no comment!

No-comment is a simple, light-weight library that can remove comments of various styles and dialects.

The library avoids expensive regular-expression matching and uses minimalstic state machines for optimal performance.

Supported comment styles

Currently, only C-Style comments can be stripped. Future dialects will be added.

If you require a specific style, create a feature request in the issue tracker. Pull-requests for new dialects are welcome, as long as they are well-tested and cover all special cases correctly.

Special cases

All special cases are handled correctly and the behaviour is validated with unit-tests. Although different comment styles have different properties, many share the same special cases. These can include:

• Block comments can span multiple lines

• Comments cannot start within quoted regions

  text "quoted // text"

• Quoted regions can be escaped

  text \"not quoted "quoted \" quoted"

• Escape characters can be escaped

  text \\\\"quoted text\\\\" not quoted

• Quoted regions can span multiple lines, if new-line characters are escaped

  text "quoted text \\n quoted text on second line"

• Comments are not allowed to start, if a quote does not have a matching end-quote

  text "nearly quoted text //not a comment

• Comment starts and ends cannot be escaped text \/*comment\*/ not a comment

The above rules are some common examples that can be encountered and which are correctly treated by the library. Additional special cases might apply for certain dialects.

Usage

package main

import (
	"fmt"
	"github.com/maja42/no-comment"
)

func main() {
	input := `
	Line comment //gets stripped away!
	Block /*gets stripped away!*/ comment
	"Quoted /*text*/ \" stays 'til the end! \\" /* comments don't \*/ really!
	"And quoted text \
	//can also span multiple lines!"
	`

	out := nocomment.StripCStyleComments(input)
	fmt.Println(out)
	// Prints:
	// 		Line comment
	// 		Block  comment
	// 		"Quoted /*text*/ \" stays 'til the end! \\"  really!
	// 		"And quoted text \
	// 		//can also span multiple lines!"
}

Installation

go get github.com/maja42/no-comment

Demo

The _example folder contains a small example for stripping c-style comments.

cd _example/
go run main.go