https://github.com/axkr/java_codegen

A preprocessor for Java source code. Easily extendable by implementing an interface method.
https://github.com/axkr/java_codegen

generator math preprocessor

Last synced: 10 days ago
JSON representation

A preprocessor for Java source code. Easily extendable by implementing an interface method.

• Host: GitHub
• URL: https://github.com/axkr/java_codegen
• Owner: axkr
• Created: 2018-06-15T15:14:25.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2022-04-29T10:40:51.000Z (almost 3 years ago)
• Last Synced: 2024-12-01T13:47:50.314Z (2 months ago)
• Topics: generator, math, preprocessor
• Language: Java
• Homepage:
• Size: 10.7 KB
• Stars: 1
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

README

        
## java_codegen - a simple preprocessor for Java source code.

The [axkr/java_codegen](https://github.com/axkr/java_codegen) Github project contains a simple preprocessor tool to expand ordinary strings into Java source code.

The strings are included into Java line comments opened by `// [$ ... $]` or `//[$ ... $]` and closed by `// $$` or `//$$`. The preprocessor program takes this prepared files and substitutes the comments by generated source code. 

### Simple Uppercase Example

There is a simple example [org.matheclipse.tools.HelloWorldExample](https://github.com/axkr/java_codegen/blob/master/java_codegen/java_codegen/src/org/matheclipse/tools/HelloWorldExample.java) which converts the following lines:

```

public class HelloWorldExample extends AbstractCodeGenerator {

	public final static String HELLO_WORLD1 = //

			// [$ hello world 1 $]

			"test 1"; // $$;

	public final static String HELLO_WORLD2 = //

			// [$ hello world 2 $]

			"test 2"; // $$;

```

into upper case strings in these lines:

```

public class HelloWorldExample extends AbstractCodeGenerator {

	public final static String HELLO_WORLD1 = //

			// [$ hello world 1 $]

"HELLO WORLD 1"; // $$;

	public final static String HELLO_WORLD2 = //

			// [$ hello world 2 $]

"HELLO WORLD 2"; // $$;

```

**Note:** the `;` character behind the closing `// $$` tag will be appended to the generated source code.

After running the `HelloWorldExample` you can use the Eclipse menu "Copy qualified name" for the file which you would like to convert:

```

Input qualified Java file name for converting text to upper case strings

▶ /java_codegen/src/org/matheclipse/tools/HelloWorldExample.java

```

For implementing your own conversion you have to implement the abstract `apply()` method:

```

	public boolean apply(String command, StringBuilder buf) {

		command = command.trim();

		buf.append("\"" + command.toUpperCase() + "\"");

		return true;

	}

```

### Symja math expression code generation

There is already a more sophisticated tool [ExprPreprocessor](https://github.com/axkr/symja_android_library/blob/master/symja_android_library/tools/src/main/java/org/matheclipse/core/preprocessor/ExprPreprocessor.java) in the [Symja project](https://github.com/axkr/symja_android_library), which converts math expressions into Java source code.

Because Java doesn't support operator overloading the tool simplifies the maintenance of large math expressions.

In the example from the [FunctionExpand](https://github.com/axkr/symja_android_library/blob/master/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/reflection/system/FunctionExpand.java) function the Symja expression `Gamma(1+x)` 

```

MATCHER.caseOf(Factorial(x_), //

          // [$ Gamma(1+x) $]

          F.Null); // $$);

```

will be converted into special Symja Java source code

```

MATCHER.caseOf(Factorial(x_), //

          // [$ Gamma(1+x) $]

          F.Gamma(F.Plus(F.C1, x))); // $$);

```

**Note:** the `);` characters behind the closing `// $$` tag will be appended to the generated source code.