Overview
ISO/IEC 9592-3:1997 specifies the clear-text encoding for PHIGS archive files (Programmer’s Hierarchical Interactive Graphics System). As Part 3 of the ISO/IEC 9592 series, this standard defines a human-editable, human-friendly, and machine-readable text representation of the PHIGS archive file syntax so archive files can be typed, read, edited and parsed using ordinary text editors and standard character sets.
The standard maps each archive-file element (as defined in ISO/IEC 9592‑2) to a clear-text form, describes the overall file format, how comments are embedded, and the rules for element names, separators, parameter encoding and conformance.
Key topics and technical requirements
- Objectives: Emphasizes being human-editable, easy to read, machine-parseable, usable in a variety of editors, and interchangeable across systems.
- Character repertoire: Uses a subset of ISO/IEC 646 (7-bit) characters for element names and tokens; string parameters may include broader character sets. Lowercase and uppercase letters are equivalent outside string parameters.
- Element delimiters: Elements end with a SLASH (/) or SEMICOLON (;). These delimiters do not terminate elements when inside string parameters.
- Separators: Distinguishes soft separators (spaces and common control format characters treated as spaces) and hard separators (comma with optional surrounding space). Omitting parameters is supported (e.g., consecutive commas indicate an omitted value).
- Parameter encoding: Formal encodings for integer-bound, real-bound, string-bound, enumerated and derived types are specified so data values are unambiguous and parseable.
- Names and abbreviations: Rules for forming archive file element names, standardized abbreviations and sentinel sequences are provided to ensure consistent naming and minimal surprise.
- Comments and formatting: Comments may be interspersed; format-effecting control characters (CR, LF, TAB, etc.) are treated as whitespace outside strings.
- Conformance and grammar: A formal grammar and conformance rules define how clear-text archive files must be structured for interoperability.
Applications and users
Who uses ISO/IEC 9592-3:
- Software developers and integrators implementing PHIGS archive file generators and parsers
- CAD, visualization and legacy graphics tool vendors maintaining or converting PHIGS data
- Data archivists and migration teams needing a readable interchange format
- Implementers concerned with cross-system interoperability and editable graphics archives
Practical uses:
- Creating readable PHIGS archive files for debugging or version control
- Manual editing or hand-construction of graphics structures
- Interchange of PHIGS data between heterogeneous systems using standard text encodings
Related standards
Keywords: ISO/IEC 9592-3, PHIGS, clear-text encoding, archive file, computer graphics, archive format, element delimiters, separators, ISO/IEC 646, machine-readable, human-editable.