new object[] { "==", "circle", "circle" }); // ("circle" == "circle")
illogical.Statement(new object[] { "==", true, true }); // (True == True)
illogical.Statement(new object[] { "==", "$name", "peter" }); // ({name} == "peter")
illogical.Statement(new object[] { "NONE", "$RefA" }); // ({RefA} <is none>)

// Logical expression

illogical.Statement(new object[] {
    "AND",
    new object[] { "==", 5, 5 },
    new object[] { "==", 10, 10 }
}); // ((5 == 5) AND (10 == 10))

illogical.Statement(new object[] {
    "AND",
    new object[] { "==", "circle", "circle" },
    new object[] { "==", 10, 10 }
}); // (("circle" == "circle") AND (10 == 10))

illogical.Statement(new object[] {
    "OR",
    new object[] { "==", "$name", "peter" },
    new object[] { "==", 5, 10 }
}); // (({name} == "peter") OR (5 == 10))

Parse

Parse the expression into a IEvaluable object, i.e. it returns the parsed self-evaluable condition expression.

illogical.parse(Comparison Expression or Logical Expression) ⇒ IEvaluable

IEvaluable

• evaluable.Evaluate(context) please see Evaluation Data Context.
• evaluable.Simplify(context) please see Simplify.
• evaluable.Serialize() please see Serialize.
• $"{evaluable}" | evaluable.ToString() please see Statement.

Example

var evaluable = illogical.Parse(new object[] { "==", "$name", "peter" });

evaluable.Evaluate(new Dictionary<string, object?> { { "name", "peter" } }); // true

Console.WriteLine(evaluable); // ({name} == "peter")

Simplify

Simplifies an expression with a given context. This is useful when you already have some of the properties of context and wants to try to evaluate the expression.

Example

var evaluable = illogical.Parse(new object[] {
  "AND",
  new object[] { "==", "$a", 10 },
  new object[] { "==", "$b", 20 }
});

evaluable.Simplify(new Dictionary<string, object?> { { "a", 10 } }); // ({b} == 20)
evaluable.Simplify(new Dictionary<string, object?> { { "a", 20 } }); // false

Values not found in the context will cause the parent operand not to be evaluated and returned as part of the simplified expression.

In some situations we might want to evaluate the expression even if referred value is not present. You can provide a list of keys that will be strictly evaluated even if they are not present in the context.

Example

public class SimplifyOptions : ISimplifyOptions
{
    public string[]? IgnoredPaths { get; }

    public Regex[]? IgnoredPathsRx { get; }

    public SimplifyOptions(string[]? ignoredPaths, Regex[]? ignoredPathsRx)
    {
        IgnoredPaths = ignoredPaths;
        IgnoredPathsRx = ignoredPathsRx;
    }
}

var illogical = new Illogical(simplifyOptions: new SimplifyOptions(
    new string[] { "ignored" }, new Regex[] { new Regex(@"^ignored") }
));

var evaluable = illogical.Parse(new object[] {
    "AND",
    new object[] { "==", "$a", 10 },
    new object[] { "==", "$ignored", 20 }
});

evaluable.Simplify(new Dictionary<string, object?> { { "a", 10 } }); // false
// $ignored" will be evaluated to null.

Alternatively we might want to do the opposite and strictly evaluate the expression for all referred values not present in the context except for a specified list of optional keys.

Example

var illogical = new Illogical(simplifyOptions: new SimplifyOptions(
    new string[] { "ignored" }, new Regex[] { }
));

var evaluable = illogical.Parse(new object[] {
    "OR",
    new object[] { "==", "$a", 10 },
    new object[] { "==", "$b", 20 },
    new object[] { "==", "$c", 20 }
});

evaluable.Simplify(new Dictionary<string, object?> { { "c", 10 } }); // ({a} == 10)
// except for "$b" everything not in context will be evaluated to null.

Serialize

Serializes an expression into the raw expression form, reverse the parse operation.

Example

evaluable = illogical.parse(new object[] {
  "AND",
  new object[] { "==", "$a", 10 },
  new object[] { "==", 10, 20}
});

evaluable.Serialize()
// new object[] { "AND", new object[] { "==", "$a", 10 }, new object[] { "==", 10, 20 } }

Working with Expressions

Evaluation Data Context

The evaluation data context is used to provide the expression with variable references, i.e. this allows for the dynamic expressions. The data context is object with properties used as the references keys, and its values as reference values.

Valid reference values: Dictionary, string, char, int, float, decimal, double, array of (bool, string, char, int, float).

To reference the nested reference, please use "." delimiter, e.g.: $address.city

Accessing Array Element:

$options[1]

Accessing Array Element via Reference:

$options[{index}]

• The index reference is resolved within the data context as an array index.

Nested Referencing

$address.{segment}

• The segment reference is resolved within the data context as a property key.

Composite Reference Key

$shape{shapeType}

• The shapeType reference is resolved within the data context, and inserted into the outer reference key.
• E.g. shapeType is resolved as "B" and would compose the $shapeB outer reference.
• This resolution could be n-nested.

Data Type Casting

$payment.amount.(Type)

Cast the given data context into the desired data type before being used as an operand in the evaluation.

Note: If the conversion is invalid, then a warning message is being logged.

Supported data type conversions:

• .(String): cast a given reference to String.
• .(Number): cast a given reference to Number.
• .(Integer): cast a given reference to Integer.
• .(Float): cast a given reference to Float.
• .(Boolean): cast a given reference to Boolean.

Example

// Data context
var context = new Dictionary<string, object?> {
    { "name",    "peter" },
    { "country", "canada" },
    { "age",     21 },
    { "options", new object[]{1, 2, 3 } },
    { "address", new Dictionary<string, object?> {
        { "city", "Toronto" },
        { "country", "Canada" },
    } },
    { "index",     2 },
    { "segment",   "city" },
    { "shapeA",    "box" },
    { "shapeB",    "circle" },
    { "shapeType", "B" },
};

// Evaluate an expression in the given data context

illogical.Evaluate(new object[] { ">", "$age", 20 }, context); // true
illogical.Evaluate(new object[] { "==", "$address.city", "Toronto" }, context); // true

// Accessing Array Element
illogical.Evaluate(new object[] { "==", "$options[1]", 2 }, context); // true

// Accessing Array Element via Reference
illogical.Evaluate(new object[] { "==", "$options[{index}]", 3 }, context); // true

// Nested Referencing
illogical.Evaluate(new object[] { "==", "$address.{segment}", "Toronto" }, context); // true

// Composite Reference Key
illogical.Evaluate(new object[] { "==", "$shape{shapeType}", "circle" }, context); // true

// Data Type Casting
illogical.Evaluate(new object[] { "==", "$age.(String)", "21" }, context); // true

Operand Types

The Comparison Expression expect operands to be one of the below:

Value

Simple value types: string, char, int, float, decimal, double, bool, null.

Example

var val1 = 5;
var var2 = "cirle";
var var3 = true;

illogical.Parse(new object[] {
    "AND",
    new object[] { "==", val1, var2 },
    new object[] { "==", var3, var3 }
});

Reference

The reference operand value is resolved from the Evaluation Data Context, where the the operands name is used as key in the context.

The reference operand must be prefixed with $ symbol, e.g.: $name. This might be customized via Reference Predicate Parser Option.

Example

Expression	Data Context
["==", "$age", 21]	{age: 21}
["==", "circle", "$shape"]	{shape: "circle"}
["==", "$visible", true]	{visible: true}

Collection

The operand could be an array mixed from Value and Reference.

Example

Expression	Data Context
["IN", [1, 2], 1]	null
["IN", "circle", ["$shapeA", "$shapeB"]	{shapeA: "circle", shapeB: "box"}
["IN", ["$number", 5], 5]	{number: 3}

Comparison Expressions

Equal

Expression format: ["==", Left Operand, Right Operand].

Valid operand types: string, char, int, float, decimal, double, bool, null.

["==", 5, 5]

illogical.Evaluate(new object[] { "==", 5, 5 }, context); // true

Not Equal

Expression format: ["!=", Left Operand, Right Operand].

Valid operand types: string, char, int, float, decimal, double, bool, null.

["!=", "circle", "square"]

illogical.Evaluate(new object[] { "!=", "circle", "square" }, context); // true

Greater Than

Expression format: [">", Left Operand, Right Operand].

Valid operand types: int, float.

[">", 10, 5]

illogical.Evaluate(new object[] { ">", 10, 5 }, context); // true

Greater Than or Equal

Expression format: [">=", Left Operand, Right Operand].

Valid operand types: int, float.

[">=", 5, 5]

illogical.Evaluate(new object[] { ">=", 5, 5 }, context); // true

Less Than

Expression format: ["<", Left Operand, Right Operand].

Valid operand types: int, float.

["<", 5, 10]

illogical.Evaluate(new object[] { "<", 5, 10 }, context); // true

Less Than or Equal

Expression format: ["<=", Left Operand, Right Operand].

Valid operand types: int, float.

["<=", 5, 5]

illogical.Evaluate(new object[] { "<=", 5, 5 }, context); // true

In

Expression format: ["IN", Left Operand, Right Operand].

Valid operand types: string, char, int, float, decimal, double, bool, null and an array of (string, char, int, float, decimal, double, bool, null).

["IN", 5, [1, 2, 3, 4, 5]]
["IN", ["circle", "square", "triangle"], "square"]

illogical.Evaluate(new object[] {
    "IN", 5, new object[] { 1, 2, 3, 4, 5 }
}, context); // true

illogical.Evaluate(new object[] {
    "IN", new object[] { "circle", "square", "triangle" }, "square" },
context); // true

Not In

Expression format: ["NOT IN", Left Operand, Right Operand].

Valid operand types: string, char, int, float, decimal, double, bool, null and array of (string, char, int, float, decimal, double, bool, null).

["IN", 10, [1, 2, 3, 4, 5]]
["IN", ["circle", "square", "triangle"], "oval"]

illogical.Evaluate(new object[] {
    "NOT IN", 10, new object[] { 1, 2, 3, 4, 5 }
}, context); // true

illogical.Evaluate(new object[] {
    "NOT IN", new object[] { "circle", "square", "triangle" }, "oval" },
context); // true

Prefix

Expression format: ["PREFIX", Left Operand, Right Operand].

Valid operand types: string.

• Left operand is the PREFIX term.
• Right operand is the tested word.

["PREFIX", "hemi", "hemisphere"]

illogical.Evaluate(new object[] { "PREFIX", "hemi", "hemisphere" }, context) // true
illogical.Evaluate(new object[] { "PREFIX", "hemi", "sphere" }, context) // false

Suffix

Expression format: ["SUFFIX", Left Operand, Right Operand].

Valid operand types: string.

• Left operand is the tested word.
• Right operand is the SUFFIX term.

["SUFFIX", "establishment", "ment"]

illogical.Evaluate(new object[] { "SUFFIX", "establishment", "ment" }, context) // true
illogical.Evaluate(new object[] { "SUFFIX", "establish", "ment" }, context) // false

Overlap

Expression format: ["OVERLAP", Left Operand, Right Operand].

Valid operand types: list; set; tuple of (string, char, int, float, decimal, double, bool, null).

["OVERLAP", [1, 2], [1, 2, 3, 4, 5]]
["OVERLAP", ["circle", "square", "triangle"], ["square"]]

illogical.Evaluate(new object[] {
    "OVERLAP", new object[] { 1, 2, 6 }, new object[] { 1, 2, 3, 4, 5 }
}, context); // true

illogical.Evaluate(new object[] {
    "OVERLAP", new object[] {"circle", "square", "triangle" }, new object[] {"square", "oval" }
}, context); // true

None

Expression format: ["NONE", Reference Operand].

["NONE", "$RefA"]

illogical.Evaluate(new object[] { "NONE", "RefA" }, null); // true
illogical.Evaluate(new object[] { "NONE", "RefA" }, new Dictionary<string, object?> { { "RefA", 10 } }); // false

Present

Evaluates as FALSE when the operand is UNDEFINED or NULL.

Expression format: ["PRESENT", Reference Operand].

["PRESENT", "$RefA"]

illogical.Evaluate(new object[] { "PRESENT", "RefA" }, null); // false
illogical.Evaluate(new object[] { "PRESENT", "RefA" }, new Dictionary<string, object?> { { "RefA", 10 } }); // true
illogical.Evaluate(new object[] { "PRESENT", "RefA" }, new Dictionary<string, object?> { { "RefA", false } }); // true
illogical.Evaluate(new object[] { "PRESENT", "RefA" }, new Dictionary<string, object?> { { "RefA", "val" } }); // true

Logical Expressions

And

The logical AND operator returns the bool value TRUE if both operands are TRUE and returns FALSE otherwise.

Expression format: ["AND", Left Operand 1, Right Operand 2, ... , Right Operand N].

Valid operand types: Comparison Expression or Nested Logical Expression.

["AND", ["==", 5, 5], ["==", 10, 10]]

illogical.Evaluate(new object[] {
    "AND",
    new object[] { "==", 5, 5 },
    new object[] { "==", 10, 10 }
}, context); // true

Or

The logical OR operator returns the bool value TRUE if either or both operands is TRUE and returns FALSE otherwise.

Expression format: ["OR", Left Operand 1, Right Operand 2, ... , Right Operand N].

Valid operand types: Comparison Expression or Nested Logical Expression.

["OR", ["==", 5, 5], ["==", 10, 5]]

illogical.Evaluate(new object[] {
    "OR",
    new object[] { "==", 5, 5 },
    new object[] { "==", 10, 5 }
}, context); // true

Nor

The logical NOR operator returns the bool value TRUE if both operands are FALSE and returns FALSE otherwise.

Expression format: ["NOR", Left Operand 1, Right Operand 2, ... , Right Operand N]

Valid operand types: Comparison Expression or Nested Logical Expression.

["NOR", ["==", 5, 1], ["==", 10, 5]]

illogical.Evaluate(new object[] {
    "NOR",
    new object[] { "==", 5, 1 },
    new object[] { "==", 10, 5 }
}, context); // true

Xor

The logical NOR operator returns the bool value TRUE if both operands are FALSE and returns FALSE otherwise.

Expression format: ["XOR", Left Operand 1, Right Operand 2, ... , Right Operand N]

Valid operand types: Comparison Expression or Nested Logical Expression.

["XOR", ["==", 5, 5], ["==", 10, 5]]

illogical.Evaluate(new object[] {
    "XOR",
    new object[] { "==", 5, 5 },
    new object[] { "==", 10, 5 }
}, context); // true

["XOR", ["==", 5, 5], ["==", 10, 10]]

illogical.Evaluate(new object[] {
    "XOR",
    new object[] { "==", 5, 5 },
    new object[] { "==", 10, 10 }
}, context); // false

Not

The logical NOT operator returns the bool value TRUE if the operand is FALSE, TRUE otherwise.

Expression format: ["NOT", Operand]

Valid operand types: Comparison Expression or Nested Logical Expression.

["NOT", ["==", 5, 5]]

illogical.Evaluate(new object[] { "NOT", new object[] { "==", 5, 5 } }, context); // true

Engine Options

Reference Serialize Options

Usage

class SerializeOptions : ISerializeOptions
{
    public string? From(string operand) =>
        operand.Length > 2 && operand.StartsWith("__")
            ? operand.Substring(2)
            : null;

    public string To(string operand) => $"__{operand}";
}

var illogical = new Illogical(serializeOptions: new SerializeOptions());

From

A function used to determine if the operand is a reference type, if so, return a raw value operand value

Return value:

• string = reference type
• null = value type

Default reference predicate:

The $ symbol at the begging of the operand is used to predicate the reference type., E.g. $State, $Country.

To

A function used to transform the operand into the reference annotation stripped form. I.e. remove any annotation used to detect the reference type. E.g. "$Reference" ⇒ "Reference".

Default reference transform: It removes the $ symbol at the begging of the operand name.

Collection Serialize Options

Usage

var illogical = new Illogical(escapeCharacter: '*');

Escape Character

Charter used to escape fist value within a collection, if the value contains operator value.

Example

• ["==", 1, 1] // interpreted as EQ expression
• ["\==", 1, 1] // interpreted as a collection

Default escape character: \

Simplify Options

Options applied while an expression is being simplified.

Usage

var illogical = new Illogical(simplifyOptions: new SimplifyOptions(
    new string[] { "ignored" }, new Regex[] { new Regex(@"^ignored") }
));

Ignored Paths

Reference paths which should be ignored while simplification is applied. Must be an exact match.

Ignored Paths RegEx

Reference paths which should be ignored while simplification is applied. Matching regular expression patterns.

Operator Mapping

Mapping of the operators. The key is unique operator key, and the value is the key used to represent the given operator in the raw expression.

Usage

var operatorMapping = new Dictionary<Operator, string>(Parser.DEFAULT_OPERATOR_MAPPING);
operatorMapping[Operator.EQ] = "IS";

var illogical = new Illogical(operatorMapping: operatorMapping);

Default operator mapping:

var DEFAULT_OPERATOR_MAPPING = new Dictionary<Operator, string> {
    // Logical
    { Operator.AND, "AND" },
    { Operator.OR, "OR" },
    { Operator.NOR, "NOR" },
    { Operator.XOR, "XOR" },
    { Operator.NOT, "NOT" },
    // Comparison
    { Operator.EQ, "==" },
    { Operator.NE, "!=" },
    { Operator.GT, ">" },
    { Operator.GE, ">=" },
    { Operator.LT, "<" },
    { Operator.LE, "<=" },
    { Operator.NONE, "NONE" },
    { Operator.PRESENT, "PRESENT" },
    { Operator.IN, "IN" },
    { Operator.NOTIN, "NOT IN" },
    { Operator.OVERLAP, "OVERLAP" },
    { Operator.PREFIX, "PREFIX" },
    { Operator.SUFFIX, "SUFFIX" },
};

---

Contributing

See contributing.md.

License

Illogical is released under the MIT license. See license.md.