Merge pull request #2 from sidhant92/antlr

README file updated

Author: sidhant92

README.md

@@ -1,2 +1,138 @@
 # bool-parser-java
-Boolean Expression Parser in Java
+A Boolean Expression Parser for Java
+
+The library can help parse complex and nested boolean expressions.
+The expressions are in SQL-like syntax, where you can use boolean operators and parentheses to combine individual expressions.
+
+An expression can be as simple as `name = Sidhant`.
+A Complex expression is formed by combining these small expressions by logical operators and giving precedence using parenthesis
+
+### Examples
+#### Textual Equality
+
+Format: `${attributeName} = ${value}`
+
+Example: `name = john`
+
+#### Numeric Comparisons
+
+Format: `${attributeName} ${operator} ${value}`
+
+Example: `price > 12.99`
+
+The ${value} must be numeric. Supported operators are `<`, `<=`, `=`, `!=`, `>=` and `>`, with the same semantics as in virtually all programming languages.
+
+#### Numeric Range
+
+Format: `${attributeName} ${lowerBound} TO ${upperBound}`
+
+Example: `price 5.99 TO 100`
+
+`${lowerBound}` and `${upperBound}` must be numeric. Both are inclusive.
+
+#### Boolean operators
+
+Example:
+
+`price < 10 AND (category:Book OR NOT category:Ebook)`
+
+Individual filters can be combined via boolean operators. The following operators are supported:
+
+* `OR`: must match any of the combined conditions (disjunction)
+* `AND`: must match all of the combined conditions (conjunction)
+* `NOT`: negate a filter
+
+Parentheses, `(` and `)`, can be used for grouping.
+
+#### Usage Notes
+* Phrases that includes quotes, like `content = "It's a wonderful day"`
+* Phrases that includes quotes, like `attribute = 'She said "Hello World"'`
+
+## Usage
+POM
+```xml
+    <dependencies>
+        <dependency>
+            <groupId>com.github.sidhant92</groupId>
+            <artifactId>bool-parser-java</artifactId>
+            <version>1.0.0</version>
+        </dependency>
+    </dependencies>
+```
+Gradle
+```
+dependencies {
+	implementation "com.github.sidhant92:bool-parser-java:1.0.0"
+}
+```
+
+
+Code
+```
+final BoolParser boolParser = new BoolParser();
+final Try<Token> tokenOptional = boolParser.parseExpression("name = test");
+```
+
+### Token Types Post Parsing
+####
+StringToken
+```
+private final String field;
+
+private final String value;
+```
+
+####
+NumericToken
+```
+private final String field;
+
+private final Object value;
+
+private final Operator operator;
+
+private final DataType dataType;
+```
+
+####
+NumericRangeToken
+```
+private final String field;
+
+private final Object fromValue;
+
+private final Object toValue;
+
+private final DataType fromDataType;
+
+private final DataType toDataType;
+```
+
+####
+BooleanToken
+```
+private Token left;
+
+private Token right;
+
+private LogicalOperationType operator;
+```
+
+####
+UnaryToken
+```
+private final DataType dataType;
+
+private final Object value;
+```
+
+####
+InToken
+```
+private final String field;
+
+private final List<Pair<DataType, Object>> items;
+```
+
+
+[For a complete list of examples please check out the test file](src/test/java/com/github/sidhant92/boolparser/application/BooleanExpressionEvaluatorTest.java)