ISO/IEC 30170:2012 情報技術—プログラミング言語— Ruby | ページ 2

Foreword

ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, 2.

The main task of the joint technical committee is to prepare International Standards. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.

ISO/IEC 30170 was prepared by the Japanese Industrial Standards Committee (as JIS X3017) and was adopted, under a special"fast-track procedure", by Joint Technical Committee ISO/IEC JTC 1, Information technology, in parallel with its approval by the national bodies of ISO and IEC.

Introduction

This International Standard is based upon a submission from the Japanese National Standards Body called JIS X3017"Programming Language Ruby", registered and published in 2011.

Ruby is an object-oriented scripting language designed to be developer-friendly, productive and intuitive. There is a continuing growth of interest in Ruby around the world, especially among web application developers, while its use spans from web applications to private tools.

As the Ruby language grows and spreads, there is no globally agreed upon documented Ruby specification. In order to avoid confusion as a result of diversification of usage and incompatibility among implementations, the Japan Industry Standard is proposed as an international standard.

There are multiple Ruby implementations available. Many of them are distributed as open source software. The implementation called"Matz Ruby Implementation (MRI)" has been treated as a reference implementation insofar as virtually all implementers check compatibility of their implementations by comparing them to MRI. Therefore, this specification of Ruby is codified as a strict subset of MRI.

This International Standard specifies only core language features and core libraries which are stable enough and common between MRI versions and compatible between existing implementations. There are two versions of MRI currently distributed and maintained: MRI 1.8, which has been available since 2003 and MRI 1.9, which was released in 2010. Currently, MRI 1.8 is more widely used than MRI 1.9. Use of MRI 1.9 will likely spread in the next several years. To avoid future divergence, features which are planned or prospected to be changed are excluded from this version of the specification, or it is clearly stated that the behavior of the features are not specified. For example, this specification does not specify the handling of character type in detail because it is planned to be changed in MRI 1.9 for full support of ISO/IEC 10646. The full support of ISO/IEC 10646 is going to be standardized in a future version of this standard. The library defined in this specification is limited to that which is commonly used or necessary to write simple programs.

This International Standard introduces special notations and a concept called"Execution context" in order to specify flexible syntax and dynamic semantics of the Ruby language as simple as possible.

1 Scope

This International Standard specifies the syntax and semantics of the computer programming language Ruby, and the requirements for conforming Ruby processors, strictly conforming Ruby programs, and conforming Ruby programs.

This International Standard does not specify,

• • the limit of size or complexity of a program text which a conforming processor evaluates,
• • the minimal requirements of a data processing system that is capable of supporting a conforming processor,
• • the method for activating the execution of programs on a data processing system, and
• • the method for reporting syntactic and runtime errors.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

4 Terms and definitions

For the purposes of this document, the following terms and definitions apply. Other terms are defined where they appear in bold slant face or on the left side of a syntax rule.