Opening a Y File

The Y file type is primarily associated with Yacc.

Y	File extension: Y
	File type:	grammar file

What is a Y file?

Y files mostly belong to Yacc by Stephen C Johnson. Y is a file extension associated with Yacc (Yet Another Compiler-Compiler). Yacc is a programming tool for the Unix operating system that generates a parser based on a given grammar. It is included with BSD and AT&T Unix as a standard utility. A parser is the part of a compiler that makes syntactic sense of the source code written in a particular language. Y is the input for this particular parser generator. The Y file contains the specifications of the syntax (i.e. the grammar) of the source language that is to be parsed.

Grammar: The grammar in a Y file is written in a notation that is similar to Backus–Naur Form (BNF). It has snippets of C code attached to its rules. These snippets are called "actions".
Output: The parser generated using Y input is a Look Ahead Left-to-Right (LALR) parser. The output file contains C subroutines and is named y.tab.C. In addition to this, a header file that has the definitions of token names is also created. It is named y.tab.H.

The Y extension is a naming convention that is recognized by other operating system commands, but it is not necessary to use this suffix.

How to open Y files

You need a suitable software like Yacc to open a Y file. Without proper software you will receive a Windows message "How do you want to open this file?" or "Windows cannot open this file" or a similar Mac/iPhone/Android alert. If you cannot open your Y file correctly, try to right-click or long-press the file. Then click "Open with" and choose an application. You can also display a Y file directly in the browser:. Just drag the file onto this browser window and drop it.

Online Y Text Viewer

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Programs that open and convert Y files:

Yacc by Stephen C Johnson
See the previous paragraphs to learn more about the main application. Y files are often referred to as Yacc developers because this type of file is primarily created or used by this software.
AmigaOS (compressed archive file) by Hyperion Entertainment
AmigaOS is a family of operating system that was first developed by Commodore for the Amiga personal computer in 1985. The operating system is now maintained by Hyperion Entertainment. Y is the file extension for the Amiga Yabba compressed archive format in AmigaOS. This file format is classified as Compressed. Related links: AmigaOS on Wikipedia, AmigaOS Old Website
QuickTime (raster image) by Apple
QuickTime is a media player from Apple that is included with macOS and is available for Windows. QuickTime can open Y files. Y files are obtained by splitting MPEG into Y, U, and V files. These are the components of the the YUV (more accurately, YCbCr) color space. This file format is classified as Raster Image. Related links: QuickTime on Wikipedia, Technical Notes about QuickTime YUV Rendering
Windows Media Player (raster image) by Microsoft
The Windows Media Player is a media playback, music management, and media streaming application developed by Microsoft. It is included with all versions of the Microsoft Windows operating system starting with Windows 3.0. Windows Media Player can open Y files with the YUV Genius renderer. Y files are obtained by splitting MPEG into Y, U, and V files. This file format is classified as Raster Image. Related links: Windows Media Player on Wikipedia, Windows Media Player History, Obtaining YUV Color Space Components from MPEG
Xcode (grammar file) by Apple
Xcode is an Integrated Development Environment (IDE) for macOS from Apple. Xcode can be used with Yacc, which generates a parser based on a given grammar. The input file for Yacc has the Y extension. It contains the specifications of the grammar of the source language. This file format is classified as Developer. Related links: Xcode on Wikipedia, Yacc Reference in Xcode Book

Y file format:

A file format defines how the data in the file is structured. The initial characters of a file are called signature, sometimes also referred to as "magic bytes". The signature can be used to infer the file format. If the file extension or signature does not match the file format, errors will occur when opening or editing the file. Exact knowledge of the format is therefore important in order to solve problems occurring in files. Our examination of the Y files comes to the following conclusion:

As a file extension, Y isn't very common and includes different formats for the applicable programs. The file formats most commonly found in Y files are:

35% of all Y files start with the magic bytes 25 7B, which are always the first bytes of this file format. The contents of these files can even be read by a human. The files are often between 460 bytes and 9 KB in size. It is a modern file type. Several words can almost always be found in the files, e.g. token, char, #include <stdio.h>, #include <stdlib.h>, void, #include<stdio.h>, string, yyerror and yylex. A usual file name is parser.y or calc.y.
10% of all Y files start with the bytes 2F 2A, which are crucial for this file format. These files are text files, so they contain words and text. The file size is in the range of 980 bytes to 9 KB. Several words can almost always be found in the files, e.g. include, stdio and yacc. The file name parser.y is characteristic of these files.

All other Y files (55%) have different formats, such as ZIP and Adobe. Files like these are sometimes linked to foreman, output, cminus, gowri or parse. Drag & drop your file here to see the file format and a preview of your Y file!

Technical Data for Y File Extension

File classification:

Developer

Related files:

l, lex, yy, c, i, cmyk, m, k, x, txt, rar, zip, 7z

Mime type:

text/x-yacc

The following listing is compiled from the database produced by the 'Associate This!' program, selected data from the main FILExt database and file extension information submitted by users.

ProgramID: Python.File
EXEFile: %ProgramFiles%\Journyx\python\Python.exe %1 %*

ProgramID: Python.File
EXEFile: C:\Python23\python.exe %1 %*

a y grammar file is a special file format by Stephen C Johnson and should only be edited and saved with the appropriate software.

How to solve problems with Y files

Associate the Y file extension with the correct application.
Update your software that should actually open grammar files. Because only the current version supports the latest Y file format. Search, therefore, e.g. on the Stephen C Johnson manufacturer website after an available Yacc update.
To make sure that your Y file is not corrupted or virus-infected, get the file again and scan it with Google's virustotal.com.
Click here to open your .Y file online - secure, fast, and no downloads needed.